Reports

Research Reports

RR-0201: Advanced Framing: Using Wood Efficiently From Optimizing Design to Minimizing the Dumpster — by Building Science Corporation — last modified 2009/10/28

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.

RR-0202: Basement Insulation Systems — by Building Science Corporation — last modified 2008/10/16

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.

RR-0501: Guide to Insulating Sheathing — by Joseph Lstiburek and Peter Baker — last modified 2009/04/16

This document looks at methods of incorporating insulating sheathing into the design of wall assemblies. Through examining and understanding the various material properties, these properties can then be used to our advantage in the design of water management details, vapor control strategies, and increased thermal resistance in wall assemblies.

RR-0601: Analysis of Indoor Environmental Data — by Building Science Corporation — last modified 2008/10/20

This summary and analysis of indoor temperature and humidity data has been collected over a three and a half year period from 43 houses located mostly in the hot, humid gulf coast region.

RR-0502: Review of Residential Ventilation Technologies — by Building Science Corporation — last modified 2008/10/20

This paper reviews current and potential ventilation technologies for residential buildings with particular emphasis on North American climates and construction.

RR-0401: Conditioned Crawl Space Construction, Performance and Codes — by Joseph Lstiburek — last modified 2009/04/16

This paper discusses the differences between vented, unvented and conditioned crawl spaces. Best practice construction techniques and assemblies for conditioned crawl spaces are discussed, the results of a field monitoring program are presented, and the code language addressing crawl spaces is explained.

RR-0701: Whole House Ventilation Systems Options—Phase 1 Simulation Study — by Joseph Lstiburek, Betsy Pettit, Armin Rudd — last modified 2009/04/16

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.

RR-9401: Development of Moisture Storage Coatings for Enthalpy Storage Wallboard — by Armin Rudd — last modified 2009/04/16

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. Since there are large surface areas of interior gypsum wallboard in nearly all new houses, the effort centered around coatings that could be applied to those surfaces.

RR-9301: Phase-Change Material Wallboard for Distributed Thermal Storage in Buildings — by Armin Rudd — last modified 2009/04/16

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. Most important, it was determined that small-scale differential scanning calorimetry can adequately predict (within 9%) the performance of PCM wallboard when installed in full-scale applications.

RR-0001: Measurement of Ventilation and Interzonal Distribution in Single-Family Homes — by Armin Rudd and Joseph Lstiburek — last modified 2009/04/16

Ventilation air change rate, local mean age-or-air, and interzonal ventilation air distribution were measured for two single-family homes and eight ventilation systems. A multi-zone, single-gas, tracer gas decay measurement technique was used. A single-story, slab-on-grade 1350 sq. ft. house was tested in Las Vegas, Nevada, and a two-story, 3192 sq. ft. house with basement was tested in Minneapolis, Minnesota. The ventilation systems studied included various configurations of exhaust, supply, and balanced ventilation, with and without whole-house recirculation by the central heating and cooling air-handler unit fan. Some of the systems were independent of the central air distribution system, while others were integrated with it. In general, results showed that all ventilation systems benefitted from periodic operation of the central fan, giving excellent uniformity of ventilation air distribution. System without central fan recirculation showed poor ventilation air distribution for closed rooms where there was no ventilation system duct.

RR-9801: Vented and Sealed Attics in Hot Climates — by Armin Rudd and Joseph Lstiburek — last modified 2009/04/16

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. However, the space conditioning energy use and roof temperature implications of this approach have not been extensively studied. A computer modeling study (Rudd 1996) was performed to determine the effects of sealed residential attics in hot climates on space conditioning energy use and roof temperatures.

RR-0702: Monitored Indoor Moisture and Temperature Conditions in Hot-Humid US Residences — by Armin Rudd — last modified 2009/04/16

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. A range of house and mechanical system types were evaluated, including standard building enclosures and cooling systems and high-performance building envelopes with enhanced cooling or supplemental dehumidification systems. Conventional cooling systems in standard houses usually provide reasonable humidity control (below 60% RH) in midsummer. However, high humidity levels are observed at times when cooling loads are modest. The addition of continuous mechanical ventilation to standard houses is humid climates did not consistently increase indoor humidity levels. Indoor humidity levels were highest in high-performance, low sensible heat gain homes with mechanical ventilation. In these homes, the temperature balance point is higher, so there are many hours when sensible cooling is not required yet there are still significant moisture loads from internal sources and ventilation. These homes often require a separate dehumidifier to maintain space humidity in the swing seasons and at night when the thermostat is satisfied. The use of supplemental dehumidification in a high-performance house enables the implementation of efficiency improvements that significantly reduce sensible cooling demand while still maintaining proper humidity levels.

RR-0203: Relative Humidity — by Joseph Lstiburek — last modified 2009/04/16

What relative humidity should I have in my home? Seems like a simple enough question. However, the answer can sometimes be difficult to understand. Elevated relative humidity at a surface – 70 percent or higher - can lead to problems with mold, corrosion, decay and other moisture related deterioration. When relative humidity reaches 100 percent, condensation can occur on surfaces leading to a whole host of additional problems. An elevated relative humidity in carpet and within fabrics can lead to dust mite infestation and mildew (mildew is mold growing on fabrics).

RR-0301: Unvented Roof Summary Article — by Kohta Ueno — last modified 2009/07/10

This article was written to tie together and summarize the various papers on unvented conditioned cathedralized attics found on our website. We realize that there is a wealth of information, and much of it too detailed to understand or digest in a single sitting. Furthermore, building officials might not have the time available to carefully examine the many documents on the page; this is meant to summarize the main arguments, and provide pointers to where detailed information and measured data can be found.

RR-0405: Community-Scale Evaluation Results — by Building Science Corporation — last modified 2008/10/20

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. There are few inherent or natural links between the two (particularly in the production home setting); the connections must be either imposed (by government entities) or created in the marketplace. Because communities often involve two very distinct players—the developer and the builders—and the project often spans up to 10 years, it is challenging to develop and sustain either an imposed or marketed system with strong and meaningful links between high performance homes and neighborhoods.

RR-0403: Air Barriers — by Joseph Lstiburek — last modified 2009/04/16

Air barriers are systems of materials used to control airflow in building enclosures. They typically completely enclose the air within a building .The physical properties which distinguish air barriers from other materials are the ability to resist air flow and air pressure.

RR-0404: Roof Design — by Joseph Lstiburek — last modified 2009/04/16

Roofs can be designed and constructed to be either vented or unvented in any hygro-thermal zone. Air barrier systems are typically the most common approach, however, air pressure control approaches are be-coming more common especially in cases involving remedial work on existing structures. Vapor diffusion should be considered as a secondary moisture transport mechanism when designing and building roofs. Specific vapor retarders are often unnecessary if appropriate air movement control is provided or if control of condensing surface temperatures is provided.

RR-9908: Design Methodology and Economic Evaluation of Central-Fan-Integrated Supply Ventilation Systems — by Armin Rudd and Joseph Lstiburek — last modified 2009/04/16

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. Air flow measurements were taken for 7.6 m lengths of 12.7 cm through 22.9 cm diameter flexible ducts, with a 15.2 cm wall-cap, at duct pressures of -10 Pa to -120 Pa. Using these measurements and field experience, a five-step method was developed as a guide for sizing and installing the ventilation system. An economic evaluation was made by conducting hourly computer simulations to determine the impact on heating, cooling, and fan energy use for four U.S. climates. An effective ventilation system can be achieved using a filtered duct from out doors to the return side of a central air distribution fan with a specialized fan control that automatically cycles the fan if the fan has been inactive for a period of time.

RR-9907: Measured Air Change Rates and Distribution Ventilation Air in a Single Family Home — by Armin Rudd — last modified 2009/04/16

A single-story, single-family, 1350 ft2house 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.

RR-9904: Unvented-cathedralized attics: Where we've been and where we're going — by Armin Rudd, Joseph Lstiburek, Kohta Ueno — last modified 2009/04/16

Current work is focusing on the performance and durability of unvented-cathedralized attics in hot-humid climates with both tile and asphalt shingle roofing. The advantages for the hot-humid climate are expected to be even greater than for the hot-dry climate.

RR-9905: Air Pressure and Building Envelopes — by Joseph Lstiburek — last modified 2009/04/16

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.

RR-0303: Ventilation and Air Leakage — by Building Science Corporation — last modified 2008/10/20

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.

RR-0205: Moisture Control for Buildings — by Joseph Lstiburek — last modified 2009/04/16

When designing a building’s envelope and its interaction with the mechanical system, temperature, humidity, rain and the interior climate often are ignored. The focus for the building may be more on aesthetics and cost than on performance.

RR-0402: Singing the "blues" in the key of "low-e" — by Building Science Corporation — last modified 2008/10/20

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.

RR-0505: Residential Dehumidification Systems Research for Hot-Humid Climates — by Armin Rudd, Joseph Lstiburek, Kohta Ueno — last modified 2009/04/16

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.

RR-9802: Performance of Building America Initiative Houses with Unvented Attics and Tile Roofs Constructed by Pulte Homes, Las Vegas Division — by Armin Rudd — last modified 2009/04/16

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. This model was then used to simulate hourly space conditioning energy use, and roof and attic temperatures, for peak cooling days and annual weather, for Orlando, Florida and Las Vegas, Nevada. Results showed that, when compared to typically vented attics with the air distribution ducts present, sealed cathedralized attics (i.e. unvented attic with the air barrier and insulation at the sloped roof plane) can be constructed without an associated energy penalty in hot climates.

RR-9902: Mold Control in Publicly Funded Housing Developments — by Betsy Pettit, FAIA and Joseph Lstiburek — last modified 2009/04/16

This presentation examines health related building problems in public housing.

RR-0204: Practical and Effective Approaches to Residential Ventilation for Production Builders — by Armin Rudd — last modified 2009/04/16

This presentation examines durability with respect to moisture, and how mechanical ventilation can be used to control it.

RR-0302: Roof and Attic Ventilation Issues in Hot-Humid Climates — by Armin Rudd — last modified 2009/04/16

A presentation examining the requirement for roof/attic venting in hot-humid climates.

RR-9302: Humidity Control in the Humid South — by Joseph Lstiburek — last modified 2009/04/16

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. The issue becomes even more complex when you realize that you can replace the word humidity in the previous sentences with the words "indoor air quality " and not change the meaning or impact. Dilution is often used as the solution to indoor pollution in heating climates. Unfortunately, in humid, air conditioning climates, the greater the rate of dilution, ventilation or air change, the greater the rate of moisture entry with the exterior air. Therefore, the greater the likelihood of mold and other biological growth problems, particularly if the moisture in this incoming air is not removed.

RR-9402: Establishing Priorities for the Design of Affordable, Environmentally Responsible Housing in Dallas, Texas, a Mixed Climate Zone — by Betsy Pettit, FAIA and Joseph Lstiburek — last modified 2009/04/16

Twelve affordable, healthy, environmentally responsible single family houses were designed and built on an urban infill in Dallas, Texas. They will sell for under $80,000 each, making them affordable to families earning less than 80 percent of the median income in the Dallas metropolitan area (under $35,000). Monthly payments will range between $500 to $700 per month. Utility costs (heating, cooling, and hot water) are expected to be $30 per month. Typical utility costs for houses of similar size in Dallas have ranged Between $80 and $100 per month. The building system design resulted in a 60- to-70 percent reduction in energy consumption. A minimum of $50 per month for utility cost will be saved.

RR-9701: Measurement of Attic Temperatures and Cooling Energy Use in Vented and Sealed Attics in Las Vegas, Nevada — by Armin Rudd and Joseph Lstiburek — last modified 2009/04/16

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 300square feet of attic floor area (1:300) to one square foot per 150 square feet (1:150). In cold climates, the primary purpose of attic ventilation is to maintain a cold roof temperature to avoid ice dams created by melting snow, and to vent moisture that moves from the conditioned space to the attic. In cooling dominated climates, the primary purpose of attic ventilation is to vent hot air, heated by solar gain on the roof, thus reducing the cooling load contribution from the roof. The magnitude of the roof cooling load contribution is often in the area of ten percent of the total cooling load for an occupied house.

RR-9901: Air Distribution Fan and Outside Air Damper Recycling Control — by Armin Rudd — last modified 2009/04/16

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. The state of Minnesota will soon enact regulations for mechanical ventilation in homes, and it is expected that this trend will continue. Of all the options currently available, the low cost and low maintenance central-fan-integrated ventilation approach is the most acceptable to large production builders and manufactured home producers. In this approach, fresh air is filtered and ducted to the return air side of the central system fan. The central system fan and ducts then distribute the ventilation air throughout the living space. This is a resource and energy efficiency strategy that utilizes the existing air ducts and the normal cycling of the fan, in response to demand from the thermostat, to distribute ventilation air and conditioned air at the same time. The patented AirCycler™ control can be used to automatically operate the fan if the fan has been inactive for a period of time, and to control a motorized outside air damper to limit the intake of ventilation air independent of fan operation.

RR-0003: An Advanced Systems Engineering Approach to Affordable Single Family Homes — by Betsy Pettit, FAIA — last modified 2009/04/16

This presentation examines the integrated system concepts of advanced framing, air flow retarder system, thermal envelope system, air distribution system and mechanical systems.

RR-0101a: Moisture, Building Enclosures, and Mold—Part I — by Building Science Corporation — last modified 2008/09/11

How water gets into a structure, why it doesn’t leave, and how these architectural flaws become HVAC headaches.

RR-0101b: Moisture, Building Enclosures, and Mold—Part II — by Building Science Corporation — last modified 2008/09/11

How water gets into a structure, why it doesn’t leave, and how these architectural flaws become HVAC headaches.

RR-0504: Integrating Systems for Green Design — by Betsy Pettit, FAIA — last modified 2009/04/16

The effects of building development on the environment are at the most basic level about durability. Building a house or community is really about the durability of people, the durability of buildings, and the durability of the planet. Durability is really another way of expressing the concept of sustainability to the building community.

RR-0002: Practical Approaches to Residential Ventilation for Improved Durability and Indoor Air Quality — by Armin Rudd — last modified 2009/04/16

This presentation examines how to provide durability for little or no incremental cost, as a goal of the Building America program.

RR-0004: Air Barriers vs. Vapor Barriers — by Joseph Lstiburek — last modified 2008/10/03

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.

RR-0005: Transfer Grille Sizing — by Armin Rudd — last modified 2008/10/03

Sizing information excerpted from “RR-0006: Discussion of the Use of Transfer Grilles to Facilitate Air Flow in Central Return Systems.”

RR-0006: Discussion of the Use of Transfer Grilles to Facilitate Return Air Flow in Central Return Systems — by Armin Rudd — last modified 2008/11/25

Transfer grilles represent a cost-effective alternative to individual return ducts if they are properly configured for air flow, privacy, and aesthetics.

RR-0103: Water Management — by Joseph Lstiburek — last modified 2008/10/15

This is a concise overview of the principles and steps to follow when dealing with water from the foundation to the roof.

RR-0206: Foundations—Moisture Resistant Construction — by Joseph Lstiburek — last modified 2008/10/16

Builders for many years have put mechanical equipment and ducts in non-living spaces such as crawls and attics primarily to save valuable floor space. Be that as it may (there are lots of good reasons for having this equipment in conditioned spaces, GIVEN proper attention to ventilation and pressurization issues), it makes perfect sense to condition these areas, for a variety of energy, moisture and durability reasons.

RR-0407: Installing a Window with Building Paper on OSB over Wood Frame Wall — by Joseph Lstiburek — last modified 2008/10/20

Details on how to install a window using building paper as the drainage plane

RR-9909: Drainage Planes and Air Spaces — by Joseph Lstiburek — last modified 2008/10/21

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.

RR-9911: Heating Choices — by Joseph Lstiburek — last modified 2008/10/21

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.

RR-9912: Discussion of Ventilation System Energy Performance and Cost — by Armin Rudd — last modified 2010/03/11

An hourly simulation study using DOE2.1E was conducted to determine the annual difference in energy consumption between various ventilation options in different climates.

RR-0304: Central Fan Integrated Supply Ventilation—The Basics — by Armin Rudd — last modified 2008/10/20

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.

RR-0305: Why It's So Important (and Troubling) to Keep Ducts and Equipment in Conditioned Space — by Building Science Corporation — last modified 2008/10/20

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). It’s an important and even driving element for each of the four case studies in this report.

RR-0306: Unvented Roofs, Hot-Humid Climates, and Asphalt Roofing Shingles — by Building Science Corporation — last modified 2008/10/20

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.

RR-0408: The deKieffer Bypass — by Building Science Corporation — last modified 2008/10/20

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.

RR-0506: Vapor Permeance Chart — by Building Science Corporation — last modified 2008/10/20

Good design and practice involve controlling the wetting of building assemblies from both the exterior and interior and different climates require different approaches. This chart lists some common vapor permeance characteristics.

RR-0105: Brick, Stucco, Housewrap and Building Paper — by Joseph Lstiburek — last modified 2008/10/15

The manufacturers of housewraps have for years promoted the fantasy that water vapor in wall assemblies only moves one way – from the inside out. So, therefore, walls should be designed to “breathe” outwards. So, therefore, you should buy a highly vapor permeable housewrap. So, therefore, you should buy “our product.”

RR-0106: Problems with Housewraps — by Joseph Lstiburek — last modified 2008/10/16

The primary function of a housewrap or building paper is rain penetration control. It is not air infiltration despite what the manufacturers say. The energy aspects of housewraps are vastly overstated. They have been embraced by builders for this function as can be evidenced by their market penetration. Yet their critical role in building durability is under appreciated and not marketed. It has been a triumph of marketing over physics.

RR-0207: Residential Ventilation and Latent Loads — by Joseph Lstiburek — last modified 2008/10/16

Adding outdoor air in hot, humid climates causes moisture problems, right? The answer is sometimes. It all depends on the condition of the house before outdoor air is added. In fact, most houses in hot, humid climates are over-ventilated due to duct leakage and induced air change from internal air pressure effects.

RR-0107: Drywall, Wood and Truss Uplift — by Joseph Lstiburek — last modified 2009/04/16

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.

RR-0208: What You Need to Know About Mold — by Joseph Lstiburek — last modified 2008/10/16

This article answers your questions about mold, what it is, where it grows, how it spreads, how can I prevent it.

RR-0007: Advanced Space Conditioning — by Joseph Lstiburek — last modified 2009/04/16

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.

RR-0209: Mold Testing — by Joseph Lstiburek — last modified 2009/04/16

Although this article is titled "Mold Testing" it actually tells you why testing for mold is usually not needed.

RR-0210: Mold Remediation in Occupied Homes — by Joseph Lstiburek — last modified 2009/04/16

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.

RR-0211: Mold—Causes, Health Effects and Clean-up — by Joseph Lstiburek — last modified 2009/04/16

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.

RR-0212: PV Primer — by Building Science Corporation — last modified 2008/10/16

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. Here are the nitty-gritty details of photovoltaic systems. The details are meant to “de-mystify” both the technology and its economics.

RR-0307: Windows and Occupant Comfort — by Building Science Corporation — last modified 2008/10/20

How windows are part of a high performance wall system and what that means to the occupants.

RR-0308: The How and Why of Your High Performance HVAC System — by Building Science Corporation — last modified 2008/10/20

Concise explanation of how a high performance HVAC system works in a high performance home.

RR-0309: Renovating Your Basement — by Building Science Corporation — last modified 2008/10/20

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.”

RR-0409: Painting — by Joseph Lstiburek — last modified 2009/04/16

Exposure to sunlight (ultraviolet radiation) and moisture are the major factors affecting the durability of paint coatings and the durability of the substrate.

RR-0213: Combo Space/Water Heating Systems—"Duo Diligence" — by Building Science Corporation — last modified 2008/06/19

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.

RR-0214: Conditioning Air in the Humid South—Creating Comfort and Controlling Cost — by Building Science Corporation — last modified 2008/10/16

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.

RR-0310: EcoVillage Homeowner Handbook — by Building Science Corporation — last modified 2008/10/20

After a high performance home has been designed, constructed, and commissioned, what ensures that the home is actually operated at peak performance? It takes just 24 easy-reading pages for the homeowner to learn just how simple it is to achieve the full benefits of these particular energy-efficient, comfortable, healthy, and durable homes.

RR-0410: Vapor Barriers and Wall Design — by Joseph Lstiburek — last modified 2009/04/16

Good design and practice involve controlling the wetting of building assemblies from both the exterior and interior and different climates require different approaches.

RR-0411: Vent on Venting — by Joseph Lstiburek — last modified 2009/04/16

Just about everyone in the building industry can be guilty of using building terms loosely, and a prime example is with attics, roof assemblies. Just so that we are all on the same page.

RR-0412: Insulations, Sheathings and Vapor Retarders — by Joseph Lstiburek — last modified 2009/04/16

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. It gets complicated because, sometimes, the best strategies to keep water vapor out also trap water vapor in.

RR-0413a: The Snapshot—A Quick Description — by Building Science Corporation — last modified 2008/10/30

SNAPSHOT stands for Short, Non-destructive Approach to Provide Significant House Operation Thresholds.

RR-0507: Affordable Housing—Toward Zero Energy — by Betsy Pettit — last modified 2008/10/20

A presentation discussing zero energy homes, affordable housing and the available technologies to reach zero energy.

RR-0508: Understanding Green Homes & Durability — by Betsy Pettit — last modified 2008/10/20

Presentation discussing the systems integration approach to energy efficient, durable, sustainable homes.

RR-0509a: Details for Mold-Free Homes — by Betsy Pettit — last modified 2008/10/20

A presentation discussing the causes of house failures due to mold.

RR-0509b: Details for Avoidance of Mold—Foundations — by Betsy Pettit — last modified 2008/10/20

A presentation discussing the details for building a dry foundation.

RR-0509c: Renovating Existing Basements — by Betsy Pettit — last modified 2008/10/20

A presentation discussing the details for renovating existing basements.

RR-0509d: Crawlspaces — by Betsy Pettit — last modified 2008/10/20

A presentation discussing the details for building conditioned crawlspaces.

RR-0509e: Slabs — by Betsy Pettit — last modified 2008/10/20

A presentation discussing the details for building slabs.

RR-0008: Time-Based Scheduling of Residential Ventilation — by Armin Rudd — last modified 2008/10/15

Discussion of the purposes and practices of residential ventilation.

RR-0108: Unvented Roof Systems — by Joseph Lstiburek — last modified 2008/10/16

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.

RR-0109: Sizing and Startup Procedures for Cooling Systems — by Armin Rudd — last modified 2008/10/16

High performance building envelopes deserve high performance comfort conditioning systems. Especially for refrigerant based cooling systems, proper sizing and startup procedures are critical.

RR-0110: HVAC Equipment Sizing Strategies: Taking Advantage of High-Performance Buildings — by Kohta Ueno — last modified 2008/10/16

If you are going to fine-tune your building enclosure, fine-tuning your HVAC system becomes even more important. This presentation covers everything you need to know to right-size your HVAC for better performance, fewer callbacks, and happier customers.

RR-0111: Placement of Ducts and HVAC Systems in Conditioned Space: An Overview — by Kohta Ueno — last modified 2008/10/16

A discussion of the placement of ducts and HVAC equipment inside the conditioned space.

RR-0215: Dehumidification Systems Research Results — by Armin Rudd — last modified 2008/10/16

Moisture is the number one enemy of the durability of a house. Installing controlled mechanical supply ventilation systems, and dehumidification separate from cooling for humid climates is one of the ways to insure durability with respect to moisture.

RR-0216: Special Topics on Residential HVAC — by Armin Rudd — last modified 2008/10/20

Discussion of cyclical trade-offs between building envelope improvements, reduced system size, and more efficient systems.

RR-0217: Building America Pilot Program—Guaranteed Resource- & Energy-Efficiency Now — by Building Science Corporation — last modified 2008/10/20

A performance-based industry collaborative program in which energy, water, and maintenance guarantees can be translated into home buyer savings. The guarantees drive product performance, market demand, and environmental benefit. Collaboration among a wide variety of industry players ensures that the shared benefits of such a bold initiative outweigh the shared risks.

RR-0703: Introducing the market to high-performance building on Hilton Head Island — by Armin Rudd — last modified 2009/04/16

Primarily as a resort location, Hilton Head Island has a somewhat different residential housing market than other more traditional areas.

RR-0704: Building a Durable and Energy Efficient Home in Post-Katrina New Orleans — by Peter Baker — last modified 2009/04/16

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.

RR-0801: Towards Sustainability—Green Building, Sustainability Objectives, and Building America Whole House Systems Research — by Building Science Corporation — last modified 2008/10/20

Green building is growing up in the United States.

RR-0104: Solar Driven Moisture in Brick Veneer — by Joseph Lstiburek — last modified 2009/04/16

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.

RR-9906: Air Handler Leakage Testing—Sierra Air Conditioning, Las Vegas, Nevada — by Stephanie Finegan — last modified 2008/08/14

Duct leakage is a concern in the HVAC field, due to energy consumption, pressure balance problems, bypassing of the filter by leakage air, and contaminant draw from unconditioned spaces. Therefore, certain energy efficiency programs set duct leakage performance requirements that must be met to enter the program. However, the overall duct system tightness is limited by leakage at the air handler.

RR-9906: Air Handler Leakage Testing: Sierra Air Conditioning, La Vegas, Nevada — by Building Science Corporation — last modified 2008/10/27

Duct leakage is a concern in the HVAC field, due to energy consumption, pressure balance problems, bypassing of the filter by leakage air, and contaminant draw from unconditioned spaces. Therefore, certain energy efficiency programs set duct leakage performance requirements that must be met to enter the program. However, the overall duct system tightness is limited by leakage at the air handler.

RR-0602: Field Test of Room-to-Room Uniformity of Ventilation Air Distribution in Two New Houses — by Armin Rudd — last modified 2009/04/16

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. The primary purpose of this field test was to characterize the uniformity of room-to-room ventilation air distribution under various operating conditions by examining multi-zone tracer gas decay curves and calculating local age-of-air.

RR-0802: Field Test of Room-to-Room Distribution of Outside Air with Two Residential Ventilation Systems — by Building Science Corporation — last modified 2008/10/27

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. To characterize outside air distribution in residential buildings, the authors developed a practical methodology adapted from ASHRAE Standard 129. Our methodology includes the examination of multi-zone single tracer gas decay curves, and the calculation of reciprocal local mean age-of-air to allow direct, quantitative comparisons of various ventilation approaches that might be factored into ventilation rate trade-offs in future updates to ASHRAE Standard 62.2. Two types of ventilation systems were tested using this method: single-point exhaust ventilation and central fan integrated supply ventilation. Analysis of the measured data showed that age-of-air analysis worked well to characterize outside air distribution as long as weather conditions were sufficiently steady-state. Test results indicated that ventilation supplied through a central air distribution system was distributed much more uniformly than by a single-point exhaust system. Operation of the air handler at a 33% duty cycle maintained relatively well-mixed conditions regardless of ventilation rate and type of system. For single-point exhaust ventilation, opening bedroom doors appeared to significantly increase the mixing of outside air among rooms, but passive air transfer grilles increased mixing only slightly.

RR-0803: Volatile Organic Compound Concentrations and Emission Rates in New Manufactured and Site-Built Houses — by Armin Rudd — last modified 2008/10/30

Concentrations of 54 volatile organic compounds (VOCs) and ventilation rates were measured in four new manufactured houses over 2 - 9.5 months following installation and in seven new site-built houses 1 -2 months after completion. The houses were in four projects located in hot-humid and mixed-humid climates.

RR-0413b: SNAPSHOT Form — by Building Science Corporation — last modified 2008/10/30

This is a test form used in the Building America program to ascertain house performance and specifications.

RR-0901: Thermal Metrics for High Performance Walls—The Limitations of R-Value — by John Straube — last modified 2009/01/27

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.

RR-0903: Building America Special Research Project—High-R Walls Case Study Analysis — by John Straube and Jonathan Smegal — last modified 2009/08/07

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. More building codes are being modified to require higher levels of thermal control than ever before. 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.

RR-9403: Measure and Predicted Energy Savings from an Industrialized House — by Armin Rudd — last modified 2009/04/14

From the 1994 ACEEE Conference Proceedings. Side-by-side energy testing and monitoring was conducted on two houses in Louisville, KY. Both houses were identical except that one house was constructed with conventional U.S. 2x4 studs and a truss roof while the other house was constructed with stress-skin insulated-core panels for the walls and second floor ceiling. Air-tightness testing included fan pressurization by blower door, hour-long tracer tests using sulphur hexafluoride, and two-week-long time-averaged tests using perfluorocarbon tracers. Thermal insulation quality testing was done by infrared imaging. Pressure differential testing resulted in recommendations to use sealed combustion appliances,and to increase return air flow from closed rooms. By calculation, the conductive building load coefficient (UA) differed by only 2% between the two houses. Heating energy-use monitoring showed savings for the panel house of 12% with electric heating and 15% with gas heating. A comparison of the two monitoring periods showed that the combined efficiency of the gas furnace and air distribution system for both houses was close to 80%. Measured energy-use regression models with Typical Meteorological Year weather data gave a prediction of seasonal energy savings of 16% for electric heating and 19% for gas heating. Seasonal heating energy-use predictions were also made with the DOE2.1E hourly building energy simulation program, which gave savings of 7% for electric heating and 6% for gas heating. The discrepancy between savings predicted by measurement and simulation may be related to rated performance versus field performance of insulation systems. From the data, it appears that this type of industrialized construction has energy efficiency advantages over conventional construction.

RR-0603: Impact Resistance of Advanced Framed Wall Systems with Insulating Sheathing as the Primary Sheathing — by Building Science Corporation — last modified 2009/05/29

Advanced framed wall systems that use 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. The purpose of this research program was to determine the impact resistance performance of advanced framed wall systems with insulating sheathing as the primary sheathing from wind blown debris. With no standards available for testing wall assemblies, a window industry standard ASTM E1886-05 and E1996-05 Missile Level D, Wind Zone 1 and Wind Zone 2 Enhanced Protection and Wind Zone 3 Basic Protection Standard was adopted was used as a starting point for the research. The testing demonstrated two surprising outcomes: 1. None of the walls passed at an impact velocity of 50 fps including the ½” OSB wall, and 2. The high performance wall assembly (1” of insulating sheathing, housewrap, and 2 inches of closed cell spray foam installed in the cavity space) out-performed the baseline house (framed wall with 1/2” OSB sheathing) at a slightly reduced impact velocity of 43 fps. These results indicate that high performance wall assemblies provide equivalent or even better impact performance then standard wall assemblies.

RR-0904: Adhered Veneers and Inward Vapor Drives: Significance, Problems, and Solutions — by John Straube — last modified 2009/06/01

Adhered veneers, in which masonry units are directly attached to a substrate via mortar and ties without a drainage or ventilation gap, have become a very popular finish in residential and light commercial construction. Typical applications apply masonry over a bed of lath-reinforced mortar over a drainage plane (often of building paper or felt). When used over wood- or steel-framed walls, numerous reports of moisture problems and failures have been received.

RR-0503: Rainwater Management Performance of Newly Constructed Residential Building Enclosures — by Joseph Lstiburek — last modified 2009/06/05

 

RR-0406: Face Sealed vs. Drainable EIFS — by Joseph Lstiburek — last modified 2009/06/05

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.

RR-9910: Wood Durability — by Building Science Corporation — last modified 2009/06/05

“We have accepted that design and construction must be responsive to varying seismic regions, wind loads and snow loads. Yet we typically ignore temperature, humidity, rain and the interior climate.” This article puts the durability of wood in the proper context—the environmental context in which we ask it to perform.

RR-0905: Modeled and Measured Drainage, Storage and Drying Behind Cladding Systems — by John Straube and Jonathan Smegal — last modified 2009/08/26

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.

RR-0906: Field Monitoring and Hygrothermal Modeling of Interior Basement Insulation Systems — by John Straube — last modified 2009/08/26

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. The work described here is part of a Canada Mortgage and Housing Corporation (CMHC) sponsored research program to determine the significance or insignificance of potential moisture problems due to an impermeable polyethylene layer in above- and below-grade walls (Wilkinson et al. 2007).

RR-0907: Ventilated Wall Claddings: Review, Field Performance, and Hygrothermal Modeling — by John Straube — last modified 2009/08/26

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. Many common building materials have little safe storage capacity, that is, they cannot be exposed to high levels of moisture for long periods of time.

RR-9913: Case Studies in Resource-Efficient Residential Buildings: The Building America Program — by Betsy Pettit, AIA and Ann Edminster — last modified 2009/08/27

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.

RR-0908: A Method for Modifying Ventilation Airflow Rates to Achieve Equivalent Occupant Exposure — by Aaron Townsend — last modified 2010/03/16

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 method for quantitatively comparing dissimilar ventilation systems has been developed. A calibrated ventilation model was exercised over a range of parameters seen in new and existing housing in the United States. Varied parameters included climate, building enclosure air leakage, presence or absence of a central forced-air space conditioning system, ventilation system type, ventilation airflow rate, and contaminant generation locations. A baseline exposure was established based on the ASHRAE Standard 62.2-2007 ventilation rate using a fully-ducted balanced ventilation system as the reference system and a moderately airtight building enclosure (3.5 ach50). A ventilation airflow coefficient was then determined for each ventilation system such that the occupant exposure using the subject ventilation system was equal to the occupant exposure using the reference system at the baseline ventilation rate. These coefficients can be used to compare the effectiveness of different ventilation systems.

RR-0909: A Calibrated Multi-Zone Airflow Model for Extension of Ventilation System Tracer Gas Testing — by Aaron Townsend — last modified 2010/03/16

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. Replicate in-field tracer gas decay measurements of a new 2-story, 2600 ft2 (240 m2), single-family house in Sacramento, CA under different whole-house dilution ventilation scenarios. The model incorporated measured values of ventilation system airflow rate, building enclosure leakage, fan-forced mixing between floor levels, indoor and outdoor temperature, and wind speed and direction. The enclosure leakage distribution was adjusted to tune the model to the measured tracer gas concentration data. The calibrated model was then used to compare different ventilation systems under identical outdoor conditions over a one-day period. Zones that received more ventilation air had faster concentration decay rates compared to zones that received less ventilation air. Results showed that ventilation systems that delivered air to all zones, either by a dedicated duct system or by incorporation of the central forced-air space conditioning system, had more uniform ventilation air distribution.

RR-9001: Description of an Indoor Test Facility for Evaluating a Roof Integrated Cooling Concept — by Armin Rudd — last modified 2009/10/16

An advanced roof test facility has been designed, constructed, debugged and made operational at the Florida Solar Energy Center. The facility operational at the Diurnal Test Facility and was designed to provide high quality data which could be used for verification and improvement of the analytical model of the desiccant enhanced radiant cooling (DESRAD) concept. 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.

RR-9404: Measured and Predicted Energy Savings from an Industrialized House — by Armin Rudd — last modified 2009/10/16

Side-by-side energy testing and monitoring was conducted on two houses in Louisville, KY. Both houses were identical except that one house was constructed with conventional U.S. 2x4 studs and a truss roof while the other house was constructed with stress-skin insulated-core panels for the walls and second floor ceiling. Air-tightness testing included fan pressurization by blower door, hour-long tracer tests using sulphur hexafluoride, and two-week-long time-averaged tests using perfluorocarbon tracers. Thermal insulation quality testing was done by infrared imaging. Pressure differential testing resulted in recommendations to used sealed combustion appliances, and to increase return air flow from closed rooms. By calculation, the conductive building load coefficient (UA) differed by only 2% between the two houses. Heating energy-use monitoring showed savings for the panel house of 12% with electric heating and 15% with gas heating. A comparison of the two monitoring periods showed that the combined efficiency of the gas furnace and the air distribution system for both houses was close to 80%. Measured energy-use regression models with Typical Meterological Year weather data gave a prediction of seasonal energy savings of 16% for electric heating and 19% for gas heating. Seasonal heating energy-use predictions were also made with the DOE2.1E hourly building energy simulation program, which gave savings of 7% for electric heating and 6% for gas heating. The discrepancy between savings predicted by measurement and simulation may be related to rated performance versus field performance of insulation systems. From the data, it appears that this type of industrialized construction has energy efficiency advantages over conventional construction.