Q&A Spotlight

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."

Designing a Combined Hot Water System

Posted on November 21, 2016 by Scott Gibson

Vladimir Polyakov's two-story colonial is undergoing a down-to-the-studs rehab, with insulation upgrades and a new heating system on the way.

An Owner-Builder Weighs His Options

Posted on November 7, 2016 by Scott Gibson

Too big, too complicated, too expensive — all problems in Mike Sterner's current home, and exactly what he'd like to correct in the new house he's planning in northern Wisconsin.

Writing in a Q&A post, Sterner lays out his basic plan for a "pretty good house that finds that happy place between great energy efficiency and economy."

The site is vacant farmland with a south-facing slope. Sterner's woodlot has lots of pine and oak he intends to mill for use in his new house.

Is a Ground-Source Heat Pump the Right Choice?

Posted on October 24, 2016 by Scott Gibson

Ben Rush likes the idea of a ground-source heat pumpHome heating and cooling system that relies on the mass of the earth as the heat source and heat sink. Temperatures underground are relatively constant. Using a ground-source heat pump, heat from fluid circulated through an underground loop is transferred to and/or from the home through a heat exchanger. The energy performance of ground-source heat pumps is usually better than that of air-source heat pumps; ground-source heat pumps also perform better over a wider range of above-ground temperatures., despite their reputation for higher cost than other heating and cooling alternatives.

A ground-source heat pump (GSHPs) requires heat-exchange tubing buried in the ground or inserted in a well or pond. The excavation required to bury the lines (or drill an extra well or two) helps to make GSHPs more expensive than air-source units. In addition, the equipment itself tends to be more costly. In all, GSHPs suffer a significant disadvantage when it comes to cost.

Questions About HVAC, Insulation, and Ventilation

Posted on October 10, 2016 by Scott Gibson

C. Clark is preparing to move from a dry region to Lady's Island, South Carolina, an area with a warm, humid climate that is the mirror opposite of the climate in Clark's former home. Clark is highly allergic to mold, and that has him thinking about ventilation, insulation, and his HVAC(Heating, ventilation, and air conditioning). Collectively, the mechanical systems that heat, ventilate, and cool a building. system.

Heading Off Ice Dams

Posted on September 26, 2016 by Scott Gibson

With the onset of another winter just a few months away, Jake Rabe is looking for suggestions on how to prevent the recurrence of ice dams on his older Ontario home.

"Each winter I have to deal with ice damming along two sides of the roof — nowhere else," he writes in a Q&A post at Green Building Advisor. "The areas in question are a low-slope roof (3/12 pitch, east and west side of the ridge) and a cathedral style roof (8/12 pitch)... My goal is to stop the ice damming."

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