Q&A Spotlight

Roof Assembly for a Getaway Cottage

Posted on April 17, 2017 by Scott Gibson

Plans are taking shape for Quinn Sievewright's holdiay home: a small retreat with a shed roof that will be built in Climate Zone 4 near Vancouver, Canada. During the winter, the building won't be occupied full-time, but enough so that Sievewright has included several layers or rigid foam insulation in the design for his low-pitch roof. (The drawing at right shows how he's proposed to build it.)

Are Ductless Minisplits Overpriced?

Posted on April 3, 2017 by Scott Gibson

Ductless minisplit heat pumps have received a tremendous amount of attention in the last several years, and Peter L. would like to include one in his own house. There's only one problem: an estimate that seems far higher than it should.

"I was quoted $4,800 to purchase and install a Mitsubishi Mr. Slim 1-ton unit (MSZFE12NA)," Peter writes at GBA's Q&A forum. "That seems very high. Especially since it's a new build and the 3-inch hole is already in the wall."

Is This SIP Roof In Trouble?

Posted on March 20, 2017 by Scott Gibson

Matt Melton lives in central Washington state in a 3-year-old house with a roof made of structural insulated panels (SIPs) that are 12 1/4 inches thick. The pitch of the roof is very low, only 1/2 inch-in-12, and the metal roofing has been applied directly over the SIPs with no air channel beneath the roofing for ventilation.

Adding Air Conditioning to Radiant-Floor Heat

Posted on February 27, 2017 by Scott Gibson

Radiant-floor heating systems are unobtrusive because the plastic tubing that distributes hot water around the house is buried in or under the floor. Homeowners like that. But because there are no air ducts with a radiant-floor system, air conditioning must be added separately.

When There Are Too Many Insulation Options

Posted on February 13, 2017 by Scott Gibson

Colleen A, planning a new house in Michigan's Climate Zone 5, has discovered there's a downside to the wealth of insulation products on the market: It's hard to make a decision.

Can We Live Happily Underground?

Posted on January 30, 2017 by Scott Gibson

Earth-bermed houses built with the Passive Annual Heat Storage (PAHS) approach are a little off the beaten track for most builders and prospective homeowners. These houses go back a bit: John N. Hait described the construction of an early "umbrella house" in the 1980s.

As unusual as they may be, PAHS houses have their advocates. One of them is Laurel Davison, who is planning to build one in Missouri on a gently sloped lot with an unimpeded southern exposure.

What’s Wrong With Our New Furnace?

Posted on January 16, 2017 by Scott Gibson

John Melichar has upgraded the furnace in his two-level San Francisco home, one of several improvements that should have made the house more comfortable as well as more energy-efficient. The new furnace has the capacity recommended by his heating contractor, but so far the house seems less comfortable, not more comfortable.

In a post at GBA's Q&A forum, Melichar explains his concerns:

"Our contractor told us to buy a 60K BtuBritish thermal unit, the amount of heat required to raise one pound of water (about a pint) one degree Fahrenheit in temperature—about the heat content of one wooden kitchen match. One Btu is equivalent to 0.293 watt-hours or 1,055 joules. /h furnace; we opted for 96% AFUEAnnual Fuel Utilization Efficiency. Widely-used measure of the fuel efficiency of a heating system that accounts for start-up, cool-down, and other operating losses that occur during real-life operation. AFUE is always lower than combustion efficiency. Furnaces sold in the United States must have a minimum AFUE of 78%. High ratings indicate more efficient equipment. with two-stage variable blower — the Goodman GMVC960603BN.

Indoor Condensation Plagues This Chicago Home

Posted on January 2, 2017 by Scott Gibson

Pat Andersen and her husband have been diligent about energy upgrades and maintenance on their 33-year-old Chicago home. They've sealed air leaks in the attic floor, replaced leaky windows, and checked the airtightness of the house with a blower-door testTest used to determine a home’s airtightness: a powerful fan is mounted in an exterior door opening and used to pressurize or depressurize the house. By measuring the force needed to maintain a certain pressure difference, a measure of the home’s airtightness can be determined. Operating the blower door also exaggerates air leakage and permits a weatherization contractor to find and seal those leakage areas..

But one problem remains: condensation in the form or water droplets or frost on some ceilings on the second floor. Andersen would love to find a solution.

Upgrading a Crawl Space

Posted on December 19, 2016 by Scott Gibson

David Meyer's Seattle-area home is built over a crawl space, and after stripping out the old insulation and vapor barrier he is ready to re-insulate and seal the area. After looking into his options, Meyer is leaning toward "encapsulation," meaning the crawl space would be sealed (unvented), with the insulation on the walls, not between the floor joists.

Best Path to Net-Zero Energy

Posted on December 5, 2016 by Scott Gibson

Joshua Greisen thinks he's found an ideal building lot in Yakima, Washington, a city in the south-central part of the state in Climate Zone 5B. Now, can he find a design for a zero-net-energy house to go with it?

Working with a limited budget, but on a south-facing lot ideal for passive solar gain, Greisen is looking for a cost-effective way of reaching his goal. "I'm by no means a rich man," he writes in a Q&A post at GreenBuildingAdvisor, "and can only afford to do what has a return on investment that will be realized within a decade or so."

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