Here Comes the Sun
Get the basics on solar water heaters for your home
At first glance, hot water isn’t a very sexy topic (unless your mind immediately strays to a hot bath by candlelight). But with solar water heaters becoming cheaper and more convenient to install than ever, it can be. After all, these hot water heaters, which harness the power of the sun to meet a household’s hot water needs, are a great intermediate step on the path to owning a truly sustainable home—solar panels and all. Plus, what could be sexier than a government rebate to offset the cost of your new system?
Hot water basics
Heating water accounts for approximately 25 percent of your household’s annual energy use, making your hot water heater a worthwhile target for an energy audit. According the Natural Resources Canada (NRC), most Canadian homes have hot water heaters powered by conventional fuel sources such as electricity and natural gas, as well as oil and propane. An electric water heater, for example, usually consists of an insulated storage tank, thermostats to regulate temperature and heating elements submerged inside the tank. Hot water is stored then distributed to sinks, showers, dishwashers and other devices as needed.
Although newer systems, featuring extra insulation, heat traps and other energy-saving features, are generally very efficient, they still lose heat through the tank walls and base, as well as the conducting pipes. Tankless water heaters, also known as demand or instantaneous water heaters, circumvent this problem by heating water only as needed, rather than storing it for later use. In the past, tankless models struggled to provide an average-size household with hot water, but today there is a new technology, called low-mass water heaters, that are a much more effective option.
Going solar
Unlike conventional options, solar water heaters rely on a free, renewable source of energy that won’t harm the environment: the sun’s ultraviolet rays. And despite Canada’s long, cold winters and northern latitudes, NRC estimates that they can easily meet 50 percent of a household’s yearly hot water needs: ranging from 90 percent in summer to 10 percent in winter. This translates to a 50 percent annual savings on your water bill, but requires that you have a backup water source in place when demand is high or light conditions aren’t optimal.
Solar heaters consist of collectors (a series of tubes), mounted on the roof and generally aimed southward to capture as much solar radiation as possible throughout the year, plus a storage tank, located inside the home, and possibly a pump. In Canada, most solar water heaters are designed to work as a pre-heater for a home’s conventional water heater.
According to the Canadian Solar Industry Association (CanSIA), which certifies installers, there are three types available:
- seasonal collectors: circulate water through plastic pipes; offer little protection from freezing; most basic design.
- flat plate collectors: may circulate an anti-freeze fluid through insulated pipes; collected heat is released through a heat exchanger.
- evacuated tube collectors: highly insulated glass cylinders; most advanced design, maximizing heat absorption and minimizing heat loss.
Is solar right for you?
First and foremost, your home must have an unshaded patch of roof (or a patch of ground close to the house) where the collectors can be installed. It is also a good candidate for a solar water heater if your current system burns expensive and polluting fossil fuels, such as oil, or electricity (especially if you live in a province where coal-fired electricity is common), or is reaching the end of its lifespan. And it goes without saying that if your household places high demands on a water heater (think dishwashers, hot tubs, and even teenagers and babies!), they’re a good option to consider.
For the tech-minded, NRC has developed a piece of software, RETScreen, that can be used to assess various factors associated with renewable energy technologies (RETs), including solar hot water heaters. Users can analyze energy saving, cost, emissions reductions and more.
Costs and rebates
Like most energy-efficient choices, the upfront costs of a solar water heater run a little higher than conventional systems: averaging $3,500 to $7,000. However, CanSIA estimates that the systems pay for themselves in energy costs over five to 10 years. Units are designed to last 20 years and generally come with a manufacturer’s warranty.
And don’t forget the rebates. Domestic solar hot water heaters qualify for a $1250 rebate from the federal government through the ecoENERGY Retrofit program. Most provinces and municipalities also offer rebates that can offset most of the costs of the installation. For example, SolarBC offers a $1000 discount at the point of sale. So before you hire an installer, make sure that he or she can advise you on the rebates you may qualify for.
Getting started
CanSIA maintains a list of certified hot water heater installers across Canada. If you live in Toronto, Ottawa, Vancouver or Calgary, consult the Green Living Guides for your options.
Before you buy, installers such as GreenSaver, an Ontario-based not-for-profit organization, will conduct a solar audit to ensure there will be no shading or technical issues associated with the installation and to generate a cost-savings estimate.
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