Thinking Tech

Striving for a Zero Energy Home

Striving for a Zero Energy Home

Posting in Energy

"How realistic is it to keep building grossly inefficient homes?" Well put.

In constructing a new home, owners should consider features that can lower electricity costs to zero or even generate a small profit selling watts back to the grid. But given extra cost, how realistic is it?

David Ruggeiro, project manager for the Zero Energy Challenge in Massachusetts, poses the question differently. "How realistic is it to keep building grossly-inefficient homes?" Well put.

The Zero Energy Challenge is a pilot program where four electric utilities in the state banded together and backed five contractors to build homes that consume zero electricity.  The winners will be announced on June 29 and will split $50,000 in prize money.

Zero Challenge Bread and Roses House in Lawrence, Mass.

"Technology was not the issue. None of the technologies were exceedingly new or difficult to facilitate. Rather, this was an exercise in financial and program management," he said. "The cost averages out to an additional $8.81 per square foot. Wouldn't you pay that to have no utility bills?" he asks. In Massachusetts, cost per square for new home construction ranges between $100-$300 per square foot.

So, yes, I would.

"We delivered five homes with 93% better efficiency than the average. For every dollar you spend on home energy, we spent seven cents." Each home was judged using EnergyStar's Home Energy Rating System or HERS which sets the reference home at score 100. For every 1% decrease, the score drops by 1 from 100 so the lower HERS score, the better.

While scores were not given for each of the five homes, at least one of the builders has reportedly achieved scores of under 40 with other super-insulated homes.

The technology includes super-insulating that exceed buildings codes by three times and solar photo-voltaics (PV) to produce electricity. "The super-insulation was rated [up to R40] versus R13-19 [in typical homes.] Glass performance 20-30% better than [a typical] Andersen [double-glazed] window. These homes are unaffected by every gust of wind."

High-efficient furnaces were used, but not always.

"People go with highly-efficient furnaces that are grossly-oversized or undersized for their home. We're looking for the most well-suited to do the task even if they are slightly less efficient," he says. If we could not find something small enough for one the homes, we might use one that is not EnergyStar compliant."

The homes averaged 1,746 square feet versus the traditional 2,300-2,400 in Massachusetts. All the homes had to be affordable meaning they could be bought with someone earning 80% of the area's mean income. The areas were mean to low income with the exception of one.

Here's the kicker, according to Ruggiero. Only 20% of the cost of the super insulation, PV and high-efficiency furnaces and windows are borne by the owners (two house were privately commissioned. The utilities paid for the others).

The extra cost was $31,000, some $22,854 of which was covered by state and federal rebates. Another $2,410 came from utility rebates. How can we afford not to this?

This video describes the work of one Zero Challenge Energy builder and what looks like one of the homes, but maybe not. One goal of the Zero Energy Challenge is replicate these homes to bring down cost. About 100 of them are planned by the five builders.

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John Dodge

Contributing Editor

Contributing Editor John Dodge has written for the Wall Street Journal, Boston Globe, PC Week (now eWeek), EDN, Design News, Electronic Business, Bio-IT World, Health-IT World, Lowell Sun, Haverhill Gazette and Newburyport Daily News. He is based in Massachusetts. Follow him on Twitter. Disclosure