Q&A Spotlight

Will Welch has chosen to build his high-performance house in Nederland, Colorado. The site is at the border of Climate Zones 6 and 7, and it poses some challenges: it's at an elevation of 8,600 feet; the area gets a generous amount of snow and wind; and the number of heating degree days tops 8,800 a year.

But Welch has one more concern: the threat of wildfires.

David Voros owns a vacation home that isn't used frequently, but every so often the house sees a lot of guests. What, he asks, is the best way of providing enough hot water for a crowd?

Voros sketches out these parameters in a recent Q&A post: very cold incoming water temperatures, a limited amount of space for a tank-style heater, and limited availability of gas. The house has photovoltaic(PV) Generation of electricity directly from sunlight. A photovoltaic cell has no moving parts; electrons are energized by sunlight and result in current flow. panels, and Voros would like to avoid running another exhaust pipe through the building envelopeExterior components of a house that provide protection from colder (and warmer) outdoor temperatures and precipitation; includes the house foundation, framed exterior walls, roof or ceiling, and insulation, and air sealing materials..

A warm bathroom floor is a something to look forward to on a chilly winter morning, and C.L. is poking around for ideas on the best way of accomplishing that.

One option is installing a grid of electric cables beneath the finish floor in tandem with a polyethylene underlayment manufactured by Schluter Systems called Ditra. These installations are often topped with ceramic tile, which is impervious to water damage and readily transmits heat from the buried cables.

But C.L. has another idea.

Emerson has moved into a house in Climate Zone 4A, a region where humidity can be relatively high. As Emerson explains in a Q&A post, the crawlspace beneath part of the house has been closed to the outside, and now the question is how to insulate the space to help keep the house comfortable.

Low temperatures where David Gadbois lives aren't Siberian, but he's still interested in supplementing his ductless minisplit heating system with electric resistance heaters, something to provide a boost on just the coldest days of the year.

GBAGreenBuildingAdvisor.com reader Erik is building a new house in southwestern Washington state, and he's thought through most of the details with care. But as the time nears to install the standing-seam metal roof, Erik realizes he may have overlooked something important in the construction details.

A GBAGreenBuildingAdvisor.com reader named Inverter0815 lives in a two-story colonial in New Jersey that's hard to keep comfortable in summer. In order to get the three upstairs bedrooms down to a relatively comfortable 75° in July and August, Inverter must set the thermostat on his single-zone 2 1/2-ton air conditioner to 67°.

In coastal Massachusetts, Justin Brown is looking for ways to upgrade the energy performance of his very old house. It sounds as if previous owners had taken some steps to tighten up the building envelopeExterior components of a house that provide protection from colder (and warmer) outdoor temperatures and precipitation; includes the house foundation, framed exterior walls, roof or ceiling, and insulation, and air sealing materials., but they didn't go far enough with either air sealing or insulation. Now, Brown wants to complete the job.

One area of particular concern is the attic. It's insulated with a mix of fiberglass and cellulose, he writes in a Q&A post, but a cold snap this winter produced some frost on the underside of the roof sheathingMaterial, usually plywood or oriented strand board (OSB), but sometimes wooden boards, installed on the exterior of wall studs, rafters, or roof trusses; siding or roofing installed on the sheathing—sometimes over strapping to create a rainscreen. .

Writing from central Kentucky, Clay Whitenack poses this question: in an all-electric house, what's the best way of providing power when the grid is down?

Whitenack and his family live in a new house, a house that does not have a fireplace or a wood stove. "This leaves us vulnerable in the event of a power outage during a bad winter," he writes in a post at the Q&A forum. "We live in central Kentucky, so the winters here are usually not too bad, but we do have times when the temps get below freezing for extended periods of time."

Jill D has done her homework, and now it's time to choose a new heating and cooling system for her Climate Zone 5B home.

There are three distinct zones to consider: the main house, a sunroom addition, and an office addition. Neither the office nor the sunroom is ducted, although heating and cooling loads there are relatively low. In the main house, the heating loadRate at which heat must be added to a space to maintain a desired temperature. See cooling load. has been calculated at between 28,000 and 36,000 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. per hour, and the cooling load at between 24,000 and 36,000 Btu per hour.