Lawrence Berkeley National Lab (LBNL) scientists, led by Max Sherman and Iain Walker, are investigating whole-house ventilation options to support California’s Zero Net Energy Homes initiative. This research project is called Smart Ventilation for Advanced California Homes (SVACH). California’s energy-and-climate goal calls for all new residential buildings in California toContinue Reading

My complements to the European high-performance window manufacturers for providing built-in sills for their windows. I hope that North American high-performance window manufacturers soon provide built-in sills. The built-in sills, along with block-frame window installation, sure simplify installing high-performance windows in superinsulated walls. American builders have tried dozens of differentContinue Reading

The best time to make major energy retrofits (also called deep energy retrofits) is during a renovation. This is when you’re making major changes to the building, and probably getting a building permit. Ideally, the house will be vacant during this process. Here are 10 major energy retrofits that should be part of every homeContinue Reading

A roof’s purpose Before you choose a roof design for a new building, you should understand the purpose of a roof. The primary purpose of roof is to shed rainwater and snow. A secondary purpose — and a less appreciated one — is to provide shade. A roof’s enemies Moisture, and to aContinue Reading

Building assemblies can get wet Building scientists assume that some rainwater leaks through the cladding or roofing and that water vapor migrates through insulated building assemblies, sometimes condensing within those cavities. These two phenomena both can dampen building assemblies. What are rainscreens? Builders often provide a 3/4-inch air space between siding and theContinue Reading

Relative Humidity, Temperature, and Moisture Content This is Part 2 of a two-part series on cellulose insulation and moisture. Cellulose insulation is a hydrophilic material, meaning that absorbs moisture readily. Under certain conditions condensation dampens cellulose insulation causing permanent damage due to shrinking, slumping, and very slow drying. Moisture adsorptionContinue Reading