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Deep Energy Retrofit—Total Residential Makeover Raises Energy Efficiency

How to Climate-Ready A Home, Reduce Emissions, and Save Money


The idea of home energy retrofits has come a long way.  ©David Dodge
The idea of home energy retrofits has come a long way. ©David Dodge

The idea of home energy retrofits has come a long way. Remember the programs that encouraged people to caulk the cracks, change light bulbs, and add a little insulation here and there?

That was then; this is now.


Today, wildly fluctuating energy prices, severe weather patterns, and rapidly evolving technological expertise make it indispensable as well as possible to radically improve homes’ energy efficiency, produce one’s energy, and divorce from the vagaries of energy utilities.


It’s called deep energy retrofitsa holistic, whole-home approach to improving homes' energy efficiency, comfort, and operational affordability.


Save Money, Reduce Emissions


Buildings are responsible for about 40% of greenhouse gas emissions—around 28% comes from “operational emissions (such as the energy needed to heat, cool, and power them), and 11% from materials and construction known as embodied carbon.” (See “Decarbonizing the Building Sector,The Earth & I.)


The good news is that there is a growing body of knowledge about how to raise the energy efficiency of homes, heat and cool them with electric heat pumps, and power them with solar.

Harold Orr was one of the pioneers of the passive house concept, which involves super-insulated homes that require very little energy to heat.  ©David Dodge
Harold Orr was one of the pioneers of the passive house concept, which involves super-insulated homes that require very little energy to heat. ©David Dodge

The good news is that there is a growing body of knowledge about how to raise the energy efficiency of homes, heat and cool them with electric heat pumps, and power them with solar.


Housing engineer Harold Orr figured this out in the 1970s during the so-called “oil crisis.” He and his colleagues at the Saskatchewan Research Council, Canada, were asked to build a solar-powered home. But they realized it couldn’t be done without overhauling the home's insulation. Orr became one of the pioneers of the passive house concept. Today, there are numerous strategies to retrofit homes to become super energy-efficient.


Moving From ‘Dabbling’ to ‘Deep’ Energy Retrofit


At first, Canadian energy expert Jim Sandercock, PhD, who owned an energy inefficient 1951 bungalow, did what many people do: He dabbled in energy efficiency, upgraded his insulation a little bit, replaced his roof, and added solar panels.


But these improvements didn’t make much of a difference, and then he was burdened with those sunk costs. It was after doing the minor retrofits that Jim Sandercock realized he really wanted a Deep Energy Retrofit to take his home all the way to net-zero. The term net-zero refers to a home that produces all its energy on a net annual basis.


Sandercock viewed his home as having “great bones” and well worth the retrofit effort. He became aware of a pilot program in Canada that was using the EnergieSprong concept from the Netherlands. It performed deep energy retrofits by laser scanning the home and literally dropping new walls and a roof over the old ones.


The Sandercock home was renovated to net-zero by building new walls in a factory and craning them over top of the old walls to create super-insulated walls.  ©David Dodge
The Sandercock home was renovated to net-zero by building new walls in a factory and craning them over top of the old walls to create super-insulated walls. ©David Dodge

It would allow Sandercock to double down on insulation, tighten up the home, and bring it to net-zero. So that’s what he did. New wall panels were built in a factory, delivered, and craned in, right over the top of the old 2x4 R12 walls, bringing the walls to an amazing R40 level of insulation.


How to Do a Deep Energy Retrofit


Here are the steps to do one’s own Deep Energy Retrofit.


1. Home Energy Evaluation

The blower door test reveals how leaky the home is.  ©David Dodge
The blower door test reveals how leaky the home is. ©David Dodge

A good home energy evaluation will check the insulation, windows, and mechanical systems, and, most importantly, a blower-door test will be done to find out how leaky the current home is. Most older homes are very porous, allowing four, five, six, or more air exchanges per hour due to cracks, electrical outlets and holes in the house, bathroom vents, chimney stacks, and other things. By comparison, a net-zero home typically allows one air exchange per hour.


The evaluation will show how much energy a home requires, and a good evaluation will itemize the improvements one can make and the benefits of each.


2. Building Envelope


Insulation levels are the most critical factors in making a home much more efficient. Deep energy retrofits often target R35 or R40 walls, about R80 in the roof, and insulation is added down the wall underground right down to the home's foundation to form an unbroken blanket of insulation. (The R-value indicates a material's ability to reduce heat flow, with a higher number meaning better insulation.) Often, a new wall is built with space between the old and new wall that can be filled with insulation. Windows are the weakest link in the home, so triple-paned windows are often used to cut down on heating/cooling losses.


3. Net-zero ready heating and cooling


Net-zero builder Peter Amerongen with the double-studded wall system that he and many others use to produce R35-R40 walls.  ©David Dodge
Net-zero builder Peter Amerongen with the double-studded wall system that he and many others use to produce R35-R40 walls. ©David Dodge

One of the significant benefits of a super-insulated home is that it will require 70%–90% less energy to heat it. For this reason, most deep energy retrofit projects replace gas furnaces with heat pumps. Air source heat pumps are up to 300% efficient and are rated to be operational at -31 °F (-35 °C). A geothermal ground source heat pump is even more robust but more expensive. Heat pump water heaters are also very efficient, and the best part is both of these systems run on electricity, allowing homeowners to potentially cut the gas line and, more importantly, the gas bill.


Finally, a heat recovery ventilator (HRV) or energy recovery ventilator (ERV) is added to provide plenty of fresh air to the new super-tight home. These devices recover more than 70% of the heat from exhaust air, saving even more energy.


Heat pumps are a very efficient way to warm the home, create hot water, and even dry clothes. ©David Dodge
Heat pumps are a very efficient way to warm the home, create hot water, and even dry clothes. ©David Dodge

4. Generating one’s renewable energy


Net-zero homes produce all their own energy on a net-annual basis using solar modules.  ©David Dodge
Net-zero homes produce all their own energy on a net-annual basis using solar modules. ©David Dodge

Solar is now one of the cheapest ways to generate electricity on the planet, and solar is the coup de grâce of the deep energy retrofit to get to net-zero. Alberta, Canada, homeowners Darcy and Darren Crichton did their DIY (do-it-yourself) deep energy retrofit using geothermal heating and cooling, and their utility bill last year ended with a positive balance. They cut their gas line and only have an electricity bill these days.


Solar is now one of the cheapest ways to generate electricity on the planet, and solar is the coup de grâce of the deep energy retrofit to get to net-zero.

5. ‘Icing on the Cake’



Induction cooktops are twice as efficient as electric stoves.  ©David Dodge
Induction cooktops are twice as efficient as electric stoves. ©David Dodge

Those first four steps can easily deliver a net-zero home, but a few other cool things can further improve a home. Speaking of baking cakes, an induction range is twice as energy efficient as a standard electric stove and performs better than any other kind of stove. Heat pump dryers are much more efficient, and many come in ventless models, thus eliminating another hole (the vent) in a wall. And, of course, homeowners can use LED lights, low-flow water devices, and smart home technologies to make the home even more efficient and functional.


Whom to Call?


A deep energy retrofit done all at once can cost $100,000 or more. It will pay for itself in time, but it’s important to work with contractors who have already done similar work and can provide references.


State, local, and national incentive programs often provide a homeowner with incentives for various components.

State, local, and national incentive programs often provide a homeowner with incentives for various components, so explore these options. Some areas also have Property Assessed Clean Energy (PACE) financing programs that provide loans with payment plans that are synced to the paybacks of the investment, so one does not pay out of pocket. In Canada, a federal interest-free loan is available, but it’s capped at CAD 40,000.


Canadians Jesse and Jena Tufts have a 1953 bungalow in Edmonton. The home needed some work anyway, and they wanted to transform their story-and-a-half home into a two-story home. According to a February 2023 article by the City of Edmonton, they transformed their old home into a dream home with R44 insulated walls by adding most of the features described above. They replaced their roof with a solar-optimized south-facing roof with a rooftop deck surrounded by the roof’s solar panels. Jesse is an engineer, and after the renovation, he took a job with the company that did the renovation. He is now one of the most knowledgeable deep energy retrofitters out there.


What about DIY?


Staging one’s project DIY over time for budgetary reasons, the key is doing it right the first time, one step at a time. Sandercock, for instance, had to remove his solar panels from his home and reinstall them after his deep energy retrofit.


For a DIY renovation, one must do the homework. It’s better to do one thing right rather than dabble in half measures. The results will be better, and there won’t be any regrets when one decides to take the home to the next level.


That’s what the Crichtons did. They began their deep energy retrofit 20 years ago before anyone knew what deep energy retrofit or net-zero even meant!


In their inspiring story, the couple researched their options and added double walls, replaced the roof, added a geothermal ground source heat pump and solar panels, and make money on their utilities today.


One year ago, the Crichtons still had a gas line, a gas stove, and a gas heater in the workshop. They were so inspired after adding the geothermal system that they ditched the gas stove, bought an induction stove, added even more solar panels, and cut the gas line. They benefited from a bevy of incentives and grants and are very happy with the result.

Whether DIY or hiring a contractor, doing it right will pay dividends for the life of the home and add value to it as well.

 

*David Dodge is an environmental journalist, photojournalist, and the host and producer of GreenEnergyFutures.ca, a series of micro-documentaries on clean energy, transportation, and buildings. He’s worked for newspapers and published magazines and produced more than 350 award-winning EcoFile radio programs on sustainability for CKUA Radio.


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