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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.

Research Reports
Betsy Pettit

As materials and equipment have improved, energy reduction as a goal has increasingly been replaced with the goal of net-zero energy use. But the general approach to building energy efficient homes that has been recommended has always been the same. This approach to achieving net-zero energy homes is reflected in the ten general principles for the design of net-zero energy capable houses that are presented and discussed in the first part of this paper. In the second part of the paper, specific strategies and details are described that were used for the design of the Net Zero Energy Residential Test Facility (NZERTF), a NIST laboratory in the form of a typical residence for a family of four that has been constructed on the NIST campus in Gaithersburg, MD.

Research Reports
Jonathan Smegal, John Straube

This report is an extension of a previous analysis study titled “RR-1014: High R Walls for the Pacific Northwest – A Hygrothermal Analysis of Various Exterior Wall Systems”, conducted by BSC for Walsh Construction, dated June 1, 2010 that examined the predicted thermal and hygrothermal performance of 17 different wall assemblies in Portland, Oregon.

Marine
Research Reports
Jonathan Smegal, John Straube

This report considers a number of promising wall systems that can meet the requirement for better thermal control. Unlike previous studies, this one considers performance in a more realistic matter, including some two- and three-dimensional heat flow and analysis of the relative risk of moisture damage.

Marine
Research Reports
John Straube

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. As the building industry strives to reduce energy consumption for environmental and economic reasons, building enclosures with high thermal performance, reliably and affordably installed in the field are required. The R-value was developed over 50 years ago to provide users and specifiers of insulation with and easy-to-compare, repeatable measure of insulation performance. The strength of the R-value is that it is simple to measure, easy to communicate, and widely accepted.

Published Articles
Betsy Pettit

Can a 150-year-old house approach zero energy use? Three case studies point the was from the 19th to the 21st century. Reprinted with permission from Fine Homebuilding, April/May 2008, pages 51-57.

Cold
Guides and Manuals
Betsy Pettit, Ken Neuhauser, Cathy Gates
The purpose of this guide is to provide useful examples of high performance retrofit techniques for the building enclosure of wood frame residential construction in a cold and somewhat wet climate....
Cold
Conference Papers
Kohta Ueno

Exterior insulation retrofit is a reasonable step if a recladding of the building is already being done for aesthetic or ongoing maintenance reasons. This paper presents many of the lessons learned from superinsulation retrofit experiences, including overall enclosure strategies, such as air barriers, drainage planes, and moisture control. Several case-specific solutions to particular problems are described, including exterior air barrier approaches, wall sill replacement, and several approaches dealing with window penetrations. In addition, detailing recommendations and economic analysis of these measures are presented. Hygrothermal simulations were run to evaluate the changes in sensitivity to moisture intrusion due to these retrofit measures.

Cold
Building Science Insights
Joseph Lstiburek
Simple physics…complicated language“Code world” is an interesting place where seemingly convoluted language is used to express simple concepts in clearly complicated ways.  The reasons for this are...
Building Science InsightsNewsletters
Joseph Lstiburek
Chicago is well known for a bunch of things—among them a baseball team that does not win, fabulous pizza1, and uninsulated masonry buildings. The Windy City2 does not want to be known for its...
Building Science InsightsNewsletters
Joseph Lstiburek
I remember sitting around listening to stories my dad and his friends would tell when they were hanging around in the basement playing cards. They would laugh uproariously, tease each other, get...
Building Science InsightsNewsletters
Joseph Lstiburek
It was the ants that finally did it.1 It wasn’t the shingles that needed to be replaced. It wasn’t the three-dimensional airflow network in the roof assembly. It wasn’t the lack of racking...
Building Science Insights
Joseph Lstiburek
North of the Arctic Circle there are only two seasons—this winter and last winter. Who would ever want to live there? Being human, we can’t help ourselves. We’ve been there a long time. And, we are...
Very Cold
Building Science Insights
Joseph Lstiburek
You have got to love salesmen. They figure things out way before physicists, usually before engineers and certainly before greenie weenies. Harry Tschumi and Les Blades,1 a pair of salesmen from...
Building Science Digests
Betsy Pettit

The American Foursquare, a Sears, Roebuck & Co. kit home, was a staple of small American towns between 1908 and 1940. More than 100,000 of them were built in America. Homes built prior to 1980 make up 80% of the housing stock in the United States, and are responsible for a majority of the residential energy use in the country. All of the renovations used systems engineering principles to ensure good indoor air quality and longterm durability while providing deep energy reductions.

Cold
Building America Reports
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
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
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
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.

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