Is it worth it to put solar panels on your home?

The cost of solar panels has plunged in the past decade, so it seems like rooftop solar could be a good opportunity for homeowners to save on electricity bills and cut carbon emissions.

That's what Ashley Reid thought when she installed solar panels on her home in the Kitchener-Waterloo area of Ontario a year and a half ago. 

"I'm an accountant," she said, "and when you do the math … financially it makes sense to have solar on your house." 

A Radio-Canada analysis earlier this year found that's the case in most major Canadian cities.

But not everyone agrees. "I would not be recommending people install it for economic reasons," said Heather McDiarmid, a climate and energy consultant who released a report earlier in August on the climate and financial benefits of residential rooftop solar for the Ontario Clean Air Alliance.

Environmentally, the case for solar is clearer, and a recent study found rooftop solar is even better for the climate than large-scale solar farms.

Here's a closer look at rooftop solar in Canada and things to consider, including the up-front cost and a mix of policies and incentives that vary widely across the country.

While large-scale solar farms are cheaper to install per kilowatt, a recent study led by Western University engineering professor Joshua Pearce found that residential solar is actually greener. 

"You just have less materials involved," he said, noting that solar farms mount panels using concrete or steel, which generate a lot of emissions during production, whereas residential installations mostly use existing infrastructure — your roof.

The study found that rooftop solar systems generate 18 to 59 per cent fewer carbon emissions than solar farms per kilowatt during production and installation. 

Both Pearce and McDiarmid found solar panels generate more energy than were used to produce them in less than two years, even in Canada. 

Residential solar is especially beneficial for the climate in provinces where it displaces electricity generated from fossil fuels, such as Alberta and Saskatchewan, which also happen to be the sunniest.

The new report from the Ontario Clean Air Alliance notes that solar generates the most electricity at times of day when Ontario relies most heavily on gas power plants. It calculates that a 10 kW solar array could avoid 1.5 tonnes of carbon emissions in 2024 and 3.9 tonnes of emission per year (roughly the amount of emissions generated by a car) by 2030, when Ontario is expected to rely more heavily on gas generation at peak times.

But only one per cent of electricity generated in 2022 came from solar, Natural Resources Canada reports. According to the Canadian Renewable Energy Association (CanREA), most of it came from large-scale solar farms, also known as utility-scale solar.