How Many Solar Panels Do I Need For My House in Ontario?

Aniket Bhor in Residential Solar

The transition to solar power from grid power is as inevitable and obvious as the transition to smartphones a decade ago. As solar power steadily becomes a mainstream power source, an increasing number of homeowners are trying to learn as much about the technology as possible.

One of the most common questions we come across is about the number of solar panels needed by a typical house in Ontario. While it depends on many factors such as the existing energy consumption, size of the roof, and available sunlight, we can still try to find out the average number of solar panels required by an Ontario household.

Average Number of Solar Panels Needed by an Ontario Household

According to the Ontario Energy Board (OEB), an average household consumes about 9000 kWh of energy in a year. Using this number, we can calculate the system size to offset 100% of energy consumption. When we do, we find out that an 8 kW system will be sufficient to power the average-sized home in Ontario.

If you consider the usual solar panel size of around 400 watts, that means you would need about 20 panels to power your entire house. Although these are the numbers for an average household, the size of a solar power system required by home may vary anywhere between 5 and 10 kW (with some exceptions going lower and higher than those too).

But as they say, few are really on the average mark, and it’s still important to know how many panels your house needs. Let’s see how to find out.

Calculating the Number of Panels Needed for Your House

If you’re wondering how many panels your house will need, the easiest way is to contact a reputed solar company that installs panels in your area. But if you are a curious soul who wants to figure it out yourselves, pick up your hydro bills and follow the three easy steps below.

Firstly, locate the section for kWh consumed. Add the values of monthly kWh to get the value for yearly kWh consumed.

A typical Ontario Hydro One bill

You can also log into your utility’s online account to view bills. Let us say that your annual consumption totals 10,000 kWh. To find out the number of solar panels you need, you need to divide the annual consumption with your location’s solar irradiation value, or in simpler words, the solar power generation potential.

The second step is now to find out the size of the system required. Supposing that you are located in Ontario, your house receives enough sunlight to generate 1166 kWh/kW.year on average. 

Solar power system size required = 10,000 ÷1166 = 8.57 kW

And lastly, for the number of panels – let us again consider that you will be using 400 W panels. Thus we have – 

8570 W ÷ 400 W = 21.42 solar panels

This is a little impossible as we obviously cannot break the 22nd panel. It would thus make sense to use 22 panels. 

Also, as we discussed previously, the number of solar panels required depends on many factors – more than just energy consumption. The orientation and inclination of your roof are some of the factors in play. Any additions in the near future such as the use of an electric vehicle might also be needed to be taken into account. Therefore, as stated before, an experienced solar installer can design the perfect system for you.

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Can the House Run On Solar Alone?

Once you have the number of solar panels required, the next question is whether the house can be run only with solar power. This is an important question, and the answer is a bit more complex than just a yes or no. 

Firstly, we calculated the required solar panels based on the annual consumption. Your daily consumption will not be uniform throughout but fluctuating, which means that on some days your panels will generate more power than required, and on some days it will be less than sufficient.

What we can do is speak of average values of consumption and generation. On most days, the average solar power generation can suffice your average energy usage for most days. Of course, this also depends on whether you have sufficient roof space available, which brings us to the next most common question. 

How Many Solar Panels are Needed for a 1500 sq. ft. House?

We are often asked how many solar panels would be required for a certain size of a home. For instance, a lot of customers ask about the system size needed for a 1500 sq. ft. house. A more logical question is – “How many solar panels can a 1500 sq. ft. roof fit?”

The reason being, as we previously discussed, the amount of solar power needed depends more on your energy use and less on the size of the house. As for the question of how many panels can fit, every 100 sq. ft can accommodate 1 kW of solar panels. A 1500 sq. ft. house can thus fit at least 15 kW of solar panels.

How Much Do Solar Panels Cost for a 1500 sq. ft. House?

Naturally, the question that follows (and often precedes other ones) is the pricing. Going back to our example above, although we’ve established that an average house might need an 22 solar panels, they are only one of the many components of the system.

The multitude of individual equipment that makes up a solar power system includes solar panels, racking, inverters, charge controllers, wiring, electrical panels, etc. So a more meaningful question becomes the price of the system and not just of the panels. 

A typical system costs between $3 and $3.5 per watt of installed capacity. So an 8 kW system would need around $24,000, which can reduce based on the available incentives and rebates.


To summarize, we can say that a typical Ontario house needs anywhere between 5 and 10 kW of solar panels, depending on the energy consumption of its residents. And that the price can cost anywhere between $15,000 and $30,000, and can be lowered using incentives.

Ultimately, all the questions discussed above are a part of one big question, or at least lead us to that question – Is going solar worth it? The answer to that, unlike the previous questions, is not complex at all. Going solar is totally worth it, thanks to plummeted prices coupled with the unreliability and rising costs of grid power.

And going solar with an experienced installer like Green Integrations might as well be your best decision of this year!

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