Research Reports are technical reports written for researchers but accessible to design professionals and builders. These reports typically provide an in-depth study of a particular topic or describe the results of a research project. They are often peer reviewed and also provide support for advice given in our Building Science Digests. The most recent documents posted are at the top of the list below.
There is little consensus on the incidence of and physics behind moisture problems in dense-packed roof assemblies. Only a handful of field research projects have considered the moisture performance of dense-packed roof assemblies and the majority of these were proprietary studies that were not made public. This document focuses on dense-packed insulation retrofits to roof assemblies in cold climates and identifies, describes and compares four strategies that designers, builders and manufacturers have implemented to avoid moisture problems in dense-packed roof assemblies.
There are many existing buildings with load-bearing mass masonry walls, whose energy performance could be improved with the retrofit of insulation. However, adding insulation to the interior side of walls of such masonry buildings in cold climates may cause performance and durability problems. Some concerns have known solutions, but there are known knowledge gaps. Four topics were studied in more detail to address these gaps: the topics included moisture risks to embedded wood members, an examination of frost dilatometry test results for data patterns, the effect of dissolved salts on masonry durability, and optimization of the methodology of frost dilatometry testing.
This report analyzes the performance of walls clad with HardiePlank fiber cement siding and compares them to traditional stucco assemblies. The data presented is a subset of experimental data from a multi-phase, multi-year research project at the Vancouver Field Exposure Test Facility led by Building Science Corporation (BSC) and Gauvin 2000 Construction Limited. The analysis includes results from normal operating conditions in a high stress exterior moisture environment (typical of the Pacific Northwest climate) and under intentional controlled wettings to the interior and exterior of the sheathing.
This report describes the construction and instrumentation of Phase IV of a multi-phase, multi-year research project at the Vancouver Field Exposure Test Facility in Coquitlam, British Columbia. The main objective of Phase IV is to determine how various configurations of exterior low vapor permeance insulation affect the moisture durability risk of structural wood-based sheathing. To assist with this analysis, the walls will be subjected to elevated interior relative humidities, and intentional controlled surface wetting of the interior and/or exterior of the OSB sheathing.
This report describes the construction and instrumentation of Phase III of a multi-phase, multi-year research project at the Vancouver Field Exposure Test Facility in Coquitlam, British Columbia. Phase III focusses on the performance of various sheathings and claddings in a high stress moisture environment that is typical of the Pacific Northwest climate. The main research goal is to examine the performance of the various walls under the influence of intentional exterior wetting events in the drainage space.
Transformations, Inc. is a residential development and building company that has partnered with Building Science Corporation to build new construction net-zero energy houses in Massachusetts under the Building America program. There are three communities that are being constructed through this partnership: Devens Sustainable Housing (“Devens”), The Homes at Easthampton Meadow (“Easthampton”) and Phase II of the Coppersmith Way Development (“Townsend”). This report covers all of the single-family new construction homes that have been completed to date. The houses built in these developments are net zero energy capable homes built in a cold climate. The set of measures offered by the developer exceeds the 30% energy saving goals set by the Building America program for New Homes in the cold climate for 2013. The houses will contribute to developing solutions and addressing gaps in enclosures and space conditioning research.
Merrimack Valley Habitat for Humanity (MVHfH) has partnered with Building Science Corporation to provide high performance affordable housing for 10 families in the retrofit of an existing brick building (a former convent) into condominiums. The condominium conversion project will contribute to several areas of space conditioning, water heating, and enclosures research. Enclosure items include insulation of mass masonry building on the interior, airtightness of these types of retrofits, multi-unit building compartmentalization, window selection and roof insulation strategies. Mechanical system items include combined hydronic and space heating systems with hydronic distribution in small (low load) units, and ventilation system retrofits for multifamily buildings.
This research provides simple, long term, and durable solutions when using tapes and flashing membranes in conjunction with the exterior face of rigid polymeric foam sheathing to create the drainage plane of a wall system. The knowledge gained from this research will be used in future Building America construction prototypes and well as other residential construction projects to increase the long-term moisture related durability of the enclosure, and reduce the risk of liquid water intrusion. The following are best practice and product recommendations from the interviewed contractors and homebuilders who collectively have a vast amount of experience.
In multifamily buildings, central (typically rooftop) ventilation systems often have poor overall performance, overventilating some portions of the building (resulting in excess energy use), while simultaneously underventilating other portions of the building (resulting in diminished indoor air quality). These issues are often tied to multistory stack effects (warm air rising at cold outdoor conditions), and a lack of compartmentalization (airtightness) between floors and between units. These issues are exacerbated by the presence of multistory shafts (e.g., elevator shafts, stairwells, and ventilation shafts). Central corridor supply and makeup air systems combined with rooftop central exhaust systems are particularly problematic. The recommended solution is to isolate the units from one another and from corridors, shafts, elevators, and stairwells by means of greater airtightness.
Project Home Again is a development in New Orleans, Louisiana, created to provide new homes to victims of Hurricane Katrina. Building Science Corporation (BSC) acted as a consultant for the project, advocating design strategies for durability, flood resistance, occupant comfort, and low energy use while maintaining cost effectiveness. These techniques include the use of high density spray foam insulation, LowE3 glazing, and supplemental dehumidification to maintain comfortable humidity levels without unnecessary cooling. Stringent airtightness goals were achieved by the project, helping to meet the Builder’s Challenge targets set by Project Home Again. Floor plans, enclosures, and heating, ventilation, and air conditioning attributes are quite similar among different homes in the project.
This report compares the moisture related performance of an exterior insulated wall to the performance of two other common construction methods, side-by-side. The data presented is a subset of experimental data from a multi-phase, multi-year research project at the Vancouver Field Exposure Test Facility led by Building Science Corporation (BSC) and Gauvin 2000 Construction Limited. The analysis includes results from normal operating conditions in a high stress exterior moisture environment (typical of the Pacific Northwest climate) and under intentional controlled wettings to the interior and exterior of the sheathing. There were no measured or observed moisture related durability concerns of the wood structural sheathing when 1.5” of exterior insulation was installed.
This measure guideline provides information and guidance about rehabilitating, retrofitting, and replacing wood window assemblies in residential construction. It is intended primarily to help contractors and homeowners understand the options for safely improving the performance of their wood windows.
Building Science Corporation (BSC) has been working with Byggmeister, a partner on the Building America (BA) team, on retrofit projects under the BA program. Byggmeister is a local design-build firm that specializes in energy efficient retrofits and new construction. The Duclos, Eldrenkamp and Panish Energy Group (DEEP Energy Group), which is associated with Byggmeister, conducts design-phase energy analysis and monitors completed projects. The Byggmeister multifamily test home located in Jamaica Plain, Massachusetts (Jamaica Plain or J.P. Three-Family) is a three-story brick row house . The test home is examined with the goal of producing a case study that could be applied to similar New England homes. Basic areas of research that this report is expected to contribute include finding the combination of measures that are feasible, affordable, and suitable for this type of construction and acceptable to homeowners.
This guideline pertains to design and application guidance for combination space and tankless domestic hot water (DHW) heating systems (combination systems) used in residential buildings, based on field evaluation, testing, and industry meetings. As residential building enclosure improvements continue to drive heating loads down, using the same water heating equipment for both space heating and domestic water heating becomes attractive from an initial cost and space-saving perspective. This topic is applicable to single- and multifamily residential buildings, both new and retrofitted. Before committing to wide-scale implementation of such combination space and domestic water heating systems for high performance buildings, whether new or retrofit, design decisions and site conditions affecting performance, maintenance, and occupant acceptability should be well understood. Current performance rating procedures for this type of hot water heating system and its many variants are inadequate to provide convincing prediction of estimated savings. In order to be assured of meeting the Building America savings goals, and the persistence of those savings after installation, continued sharing of lab and field testing results is needed.
This project examines implementation of advanced retrofit measures in the context of a large-scale weatherization program and the archetypal Chicago, Illinois, brick bungalow. In response to the apparent weatherization program limitations with respect to homes with masonry bearing wall construction, this research project examines two distinct strategies for insulating and air sealing the top of houses. One strategy applies best practice air sealing methods and a standard insulation method to the attic floor. The other strategy creates an unvented roof assembly using materials and methods typically available to weatherization contractors.
This research project developed baseline engineering analysis to support the installation of thick layers of exterior insulation (2” to 8”) on existing masonry walls and wood framed walls through the use of wood furring strips (fastened through the insulation back to the structure) as a cladding attachment location. Furthermore, water management details necessary to connect the exterior insulated wall assemblies to roofs, balconies, decks, and windows were created to provide guidance on the integration of exterior insulation strategies with other enclosure elements.
Basements can account for up to one quarter of the typical energy consumption in a house. Therefore, insulating foundations is a critical measure for achieving high performance buildings. This is important in both new construction and retrofits of existing buildings. The fundamental problems and “best practice solutions” for moisture-safe basement insulation have been well established. However, many foundations are damp (either due to bulk water or capillary “wicking” of moisture) or of a type of construction that is not easy or straightforward to insulate (such as rubble foundations). Damp foundation repair methods can be “leveraged” to provide energy efficiency benefits. An example of this “hybrid” approach is spray foam insulation, which can be an effective means of liquid phase water control (leaking basement), vapor phase water control (diffusion and air leakage transported condensation) as well as an effective insulation.
Building Science Corporation seeks to further the energy efficiency market for cold climate, New England area retrofits by supporting projects based on solid building science fundamentals and verified implementation. The utility company National Grid engaged BSC as a partner to develop guidelines for its Deep Energy Retrofit Pilot Program. In addition to guideline development, BSC has acted as a consultant for these projects and others following similar retrofit strategies.
This report is an extension of a previous analysis study titled “High R Walls for the Pacific Northwest – A Hygrothermal Analysis of Various Exterior Wall Systems”, conducted by BSC for Walsh Construction, dated June 1, 2010 that examined the predicted thermal and hygrothermal performance of 17 different wall assemblies in Portland, Oregon.
Load-bearing masonry buildings are a significant portion of the existing building stock. Given the Building America goals of reducing home energy use by 30%-50% (compared to 2009 energy codes for new homes and pre-retrofit energy use for existing homes), insulation and air sealing of mass masonry walls will need to be a component of this work if mass masonry residential buildings are to be addressed.
This project examines a large scale renovation project within a 500 unit, 1960’s era subsidized urban housing community. The development comprises low-rise and mid-rise structures both of which exhibit exposed concrete frames with uninsulated masonry infill walls. The renovation project has a particular focus on indoor environmental quality and energy performance. The nature of occupied rehabilitation necessarily limited the scope of work implemented within apartment units. This research focuses on the airflow control and window replacement measures implemented as part of the renovations to the low-rise apartment buildings.
Through discussion of five case studies (test homes), this project evaluates strategies to elevate the performance of existing homes to a level commensurate with best-in-class implementation of high performance new construction homes. The test homes featured in this research activity participated in Deep Energy Retrofit (DER) Pilot Program sponsored by the electric and gas utility National Grid in Massachusetts and Rhode Island. Retrofit strategies are evaluated for impact on durability and indoor air quality in addition to energy performance.
Historically, weatherization programs have required that cellulose insulation materials be dense-packed to a minimum installed density of 3.5 pcf. This density limit was, in part, required to realize beneficial reductions in air leakage. The Building Performance Institute (BPI) currently has under development two standards that will set requirements for the airflow resistance of insulations used in retrofit cavity (i.e. dense-pack) installations (BPI-102) and define acceptable test methods to measure the airflow resistance of insulation materials used in dense-pack applications (BPI-103).
This report summarizes hygrothermal analysis of specific attics constructed in California. The analysis was done using historical experience, published work in journals and trade publications, current building code requirements and WUFI hygrothermal simulations to assess benefits and risks associated with insulating the roof decks in both vented and unvented configurations. The majority of the configurations evaluated are well understood and have been addressed in previous published work or in the model building codes. However, the focus of this report is on modifying conventional, ventilated attics, constructed with impermeable roof shingles (with fiberglass batt insulation on the ceiling plane) by adding fiberglass batt (or netted fiberglass or netted cellulose or spray applied fiberglass) insulation to the underside of the roof deck (i.e. on the slope) while leaving the attic air space ventilated to outdoors.
This paper was first presented at the 2011 ASHRAE Annual Conference. A homebuilder in the New England area has been building net zero energy single family homes since 2008 and is continuing with multiple small-scale subdivisions of 20 or more homes. This builder specializes in net zero affordable homes and sustainable net zero communities, while retaining houses with a familiar local vernacular appearance.
This paper was first presented at the 2011 ASHRAE Annual Conference. A startup builder in the San Francisco Bay Area has a goal of producing factory built/modular houses with net zero energy performance. Their first prototype was a two-story, two bedroom, urban infill townhouse design. It has been in operation for roughly a year, and has been extensively measured and monitored, providing information about its net zero performance.
The following report is an excerpt from the 2010 Building Science Corporation Industry Team Building America Annual Report. Many concerns, including the rising cost of energy, climate change concerns, and demands for increased comfort, have lead to the desire for increased insulation levels in many new and existing buildings. Building codes and green building codes are being changed to require higher levels of thermal insulation both for residential and commercial construction. This report will review, and summarize the current state of understanding and research into enclosures with higher thermal resistance, so-called “High-R
Enclosures”. Recommendations are provided for further research.
This paper is from the proceedings of the Thermal Performance of the Exterior Envelopes of Whole Buildings XI International Conference, December 5-9, 2010 in Clearwater, Florida. This paper summarizes some of the limitations of the various approaches to assessing the freeze-thaw resistance of brick masonry units and presents a detailed methodology for using frost dilatometry to determine the critical degree of saturation of brick material. Test results are presented for bricks from several historical load-bearing masonry. Recommendations are made for applying this approach together with hygrothermal model in the design of retrofit insulation projects.
This paper is from the proceedings of the Thermal Performance of the Exterior Envelopes of Whole Buildings XI International Conference, December 5-9, 2010 in Clearwater, Florida. The issues of climate change, energy security, and economics are all strong drivers for improving energy efficiency levels in a variety of sectors. In residential construction, although some inroads have been made in new houses, the stock of existing housing represents a huge opportunity for energy retrofits. The vanguard of these efforts has been pushing toward retrofitting very high insulation levels (i.e., “superinsulation,” or “deep energy retrofits”). Several cold-climate residential retrofit projects have been completed using an exterior insulation approach on light-frame above-grade walls. This type of retrofit is a reasonable step if a recladding of the building is already being done for aesthetic or ongoing maintenance reasons. The methods demonstrated here result in walls with insulation levels in the R-35 to R-40 range. This paper presents many of the lessons learned from these experiences, including overall enclosure strategies, such as air barriers, drainage planes, and moisture control. Several case-specific solutions to particular problems are described, including exterior air barrier approaches, wall sill replacement, and several approaches dealing with window penetrations. In addition, detailing recommendations and economic analysis of these measures are presented. Hygrothermal simulations were run to evaluate the changes in sensitivity to moisture intrusion due to these retrofit measures.
This paper is from the proceedings of the Thermal Performance of the Exterior Envelopes of Whole Buildings XI International Conference, December 5-9, 2010 in Clearwater, Florida. The issue of solar driven moisture that is associated with water absorptive claddings has often been raised, and it is becoming increasingly relevant as the demand for improved energy efficiency buildings continues to rise. Improved energy efficiency building enclosures generally means an increase in R-value and reduced air leakage, which commonly reduces the drying potential of wall assemblies. Essentially, less energy is available from inside the structure to assist the transport of moisture away from the building enclosure. As energy efficiency requirements are pushing towards zero-energy structures, passive means the sun or wind become more critical approaches for achieving enhanced drying. This paper investigates the hygrothermal performance of wall assemblies with brick veneer cladding as well as manufactured adhered stone veneer with two different types of water resistive barriers. One type is a conventional spunbonded polyolefin-based WRB, and the other type is an innovative three-dimensional dual ventilated sheet. This paper not only shows field-monitored data for both assemblies, but it also explains the building physics involved in both systems. The field performance data is based on one year-long field studies with wood-framed test walls installed on the north and south side of test huts located in Charleston, SC and Waterloo, ON. This paper demonstrates the beneficial effects of passively driven airflow through both solar and wind forces allowing small amounts of air flow to provide a significant increase in drying potential to walls that include dual ventilation water resistive barriers. Results show that the three-dimensional dual ventilated WRB not only provides enhanced drying potential by deploying passive solar energy, but it also provides a control layer against warm-weather inward vapor drives from the absorptive claddings, which have been implicated as reasons for numerous moisture related problems.
The following report is an excerpt from the 2010 Building Science Corporation Industry Team Building America Annual Report. The main focus for this research project is the integration of a combination space and domestic hot water heating system (“combi
system”) with a high-efficiency air source heat pump to optimize efficiency and comfort.
The following report is an excerpt from the 2010 Building Science Corporation Industry Team Building America Annual Report. The main focus for this research project is on the AAON heat pump system with digital scroll compressor and modulating hot-gas condenser reheat installed in the GreenCraft Builders prototype house in Lewisville, TX.
The following report is an excerpt from the 2010 Building Science Corporation Industry Team Building America Annual Report. A wide variety of ventilation systems are installed in US houses to reduce interior contaminant levels and safeguard occupant health. The relative merits of these systems are subjects of ongoing research. Prior work by Building Science Corporation has investigated the effects of air distribution and mixing on pollutant levels within the building. The present work is aimed at discovering the energy costs of various ventilation approaches in operation, through modeling of typical houses across the TMY2 location set. Both measures are helpful in recommending a particular ventilation system.
The following report is an excerpt from the 2010 Building Science Corporation Industry Team Building America Annual Report. The goal of this research is to find optimally designed, cost effective roof insulation systems that can be included with other enclosure details to help reduce whole house energy use by 70%. This report will compare a variety of roof insulating strategies and present their advantages and disadvantages according to several comparison criteria.
The following report is an excerpt from the 2010 Building Science Corporation Industry Team Building America Annual Report. This report investigates the implementation of advanced framing in both production and prototype built homes built in a variety of climate regions across the USA. This work is part of a large research project on High R-value enclosures. The current industry standard wall is being replaced by a 2×6 frame at 24-inch centers with single top plates, two-stud corners, no jack studs, no cripples and single headers (and in many cases no headers at all). The advanced framing system is cheaper because it uses 5% to 10% less board feet of lumber, and it is faster because it uses 30% fewer pieces. It saves energy because it provides a 60% deeper cavity (which allows 60% more cavity insulation) and because it reduces the framing factor. Advanced framing can save energy, greenhouse gas emissions, and money if properly implemented. Through BSC’s experience we have found that builders can save $1000 per house on advanced framing. To maximize cost savings and energy savings for the homeowner, the builder financial savings are best shifted to implementing more energy saving measures.
The following report is an excerpt from the 2010 Building Science Corporation Industry Team Building America Annual Report. Many concerns, including the rising cost of energy, climate change concerns, and demands for increased comfort, have lead to the desire for increased insulation levels in many new and existing buildings. Building codes are improving to require higher levels of thermal control than ever before for new construction. This report considers a number of promising foundation and basement insulation strategies that can meet the requirement for better thermal control in colder climates while enhancing moisture control, health, and comfort.
Tankless water heaters offer significant energy savings over conventional storage-tank water heaters, because thermal losses to the environment are much less. Although standard test results are available to compare tankless heaters with storage tank heaters, actual savings depend on the draw details because energy to heat up the internal mass depends on the time since the last draw. To allow accurate efficiency estimates under any assumed draw pattern, a one-node model with heat exchanger mass is posed here. Key model parameters were determined from test data. Burner efficiency showed inconsistency between the two data sets analyzed. Model calculations show that efficiency with a realistic draw pattern is ~8% lower than that resulting from using only large ~40 liter draws, as specified in standard water-heater tests. The model is also used to indicate that adding a small tank controlled by the tankless heater ameliorates unacceptable oscillations that tankless with feedback control can experience with pre-heated water too hot for the minimum burner setting. The added tank also eliminates problematic low-flow cut-out and hot-water delay, but it will slightly decrease efficiency. Future work includes model refinements and developing optimal protocols for parameter extraction.
This report considers a number of promising wall systems that can meet the requirement for better thermal control. Unlike previous studies, this one considers performance in a more realistic matter, including some two- and three-dimensional heat flow and analysis of the relative risk of moisture damage.
This paper describes a hygrothermal modeling study, including all of the US climate zones, a range of interior humidity levels and numerous arrangements and types of insulation. The results showed that so long as airtightness is provided, and wintertime humidity is controlled, numerous unvented solutions using either or both spray foam (open and closed cell) and fibrous insulation (cellulose and mineral fiber) can be successful. Climate, the solar properties and exposure of the roofing, the air and vapor permeance of the insulation(s) and interior humidity are the most important factors to be considered in the design of moisture-safe unvented roof systems.
Successfully executing strategies to control bulk water for foundations is critical for building durability, indoor air quality, and creating acceptable conditions and/or living spaces within the foundation space. Although the energy impacts of properly done bulk water control are small to insignificant, it should be considered a base requirement for any high performance house. In addition, measures such as basement insulation are predicated on properly managed foundation bulk water.
The following report is an excerpt from the 2009 Building Science Corporation Industry Team Building America Annual Report.
The software CONTAM was used to create a calibrated mulit-zone model to replicate in-field tracer gas decay measurements of a new two story, 2,600 sq. ft., single-family house in Sacramento, CA under different whole-house dilution ventilation scenarios. This report was first published in ASHRAE Transactions (17, Louisville 2009). American Society of Heating Refrigeration and Air-Conditioning Engineers, Atlanta, GA. Reprinted with permission.
A calibrated ventilation model was exercised over a range of parameters seen in new and existing housing in the United States. This report was first published in ASHRAE Transactions (17, Louisville 2009). American Society of Heating Refrigeration and Air-Conditioning Engineers, Atlanta, GA. Reprinted with permission.
This paper describes a fully instrumented large-scale mock-up completed in a southern Ontario private school to allow direct comparisons between insulated and non-insulated walls with a focus on the evaluation of freeze-thaw and corrosion risks. Climate conditions and wall temperature, relative humidity and moisture content are compared and discussed. Climate conditions (wetting and temperature) over the monitoring period were less severe than average. As a result, measured values were used to refine computer models to simulate wall performance under more severe climate conditions.
The balance between wetting, drying, and safe storage is critical to the long term performance of building enclosures. Where wetting cannot be controlled to acceptable levels, safe storage and drying become critical.
The research reported in this paper is aimed at increasing the understanding of the hygrothermal performance of interior basement insulation systems by a combination of field monitoring of four assemblies and one-dimensional computer modeling.
This paper documents the experimental methodology, details, and results and discuss how this information can be applied to modeling drained wall systems. Practical applications and research questions arising from the work are presented.
Exterior insulation and finishing systems (EIFS) are inherently defective and unfit of use as an exterior cladding system where moisture sensitive components are used without a provision for drainage or in locations and assemblies without adequate drying.
A performance review of residential assemblies in the central Florida (Orlando) area during the three hurricanes in August and September 2004.
This paper reports on field measurements collected from over a year of monitoring two types of wood-framed walls: one with an air gap membrane and another installed following standard practice. Each type of wall was faced either north or south in a test hut located in southwestern Ontario.
Advanced framed wall systems that use a stud spacing of 24 inches on center and eliminate the plywood or OSB sheathing from the wall and replace it with insulating sheathing is a type of enclosure assembly that has been designed to be energy efficient combined with efficient material use.
This report considers a number of promising wall systems that can meet the requirement for better thermal control. Unlike previous studies, this one considers performance in a more realistic matter, including some true three-dimensional heat flow and the relative risk of moisture damage.
This report is available from the Canadian Urethane Foam Contractors Association (http://www.cufca.ca/home_e.php). It is reproduced here for convenience. A common question encountered by SPF applicators, building designers, and code officials is the need for an additional vapor barrier or retarder. Experience by many contractors and some consultants suggest that special low permeance layers such as polyethylene are rarely needed in many types of walls. Theory indicates that closed cell foam is sufficiently vapor impermeable to control diffusion condensation and that low-density open-cell foam applications may require additional vapor diffusion control in some extreme environments. However, the need for, and type of additional vapor control layers remains unanswered to many.
This document summarizes the theory behind thermal insulation and building system heat flow control metrics and presents a literature review of selected research into this area.
This report is an excerpt from the 2008 Building America Annual Report. Following the almost complete destruction of Greensburg, Kansas by a tornado in May, 2007, Building Science Corporation (BSC) was contracted to provide example house plans, support for
the reconstruction of energy efficient houses and training for builders and trades. This report describes the planning, execution, and results of BSC’s builder training program in Greensburg.
This report is an excerpt from the 2008 Building America Annual Report. Following the almost complete destruction of Greensburg, Kansas by a tornado in May, 2007, Building Science Corporation (BSC) was contracted to provide example house plans, support for the reconstruction of energy efficient houses and training for builders and trades. This report describes the results of BSC’s work to construct more than 20 energy efficient, affordable, durable houses in Greensburg, Kansas.
The following report is an excerpt from the 2008 Building Science Corporation Industry Team Building America Annual Report. The purpose of this research project is to design and install a solar hot water system that features a tankless water heater integrated with a solar hot water panel such that consistent temperature control can be achieved at the domestic taps.
The following report is an excerpt from the 2008 Building Science Corporation Industry Team Building America Annual Report. This summary includes whole-house performance and systems engineering, construction support, source energy savings and quality control requirements and integration.
Concentrations of 54 volatile organic compounds (VOCs) and ventilation rates were measured in four new manufactured houses over 2-to-9.5 months following installation and in seven new site-built houses 1-to-2 months after completion. The houses were in four projects located in hot-humid and mixed-humid climates. They were finished and operational, but unoccupied.
Uniform distribution of outside air is one way to ensure that residential dilution ventilation systems will provide a known amount of fresh air to all rooms regardless of house geometry and occupant behavior.
In order for dilution ventilation systems to provide predictable results independent of the geometry of individual homes, outside air must be uniformly distributed throughout the house
Brick is a reservoir cladding, meaning that it absorbs and stores water (rain) when it becomes wet. In some homes, with brick veneer cladding systems, mold contamination has occurred within exterior wall cavities. In some homes, wood decay at bottom plates has also occurred.
This paper discusses Building America whole house systems research within the broad effort to reduce or eliminate the environmental impact of building and provides specific recommendations for future Building America research based on Building Science Corporation’s experience with several recent projects involving green home building programs.
Given what happened in New Orleans during hurricane Katrina, changes in the way we build are needed. Looking to key sustainability concepts of durability and energy efficiency, new flood resistant design concepts were developed.
Primarily as a resort location, Hilton Head Island has a somewhat different residential housing market than other more traditional areas.
Unvented roof systems can be safely used in many different climates. In cold climates, insulating sheathing must be added exterior to the roof sheathing to prevent condensation on the underside of the roof sheathing.
Two seemingly innocuous requirements for building enclosure assemblies bedevil builders and designers almost endlessly: keep water vapor out, let the water vapor out if it gets in.
Just about everyone in the building industry can be guilty of using building terms loosely, and a prime example is with attics, roof assemblies.
Combo systems use a gas water heater to provide domestic water and space heating. Find out when its appropriate to use such a system and guidelines for doing it right.
Heat loss through uninsulated basement walls can account for up to one-third of the heat loss from an average home. Installing insulation on basement walls is often inexpensive, easy to accomplish and frequently combined with “finishing the basement.”
A concise explanation of how a high performance HVAC system works in a high performance home.
PV systems have come a long way in the last two decades. While they may not work for all homes, residential installations are becoming a practical reality under more and more conditions
This article briefly repeats some of the information in the other mold articles but also includes information on how to prevent mold in residential structures.
This article provides both general guidelines for mold remediation as well as specific guidelines for the typical locations where mold is most often found in houses.
Although this article is titled "Mold Testing" it actually tells you why testing for mold is usually not needed.
Everything you ever wanted to know about HVAC for homes-thermal comfort, air distribution, nature of and dealing with contaminants, HVAC strategies, and climate-appropriate graphics to boot.
This article answers your questions about mold, what it is, where it grows, how it spreads, how can I prevent it.
Wood moves. Drywall does not move. Interesting problem. The more you attach drywall to wood, the more cracks you have. Easy, attach the drywall to less wood, and, in a way, that allows the wood to move.
The primary function of a housewrap or building paper is rain penetration control. It is not air infiltration despite what the manufacturers say.
The manufacturers of housewraps have for years promoted the fantasy that water vapor in wall assemblies only moves one way – from the inside out.
When constructing unvented roofs with asphalt shingles in hot-humid climates, a vapor barrier must be installed between the asphalt shingles and the roof deck.
Perhaps the single most challenging BSC performance for Building America production homebuilders is that all ducts and HVAC equipment must be within the conditioned space (this means no ducts in outside walls and no ducts or air handlers in garages, vented attics or vented crawlspaces).
The simplest, most effective, and most economical way to introduce fresh air in homes with central forced air systems is to use the central fan to pull in and distribute a controlled amount of outside air.
Details on how to install a window using building paper as the drainage plane.
Builders for many years have put mechanical equipment and ducts in non-living spaces such as crawlspaces and attics primarily to save valuable floor space.
This is a concise overview of the principles and steps to follow when dealing with water from the foundation to the roof.
Transfer grilles represent a cost-effective alternative to individual return ducts if they are properly configured for air flow, privacy, and aesthetics.
Sizing information excerpted from “RR-0006: Discussion of the Use of Transfer Grilles to Facilitate Air Flow in Central Return Systems.”
Most of us are not aware of just how differently these two barriers work in building assemblies. This article makes the differences as clear as the polyethylene film that should (or more likely should NOT) be in your walls.
Using four Building Science Consortium Building America community-scale projects, this paper investigates the nature, strength, and durability of connections between high performance dwellings and developments.
Roofs can be designed and constructed to be either vented or unvented in any hygrothermal zone. Air barrier systems are typically the most common approach, however, air pressure control approaches are becoming more common especially in cases involving remedial work on existing structures.
Air barriers are systems of materials used to control airflow in building enclosures. They typically completely enclose the air within a building.
A single-story, single-family, 1350 sq. ft. house located in Las Vegas, NV was outfitted with two separate ventilation systems. The systems were independent of each other, and were operated at different times to evaluate the relative difference in air change rate and distribution of ventilation air induced by their operation.
Twenty homes were tested and monitored in the hot-humid climate of Houston, Texas, to evaluate the humidity control performance and operating cost of six different integrated dehumidification and ventilation systems that could be applied by production homebuilders.
High performance compact fluorescent lighting (CFLs) is not just about energy savings; it’s also about the other aspects of performance such as color rendering.
When designing a building’s envelope and its interaction with the mechanical system, temperature, humidity, rain and the interior climate often are ignored.
Indoor moisture and temperature conditions and equipment operation were measured and analyzed for 43 homes in warm-humid and mixed-humid climate regions of the United States.
Buildings leak water and air, which is normal and unavoidable. Therefore, designers should not fixate on preventing leakage, i.e. making buildings “airtight.” Because even if all cracks were sealed, buildings have doors and windows.
Energy efficient homes are inherently airtight and require ventilation for acceptable indoor air quality. Recognizing this fact, two building code jurisdictions, the federal department of Housing and Urban Development and the State of Washington, require mechanical ventilation for homes.
Traditionally, building codes have required that attics of residential buildings be vented. The ventilation requirement varies between one square foot of net free ventilation area per 300 square feet of attic floor area (1:300) to one square foot per 150 square feet (1:150).
Twelve affordable, healthy, environmentally responsible single family houses were designed and built on an urban infill in Dallas, Texas.
Humidity concerns in the southern humid climates are particularly difficult to resolve. This is because one of the most effective approaches to dealing with humidity in heating climates, ventilation, can cause major humidity problems in the humid south.
What relative humidity should I have in my home? Seems like a simple enough question. However, the answer can sometimes be difficult to understand.
Sealed attic construction, by excluding vents to the exterior, can be a good way to exclude moisture-laden outside air from attic and may offer a more easily constructed alternative for air leakage control at the top of residential buildings.
Ventilation air change rate, local mean age-of-air, and interzonal ventilation air distribution were measured for two single-family homes and eight ventilation systems.
Development and testing were conducted for a prototype phase-change material (PCM) wallboard to enhance the thermal energy storage capacity of buildings with particular interest in peak load shifting.
Two moisture-storage coating mixtures developed and tested between late 1990 and early 1991 could provide a low-cost, building-integrated method of managing indoor humidity in hot and humid climates.
A comprehensive literature review was made to investigate whole house ventilation system options, various simulation and engineering analysis tools and techniques, and baselines for comparing the current project results.
This paper discusses the differences between vented, unvented and conditioned crawlspaces. Best practice construction techniques and assemblies for conditioned crawlspaces are discussed, the results of a field monitoring program are presented, and the code language addressing crawlspaces is explained.
This report summarizes indoor temperature and humidity data that have been collected from houses by the Building Science Consortium of the US Department of Energy Building America Program.
Americans have been building homes with wood—shaping logs, joining timbers, nailing studs—for almost 400 years. Our current approach, stick framing, grew poplular in the mid-1800's because it too less skill, required simpler tools, and took fewer people than timber framing. We apparently really like waste haulers, too.
With rising utility cost, concerns over availability of natural resources, and environmental impacts of our energy production and use, a push has been made to design buildings to minimize energy consumption in an attempt to work towards more sustainable communities. Creating more thermally efficient building enclosures is a necessary part of achieving this goal. The thermal resistance provided by insulating a stud cavity is limited by the standard framing sizes currently used in the United States and Canada. The options therefore are to either increase the depth of the studs used, add insulation to the interior of the wall assembly, or to add extra insulation to the exterior of the assembly. Providing rigid insulating sheathing to the exterior of a wall assembly is a technique that has been used in cold climates for more than 40 years. Recently it has begun to be integrated into enclosure designs in all climates. As with any newly adopted technology, there can be concerns for its proper application. This paper examines methods of incorporating insulating sheathing into the thermal and moisture management systems of the building enclosure in a variety of climate zones across North America. This is done through examining the material properties of the various products and how these properties can be used to achieve an energy efficient and durable building enclosure design, while avoiding problems relating moisture accumulation and degradation of materials.
This paper examines methods of using hygrothermal models, primarily WUFI, to assess the impact of energy efficient enclosure upgrades on the durability of historical buildings. Means of producing and choosing input data for the hygrothermal simulation are discussed. Methods for using the hourly results from the simulations to generate a corrosion index and a freeze-thaw count are developed. An example wall is used to demonstrate the type of output that can be expected and how this can be used in making retrofit design decisions.
The overall goal of the DOE residential research program is to reduce average whole house energy use in new residential buildings by 30-90 percent by 2020, including homes that achieve zero net energy use on an annual basis. High performance space conditioning and control systems that match the high performance of Building America enclosures are necessary to meet performance targets. Conditioning systems with integrated mechanical ventilation and year-around temperature and humidity control are necessary. The most significant climate-specific need is for system-integrated dehumidification for humidity control without overcooling the space. Cost-effective dehumidification without overcooling will enable continued and further reduction of sensible loads (including high-performance glazing) that would otherwise exacerbate humidity control problems in humid climates.
This is a test form used in the Building America program to ascertain house performance and specifications.
SNAPSHOT stands for Short, Non-destructive Approach to Provide Significant House Operation Thresholds.
Exposure to sunlight (ultraviolet radiation) and moisture are the major factors affecting the durability of paint coatings and the durability of the substrate.
Good design and practice involve controlling the wetting of building assemblies from both the exterior and interior and different climates require different approaches.
This is one of eleven projects from the full report of Building Science Consortium’s research efforts for 2004. The research program is aimed towards advanced building systems that have the potential to reduce residential building energy use by 50-60%. It is based on evaluation of market trends, industry partner needs, and initial results from our team’s system engineering research program. A total of eleven individual research projects were detailed in this report. This project report explores the development of more cost-effective, integrated supplemental dehumidification
systems.
Construction practices have improved and the HVAC systems need to improve with them. The deKieffer Bypass relieves air pressure in rooms without compromising sound or light transmission.
This article was written to tie together and summarize the various papers on unvented conditioned cathedralized attics found on our website.
An examination of five different systems that show how to cool and dehumidify inside air while maintaining sufficient introduction of outside air for ventilation efficiently and cost-effectively.
Heat loss from basements accounts for a significant portion of the energy loss from a home. In many jurisdictions, basement insulation is a building code requirement. Cost usually determines the type of insulation system used.
Twenty homes were tested and monitored in the hot-humid climate of Houston, Texas, U.S.A., to evaluate the humidity control performance and operating cost of six different integrated dehumidification and ventilation systems that could be applied by production homebuilders. Fourteen houses, that also met measured energy efficiency criteria, had one of the six directly- or indirectly-integrated dehumidification and ventilation systems. Three reference houses had the same energy efficiency measures and controlled mechanical ventilation, while three other reference houses met code minimums for energy efficiency and did not have mechanical ventilation. Temperature and relative humidity were monitored at four living-space locations and in the conditioned attic where the space-conditioning equipment and air-distribution ducts were located. Equipment operational time was monitored for heating, cooling, dehumidification, and ventilation. Results showed that energy efficiency measures, combined with controlled mechanical ventilation, change the sensible and latent cooling load fractions such that supplemental dehumidification, in addition to that provided by the central cooling system, is required to maintain indoor relative humidity below 60% throughout the year. The system providing the best overall value, including humidity control, first cost, and operating cost, involved a standard dehumidifier located in a hall closet with a louvered door and central-fan-integrated supply ventilation with fan cycling.
This is a report describing the test methodology and results for experiments run on two test houses at the Bonita Springs development in Fort Myers, FL. The goal was to determine the effect of attic ventilation in a hot-humid climate; previous work had shown that little to no benefit is derived from ventilation in terms of energy use, and that it is detrimental for moisture control. Two houses with identical orientations and plans were compared; one was ventilated at the typical 1:300 ratio, and the other had sealed vents. This work was conducted in order to move houses in hot-humid climates forward in technology in their building envelope and HVAC systems.
Building America is a program of the U.S. Department of Energy, in which teams of architects, engineers, builders, equipment manufacturers, and others collaborate in a systems engineering approach to produce homes that use up to 50 percent less energy to operate.
An hourly simulation study using DOE2.1E was conducted to determine the annual difference in energy consumption between various ventilation options in different climates.
Based on Building America experience, this report is about selecting furnaces, water heaters, both or sometimes just one to accomplish both space heating and domestic hot water.
The general principle of building durability has two components: buildings should be suited to their environment and the laws of physics must be followed. We tend to ignore the first and find the second inconvenient.
Every exterior cladding system needs an air space and drainage plane for performance and durability. This article presents the right materials and spaces for most exterior claddings—brick, stucco, and wood, metal and vinyl lap siding.
Residential ventilation systems can be categorized as supply, exhaust, or balanced systems. This effort focused on establishing a design methodology for central-fan-integrated supply ventilation systems.
Understanding the significance of the complex flow and pressure distribution problems created by the interaction of the building envelope with the mechanical system and climate can lead to changes in building design, commissioning, operations, maintenance, diagnostics and rehabilitation.
Current work is focusing on the performance and durability of unvented-cathedralized attics in hot-humid climates with both tile and asphalt shingle roofing.
A residential attic model, contained in the finite element computer program FSEC 3.0, was empirically aligned with measured attic data from three roof research facilities in Florida and Illinois.
Side-by-side energy testing and monitoring was conducted on two houses in Louisville, KY.
The effects of solar heating potential and nocturnal cooling potential are simulated in a controlled indoor environment and extensive measurements are made along and between the boundary surfaces. Air delivered to the test section is controlled to close tolerances in temperature, humidity and flow rate. Steady state conditions, step changes, functional changes or real weather conditions can be simulated. Accurate measurements are taken at the inlet and outlet of the test section to determine the amount of heat and mass transfer across the system. The facility is completely computer controlled. The control software, employing a self-tuning proportional integral control methodology, was developed in house. A description of both the DESRAD concept and the Diurnal Test Facility is presented here along with examples of the model verification data and a brief measurement uncertainty analysis.
