So you’ve got solar quotes through Glean and now you need to compare them. You’ve come to the right place! Open up your Glean quotes summary document beside this webpage and go through each item line by line. We’ve created this guide so you understand the meaning behind each point of comparison, from solar potential to manufacturer warranty.
System Cost (Excluding Rebate & GST)
This is the cost of a turn-key solar installation before any rebates and tax has been applied. This includes design and installation labour, all required system components (solar panels, inverters, racking, etc.), and permitting.
This is typically the most important factor when choosing between solar quotes. After all, when you buy solar panels, you are pre-purchasing your electricity over the next 30+ years. The lower the initial cost, the lower your average electricity price over the lifetime of the solar panels will be. However, we highly encourage you to read on to ensure you are making the best choice based on all aspects of the quotes, not just the price.
Pre Rebate Cost Per Watt (Unit Cost)
Cost per watt is the price you pay for each watt of solar installed. It is the unit price for solar which allows you to make an apples-to-apples price comparison of different solar quotes. Note that cost per watt is calculated before rebates are subtracted and before tax is applied.
Without any government grants, Glean is currently seeing $2.50 – $3.00 / watt DC installed for rooftop residential solar. For an average 5 kW residential solar installation this means a cost range of $12,500 to $15,000 before government grants. The following factors can make solar more expensive:
- The cost/watt ($/W) will increase as the size of your solar array decreases since larger solar arrays benefit from economies of scale.
- A steep roof may require scaffolding or additional safety measures
- An old roof may need replacement
- A remote location that is far from major cities/towns will require increased travel costs
- An older home may have electrical components that need replacement
Grants & Rebates
Any available grants and rebates will be subtracted here. Please see our Solar Incentives page for more information.
Net Cost (Incl. GST)
The net cost includes grants and GST. This is the end price you will pay for your solar installation.
Property Annual Electricity Use (kWh)
A kilowatt-hour (kWh) is a way to measure the amount of electricity used in one hour. For example, if it takes 1,000 watts to run a microwave for 1 hour then 1-kilowatt hour has been used.
By using your previous year’s electricity use data, we can estimate how many kWhs your home will use annually moving forward. If you have mentioned a reason that your electricity consumption will increase in the future, and we believe we can meet the utility’s requirements for claiming an increased consumption (i.e. electric vehicle purchase, installation of A/C, etc.), then this number will reflect that change.
This number is particularly important because there are rules that limit the amount of solar electricity you can produce each year. Your solar production should not greatly exceed your own past electrical consumption on a yearly basis. This is a bit of a grey area because the utility doesn’t do the calculations to predict how much any given solar array will produce, so the solar contractors will have a good idea of what is likely to get approved by the utility. This is why you may see over 100% here.
Also, this number is used to calculate the Annual Percent Electricity Offset by Solar which is explained below.
Current Average Price of Grid Electricity
Using the electricity bill you’ve provided us as well as current transmission and distribution rate data, we calculate what you currently pay for electricity from the grid. This is typically the sum of:
- Your fixed or variable electricity price. For example: $0.071/kWh
- The variable portion of your transmission fee. For example: $0.035/kWh
- The variable portion of your distribution fee. For example: $0.010/kWh
- Example current average price of grid electricity: $0.071 + $0.035 + $0.010 = $0.116/kWh
This number is important because when you purchase solar panels you are choosing to replace grid electricity with renewable electricity produced by your solar panels. When your solar panels produce electricity that gets used in your home, you save the cost of grid electricity ($0.116/kWh in the example).
It is important to note that this is your CURRENT Average Price of Grid Electricity, which will certainly change in the future. We conservatively assume that electricity prices will rise at a rate of 2% per year, even though at the moment most people are looking at a significant price increase.
Annual Solar Electricity Produced (kWh)
This number shows what the solar installer estimates the annual electricity production from their solar design to be. To determine if this number is realistic see Assumed Solar Potential (kWh/kW) below.
When each solar installer designs your system, they must account for shading, roof orientation and other factors that will impact electricity production from your solar panels. The more electricity a solar array produces per kW installed, the better the financial return will be.
The best solar quotes accurately estimate the amount of electricity that the solar array will produce. Some solar installers may even choose to conservatively estimate production to under-promise and overdeliver. Just because a solar quote promises 20% more electricity production then it other installers, it doesn’t mean it will actually happen.
Annual Percent Electricity Offset by Solar
This number shows the percentage of your annual electricity use that will be offset by solar. Anything 100% or bigger means that the installer expects that their solar installation will make your home net-zero electrically. A net-zero solar array is not necessary to make solar a good investment. This is simply a metric to show what proportion of your annual electricity use will be powered by solar.
New Average Price of Solar Electricity
In technical terms, this is the Levelized Cost of Energy (LCOE). It is a measure of the cost per kWh of energy produced by your solar installation over 25 years. This is calculated by dividing the Net Cost (Including GST) by the total number of kWh that the solar array is estimated to produce over 25 years to give a New Average Price of Solar Electricity.
25 years is used because that is the length of the performance warranty of most solar panels. Your solar installation will produce electricity well beyond 25 years, just at a lower capacity than on day one, due to the slow degradation of the silicon in the solar panel. Most manufacturers guarantee at least 80% production at 25 years old, even though most panels are performing even better than that. This means that all the electricity produced by your solar system after 25 years is not considered in any financial metrics, and is therefore a bonus, and a big one!
This metric can be compared to your Current Average Price of Grid Electricity to determine if solar electricity will be cheaper. However, although the price you pay for your solar installation can never change, the price of grid electricity can rise and fall. The more expensive grid electricity becomes, the better your investment in solar panels becomes. Solar is a hedge against rising electricity prices.
Annual Emissions Saved (tCO2e)
When you purchase solar panels, you are choosing to reduce your reliance on grid electricity. For each kWh your solar array produces, you are avoiding the use of a kWh of grid electricity. Since electricity produced by solar panels is emission-free and grid electricity is mostly produced using fossil fuels, installing solar will reduce greenhouse gas emissions. This number represents the annual tons of CO2 equivalent greenhouse gasses you are saving by installing solar. In Alberta, the grid intensity blah blah number from Natural Resources blah blah report? is use to determine how many tons of C02 are offset by using alternative sources of electricity.
What about the emissions that are created when solar panels are manufactured? Do the emissions that are saved by using solar electricity enough to offset the emissions created when they are made? Yes! In fact, most solar panels offset their own emissions in under 2 years. That is a pretty good return on your carbon investment!
Emissions Equivalent – Gasoline Saved (L/yr)
This number converts the Annual Emissions Saved (tCO2e) into the more relatable emissions equivalent of Litres of Gasoline saved. If you install solar, it will have the emissions impact equivalent to saving X Litres of gasoline. This conversion comes from…
Solar panels provide you with financial benefit in the following ways:
- When solar electricity is used in your home you save the cost of electricity as well as the variable transmission and distribution charges (see Current Average Price of Grid Electricity explained above).
- When more solar electricity is produced than your home needs, the excess electricity is sent to the grid for a credit on your electricity bill. That credit is earned at a rate equivalent to your price of electricity only. You don’t get credited for the variable transmission and distribution charges.
We estimate how much solar electricity will be used in your home and how much will be sent to the grid each year and calculate your annual electricity bill savings. Other inputs like grid price increase of 2%?
Annual Return on Investment
Return on Investment (ROI) is a profitability metric used to evaluate how well your investment in Solar will perform. It can be used to compare the profitability of solar to other investments. ROI tries to directly measure the amount of return on a particular investment, relative to the investment’s cost. It is calculated by dividing the electricity bill cost savings (or return) by the initial installation cost. Note that a conservative grid electricity price increase of 2% is assumed in this calculation. If grid electricity prices rise by more than 2% per year, the ROI will improve.
A word of caution about ROI: if you only compare the ROI of solar to other investments, it is likely that you won’t be accounting for risk. Because solar is warrantied for 25 years, the primary risk when investing in solar panels is that grid electricity prices fall. If another investment has a higher ROI be sure to assess what risks are associated with that particular investment. You might find that your solar project’s ROI is very competitive with most other investments. Too far?
Approximate Payback Year
The payback period is the length of time it takes to recover the initial investment in solar. It is essentially the point where your initial investment has doubled ?. It is calculated by dividing the Net Cost (including GST and rebates) by the annual cash flows (explain this). A conservative 2% grid electricity escalation rate is used. We typically see payback periods as low as 8 years and as high as 18 years, which is a reasonable amount of time for your initial investment to double.
A word of caution about payback period: very few other investments are judged using payback period. A payback period is never calculated when you buy a new furnace or invest your money in the stock market.
Total System Size
The Total System Size is measured in kilowatts (kW), which is 1000 watts (W). The number of kWs reflects the capacity, or potential for your solar system to produce electricity. It does not refer to the actual amount of electricity that will be produced, as that is influenced by several factors that are specific to each site. This number is easy to determine. For example, 12 solar panels rated at 455W each is a 5460W system, or more commonly, a 5.46 kW system. This is simply the number of panels (12), multiplied by the panel’s wattage (455). The kW size of the solar array is important because it is used to determine the estimated solar potential below.
Installer Solar Potential (kWh/kW)
Solar potential (or photovoltaic potential) is the expected annual kilowatt-hours (kWh’s) of electricity production resulting from 1 kW of solar installed on your roof. So, if a 5 kW solar array is expected to produce 5,500 kWh in one year, the solar potential is: 5,500kWh / 5kW = 1,100 kWh/kW.
Solar installers will use special modelling software to estimate the solar production of their proposed array on your property. They will decide on which values to input in order to predict losses due to shading, roof orientation, snow cover and other factors. Each solar quote will include annual estimated electricity production in kWhs as well as a solar array size in kWs. Glean divides these two numbers to determine what photovoltaic potential the installer is assuming. A solar quote that overestimates the solar potential of your roof should be questioned.
Glean Solar Potential (kWh/kW)
Glean uses data from Natural Resources Canada (NRCan) to estimate what range your solar potential should fall within.
Do we need to get into this? For instance, a south-facing, unshaded solar array (angled at latitude) in Alberta has a photovoltaic potential of 1,200-1,300 kWh/kW. Most homes have roofs that are much more shallow. While solar panels installed on a flat roof will achieve ~950 kWh/kW.
Please compare the Glean Solar Potential to the Installer Solar Potential to determine if the solar installer is overestimating the solar potential of their design.
For instance, if an installer claims that the solar potential of your roof is 1,250 kWh/kW while the Glean range is 1,000-1,100, the installer may be overestimating solar potential. The financials of the installer’s solar quote will be overly optimistic since they are assuming more production from their solar system.
Each solar installer will provide an installation warranty (AKA workmanship warranty) for your solar installation. It is important to read this to ensure that all aspects of the installer’s work are covered. Some important things to look for are:
- the warranty should cover roof damage or defects caused by the installation of the solar photovoltaic system subject to some exclusions
- the solar photovoltaic system must be installed in accordance with the Canadian Electrical Code by registered apprentices and journeyman electricians is this related to warranties?
There is no standard installation warranty length. However, anywhere from 1-5 years is common.
Solar Module Name
Overall, very little separates the performance of the solar panels that our installers will use, as they will all use Tier 1 rated solar panels (reference: Bloomberg report). Some slight differences can be found in efficiency, temperature coefficient, and warranty.
However, you might have an aesthetic preference for the look of the panel. Generally, the frames will either be silver or black, and the sheet behind the solar cells of the panel can be white or black. If you want more detail about the solar panels listed in your quotes, let us know and we can send over a the panels’ data sheets, which will include a picture of it.
Solar Module Performance Warranty
Regardless of the technology, you can expect performance to degrade over time, and solar panels are no exception. Because of this, solar panel manufacturers offer a power (or performance) warranty, that guarantees that their solar panel’s electricity output won’t fall below a certain level over a certain length of time. The common performance warranty is that the solar panels will produce at least 80% of their rated capacity after 25 years of operation. There is not much variation and most of the time, solar panels come with a 25-year performance warranty. can I delete this?
Solar Module Product Warranty
A solar panel product (or materials) warranty covers the integrity of the equipment itself. If any of your solar panels end up having a defect or mechanical issue the product warranty will cover it. Most manufacturers offer at least 10 years of coverage under a product warranty. In most cases, your installer should be able to tell that something is wrong during installation so the problem can be fixed before the problematic solar panel ever gets installed on your roof.
Inverters change D/C electricity that is produced by solar panels into A/C electricity that can be used by your home. See our guide to the anatomy of solar for more detail about the role of inverters. See Inverter Type (or see below? If this page is linked…I guess that doesn’t make a difference) for more detail about each inverter type.
There are 3 main types of inverters:
The solar panels in a solar array are apart of strings of about 6-12 panels, which means they are connected to each other electrically in series. There can be more than one string connected in parallel to a string inverter. String inverters turn D/C electricity to A/C electricity outside of the the solar array and are usually installed on a wall inside or outside your home. Although string inverters were the first type of inverter available and are often considered the most reliable (and cheapest) option, they may not be the best option for roofs with shading issues. If there is shading on one panel, it will bring down the production of the whole string.
Microinverters are module-level inverters meaning they are mounted on the roof along with the solar panels, so the D/C to A/C electricity conversion occurs on your roof. Each microinverter is connected to 1-4 solar panels whose production is being maximized by max power point tracking technology. This means that each panel, or each small group of panels, will be independent of the others so that any shading issues will not bring down the production of any others, as it would in a string inverter. Microinverters also allow the production from each solar panel to be monitored which can help with trouble shooting and making nerdy graphs.
D/C optimizers are used alongside string inverters to ensure that when part of a string gets shaded, the rest of the panels on that string arent affected. The optimizers are mounted to the back of each solar panel similar to microinverters. They track and regulate peak output and voltage before electricity flows to the string inverter. This optimizes the performance of each solar panel despite shading and orientation differences.
An inverter warranty covers the integrity of the equipment. If your inverter ends up having a defect or mechanical issue the product warranty will cover it. In most cases, your installer should be able to tell that something is wrong during installation so the problem can be fixed before the problematic inverter ever gets installed. Inverter warranties will vary by manufacturer and type of inverter. A standard inverter warranty should come with at least 10 years of protection. See the details of your installers labour warranty to learn at what point you may be paying for labour to replace a malfunctioning inverter.
Each Glean installer is asked to write a brief bio that may include information about the installer’s past projects, experience and mission statement. It is important to research the installer’s background, visit their website and ensure that they regularly perform solar installations. Although Master electricians are technically qualified to perform solar installations, solar is a very specific type of electrical work that requires unique knowledge and experience. You want an experienced install team on your roof!
All Glean quotes will include a mockup layout clearly showing how the solar panels will look on your roof. Although the layout can always change, you should look for a few clues in the layout to help you decide which solar installer is best. Ensure that the solar panels are:
- Not covering roof penetrations like chimneys and vent stacks.
- Arranged evenly and not crooked on the roof.
- Placed on only one roof face.
- Don’t hang over the edge of your roof.
Calculating the financial metrics for solar can be complicated and misleading depending on what assumptions are used. Glean calculates all financials using the same assumptions so that the financial metrics for each solar quote can be compared apples-to-apples. We leave no room for overly optimistic financials since we believe under-promising and over-delivering is best for the solar industry long term.