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How To Get Hot Water Without Heating The Planet

Heating water is the second biggest use of energy in our homes.

A steaming white claw-footed bathtub in a dark blue and yellow bathroom for a piece on how to heat hot water the environmentally friendly way

(Photo: iStock)

Canadians use a lot of hot water. Between bathing, showering, washing dishes and doing laundry, we each use an average of 75 litres of hot water every day. And it takes a lot of energy to heat that water. Water heaters account for nearly 20 percent of the energy used in the average Canadian home. In fact, water heating is second only to space heating when it comes to energy use, according to Dianna Miller, chief of the Energy Star program—a certification for energy efficient products and buildings run by Natural Resources Canada (NRCAN).

Heating all that water may get you and your things clean, but it can leave the planet with dirty emissions. Here’s everything you need to know about heating your water without heating the planet.

How do water heaters contribute to climate change?

Many Canadians burn fossil fuels to heat their water. In 2017, 69 percent of the water heaters used in Canada were fueled by natural gas. And every time a gas-fired water heater runs, it produces greenhouse gas (GHG) emissions. In Canada, water heating comprises 21 percent of residential GHG emissions.

An electric water heater, on the other hand, is a low-carbon way to heat your water—if you live in a province that uses clean electricity. (About 80 percent of Canada’s electricity grid is low-carbon.)

“In a hydro province, for example, like a province where electricity is generated most by hydroelectric dams,” says Miller, “an electric water heater isn’t considered to be contributing to GHG emissions.”

The only problem is, conventional electric water heaters use a lot of electricity, so they are expensive to operate. Gas water heaters, on the other hand, are up to 98 percent efficient. So until recently, we’ve had to choose between heating water with cheap and dirty fossil fuels or clean and expensive electricity.

That’s where heat pump water heaters come in.

What are heat pump water heaters?

Unlike other hot water heaters, heat pump water heaters don’t heat the water directly—they capture heat from the surrounding air and transfer it to the water tank. Heat pump water heaters are often referred to as refrigerators in reverse. While a refrigerator removes heat from an enclosed box and expels that heat to the surrounding air, a heat pump water heater draws the heat from air and transfers it to water in an enclosed tank.

Because less energy is needed to move heat than to create it, heat pump water heaters are up to 60 percent more efficient than conventional electric water heaters. So a heat pump water heater not only uses less electricity—putting less strain on the grid—but it costs less to run.

Heat pump water heaters are also referred to as “hybrid electric water heaters” because they can work using heat pump technology, electricity, or a combination of the two. They cost from about $1,000 to $3,000 plus installation, depending on the capacity of the unit and how efficient it is. (Gas water heaters cost anywhere from $700 to $3,000.) If that gives you sticker shock, remember that such an efficient system will pay for itself in as little as three years. Plus, heat pump water heaters are eligible for a rebate of up to $1,000 through the Canada Greener Homes Grant.

Are there other low-carbon hot water heaters?

If you are decarbonizing your home, you may be curious about other low or zero-carbon ways to heat your water. While heat pump water heaters are the most efficient—and the only type covered by the Canada Greener Homes program—there are some other great options.

Tankless water heaters

As the name suggests, these don’t store hot water in a tank. Instead, water flows through a heat exchanger, where it’s heated instantly by either a natural gas burner or an electric element. Also called in-demand water heaters, these deliver a constant supply of hot water as you need it. They come in different sizes and flow rates, measured in gallons per minute (GPM). The GPM dictates how much hot water they can deliver at once. If you don’t get a big enough unit, you may run into issues if someone wants to take a shower while the dishwasher is running.

Because there is no storage tank, these systems have a longer lifespan than traditional models, as there’s less rust or corrosion. They’re also more efficient, as they don’t waste energy keeping a tank of water hot. And they have a smaller physical footprint than traditional water tanks.

If you want to shrink your environmental footprint, ignore the gas-powered variety.
Electric models are low-carbon (if powered by clean electricity), and they don’t need to be vented. Because of this, they can go where gas units cannot go. And they are less expensive to buy. However, they have to be hardwired to the electrical panel, and larger units might require your home to get an electrical upgrade.

The cost for an electric tankless water heater is usually between $500 and $1,000 depending on the GPM and efficiency of the unit.

Solar water heaters

Solar water heaters use the sun’s energy to heat water. There are two system types: passive and active. Passive systems use only the sun and gravity to heat water. These are the simplest and least expensive, but they are only reliable in warm climates. In Canada you need an active system—which uses electricity to pass water through a heat exchanger and into your home.

An active solar water heater is made up of solar collectors, a heat exchanger and a hot water tank. The collectors, mounted to a roof or south-facing wall, absorb the sun’s radiation through a heat transfer fluid. The radiation is converted to thermal energy by pumping the fluid through the heat exchanger, which then transfers the heat to the water heater.

Solar water heaters are low carbon and incredibly efficient, using 60 percent less energy than a standard system. Here in Canada, they can provide up to 60 percent of your hot water.

So they’re typically used in tandem with another system. Even if they’re not the sole source of heat, they can help you save energy by preheating water before it enters the storage tank—so less energy is needed to heat the water to the temperature you need. According to Builders Ontario, a solar hot water system costs between $4,000 and $6,000, including installation.

How do I find the right heat pump water heater?

Since heat pump water heaters are fairly new to Canada, they’re not as widely advertised or promoted as conventional systems. The HVAC industry is still warming to this technology, so you won’t always get the answers you need by calling the nearest company. It’s best to do your research ahead of time.

Ask an energy advisor for recommendations

Heat pump water heaters are the only type of water heater eligible for a rebate under the Canada Greener Homes Grant program. But in order to qualify, you have to get a home energy audit—which is reimbursed under the program. A certified energy advisor will visit your home and run various tests to determine how airtight your home is, pinpoint air leakages, and recommend ways to make your home more energy efficient.

Energy advisors are great resources. They undergo standardized training and are familiar with the latest clean technology. And by inspecting your home and consulting with you, they know what your current equipment is and have a good sense of your household’s energy and water needs. They will likely be able to recommend certain systems, and they can also point you to a good supplier or installer in your area.

Look for the Energy Star label

“My first stop, when I’m buying anything, is to go to the Energy Star Canada web portal,” says Miller, “because they connect you to all of the certified products in your area, and you know that they’ll get certified with an Energy Star certification.”

Energy Star is trademarked by the United States Environmental Protection Agency, and in Canada the program is administered and promoted by NRCAN. Any product with Energy Star certification has undergone rigorous testing by an independent third party to ensure it meets strict efficiency standards. And certified products meet other relevant standards or legislation, too. You can use the Energy Star product finder tool to search for and compare heat pump water heaters.

Make sure it qualifies for a Greener Homes Grant rebate

If you’re interested in a particular model, make sure it’s included on the list of heat pump water heaters that are eligible for the Canada Greener Homes Grant. You can search for specific products or download the complete list. If you’re getting quotes from contractors, ask for them to include the Energy Star “unique ID number,” brand, model name and model number.

You also need to make sure to choose a product recommended by your energy advisor in your renovation upgrade report. Your heat pump water heater must be purchased in Canada, and online purchases are only eligible if they are ordered from an online distributor in Canada.

Things to consider when buying a water heater

Check the Uniform Energy Factor

“When comparing heat pump water heater models, compare Uniform Energy Factors (UEF),” says Patricia Kirchner, product implementation manager at A.O. Smith Enterprises Ltd, a company that manufactures water heaters. “The UEF is an indicator of the energy efficiency of a water heater, the higher the UEF, the more efficient the water heater, the better.”

If you’re narrowing your search to Energy Star models, or models covered by the Canada Greener Homes Grant, you’re already on the right track; these are within the range of 2.3 to 4.

Get the right size

No matter what type of water heater you buy, you’ll want it to provide enough hot water for your household’s needs. Take into account the number of people in your home, and how often you shower, wash dishes and do laundry. Use your current water heater as a benchmark—is it up to snuff?

“Take special note of your growing family,” says Shelly Vallée-Ewing, co-founder of Women in HVACR Canada. “ If your kids are going to be teenagers in the next few years, you should plan for their water usage.”

Give it space

“Heat pump models are taller than standard electric units, and they need room to ‘breathe,’ says Kirchner. “So the height and size of the room in which the heater is installed needs to be considered.”

Make sure you or your contractor measures the space, and check the specifications for your model—different units have different spacing requirements.

Because heat pump water heaters pull heat from the air around them, they perform better in a heated space. They also give off cool air, so they should be installed away from your main living space. (Ours is tucked away in the furnace room, beside the laundry room.)

Plan ahead

Don’t wait until your hot water heater dies before you get a new one. The last thing you need is to be mid-shower when your hot water heater conks out. And if that happens, you’ll probably be in such a hurry to replace it that you’ll default to the nearest installer—who may or may not be familiar with heat pump water heaters. So if you want to decarbonize your home, start planning in advance.

Research the different models available, know which one you’re interested in, and find out who installs them in your area. Know when your current model will reach its end of life and budget for its replacement. It’s a worthwhile investment and one that will help you go a long way towards shrinking your carbon footprint.

“If all Canadian homes used heat pump water heating, we could reduce our greenhouse gas emissions by more than three megatonnes,” says Miller, “The equivalent to taking about one million cars off the road every year.”