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 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, Sravanthi Musunuru

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, Sravanthi Musunuru

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.

Building America Reports
Sravanthi Musunuru, Betsy Pettit

This Measure Guideline describes a deep energy enclosure retrofit (DEER) solution for insulating mass masonry buildings from the interior. It describes the retrofit assembly, technical details, and installation sequence for retrofitting masonry walls. Interior insulation of masonry retrofits has the potential to adversely affect the durability of the wall; this document includes a review of decision criteria pertinent to retrofitting masonry walls from the interior and the possible risk of freeze-thaw damage.

Building America Reports
Honorata Loomis, Betsy Pettit

This Measure Guideline describes a deep energy enclosure retrofit (DEER) solution that provides insulation to the interior of the wall assembly with the use of a double stud wall. The guide describes two approaches to retrofitting the existing walls: one involving replacement of the existing cladding, and the other that leaves the existing cladding in place. It discusses the design principles related to the use of various insulation types, and provides strategies and procedures for implementing the double stud wall retrofit. It also evaluates important moisture-related and indoor air quality measures that need to be implemented to achieve a durable, high performance wall.

Building America Reports
Honorata Loomis, Betsy Pettit

This Measure Guideline provides design and construction information for a deep energy enclosure retrofit (DEER) solution of a flat roof assembly. It describes the strategies and procedures for an exterior retrofit of a flat, wood-framed roof with brick masonry exterior walls, using exterior and interior (framing cavity) insulation. The approach supported in this guide could also be adapted for use with flat, wood-framed roofs with wood-framed exterior walls. This Measure Guideline demonstrates techniques for retrofitting flat roofs from the exterior, which is less disruptive to the living space and allows the structure to remain occupied during the project. It also illustrates a solution for preparing homes to become zero energy ready.

Building America Reports
Ken Neuhauser

This Measure Guideline describes a high performance enclosure retrofit package that uses mineral fiber insulating sheathing. It describes retrofit assembly and details for wood frame roof and walls and for cast concrete foundations. Exterior insulation retrofit is important to the goal of net zero energy ready homes. Mineral fiber insulating sheathing can provide enhanced moisture durability for the exterior enclosure. Mineral fiber also represents a viable solution for high performance home builders, designers, and clients who wish to use an alternative to foam plastic insulation.

Building America Reports
Kohta Ueno

Double-stud walls insulated with cellulose or low-density spray foam can have high R-values; compared to approaches using exterior insulating sheathing, double-stud walls are typically less expensive, and have exterior details similar to typical construction. However, double stud walls have higher risks of interior-sourced wintertime condensation damage. Field monitoring was installed in a Zone 5A climate house with 12” thick double stud walls; assemblies included 12” open cell polyurethane spray foam, 12” netted and blown cellulose, and 5-½” open cell spray foam at the exterior of the stud bay. Data were collected for three winters.

Cold
Building America Reports
Kohta Ueno, Joseph Lstiburek

In cold climates, a common practice of the weatherization industry is to retrofit compact roof/ceiling assemblies with blown-in dense-pack cellulose. However, this assembly has high moisture and durability risks (due to wintertime interior-sourced condensation) and violates building code. Developing methods to retrofit dense pack insulation into compact roof assemblies while controlling moisture risks would allow for widespread application of this lowcost technique without potentially compromising building durability. In hot-humid climates, HVAC equipment is typically located in vented, unconditioned attics, with associated energy penalties; one method of moving the ductwork inside the conditioned space is to insulate at the roof deck. However, market penetration of this method has been slow, due to the expense of insulating at the roof line, typically using polyurethane spray foam. If roof assemblies with fibrous insulation could be developed that control moisture risks, this would likely reduce the first cost of unvented roofs, potentially increasing their adoption.

ColdHot-Humid
Building America Reports
Joseph Lstiburek, Christopher Schumacher, M.J. Fox

In 2011, Building Science Corporation completed research work to support the development of standards for testing the airflow resistance of insulation materials used in dense-pack retrofit applications. Recently mineral fiber insulation (MFI) materials have also been developed and/or suggested for dense-pack retrofit applications. Testing is needed to support the inclusion of MFI in new dense-pack air resistance standards. This report documents airflow resistance test results for dense-pack retrofit applications using mineral fiber insulation (MFI) materials (i.e., glass fiber and stone wool). The test results are compared to previous airflow resistance tests for dense-pack retrofit applications using 10 different cellulose fiber insulation (CFI) materials.

Building America Reports
Kohta Ueno, Honorata Loomis

This report covers the long-term performance of mini-split heat pumps (MSHPs) in Massachusetts (Zone 5A); it is the culmination of up to three years’ worth of monitoring in a set of eight houses. This research examined electrical use of MSHPs, distributions of interior temperatures and humidity when using simplified (two-point, one per floor) heating systems in high-performance housing, and the impact of door open/closed status on temperature distributions. The use of simplified space conditioning distribution (MSHPs) provides significant first cost savings, which are used to offset the increased investment in the building enclosure.

Cold
Building America Reports
Joseph Lstiburek, Peter Baker

This measure guideline provides information regarding the design and construction of wall assemblies that are using thick layers of rigid exterior insulation (in excess of 1.5 inches) that require a secondary cladding attachment location exterior of the insulation to be provided. The document is separated into several distinct sections that cover: 1) fundamental building science principles relating to the use of exterior insulation on wall assemblies, 2) design principles for tailoring the use to the specific project goals and requirements, and 3) construction detailing to help with the understanding of how the various elements of the design are implemented.

Building America Reports
Betsy Pettit

Of the various measures that can drive building performance towards net zero, passive measures are the most preferable. They result in durable construction, increased comfort, health, and resiliency, and are the most cost-effective, up to a point. In the larger picture, conservation plays a critical role in scenarios trying to shift the current energy economy towards a sustainable energy economy. Stringent conservation guidelines are necessary in addition to the aggressive build out of renewable energies so that the targets can be met. In late 2011, a volunteer Technical Committee (TC) was formed at PHIUS, and was tasked to work on standard adaptation, among other things. The involvement of the committee set the frame for the work reported here.

Building America Reports
Peter Baker

Changes in the International Energy Conservation Code (IECC) from 2009 to 2012 have resulted in an increase in minimum insulation levels required for residential building. Not only are the levels increased, but the use of exterior rigid insulation has become part of the prescriptive code requirements. With more jurisdictions adopting the 2012 IECC builders are going to find themselves required to incorporate exterior insulation in the construction of their exterior wall assemblies. This research is an extension on the previous research that has provided significant insight into the mechanics as well as long term performance of exposed assemblies that use wood furring strips attached through the insulation back to the structure to provide a cladding attachment location.

Building America Reports
Kohta Ueno, Joseph Lstiburek

Hygrothermal simulations such as WUFI are coming into increasingly common use among building science researchers and practitioners, architects and designers, and energy analysts. Such simulations have been shown to be powerful and validated tools. However, with increasing dissemination of these types of modeling tools–most notable WUFI–less-experienced or less-informed practitioners have run models that provide unrealistic results. Therefore, Building Science Corporation led a Building America Expert Meeting where presenters from national laboratories, consulting firms, and building material manufacturers presented on their research, followed by a group discussion on various topics.

Building America Reports
Phil Kerrigan

BSC worked directly with the David Weekley Homes (DWH) – Houston division to redesign three current floor plans in order to locate the heating, ventilation, and air conditioning (HVAC) system in conditioned space. The purpose of this project is to develop a cost-effective design for moving the HVAC system into conditioned space. In addition, BSC conducted energy analysis to calculate the most economical strategy for increasing the energy performance of future production houses. This is in preparation for the upcoming code changes in 2015. The builder wishes to develop an upgrade package that will allow for a seamless transition to the new code mandate.

Hot-Humid
Building America Reports
Cathy Gates, Ken Neuhauser

Between December of 2009 and December of 2012, participants in a deep energy retrofit (DER) pilot program sponsored by National Grid and conducted in Massachusetts and Rhode Island completed 42 DER projects. Building Science Corporation (BSC) provided technical support to program participants and verification of measures for the program sponsor, National Grid. The pilot program required aggressive upgrades to building enclosure systems, implementation of ventilation and combustion safety measures and also provided incentives to upgrade mechanical systems. Thirty-seven of the projects completed through the pilot were comprehensive retrofits while five were partial DERs. The collection of 42 DER projects represents 60 units of housing.

Pages