Passive and Green on the Home Front

Passive and Green on the Home Front

Since 2004, the price of residential electricity has risen by nearly 37 percent, according to the U.S. Energy Information Administration. With homeowners ever more conscious of their monthly bills, it’s not surprising that interest in passive homes are of the rise.

Passive or “net zero” homes don’t utilize any on-grid electricity, reducing heating and cooling energy 60 to 80 percent, says Michael Knezovich, director of communications at the Passive House Institute US in Chicago.

The Passive House Institute US has trained more than 1,800 architects, engineers, energy consultants, energy raters and builders. It also is the leading passive building research and information provider in North America. While most passive homes are newly constructed, retrofit construction is becoming more common in the U.S., too, Knezovich says.

Passive homes function on the basis of being air tight, using “superinsulation.” Thicker walls, high-performance windows (in cold climates they are triple paned) and strategic use of sun and shading are standard features that allow these homes to be so energy efficient. If you step foot inside a passive house, you’ll probably notice the quietness. That’s because the walls of these structures are often 12 to 18 inches thick, which helps insulate the home in addition to keeping out exterior noise. “When it’s really cold, you can stand next to a window and you don’t even notice a difference in temperature. And there’s no draft,” Knezovich says.

While consumers may worry that a home sealed too tightly can lead to problems with moisture and mold, these issues are combatted with the use of an energy recovery ventilator, which takes the place of a conventional furnace and provides a constant supply of fresh air. The ventilator is a box that runs constantly and is designed intentionally to have a balanced intake and output to maintain a constant pressure inside the home.

In a passive home, you’ll never hear the mechanical sound of a unit turning on or off, nor the blowing sound of an air conditioner. Energy recovery ventilators run constantly at a lower level that is much quieter than a forced air furnace.

Surprisingly, passive homes don’t cost much more to build than a standard home. A commonly used estimate in the industry is that construction of a passive house costs 5 to 10 percent more than conventional building.

One of the biggest drawback to living in a passive house, according to Nicholas Koch, a passive house consultant and founder of Equitable Green Group in Austin, Texas, is that your washer and dryer must be kept outdoors because dryers suck the air out of your home. In Koch’s own passive house, the units are kept on a screened-in porch.

“We’re building these buildings to last ideally a century or more,” says Dan Whitmore, a passive house consultant with Hammer & Hand, a home building and remodeling company that has around 35 passive home projects in Seattle and Portland, Oregon.

Whitmore encourages customers to look at their monthly investments in a house as the sum of their mortgage and utilities. “We can generally delivery a super efficient building for the same monthly outlay,” he says.

In Austin, Koch’s Equitable Green Group has plans to build a community of 16 passive homes called The Aviary on the city’s East side. The goal is to focus on low-energy living with features like rainwater collection, solar energy and sustainable farming, Koch says.

Lately, builders have seen a lot of interest in multi-family homes and affordable housing, Knezovich says. “What we find is that once you have a couple of projects in an area, it naturally seems to accelerate very quickly after that,” he says.

“It’s an exciting time within the efficiency building community because there’s a lot of interest and support and the expertise is just growing and growing,” Whitmore adds.


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