MOST PEOPLE WOULDN'T buy a car without knowing its fuel economy, or sign up for a cellphone plan without comparing service-provider rates. Yet when it comes to one of life’s biggest investments – purchasing a home – few people question how much it will cost to operate that house over the long term.

Ideally, a thorough energy audit of a prospective new abode will not only tell buyers how much it will cost to keep the house cool or warm, but also what is needed to improve performance, the price and where to find any help required.

Climate advocates and government would also like it made easier to compare the average utility bills and greenhouse gas emissions between houses. They believe that this is the secret to turning good intentions into action – a key part of a green building strategy.

“Any [home energy] audit that happens via a utility or conservation program has one goal in mind: the ability to translate the audit into an actual retrofit,” explains Sean Penrith, executive director of the Earth Advantage Institute, a non-profit green building centre based in Portland, Oregon. “Being able to communicate information about a home’s energy [use] is key to getting people to change,” he says.

Yet that information can be surprisingly hard to find and to understand once you do locate it. Criticized for being too complicated and unwieldy for the average person, existing home-energy rating systems have had little impact on the housing market so far, according to Penrith.

HES and HERS: apples and oranges?

There is a whole alphabet of rating systems out there: HERS (Home Energy Rating System) Index, HES (Home Energy Score), the EPS (Energy Performance Score) and the ERS (EnerGuide Rating System, now rebranded as ecoENERGY), to name only a few.

The two most widely adopted in North America are HERS (which is used in the United States to determine EnergyStar certification for new homes) and its Canadian equivalent, the ERS, developed by Natural Resources Canada. Both HERS and ERS use a yardstick measure to determine a home’s energy use. A hypothetical house that scores poorly on energy efficiency is at one end of the scale. At the other end is a hypothetical house of the same size and location that uses no energy at all. Where the home being examined falls between these two points indicates its level of efficiency.

The Canadian-made ERS scale goes from 0 to 100. For a conventional new home, a score of between 65 and 72 is standard. A home with some energy efficiency additions rises to as high as 79. A home rated between 80 and 90 is considered energy efficient and is eligible for certain perks, including a better mortgage insurance rate through the Canada Mortgage and Housing Corporation.

But ERS has its problems. In a 2007 assessment, the Canadian Home Builders Association (CHBA) identified a “logarithmic bias” with the ERS scale that makes it difficult to compare performance between homes. For example, a home with an ERS of 80 uses half the energy of one that comes in 13 points lower, at 67, but twice as much as a home with an ERS score of 86, only six points higher.

In other words, at the high end of the scale, energy efficiency measures don’t count for as much as at the lower end. “These sorts of results will not make it easier for builders to sell energy performance using ERS ratings,” concludes the CHBA report.

Also, because both ERS and HERS score existing homes against hypothetical ones, they don’t offer meaningful home-to-home comparisons. “You could have an HERS index for a mansion and a cottage and they could be exactly the same,” explains green-building advocate Penrith.

”MPG” for home energy efficiency

The Earth Advantage Institute conceptualized the idea of a “miles-per-gallon” home-energy rating system. Its staff tested five energy-calculating logarithms, comparing results to an actual utility bill, and eventually settled on a tool developed by an independent consultant named Michael Blasnik.

They next developed software to translate that information into something the average person could understand. The resulting Energy Performance Score still comes with an acronym, EPS, but it provides a real-world estimate of a home’s energy consumption and greenhouse gas emissions, as well as information about where it ranks on a national and regional scale.

Funded by the US Department of Energy, the institute has tested EPS as part of a home-energy-retrofit pilot program that will eventually be applied to 24,000 homes across four states. So far, among 5000 homes in Washington State, the system has resulted in a 50-per-cent conversion rate. Penrith says this means that half the people who received an EPS audit actually went ahead with the recommended retrofits.

The institute has recently launched the EPS platform in Canada. Auditors pay $199 to learn how to use it, then a fee of $15 to $35 each time they apply it.

Penrith says that EPS is compatible with popular home-energy-retrofit programs that match energy audits with low-interest loans for upgrades that can be repaid through utility bills or property taxes. He adds that the most striking difference between EPS and other home-energy-rating- systems is that outside expertise is not needed to interpret it.

He contrasts EPS with a system his hometown uses to approve property-tax-based financing for energy retrofits under its pioneering Clean Energy Works Portland. “They use an energy advocate to walk people through. Which is fine, but you can’t take that to scale,” explains Penrith. “A typical audit looks like 15 pages of gobbledygook.”

“The EPS is something that an auditor can share with the homeowner and the contractor,” says Penrith. “The consumer gets a scorecard that shows where they are and where they can get their home to. It generates a recommendation report and turns it into a scope of work for contractors to provide. It really distills that information down, like a weight-loss program.”

Will it change the market?

Peter Sundberg is executive director of City Green Solutions, a non-profit that does home-energy audits and other consulting work in green building from its offices in Victoria and Vancouver. He says that knowing the energy rating of one home over another is information of value that is currently missing from the marketplace.

While some major builders – including KB Homes, one of the largest home building companies in the US – have picked up on energy labelling as a way to get an edge in a market full of low-priced foreclosures, it remains to be seen whether new and improved home-energy labels will gain real traction in the housing market.

Greenworks Realty and Development Group, a Seattle-based realtor specializing in green home sales, studied whether positive green ratings boost a property’s value. The results were mixed. Its 2010 report found that certified homes in Seattle sold faster and for 9.2 per cent more per square foot than non-certified homes. Sales results in rural locations, however, were not as definitive. In an interview with the Seattle Daily Journal of Commerce, GreenWorks owner Ben Kaufman chalked the difference up to education. In places where agents and buyers are taught about green ratings, they are more likely to put a value on it.

Anecdotal evidence suggests the same may be true in Canada. Helen Goodland, executive director of Vancouver’s Lighthouse Sustainable Building Centre, had her home renovated to improve energy efficiency under the federal government’s ecoENERGY retrofit program. When she recently put it on the market at the same time as several others in her neighbourhood, hers sold first, and in just six days.

“It was up front and absolutely explicit that this is an energy efficient, high-performing home, with healthy interiors and designed with occupancy comfort in mind,” Goodland says. “The whole package together was attractive. I wouldn’t say the price was affected, but certainly the speed was affected. It’s a differentiator.”

In the end, it will be up to home buyers to decide whether HES, HERS, EPS or some other scorecard can help them recognize an energy hog for what it is.

The Harper government abruptly shut down the ecoENERGY retrofit rebate program in January, allegedly because it was just too darn popular. Join the backlash at

Colleen Kimmett is a Vancouver-based freelancer who writes about environmental issues.


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