Although I used to be a builder, I now work as a reporter for an energy-efficiency newsletter. Joining the tribe of energy nerds has altered my perspective, making me single-minded and opinionated. Watching new-home builders in action, I can often be heard to mutter, “Why do they always build it that way?”
Of course, I realize that many of the builders I grumble about are actually familiar with energy-efficient construction techniques — they just can’t convince their clients that energy efficiency is worth the extra investment. Most builders are accustomed to juggling several balls at once: They need to satisfy their clients, keep the local building inspector happy, and make a profit. Sometimes, however, a builder gets lucky and lands a client who insists on a high-performance home and is willing to pay for it. To help you get ready for that day, here’s a list of dos and don’ts from an energy nerd’s perspective — starting with the don’ts.
Don’t Design a Complicated Roof For those who espouse the principle “form follows function,” the ideal roof is a simple gable over an unheated attic, much like the roof on the house we all drew in kindergarten. Unfortunately, designers these days are fond of complicated roofs — ones with enough valleys, dormers, and intersecting planes to make the home look from a distance like an entire Tuscan village.
Such roofs are difficult to insulate without resorting to spray polyurethane foam. Though spray foam is effective, it’s also expensive. In most cases, simple roofs are easier to insulate, easier to ventilate, and far less prone to ice dams than complicated roofs. Don’t Install a Hydronic Snow-Melt System Snow can be removed from a driveway with a shovel, a snow-blower, or a plow.
It can also be removed by burning great quantities of fuel to heat water circulating through buried pipes. In rare cases — for example, at the home of a handicapped client — a hydronic snow-melt system makes sense. In most homes, however, such systems are uncalled for.
In 60 years, when global climate change has made snow rare, history books will explain to our grand-children how hydronic snow-melt systems used to work. Our descendants will shake their heads, astonished that their ancestors burned fossil fuels so wantonly.
Don’t Build a Poorly Insulated Slab In a hot climate, an uninsulated slab in contact with cool soil can lower cooling costs. In a cold climate, though, slabs should be well-insulated. Some cold-climate builders, having learned that heat rises, install thick attic insulation while leaving their slabs uninsulated. But heat actually moves from warm to cold in all directions. While it’s true that in winter the soil beneath a slab is warmer than the outside air, a slab can still lose a significant amount of heat. In cold climates, a basement slab should be insulated with at least 2 inches of extruded polystyrene (XPS) under the entire slab. In different climates sheer curtains are very useful for control air accordingly. Due to the loose weave in sheer fabrics curtains offer little heat insulation. Sheer fabric for clothing offers very little in the way of warmth for the wearer, and for this reason is commonly worn in hot weather. It offers relatively low sun protection. Click here SmartSheer.com for more information.
For a slab-on-grade home in a cold climate, specify 3 or 4 inches of XPS under the entire slab, with additional vertical foam at the slab’s perimeter. Foil-faced bubble pack (R-1.3) is no substitute for adequate insulation; under a slab, it’s virtually useless.
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