http://www.buildingscience.com daily 1 2010-02-15T02:42:46Z http://www.buildingscience.com/documents/guides-and-manuals/gm-attic-air-sealing-guide Attics should be air sealed prior to adding insulation. Adding insulation alone does not save much energy and can lead to health and durability problems. The intent of this guide is to provide information for the preparation work necessary prior to adding attic insulation. No publisher Joseph Lstiburek doc-GuideManual resources-low-energy Building America Retrofit 2013-05-02T13:46:55Z BSC File http://www.buildingscience.com/documents/digests/bsd-011-thermal-control-in-buildings 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. Heat flow occurs through the building enclosure via opaque enclosure elements, is directly transferred into the building by solar radiation through windows, is carried along with air across the enclosure by unintentional leakage and ventilation, and can be generated within the building by occupants and their activities. 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. No publisher John Straube Building Science Digests are information articles intended for professionals. The author and the publisher of this article have used their best efforts to provide accurate and authoritative information in regard to the subject matter covered. The author and publisher make no warranty of any kind, expressed or implied, with regard to the information contained in this article. The information presented in this article must be used with care by professionals who understand the implications of what they are doing. If professional advice or other expert assistance is required, the services of a competent professional shall be sought. The author and publisher shall not be liable in the event of incidental or consequential damages in connection with, or arising from, the use of the information contained within this Building Science Digest. guidance-Enclosure design principles condensation airflow-Indoor Air Quality durability air barrier doc-Digest resources-low-energy residential ventilation ASHRAE airflow-Airtightness/Air barrier airflow-Wind washing 2013-04-02T23:50:17Z BSC Article http://www.buildingscience.com/documents/digests/bsd-139-deep-energy-retrofit-of-a-sears-roebuck-house-a-home-for-the-next-100-years 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. This posting is permission of ASHRAE. Additional reproduction, distribution, or transmission in either print or digital form is not permitted without ASHRAE's prior written permission. No publisher Betsy Pettit, FAIA moisture-Diffusion/Vapor Pressure airflow-Indoor Air Quality deep energy retrofit moisture-Vapor Permeance ASHRAE doc-Digest resources-low-energy doc-PublishedArticle Retrofit 2013-03-03T02:56:58Z BSC Article http://www.buildingscience.com/documents/digests/bsd151-understanding-primary-source-site-energy The difference between site and source energy is a vital concept to understand when looking at the energy performance of buildings—failing to account for the difference will result in an apples-to-oranges comparison that does not give the true picture of a building’s energy consumption. This document explains how these two types of energy are accounted for differently and why. No publisher Kohta Ueno/John Straube site energy global warming potential electricity doc-Digest resources-low-energy Building America source energy carbon emissions power grid 2013-03-06T18:55:42Z BSC Article http://www.buildingscience.com/documents/digests/bsd152-building-energy-performance-metrics Putting metrics on building energy performance is a required step to make any progress on low-energy use and/or “green” buildings. However, there are many confusing and contradictory metrics available; to speak a common language, it is necessary to understand the topics that are behind these measurements. These topics include site vs. source energy, modeled results vs. reality, US average energy use figures, and methods of normalizing energy use. The normalization of energy use intensity (EUI), or dividing by square footage is examined; several significant problems in applying this metric to residential use are demonstrated. Various other metrics are presented, as well as a proposed method to provide all of the useful building energy information in a format that allows normalization by any chosen metric. No publisher Kohta Ueno mileage box analysis-Modelling Tools energy doc-Digest resources-low-energy Building America 2013-04-02T23:52:19Z BSC Article http://www.buildingscience.com/documents/insights/bsi-005-a-bridge-too-far An edited version of this Insight first appeared in the ASHRAE Journal. Thermal Bridges—steel studs, structural frames, relieving angles and balconies. No publisher Joseph Lstiburek moisture-Drainage plane resources-technical doc-Insight resources-low-energy ASHRAE airflow-Airtightness/Air barrier thermal-Thermal Bridging 2013-03-20T20:28:01Z BSC Article http://www.buildingscience.com/documents/insights/bsi-006-can-fully-glazed-curtainwalls-be-green 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 maintain comfort. The result, on a cold winter day, is that offices exposed to the sun require cooling, while those in the shade need heat. No publisher John Straube guidance-Windows thermal-Insulation radiation doc-Insight resources-low-energy 2013-01-25T18:25:18Z BSC Article http://www.buildingscience.com/documents/insights/bsi-007-prioritizing-green-it-s-the-energy-stupid An edited version of this Insight first appeared in the ASHRAE Journal. Many “green” buildings don’t save energy. Why? They have too much glass, they are over-ventilated, they are leaky to air, they are fraught with thermal bridges and they rely on gimmicks and fads rather than physics. No publisher Joseph Lstiburek guidance-Enclosure design principles airflow-Indoor Air Quality doc-Insight moisture-Convection/Air barriers resources-low-energy ASHRAE airflow-Airtightness/Air barrier 2013-03-06T17:31:36Z BSC Article http://www.buildingscience.com/documents/insights/bsi-012-why-energy-matters This article was first published in "Perspectives," Volume 17, Number 1. Spring 2009. The on-going consumption of energy to operate, condition, and light a building, as well as the energy embodied in on-going maintenance is the largest single source of environmental damage and resource consumption due to buildings. Reducing the operational energy use and increasing durability should be the prime concerns of architects who wish to design and building “green” buildings. No publisher John Straube guidance-Windows durability resources-technical doc-Insight resources-homeowner environment LEED resources-low-energy ASHRAE climate-Building design and climate 2013-05-24T19:20:12Z BSC Article http://www.buildingscience.com/documents/insights/bsi-014-deciding-on-energy-priorities-when-building-new The future is uncertain. This is a truism, and yet, when we design and construct a new building, we need to make decisions in the present or very near future. In fact, this is one of the critical distinctions about designing buildings: they are expected and likely to last 50 to 100 years, but we build them now. The challenge of designing for the future is no more acute than in the current choices facing the designer of an environmentally friendly building. No publisher John Straube guidance-Enclosure design principles ERV durability energy HRV guidance-Windows doc-Insight resources-low-energy photovoltaics liquid natural gas (LNG) 2013-03-06T17:30:34Z BSC Article http://www.buildingscience.com/documents/insights/bsi-020-energy-security-and-saving-the-planet An edited version of this Insight first appeared in the ASHRAE Journal. Energy security is pretty easy to get a handle on—don’t buy oil from the Middle East, Russia, Nigeria and Venezuela. The problem is that it is not cheap energy and it is not clean energy. We can make it clean, and we will, but it will be even more expensive. And actually that is good because we won’t waste it when it is expensive. No publisher Joseph Lstiburek guidance-Enclosure design principles ASHRAE relative humidity green buildings resources-low-energy doc-Insight green design resources-mold 2012-04-03T17:51:01Z BSC Article http://www.buildingscience.com/documents/insights/bsi-022-the-perfect-hvac All space-conditioning systems are intended to provide a comfortable and healthy indoor environment. But the fact is, the the most popular residential furnace/AC systems and commercial VAV systems are fundamentally flawed from their conception. No publisher John Straube guidance-Enclosure design principles ERV subsystems-HVAC airflow-Indoor Air Quality subsystems-HVAC-air handlers HRV doc-Insight resources-low-energy comp-mechanical relative humidity 2013-03-06T18:53:02Z BSC Article http://www.buildingscience.com/documents/insights/bsi-025-the-passivhaus-passive-house-standard This Insight reviews the Passivhaus (PH) low-energy house standard and briefly compares it to other cold climate low energy house standards, such as the Building America program, Energy Star, and R2000 homes. No publisher John Straube guidance-Enclosure design principles doc-Insight moisture-Convection/Air barriers resources-low-energy Building America airflow-Airtightness/Air barrier 2012-07-27T03:29:38Z BSC Article http://www.buildingscience.com/documents/insights/bsi-026-passivhaus-becomes-active-further-commentary-on-passivhaus This Insight is in response to questions from clients and interested members of the public and academia, I have recently written about some aspects of the German PassivHaus housing standard as it applies to cold climates. No publisher John Straube guidance-Enclosure design principles HRV doc-Insight resources-low-energy ASHRAE 2013-03-28T04:14:22Z BSC Article http://www.buildingscience.com/documents/insights/bsi-028-energy-flow-across-enclosures An edited version of this Insight first appeared in the ASHRAE Journal. Higher levels of thermal resistance and reduced heat gain across building enclosures has forever changed the performance of buildings—and not necessarily in a good way. No publisher Joseph Lstiburek guidance-Enclosure design principles airflow-Indoor Air Quality doc-Insight resources-low-energy ASHRAE resources-mold 2013-04-02T23:56:29Z BSC Article