Comparing Solar Quotes - What Most Ontario Homeowners Miss

Every installer uses different software, assumptions and quote formats. In some cases, key factors may be left out or certain numbers presented optimistically to make a proposal appear more competitive. Some installers offer financing, others offer leases and in some cases, leases are deliberately presented as loans. The challenge for homeowners isn't just finding the lowest price. It's identifying the most important elements in each quote, comparing them on an equal basis and understanding why differences exist between proposals.

While there are dozens of factors to compare, it's not always practical to evaluate everything at once. A good place to start is with the elements that are easiest to identify and compare across quotes.

Total price alone does not reveal much. A larger system will naturally cost more, so the unit cost is a useful way to compare quotes on equal footing:

Cost per WattThis is the unit cost of a solar panel installation. It is calculated by dividing the total system cost by the system size in watts and allows for fair comparison between quotes. = Total System (Cost) / System Size (Watts)

Note that system size is often shown in kilowatts (kW). Multiplying the system size in kW by 1,000 will give the system size in Watts.

In Ontario, most residential solar-only systems (without batteries) currently fall between roughly $2.00 and $4.00/W in the GTHA. If a quote falls outside this range, it's worth looking into why. Several factors can increase cost per wattThis is the unit cost of a solar panel installation. It is calculated by dividing the total system cost by the system size in watts and allows for fair comparison between quotes., including:

• Small system size
• Travel and logistics costs
• Required electrical upgrades
• Steep or difficult roof conditions
• Specialty roofing materials
• Premium equipment selections

Cost per wattThis is the unit cost of a solar panel installation. It is calculated by dividing the total system cost by the system size in watts and allows for fair comparison between quotes. is one of the most useful ways to compare quotes, but it doesn't tell the whole story.

Many solar quotes emphasize system size (kW), but what ultimately matters is electricity production (kWh). Two similarly sized systems can generate very different amounts of electricity depending on:

• Panel placement
• Roof angle and orientation
• Shading from trees and buildings
• Solar modelling software and assumptions

A well-designed system can provide better long-term value than a poorly designed one, even at a higher upfront cost. Compare system layouts and check whether each installer is using the most productive roof space.

In general, south-facing roof areas should be prioritized, while east- and west-facing roofs can still provide strong production. North-facing panels are rarely worthwhile in Ontario. Shading should also be carefully evaluated, as some installers fail to properly account for trees or other obstructions and their production estimates come in high as a result.

One useful metric for comparing solar quotes is solar potentialA metric used to describe the efficiency of a solar system. It represents how many kilowatt-hours a system produces annually for each kilowatt of installed capacity.:

Solar PotentialA metric used to describe the efficiency of a solar system. It represents how many kilowatt-hours a system produces annually for each kilowatt of installed capacity. = Estimated Annual Electricity Production (kWh) / System Size (kW)

Solar potentialA metric used to describe the efficiency of a solar system. It represents how many kilowatt-hours a system produces annually for each kilowatt of installed capacity. represents how many kilowattA unit of power that describes the size of a solar system. System size is calculated by adding up the wattage of each panel and converting to kilowatts.-hours of electricity a system is expected to generate annually for each kilowattA unit of power that describes the size of a solar system. System size is calculated by adding up the wattage of each panel and converting to kilowatts. of solar installed. It allows differently sized systems to be compared on a more equal basis.

Large differences in solar potentialA metric used to describe the efficiency of a solar system. It represents how many kilowatt-hours a system produces annually for each kilowatt of installed capacity. are often caused by modelling assumptions rather than real-world performance differences. For example, if two installers design nearly identical systems, but one projects 1,250 kWh/kW while another projects 1,125 kWh/kW, the higher estimate may simply reflect more optimistic assumptions around shading, snow losses or other modelling factors. If a production estimate seems unusually high, ask the installer to walk through their assumptions.

This Natural Resources Canada Map shows maximum solar potentialA metric used to describe the efficiency of a solar system. It represents how many kilowatt-hours a system produces annually for each kilowatt of installed capacity. across Canada and can be used as a reference point when comparing solar potentialA metric used to describe the efficiency of a solar system. It represents how many kilowatt-hours a system produces annually for each kilowatt of installed capacity. numbers.

Solar is a long-term investment, so warranties matter. The four most relevant warranties are:

• Installer Workmanship WarrantyA warranty provided by the installer that covers installation-related issues such as roof leaks or wiring problems. - Covers installation quality and installer-related issues such as roof leaks, wiring problems or improper mounting (typically 2-10 years)
• Solar PanelA device made up of photovoltaic cells that converts sunlight into DC electricity. Solar panels are also referred to as modules. Product Warranty - Covers solar panelA device made up of photovoltaic cells that converts sunlight into DC electricity. Solar panels are also referred to as modules. manufacturing defects (typically 10-25 years)
• Solar PanelA device made up of photovoltaic cells that converts sunlight into DC electricity. Solar panels are also referred to as modules. Performance Warranty - Guarantees that the panels will continue producing electricity at a certain percentage of their original output over time, accounting for gradual degradation (typically 25-30 years)
• InverterA device that converts DC electricity from solar panels into AC electricity for use in your home or export to the grid. Every grid-connected solar system requires an inverter. Product Warranty - Covers defects and failures of the inverterA device that converts DC electricity from solar panels into AC electricity for use in your home or export to the grid. Every grid-connected solar system requires an inverter. equipment, which is often the component most likely to require replacement during the system's lifetime (typically 10-25 years)

The workmanship warrantyA warranty provided by the installer that covers installation-related issues such as roof leaks or wiring problems. is the only warranty provided by the installer. The other three are provided by the equipment manufacturers.

Warranty coverage can vary significantly between solar quotes and details are often buried in the fine print. A good solar quote should clearly show all four warranties with coverage lengths that meet industry standards.

Estimated hydro bill savings are often where solar quotes differ the most. Some projections are conservative, while others may be overly optimistic.

Savings estimates can vary significantly depending on the type of system being proposed. A standard net-metered solar system works very differently from a load displacementA solar system configuration where any excess power sent to the grid does not receive hydro bill credits. Because exported electricity provides no financial benefit, these systems often include battery storage to capture surplus energy for later use rather than sending it to the grid without compensation. system that includes battery storageA system that stores solar electricity for later use, typically during power outages. Batteries are optional and are not required for net-metered solar systems.. In addition, projected savings depend heavily on modelling assumptions such as:

• Future electricity price growth
• Overall system performance
• Snow losses and shading
• Self-consumption vs. grid export
• Future changes in household electricity usage

Without consistent assumptions, accurately comparing savings projections between quotes is very difficult.

Ask installers how they calculated the savings estimate and what assumptions were used in their modelling. For example, a quote that assumes electricity prices will rise rapidly over time may show much larger long-term savings than a more conservative estimate.

Be cautious of unusually aggressive savings projections. If a quote appears significantly better than competing proposals, the assumptions behind it deserve close scrutiny.

The quality of the installation company is often just as important as the equipment itself. Even high-quality solar equipment can perform poorly if the system is improperly designed or installed.

When comparing quotes, look beyond price and evaluate the installer's experience and track record. Some useful things to consider include:

• Years in business
• Online reviews and customer feedback
• Experience with similar projects
• How quickly and clearly they respond to questions
• Whether installations are completed in-house or subcontracted
• Relevant certifications, licences and insurance coverage

Some of this information can be difficult to assess from a quote alone. A few ways homeowners can dig deeper when comparing installers:

• Online reviews - Google Reviews can be a useful starting point when researching installers, but they should not be relied on exclusively as they can sometimes be manipulated or fail to tell the full story.
• Company history - Homeowners can use Canadian business registries to verify when and where a company was incorporated, which can validate claims around company longevity.
• The quoting process itself - How quickly an installer provides a quote and responds to questions can be a strong indicator of the level of service during the project itself.
• Sales tactics - Be cautious of high-pressure sales tactics, unrealistic savings claims or quotes that lack important details. A trustworthy installer should be patient and willing to provide the time needed to make an informed decision.

Beyond the five factors above, several other details are worth checking across your quotes:

• Financial Payback - What is the actual breakeven point for the system on an apples-to-apples basis?
• Installation scope - Are ESAThe authority responsible for electrical inspections and approvals in Ontario. inspections and utility interconnection costs included?
• Financing terms - What are the actual interest rates and are financing claims realistic?
• Optional extras - What additional items can be added, such as inverterA device that converts DC electricity from solar panels into AC electricity for use in your home or export to the grid. Every grid-connected solar system requires an inverter. warranty extensions, rodent guard, etc?
• Payment schedule - How much is required upfront and what is the payment structure throughout the project?
• Solar panelA device made up of photovoltaic cells that converts sunlight into DC electricity. Solar panels are also referred to as modules. design image - Is a clear panel layout image included?

These details are easy to miss when installers present information in different formats, so it's worth confirming each one before making a decision.

The Home Solar Accelerator offers a free Quote Comparison Report that organizes multiple quotes into a consistent format, recalculates savings using consistent assumptions and flags areas where proposals differ significantly. Homeowners are paired with an independent solar advisor who can help gather quotes and walk through the results.