When two installers quote $19,500 and $23,000 for what look like the same roof, it is hard to know which is better value. Price per watt gives you a common yardstick. It is not the whole story, but it is where a fair comparison begins. Prices below are in Canadian dollars (CAD) and are planning ranges only.
The calculation
Take the total installed price and divide it by the system’s DC capacity in watts. If a quote is $21,000 for a 7 kW system, that is 7,000 watts, so the price is $3.00 per watt. Write down whether the figure is before or after incentives, and whether tax is included, because the same system can show different numbers depending on what is counted.
Use DC size, meaning the combined rated output of the panels, rather than the inverter’s AC rating. Twenty panels at 420 W make 8.4 kW DC, even if the inverter is rated at 7.6 kW AC. Mixing the two figures can make a quote look cheaper or dearer than it really is. The efficiency and wattage guide explains how panel ratings work.
What is typical
At the time of writing, installed cost for grid-tied residential solar has commonly been about $2.50 to $3.80 per watt before incentives. Atlantic Canada is often at the higher end. Vendor sources conflict in places, so use this as a sanity check and not as a target.
Here is the same range applied to three example sizes.
| Size | At $2.50 per watt | At $3.80 per watt |
|---|---|---|
| 5 kW | $12,500 | $19,000 |
| 8 kW | $20,000 | $30,400 |
| 10 kW | $25,000 | $38,000 |
The total cost overview shows how those ranges relate to real quotes.
Why the same roof gets different prices
System size
Fixed costs, including site visit, design, permits, inspection, utility paperwork and mobilization, are roughly the same regardless of size. Spread across more panels, they shrink per watt. A small 3 kW system can cost noticeably more per watt than a 9 kW one. See how this plays out in our system size comparison.
Equipment
Higher-efficiency panels, microinverters or optimizers, and longer warranties raise the price. They can be worth it on a shaded roof or one with several orientations, but they are not automatically better for a simple south-facing slope.
Roof and electrical work
Steep pitches, tile, multi-level roofs or a long cable run all raise labour. A service panel upgrade can add a few thousand dollars, and some quotes include it while others leave it for later.
Installer overhead and business model
A company with a large sales team, advertising and a long workmanship warranty has different costs from a small crew that does its own installs. Neither model is wrong. The point is to understand what you are paying for.
Timing and demand
Quotes can rise in busy seasons or when equipment supply is tight. Prices can move noticeably within a year.
How to compare quotes fairly
Convert each quote to price per watt on the same basis, then check four things.
- Scope. Does the price include permits, inspection, the utility application and any panel upgrade? Ask for exclusions in writing.
- Equipment. Compare model, rated wattage, efficiency and certification marks such as CSA.
- Production estimate. Ask for expected annual kWh, and the shading and tilt assumptions behind it. A quote that promises much more output from the same size system deserves a question.
- Warranties. Product, performance, workmanship and inverter terms, and whether they transfer to a new owner.
If one quote is much cheaper than the rest, find out why. It may reflect a stripped-down scope, lower-grade parts, or simply a more efficient company. The installer selection guide lists the credentials and references worth checking.
Price per watt versus price per kWh produced
Price per watt does not account for how much energy the system will actually make. Two systems of the same size can produce different amounts if one is shaded and the other is not. A more useful comparison for decision-making is cost per expected kWh over the system’s life. Take the net price, divide by expected annual production, and then by the number of years you expect to use it. If a $20,000 system makes 9,000 kWh a year for 25 years, and ignoring degradation and inverter replacement, that is roughly 9 cents per kWh. Compare that to your electricity rate, but keep in mind that degradation of about 0.4 to 0.6 percent per year, and an inverter replacement somewhere around 10 to 15 years, will shift the figure up a bit.
Watch for quotes that change the unit
Some quotes list price per panel, or price for the AC size of the inverter, which makes the number look different. Convert everything to DC watts before comparing. If an installer cannot tell you the total DC capacity plainly, that is worth noting in itself.
A note on incentives
Provincial rebates and utility programmes can lower the net price, but they change often. Ontario’s Home Renovation Savings programme and a BC Hydro solar rebate were reported active in 2026, and you should verify the current terms. No federal residential solar grant is open as far as we know. Always compare quotes both before and after incentives so a rebate does not hide a pricey bid.
Putting it together
Use price per watt to screen, scope and warranties to filter, and expected production to judge value. For wider context, browse the costs and savings hub.
Quick answers
What is a good price per watt for solar in Canada?
Recent quotes have commonly run about $2.50 to $3.80 per watt before incentives. A price inside that range is not automatically good, so compare scope and warranties too.
Why is price per watt lower for bigger systems?
Design, permitting, travel and the inverter setup cost roughly the same whether you install 5 kW or 10 kW, so the cost per watt drops as size rises.
Should I choose the quote with the lowest price per watt?
Not by that figure alone. Check equipment quality, warranty terms, included work and the installer's track record before deciding.
Where to verify
Rules and prices change. Confirm current details with the official bodies below.