New study shows energy codes are working but home efficiency opportunities abound

Written December 18th, 2012 by
Categories: Energy Efficiency, News

Newer-construction homes in the Northwest are outperforming older ones by a wide margin, thanks to stricter building codes. However there are plenty of low-hanging fruit yet to be harvested for residential energy efficiency, according to a new study spanning four states.


WHAT KIND of furnace warms that home across the street? You can’t look it up online. You would have to walk up to the door and ask, assuming you care. But energy utilities care, and a surprising dearth of data is a problem for people who craft conservation programs.

That’s right. Despite the long-term existence of the U.S. Census and the Multiple Listing Service, there is no national database of the physical characteristics of homes. When utilities devise rebate programs to incentivize energy efficiency upgrades, they need to know the size of the potential market for those rebates so they can prioritize and fund them.

So the nonprofit Northwest Energy Efficiency Alliance has developed a database to enable its 100 member utilities to find those answers.

The Residential Building Stock Assessment is a comprehensive update to a 2007 survey spanning four states.

The research began with phone surveys of thousands of single-family home owners in Idaho, Montana, Oregon and Washington. Then NEEA went into 1,400 of those homes to catalog everything in them that consumes energy.

The result is called the Residential Building Stock Assessment and it busts one myth after another about how much low-hanging fruit remains to be harvested to reduce energy consumption.

For example, would you believe that one in seven homes in the chilly Northwest still has no insulation in its walls? NEEA’s study found that 13 percent of homes are without wall insulation, and another 42 percent have inadequate wall insulation by today’s standards. This is after a substantial percentage of homes already have been retrofit through weatherization rebate programs offered by utilities. The results are similar for attic insulation, and 30 percent of homes have no insulation in their floors.

Another finding: Electric clothes dryers represent a clear opportunity to take a chunk out of household electric bills.

Jeff Harris, Northwest Energy Efficiency Alliance (NEEA photo)

“With over half of the houses in the region supplied with natural gas, to find out that only five percent of the dryers are fueled with gas or propane and the rest are electric was kind of a shock,” says Jeff Harris, director of emerging technology at NEEA. In Europe, heat-pump dryers are widely available and use about half as much energy.

“That’s what I like to refer to as mining for energy efficiency gold,” Harris adds. “We found a big nugget, a big efficiency potential sitting there, waiting for us to offer an alternative.”

Harris presented a summary of the study’s findings at a meeting in Seattle of about 50 energy-efficiency experts and utility representatives. Nancy Hirsh of the Northwest Energy Coalition, an alliance of organizations that promote energy efficiency, was in the audience.

“It is kind of disappointing to see that so much remains undone ¬†after all our collective efforts,” Hirsh says. “But it does show there is a lot more conservation potential in our homes — despite what some have claimed.”

 

ON THE BRIGHT side, the study reveals that stricter building codes are working to reduce energy waste in homes. It showed a reduction of 50 percent in heat loss between homes built before 1981 and those built after 2000.

Wall thickness is a big factor in stemming heat loss. Prior to the advent of energy codes in the 1980s and 1990s, 2×4 wall construction was used almost exclusively. By 2000, energy codes effectively mandated 2×6 construction in all four states surveyed.

As part of NEEA’s on-site surveys their field workers conducted blower door tests and duct blaster tests to find air leaks.

“In some homes the duct leaks are so big that every time the furnace comes on it’s the equivalent of turning on a kitchen exhaust fan and sucking hot air straight outside,” Harris says.

Duct sealing and weatherization remain big opportunities for energy savings, although a relatively small number of homes represent a disproportionate slice of that potential.

“I think, really, it shows there’s a percentage of the housing stock that’s just hard to get to,” Harris observes. “Rental housing has always been hard to reach. Low income housing has always been hard. We still do have a lot to accomplish, we just have to be a lot smarter about trying to figure out how to make these things happen.”

 

SMARTER IN THIS case includes finding creative ways to make improvements work financially for those hard-to-reach homeowners. Harris notes that other countries are adopting more-efficient water heaters that use ducted heat pumps. But those appliances remain expensive here in the United States.

Very efficient electric water heaters are available but cost more up front. (Rheem photo)

“It’s my understanding that they are somewhere between $1,500 and $3,000 installed,” says Mike Little, an energy planning supervisor for Seattle City Light. “That’s an expensive water heating option for most people. Over time we’ll see more manufacturers offering them and that cost will come down.”

Progressive utilities like Seattle City Light don’t intend to wait for cheap appliances to come along. Even though their accomplishments stand above the region as a whole in terms of such measures as compact-fluorescent light adoption, SCL is beefing up its energy efficiency efforts.

“We’ve hired more people,” says Little, “so we’ve got great, experienced staff that are going to be out there mining this data and collaborating with NEEA.”

 

EVEN AFTER utilities have plucked all the low-hanging fruit and done all the insulating, weatherizing, duct sealing and appliance upgrades they can, new energy hogs will be ready to use all that saved energy.

We’re talking about plug loads, like the PC I’m using to write this article, and the tablet or laptop you’re probably using to read it. The rapid growth in numbers of home entertainment electronics are sustaining homes’ appetites for electricity. NEEA found that the average electricity consumption per home — 12,800 kilowatt-hours — has hardly changed since the last study of this kind in 2007.

“If we hadn’t been working so hard to increase the efficiency of home insulation and equipment efficiency, we would be using considerably more energy than we are,” Harris says. Mike Little estimates the average energy consumption might be closer 15,000 kWh per year without efficiencies gained in other areas of the home.

NEEA’s study found an average of 2.6 TVs per household, a significant increase from 2.3 sets five years ago. It also found that one-third of homes now have one or more gaming systems and over 90 percent of homes have at least one computer. All indications are that these numbers will continue to grow.

Says Harris: “The low-hanging fruit keeps growing back.”

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Denis founded Energy Priorities Magazine on Earth Day 2004 and hosts the radio program by the same name distributed by NPR. He has authored hundreds of cleantech articles for a variety of publications, ranging from Sustainable Industries Journal to the New York Times, and he has been interviewed by major news outlets, including FORTUNE and MSNBC. He lives in the Seattle, WA area. Follow him on Twitter: @Cleantech. Contact him here. Disclosure information.
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