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Sustainability-Spotlight

Deep energy retrofit can reduce your home’s energy use by 50%.

Deep energy retrofits

You swapped out your incandescent lightbulbs for LEDs. You replaced your furnace and your air conditioning unit with a high performance heat pump. You’ve caulked for leaks around windows and doors. You got rid of the harvest gold beer fridge in the garage.

All of these steps were important and they quickly reduced your carbon footprint. They have short payback periods, and will continue to save you money in the years to come.

What’s the next step? Your house is still using a lot of electricity. Why? The house leaks air and has 1980-era insulation. You need a “deep energy retrofit.” A deep energy retrofit is designed to reduce your home’s energy use by at least 50%. Beyond the cash savings, a deep energy retrofit makes your home more comfortable (no more hot and cold spots) and prepares you to withstand extreme weather events, such as heat domes and unusual cold spells.

Deep retrofits come with several challenges. Compared to the quick wins described above, they are big projects. They are expensive. They aren’t common (yet), so finding a contractor with experience in deep energy retrofits can be hard and contractors are often averse to doing new projects or doing things in a new way.

Deep energy retrofits include building shell improvements that provide more insulation for the roof, walls and basement or crawl space. The new shell will be carefully sealed against leaks, controlling the air exchange rate. Your house was probably built with 2x4 or 2x6 wooden studs. That means that both the outside and the interior are in direct contact with the stud. During the winter, the stud becomes a “thermal bridge”, transmitting the cold from outside. You can see this in infrared photos—cold studs and warm surrounding walls. A deep energy retrofit provides continuous insulation to avoid thermal bridging.

Windows and doors are the weak link in your house’s energy. You can’t do without them but they are much more poorly insulated than typical walls and they can leak heat. During a deep energy retrofit windows and doors are replaced. It may also involve rejigging the HVAC system, controlling ventilation and recovering heat.

Finally, you may want to replace other appliances, such as the washer, dryer or stove with energy efficient models. A general rule of thumb is a deep energy retrofit brings your house up to R-20 basement walls, R-40 for the above-grade walls, R-60 roofs, and U-0.20 windows. You can see several different deep energy retrofit case studies at retrofitcanada.com/case-studies

There’s been a trend to carry out deep retrofits using factory-built structural insulated panels (SIPs). These panels act like an extra exterior “wall”, wrapping the building with a layer of high R value insulation. The house is carefully measured and walls (with windows built in) are built to specification at the factory. The pieces come directly from the factory and are lifted into place by a crane. The advantage is that construction is quicker, which could save money, and there’s less disruption to the occupants.

If you don’t have the money to carry out a complete retrofit in one go, you can stage the retrofit—take it step by step. However, this requires careful planning. You don’t want to undo or take apart previous work.

For example, if you install a heat pump before you re-insulate, the house will require a bigger and more expensive heat pump. Improving insulation and airtightness in your walls will add several inches to the thickness of the wall. High energy efficient windows are often thicker than standard double pane windows. To accommodate the additional depth, you probably want to install insulation and new windows simultaneously.

Every deep retrofit should start with an energy audit by a certified energy advisor. In B.C. you can find a local certified energy advisor at betterhomesbc.ca/ea/ (residents of Penticton should get this done for $35 through the HELP loan program).

Many deep retrofit projects are supported by low-interest loans, rebates and tax deductions. A good place to start is betterhomesbc.ca/. There is also a list of federal loans and tax deductions collected by Green Communities Canada at deepenergyretrofits.ca/rebates-incentives/.

What is the biggest hurdle to deep energy retrofits? The temptation to remodel. It is a slippery slope. Putting in new attic insulation? The kitchen really needs to be updated. Replacing windows? It would be great to have a front porch. So plan your deep retrofit. Split it into stages if you need to and don’t add the renovations.

This article is written by or on behalf of an outsourced columnist and does not necessarily reflect the views of Castanet.



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About the Author

Kristy Dyer has worked in the sustainability field for more than 10 years, including work with solar energy in New Mexico and cleantech in Silicon Valley. After she moved to the Okanagan, she ran a small business, Teaspoon Energy, doing energy audits of large houses. Most recently, she worked for a B.C. business doing carbon footprints for tourism organizations.

She has written about sustainability since 2012. You can find her columns archived at TeaspoonEnergy.blogspot.com.

Dyer has a background in physics and astronomy, and has occasionally been caught trying to impersonate an engineer.

A long-time member of First Things First, Penticton’s local climate change group, whose goals are to educate and lobby for solutions to the climate crisis, Dyer is honoured to live, work and play in the unceded, ancestral and traditional territory of the Syilx Okanagan Nation.

You can contact her at [email protected]



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The views expressed are strictly those of the author and not necessarily those of Castanet. Castanet does not warrant the contents.

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