Fill in the search criteria to search the database or view index of all documents.

climates

Very Cold - A very cold climate is defined as a region with approximately 9,000 heating degree days or greater (65°F basis) or greater and less than 12,600 heating degree days (65°F basis).

Cold - A cold climate is defined as a region with approximately 5,400 heating degree days (65°F basis) or greater and less than approximately 9,000 heating degree days (65°F basis).

Mixed-Humid - A mixed-humid and warm-humid climate is defined as a region that receives more than 20 inches of annual precipitation with approximately 4,500 cooling degree days (50°F basis) or greater and less than approximately 6,300 cooling degree days (50°F basis) and less than approximately 5,400 heating degree days (65°F basis) and where the average monthly outdoor temperature drops below 45°F during the winter months.

Hot-Humid - A hot-humid climate is defined as a region that receives more than 20 inches of annual precipitation with approximately 6,300 cooling degree days (50°F basis) or greater and where the monthly average outdoor temperature remains above 45°F throughout the year. This definition characterizes a region that is similar to the ASHRAE definition of hot-humid climates where one or both of the following occur:

  • a 67°F r higher wet bulb temperature for 3,000 or more hours during the warmest six consecutive months of the year; or
  • a 73°F or higher wet bulb temperature for 1,500 or more hours during the warmest six consecutive months of the year.

Hot-Dry/Mixed-Dry - A hot-dry climate is defined as region that receives less than 20 inches of annual precipitation with approximately 6,300 cooling degree days (50°F basis)or greater and where the monthly average outdoor temperature remains above 45°F throughout the year.

A warm-dry and mixed-dry climate is defined as a region that receives less than 20 inches of annual precipitation with approximately 4,500 cooling degree days (50°F basis) or greater and less than approximately 6,300 cooling degree days (50°F basis) and less than approximately 5,400 heating degree days (65°F basis) and where the average monthly outdoor temperature drops below 45°F during the winter months.

Marine - A marine climate meets is defined as a region where all of the following occur:

  • a mean temperature of the coldest month between 27°F and 65°F;
  • a mean temperature of the warmest month below 72°F;
  • at least four months with mean temperatures over 50°F; and
  • a dry season in the summer, the month with the heaviest precipitation in the cold season has at least three times as much precipitation as the month with the least precipitation.

information

Building Science Insights are short discussions on a particular topic of general interest. They are intended to highlight one or more building science principles. The discussion is informal and sometimes irreverent but never irrelevant.

Building Science Digests provide building professionals from different disciplinary backgrounds with concise overview of important building science topics. Digests explain the theory behind each topic and then translate this theory into practical information.

Published Articles aare a selected set of articles written by BSC personnel and published in professional and trade magazines that address building science topics. For example, our work has appeared in Fine Homebuilding, Home Energy, ASHRAE's High Performance Buildings, The Journal of Building Enclosure Design and The Journal of Building Physics. We thank these publications for their gracious permission to republish.

Conference Papers are peer-reviewed papers published in conference proceedings.

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.

Building America Reports are technical reports funded by the U.S. Department of Energy (DOE) Building America research program.

Designs That Work are residential Case Studies and House Plans developed by BSC to be appropriate for residential construction in specific climate zones. Case Studies provide a summary of results for homes built in partnership with BSC’s Building America team. The case study typically includes enclosure and mechanical details, testing performed, builder profile, and unique project highlights. House Plans are fully integrated construction drawing sets that include floor plans, framing plans and wall framing elevations, exterior elevations, building and wall sections, and mechanical and electrical plans.

Enclosures That Work are Building Profiles and High R-Value Assemblies developed by BSC to be appropriate for residential construction in specific climate zones. Building Profiles are residential building cross sections that include enclosure and mechanical design recommendations. Most profiles also include field expertise notes, material compatibility analysis, and climate challenges. High R-Value Assemblies are summaries of the results of BSC's ongoing High R-Value Enclosure research — a study that BSC has undertaken for the U.S. Department of Energy (DOE) Building America research program to identify and evaluate residential assemblies that cost-effectively provide 50 percent improvement in thermal resistance.

Guides and Manuals are "how-to" documents, giving advice and instructions on specific building techniques and methods. Longer guides and manuals include background information to help facilitate a strong understanding of the building science behind the hands-on advice. This section also contains two quick, easy-to-read series. The IRC FAQ series answers common questions about the building science approach to specific building tasks (for example, insulating a basement). The READ THIS: Before... series offers guidelines and recommendations for everyday situations such as moving into a new home or deciding to renovate.

Information Sheets are short, descriptive overviews of basic building science topics and are useful both as an introduction to building science and as a handy reference that can be easily printed for use in the field, in a design meeting, or at the building permit counter. Through illustrations, photographs, and straightforward explanations, each Information Sheet covers the essential aspects of a single topic. Common, avoidable mistakes are also examined in the What's Wrong with this Project? and What's Wrong with this Practice? mini-series.

Building Science Digests
John Straube

The control of air flow is important for several reasons: to control moisture damage, reduce energy losses, and to ensure occupant comfort and health. Airflow across the building enclosure is driven by wind pressures, stack effect, and mechanical air handling equipment like fans and furnaces. A continuous, strong, stiff, durable and air impermeable air barrier system is required between the exterior and conditioned space to control airflow driven by these forces.

Building Science Digests
John Straube

Driving rain deposition is quantitatively the largest single source of moisture for most walls and roofs leading to building enclosure deterioration. Controlling rain penetration is, therefore, one of the most important parts of a successful moisture control strategy which involves understanding and predicting moisture movement within and through the enclosure to improve building enclosure performance, particularly durability. This document will consider rain control from a general to a specific level. The following sections will cover: basic moisture control principles that should be employed in the design of above-grade building enclosures; driving rain as a moisture load on walls; a classification system of the various rain control strategies available for walls; and finally, good design practices for walls.

Building Science Digests
Joseph Lstiburek

Moisture accumulates when the rate of moisture entry into an assembly exceeds the rate of moisture removal. When moisture accumulation exceeds the ability of the assembly materials to store the moisture without significantly degrading performance or long-term service life, moisture problems result.

Building Science Digests
John Straube

Providing thermal comfort without excess space conditioning costs is one of the primary requirements of buildings. Therefore, thermal control is an important aspect in almost all buildings. Understanding heat transfer and the temperature distribution through building materials and assemblies is also important for assessing energy use, thermal comfort, thermal movements, durability, and the potential for moisture problems. The control of heat flow in buildings requires insulation layers compromised with few thermal bridges, an effective air barrier system, good control of solar radiation, and management of interior heat generation.

Building Science Digests
John Straube

Predicting the future is very difficult, but examining trends and potential tipping points is useful as an aid to understanding the direction the building industry is headed, and where it might end up. Although some future changes can only be speculated upon, other trends are already occurring and causing changes. Below is a series of changes and possible changes that may influence the building industry and society.

Building Science Digests
John Straube

Historical works, notably the Roman Vetruvius’ Ten Books of Architecture, that describe buildings begin with an historical overview.  Archaeological and anthropological studies have furthered this understanding. The history of the built form and the building enclosure is more than just a curiosity: understanding the history helps explain many of the buildings types, construction techniques and building materials that we use today. This digest provides a brief overview of the development of the building enclosure and can serve as an entry point into a deeper historically-informed study of buildings and building science.

Building Science Digests
John Straube

When I see a fully glazed, floor-to-ceiling commercial or institutional building, I see an energy-consuming nightmare of a building that requires lots of heating and cooling at the perimeter just to...
Building Science Digests
John Straube

The construction and operation of buildings consumes over a third of the world’s energy consumption, and 40% of all the mined resources. Striving to make buildings more sustainable, while saving construction and operating costs and improving health and occupant well being is not only possible and practical, it should be the goal of the building industry. Achieving this goal requires an awareness of the problem and the skills to design, specify, construct, and operate buildings in a manner that is often quite different from current standard approaches. This digest will review the challenge of sustainability, discuss methods of assessing green buildings, and recommend a process by which more sustainable buildings can be delivered.

Building Science Digests
John Straube

The future of energy is particularly unclear at present. Will the cost of oil rocket back to $150 per barrel or languish at $40? Will the cost of clean renewable energy generated by photovoltaic’s...
Building Science Digests
John Straube

The environmental crisis, and hence green building design, revolve around a wide range of issues: habitat destruction, stormwater run-off, air pollution, climate change, and resource use. However,...
Building America Reports
Joseph Lstiburek

Since we use gas hot water heaters for space heating in some of our Building America houses we thought it appropriate that we weigh in on the discussion relating to using gas hot water heaters for space heating. We do not believe they are bad choices, nor do we believe they should be outlawed by the code. 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.  

Building America Reports
Armin Rudd, Joseph Lstiburek

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.

Building America Reports
Armin Rudd

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.

Hot-Dry/Mixed-Dry
Building America Reports
Kohta Ueno

The purpose of this report is to disseminate the findings from a needs assessment of issues related to attic insulation retrofits in manufactured homes that meet building codes specified by the U.S. Department of Housing and Urban Development (HUD-code) as installed by DOE’s Weatherization Assistance Program (WAP). The original design for this research was developed by the Building Science Corporation (BSC) Building America team with input from WAP stakeholders. As part of the evaluation plan development, the design team consulted with and received feedback from various stakeholders involved with WAP, the HUD-code manufactured housing industry, and residential building science research. 

Building America Reports
Kohta Ueno, Joseph Lstiburek

This research is a test implementation of an unvented tile roof assembly in a hot-humid climate (Orlando, FL; Zone 2A), insulated with air permeable insulation (netted and blown fiberglass). Given the localized moisture accumulation and failures seen in previous unvented roof field work, it was theorized that a “diffusion vent” (water vapor open, but air barrier “closed”) at the highest points in the roof assembly might allow for the wintertime release of moisture, to safe levels. The “diffusion vent” is an open slot at the ridge and hips, covered with a water-resistant but vapor open (500+ perm) air barrier membrane. As a control comparison, one portion of the roof was constructed as a typical unvented roof (self-adhered membrane at ridge).

Hot-Humid
Building America Reports
Joseph Lstiburek, Kohta Ueno

This Technical Report describes the modeling of typical wall assemblies that have performed well historically in various climate zones. The provided information can be generalized for application to a broad population of houses, within the limits of existing experience. WUFI software model was calibrated or “tuned” using wall assemblies with historically successful performance. Running the rainwater and airflow “tuned” WUFI software model generated the library of input data and results presented. The results agree with historical experience of these assemblies constructed in the climate zones modeled. The files present various custom settings that will help avoid results that will require overly conservative enclosure assemblies.

Building America Reports
Joseph Lstiburek, Kohta Ueno

This Measure Guideline describes how to model and interpret results of models for above grade walls. It analyzes the failure thresholds and criteria for above grade walls. A library of above-grade walls with historically successful performance was used to calibrate WUFI (Wärme und Feuchte instationär) software models. The information is generalized for application to a broad population of houses within the limits of existing experience.

Building America Reports
Kohta Ueno

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 (and wet) climates may cause performance and durability problems.  Some concerns, such as condensation and freeze-thaw have known solutions.  But wood members embedded in the masonry structure will be colder (and potentially wetter) after an interior insulation retrofit. Moisture content & relative humidity were monitored at joist ends in historic mass brick masonry walls retrofitted with interior insulation in a cold climate (Zone 5A); data were collected from 2012-2015.  Eleven joist ends were monitored in all four orientations.

Building America Reports
Joseph Lstiburek

The measure guideline provides ventilation guidance for residential high performance mulitfamily construction that incorporates the requirements of the ASHRAE 62.2 2013 standard. The measure guideline focus is on the decision criteria for weighing cost and performance of various ventilation systems. The document is intended for contractors, builders, developers, designers and building code officials. The guide may also be helpful to building owners wishing to learn more about ventilation strategies available for their buildings. The measure guideline includes specific design and installation instructions for the most cost effective and performance effective solutions for ventilation in multifamily units that satisfies the requirements of ASHRAE 62.2 2013.

Building America Reports
Kohta Ueno, Joseph Lstiburek

The 2012 IECC has an airtightness requirement of 3 air changes per hour at 50 Pascals test pressure for both single family and multifamily construction in Climate Zones 3-8. Other programs have similar or tighter compartmentalization requirements, thus driving the need for easier and more effective methods of compartmentalization in multifamily buildings. Firewalls, demising walls, or area separation walls have been identified as the major source of difficulty in air sealing/compartmentalization, particularly in townhouse construction. The current research examined the use of the taping of exterior sheathing details to improve air sealing results in townhouse and multifamily construction, when coupled with better understanding of air leakage pathways.

Pages