Energy efficiency and the 2012 Building Code: What's expected, and what you need to do about it
|A Certified Energy Evaluator records air leakage rates from the controller of a blower door test apparatus.|
You've been hearing about it for years, and now it's just around the corner. The 2012 update to the B.C. Building Code will bring significant new requirements for energy efficiency.
To help builders prepare for the new Code, the Homeowner Protection Office (HPO), a branch of BC housing, has been offering seminars in communities around the province. More than 1,800 people – including builders, building officials, energy advisors, architects, tradespeople, suppliers and educators – have already attended.
In case you haven't caught a session, here's a synopsis from the seminar's main presenter, Murray Frank. Frank is a building science instructor and principal of Constructive Home Solutions.
How the energy efficiency provisions work
"As a bit of background, code writers have three different ways to approach energy efficiency," says Frank.
"The first is prescriptive – if you do these things, you're deemed to conform to code. Then there's the energy tradeoffs method: if you're unable to get the level of performance you need, say, in wall insulation, you might trade off by putting a higher level of performance in the windows or attic, to get the same overall performance on the house.
"Finally, there's energy modeling – you put exactly what you're going to build into the modeling software, and it calculates your net annual fuel utilization estimate and your EnerGuide rating, so you know where you stand."
Frank says B.C.'s code will offer builders a choice between the three different approaches, but the tradeoffs option will be limited, due to the complexity of specifying acceptable tradeoffs across B.C.'s three different climate zones.
Frank notes that the current gap between the prescriptive approach and the modeling approach – which at present requires an EG 77 rating – will be tightened.
"In 2006, if you built to the Code's prescriptive requirements and then you modeled it, it would only come in between 69-72. So nobody took the energy modeling option because if you did, you had to get to 77," he says. "Under the new Code, if you build a house prescriptively, then model it, the expectation is that the house will actually come in at 80.
"So the prescriptive approach will target a minimum performance consistent with a performance of EG 80."
That means anyone following today's minimum prescriptive approach has a distance to go to keep up.
Focus: insulation and air sealing
The new code will also sharpen builders' focus in two key areas: air sealing and insulation.
Says Frank, "The fact that we're going to EG 80 equivalent is not the only truth here. The prescriptive solutions are predicated on getting there on the merits of improved insulation and air tightness, with possibly one mechanical benefit, such as maybe a heat recovery ventilator to top up your rating.
"There's a substantial increase to the minimum insulation values for attics, basements and walls that is beyond the capacity of just simply using infill fibrous insulation inside a 2x6 wall," he says. "So your wall is going to have to be fatter, or you're going to have to have continuous insulation on the outside of the home.
"The biggest impact here is going to be very different looking basement insulation strategies or a very different looking wall, to get where you need to. Figuring out how to build more airtight and better insulated is our reality for the 2012 building code."
"Highly likely": Required blower door testing
Another element to prepare for is mandatory air leakage testing, using a blower door test.
"It's highly, highly likely," says Frank. "Unless something dramatically changes, the expectation now is that every new home built will be subject to a door fan test, no matter which way you build – prescriptively, limited tradeoff, or performance.
"Every home will have to have its air tightness declared, and there will be a minimum level that you will have to achieve – a level up to two times tighter than what's currently being built."
Frank says that often leads to concerns that new homes will be so airtight they'll become "sick homes" due to inadequate ventilation. He says those fears are unfounded.
"The requirements for ventilation of the home in the B.C. Building Code – for comfort, for safety, and to deal with odours and toxins and moisture loads – are very well developed and are under the close scrutiny of trade associations. So the Code's new provisions for ventilation are addressing comfort and safety given the increased importance placed on air tightness."
He says that the Code will include some improvements in the way homes are ventilated. "It's not a dramatic change, but it's going to lend itself that most builders will realize that a heat recovery ventilator is the smartest thing to do."
Frank says interest in the Code changes has been high across as he has toured the HPO's educational seminar across the province. "Now that the minimum requirement is going up, the question is not 'if' I should build that way, but 'how.'
"The fact is, if we're going to have a real impact on carbon reduction, we have to deal with the reality that seven percent of the carbon emitted into the B.C. environment comes from homes," says Frank. "We simply have to make them more energy efficient so that we have the same level of comfort, but we have a much smaller footprint on the environment."