The most recent blogs at Green Building Advisor

Providing Fresh Air in Our Home

Posted on February 6, 2014 by Alex Wilson in Energy Solutions

One of the features in our new house that I’m most excited about barely raises an eyebrow with some of our visitors: the ventilation system. I believe we have the highest-efficiency heat-recovery ventilator (HRV(HRV). Balanced ventilation system in which most of the heat from outgoing exhaust air is transferred to incoming fresh air via an air-to-air heat exchanger; a similar device, an energy-recovery ventilator, also transfers water vapor. HRVs recover 50% to 80% of the heat in exhausted air. In hot climates, the function is reversed so that the cooler inside air reduces the temperature of the incoming hot air. ) on the market — or at least it’s right up there near the top.

I’ll describe this Zehnder HRV and its impressive specifications and features — but not until next week. This week I’ll provide a little background on ventilation.

Green Buildings Aren’t Truly Green Without Location Efficiency

Posted on February 5, 2014 by Allison A. Bailes III, PhD, GBA Advisor in Building Science

I was one of the lucky ones. I spent only two hours in my car when the big snowstorm of 2014 hit Atlanta on Tuesday. We got only about 2 inches of snow in my part of the city, but I made the mistake of going out for lunch at a restaurant right next to Emory University and the CDC compound. It took Jeffrey and me an hour and 45 minutes to drive the 2 miles back to the office. In the first photo below, you can see that the roads themselves were still in good shape at 2 o'clock, at least where we were.

Using Interior Poly As an Air Barrier

Posted on February 4, 2014 by Martin Holladay, GBA Advisor in Musings of an Energy Nerd

Back in the 1980s, Canadian energy experts urged builders to use interior polyethylene as an air barrierBuilding assembly components that work as a system to restrict air flow through the building envelope. Air barriers may or may not act as a vapor barrier. The air barrier can be on the exterior, the interior of the assembly, or both. material. If the poly was installed conscientiously, and all seams were sealed with Tremco acoustical sealant, the approach worked well — at least in cold climates.

Been Having Those Hot Water Blues

Posted on February 4, 2014 by Carl Seville, GBA Advisor in Green Building Curmudgeon

As part of my renovation project, I needed to move the water heater out of its location in a below-grade recess in my crawl space that I was filling in to eliminate the need for a sump pump to get rid of water that collected. When considering the best type of new water heater, I considered both heat-pump water heaters and tankless heaters.

Ban the Can

Posted on February 3, 2014 by Erik North in Guest Blogs

One hates to overstate how problematic recessed lights can be, but… they sure are a pain in the energy-auditor butt. There are worse problems (wet basements), more expensive ones (insulating a complicated roof line), and more frustrating ones (the cross-purposes of energy evaluations and homeowner desires). But few elements of the house combine all three in as tidy a package as recessed light cans.

Two New Exterior Insulation Products for Walls

Posted on January 31, 2014 by Martin Holladay, GBA Advisor in Musings of an Energy Nerd

Exterior wall insulation? That usually means rigid foam and furring strips — although occasionally, it means mineral wool insulation and furring strips.

But there are other options. Two new products offer builders new ways to keep their wall 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. warm.

Report on Our Ductless Minisplit Heat Pump

Posted on January 30, 2014 by Alex Wilson in Energy Solutions

It’s been pretty chilly outside, if you haven’t noticed. A number of people have asked me how our air-source heat pumpHeat pump that relies on outside air as the heat source and heat sink; not as effective in cold climates as ground-source heat pumps. is making out in the cold weather. I wrote about the system last fall, well before we had moved in. Is it keeping us warm? We’ve only been living in the house for a few weeks, but here’s a quick report.

Should Occupants Have Control of Their Home Ventilation System?

Posted on January 29, 2014 by Allison A. Bailes III, PhD, GBA Advisor in Building Science

One of the points of contention in the great ventilation debate is whether a home's occupants should control their own ventilation systems.

District Heating

Posted on January 28, 2014 by Vera Novak in Green Building Blog

During my recent travels in Europe, I was surprised at the wide variety of approaches to heating methods and distribution. For example, in the U.K. we visited the Southampton City district heating scheme, a project that uses geothermal and CHP (combined heat and power). The centrally generated heat is supplied to surrounding buildings through underground pipes. It serves 45 businesses, and the businesses save 10% on energy costs plus all of the costs of owning and maintaining heating equipment.

Singing the Ice Dam Blues

Posted on January 27, 2014 by Scott Gibson in Q&A Spotlight

Winter is the season of icicles and ice dams, at least on houses whose roofs are poorly insulated and air-sealed.

Or, in the case of a nature center in Wisconsin, not insulated at all. Walt Ott is inquiring about the best way to fix a building with a completely uninsulated cathedral ceiling.

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