Musings of an Energy Nerd

Where Can I Find Good Advice?

Posted on June 15, 2018 by Martin Holladay

Donald Wulfinghoff is an energy consultant who works in Maryland. In 2015, he published Super House, a 700-page book that explains how an ordinary person without architectural training can design a superinsulated home that (he claims) will use only 10% to 20% as much energy for heating and cooling as a conventional home.

Growing Marijuana Indoors is an Environmental Disaster

Posted on June 8, 2018 by Martin Holladay

Many Americans live in areas of the country where the local utility sponsors energy efficiency programs — for example, one that offers homeowners free energy audits. In addition to offering this type of residential efficiency program, many utilities have also developed energy efficiency programs to help commercial customers, including retailers and manufacturers.

What Windows Should I Buy?

Posted on June 1, 2018 by Martin Holladay

Readers often post a simple question on our Q&A page: “What brand of window should I buy?” For an editor, it’s an exasperating question, because it’s unanswerable. The answer depends on a host of factors, including the buyer’s geographical location, performance expectations, budget, and personal sense of aesthetics.

Rather than attempting to answer the question, I decided to interview fourteen designers and builders of high-performance homes. I asked them, “What brand of window did you specify on recent high-performance projects — and why?”

The California Model

Posted on May 25, 2018 by Martin Holladay

Here in the U.S., it’s hard to generalize about residential new construction standards. In parts of Massachusetts and California, many residential builders pay close attention to air sealing details, and the use of blower doors is common. Meanwhile, in Kansas and Wyoming, few builders pay much attention to air sealing.

These disparities are due to a variety of factors. But the most important explanation concerns differences in regulations. Massachusetts and California have stricter building codes, and do a better job of enforcing those codes, than Kansas and Wyoming.

Ensuring Fresh Air in Bedrooms

Posted on May 18, 2018 by Martin Holladay

Green builders try to make their homes as tight as possible. To ensure good indoor air quality, green building programs (and many residential building codes) require new homes to have a mechanical ventilation system.

Building a Passive House for $163 per Square Foot

Posted on May 11, 2018 by Martin Holladay

A family in Wakefield, Rhode Island, recently moved into a new 1,840-square-foot Passive HouseA residential building construction standard requiring very low levels of air leakage, very high levels of insulation, and windows with a very low U-factor. Developed in the early 1990s by Bo Adamson and Wolfgang Feist, the standard is now promoted by the Passivhaus Institut in Darmstadt, Germany. To meet the standard, a home must have an infiltration rate no greater than 0.60 AC/H @ 50 pascals, a maximum annual heating energy use of 15 kWh per square meter (4,755 Btu per square foot), a maximum annual cooling energy use of 15 kWh per square meter (1.39 kWh per square foot), and maximum source energy use for all purposes of 120 kWh per square meter (11.1 kWh per square foot). The standard recommends, but does not require, a maximum design heating load of 10 W per square meter and windows with a maximum U-factor of 0.14. The Passivhaus standard was developed for buildings in central and northern Europe; efforts are underway to clarify the best techniques to achieve the standard for buildings in hot climates. with three bedrooms and two bathrooms. If you exclude the cost of the lot, the architectural fees, and the cost of getting the house certified by PHIUS, the construction cost was $300,420, or $163 per square foot (if you measure the area of the house on the exterior).

The members of the team that built the house include Brad and Jordan Hevenor, the homeowners; Steve Baczek, the architect; and Stephen DeMetrick, the builder.

Another Perspective on Air-to-Water Heat Pumps

Posted on May 4, 2018 by Martin Holladay

Green builders, preparing for a fossil-fuel-free future, are busy building all-electric homes. Most of these homes are heated and cooled by minisplit heat pumps. Occasionally, though, a builder who’s worried about uneven heat distribution in a home with ductless minisplits will post a question on GBAGreenBuildingAdvisor.com suggesting the use of an air-to-water heat pump hooked up to a hydronic distribution system.

Bruce Harley’s Minisplit Tips

Posted on April 27, 2018 by Martin Holladay

Bruce Harley is a Vermont energy consultant and heat-pump specialist. To GBAGreenBuildingAdvisor.com readers, he is probably best known as the author of the Taunton book, Insulate and Weatherize — one of the best available books on residential energy retrofit work.

Henri Fennell’s Advice on Cathedral Ceilings

Posted on April 20, 2018 by Martin Holladay

I first interviewed Henri Fennell, the celebrated spray foam consultant from North Thetford, Vermont, about twenty years ago. Back then, Joe Lstiburek, the founding principal at Building Science Corporation, called Henri “the foam god.” While Fennell’s former company, Foam-Tech, closed up shop years ago, Fennell hasn’t retired. He now works as a consultant, specializing in problems related to spray foam insulation or air leakage.

Exterior Insulation for an Ugly Brick Building

Posted on April 13, 2018 by Martin Holladay

How do you insulate an old building with exterior walls made of structural brick? The best approach, according to building science professor John Straube, is to install a continuous layer of exterior insulation. Straube told me, “It’s a great solution for ugly buildings.”

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