Q&A Spotlight

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.

The one-room addition on Emerson W's home is not what anyone would realistically consider over-insulated: R-11 batts in the walls and R-19 at most in the ceiling. But the immediate issue is the floor. There's no insulation at all there, and because the addition sits on concrete piers, there's nothing to stop the wind from blowing freely below.

Emerson W has acquired his first free-standing home, a Cape built in Maryland in 1952, and in no time he's compiled a long list of upgrades the house will need — everything from a new heating system to dealing with vented, unconditioned crawl spaces.

An energy auditEnergy audit that also includes inspections and tests to assess moisture flow, combustion safety, thermal comfort, indoor air quality, and durability. on BuildingNewb's upstate New York home has prompted a recommendation that he insulate the rafter bays with dense-packed cellulose, transforming what is now a ventilated attic into conditioned spaceInsulated, air-sealed part of a building that is actively heated and/or cooled for occupant comfort. .

Jeepasaurus, a GBAGreenBuildingAdvisor.com reader from Eau Claire, Wisconsin, recently bought a log house sitting atop a permanent wood foundation (PWF). Although initially reluctant to buy the house because of this detail, Jeep did enough research to convince him there's nothing inherently wrong with a wood foundation. The problem is how to insulate it.