Guest Blogs

Finished Foundation and Floor Framing Uh-Ohs

Posted on March 4, 2013 by Roger Normand

[Editor's note: Roger and Lynn Normand are building a Passivhaus in Maine. This is the 24th article in a series that will follow their project from planning through construction.]

Ductless Minisplit Performance During Cold Weather

Posted on February 22, 2013 by Marc Rosenbaum

I tried an experiment this week during our cold snap. We've kept the door closed to the first floor ell (bedroom and bath) and let it run cold, because the Fujitsu wasn't sized to heat that space too. I opened the door early in the cold snap, and let the heat pumpHeating and cooling system in which specialized refrigerant fluid in a sealed system is alternately evaporated and condensed, changing its state from liquid to vapor by altering its pressure; this phase change allows heat to be transferred into or out of the house. See air-source heat pump and ground-source heat pump. go, leaving it set on 70°F. What I found was that overnight the main space went to 66°F, and the upstairs and back bedroom were 3° to 4°F lower.

My calculated heat loss in these conditions is about 24,000 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. /hour, and the heat pump is rated at about 17,000 BTU/hour at about 10°F. You'd think it would not be able to keep up.

Blower Doors Have Become Essential

Posted on February 19, 2013 by Erik North

Blower doors are spoken of in reverential tones in energy circles. Or at least they were a few years back. Now you can’t throw a manometer without hitting a contractor setting up a blower door. Which is a very, very good thing.

With the incorporation of air leakage standards into various housing codes, blower doors are becoming essential. In fact, I tell customers that a simple shorthand for whether your insulation contractors grok building science is whether they own/use/understand blower doors.

Placing Concrete In Our ICF Foundation Walls

Posted on February 18, 2013 by Roger Normand

[Editor's note: Roger and Lynn Normand are building a Passivhaus in Maine. This is the 23rd article in a series that will follow their project from planning through construction.]

Installing Roxul Mineral Wool on Exterior Walls

Posted on February 12, 2013 by Shannon Cowan and Patrick Walshe

As the landscape around our building site disappears under a rare blanket of snow, the 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. on our houses has been disappearing under a thick layer of exterior mineral-wool insulation. Known as , this insulation has impressed us with its green virtues, versatility, and price.

Spraying Polyurethane Foam Over an Existing Roof

Posted on February 4, 2013 by Mike Litchfield

When Taya and Stephen Shoup's old tar-and-gravel roof began leaking, the couple hoped to find a replacement roofing that would be energy-conserving, leakproof, cost-competitive, and reasonably green. As the house's 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. doubled as a finished ceiling, the old insulation was scant. They broiled in the summer and hemorrhaged money during the heating season.

Major Thermal Bypasses

Posted on January 29, 2013 by Erik North

First, a bit about my writing: I write in longhand, whenever I have some spare time. Between audits, at lunch, after the gym, when stopping for a coffee. Then I type the notes up. The thing is that I find a lot more spare time in my walking-around day than at the home or office. To say there is a bottleneck getting these notes into electronic form is a disservice to good-flowing bottles everywhere. This is by way of explaining an upcoming sentence.

Construction Begins — and We Encounter a Few Snafus

Posted on January 28, 2013 by Roger Normand

[Editor's note: Roger and Lynn Normand are building a Passivhaus in Maine. This is the 22nd article in a series that will follow their project from planning through construction.]

Window Installation Tips for a Deep Energy Retrofit

Posted on January 25, 2013 by Joel Schuman

In May 2011 we began of our old, cold, drafty house in Saugerties, New York. Because the house was poorly and cheaply built in the 1840s (apparently from scraps and salvage), we were leery of opening up the walls from the outside, lest we find that the clapboard siding and incomplete 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. were all that had kept the house from collapsing.

The Flash-and-Batt Method

Posted on January 22, 2013 by Erik North

One thing I’ve noticed over the years is that construction methods don't change quickly — and when they do change, the change is apt to be along the lines of current practices. That makes sense. It’d be near impossible to run a business if you were changing your technique and product five times a week.

Flash and batt insulationInsulation, usually of fiberglass or mineral wool and often faced with paper, typically installed between studs in walls and between joists in ceiling cavities. Correct installation is crucial to performance. is one example of a new technique being implemented by insulation contractors. Flash and batt is a hybrid insulation approach combining fiberglass insulation and closed-cell spray foam.

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