It can be overwhelming to compare quotes from multiple solar companies. (And we always recommend getting at least two!) Which numbers really matter? How important is the choice of solar panels? How do I sort out conflicting information? Which system is really the right choice for my home? This guide is our honest and straightforward attempt to help you sort it all out.
Price: Compare Price per Watt
When comparing the price of your solar array, it is important to compare two different factors: (1) the total price of the system to make sure it is within your budget and (2) the price per watt to see if you are getting a good deal. The number of total watts (w) or kilowatts (kW) in your solar array determines how much energy the system can produce. All other things being equal, like the amount of shade and orientation of the panels towards south, the more kW your solar array has, the more energy it will produce.
Solar arrays are like boxes of cereal. The smaller box may appear to be the better price, but when you calculate the price per ounce, it may turn out that the larger box of cereal is actually the better price. To compare cereal across brands and sizes, you need to compare the price per ounce to find out which choice is the best deal.
To compare solar quotes and find out which choice is the best deal, compare the price per watt and not just the total cost. If the price per watt isn’t listed in the estimate, take the total price of your system before incentives, divide the number by the total kW of the system, and then divide that number by 1000 to get the price per watt. The final number is typically $2-4 per watt.
System Size: Compare the Total kW
To compare the size of a solar array, many customers are tempted to compare how many solar panels are included in each quote. Unfortunately, solar panels come in different sizes and cannot be compared equally. To find out how much solar you are getting in each quote, you need to compare the total kW size of the system, not just the number of panels. The kW size of the system determines the electricity production of the system, not the number of panels. Four 300-watt panels will produce the same power on the same roof as three 400-watt panels; they will each form a 1.2 kW (or 1200 watt) solar array. By looking at the total kW, you can compare how much electricity production capacity is included in each quote.
Solar Panel Efficiency: Consider the Panel Size
It may be tempting to think that higher-wattage solar panels are more efficient or higher quality than lower-wattage solar panels. Isn’t a 420-watt panel better than a 360-watt panel? Not necessarily. With solar panels, higher wattage does not equal higher efficiency. The physical panel size also needs to be considered.
Solar panels come in a variety of physical sizes. Higher-wattage panels tend to be physically larger (such as a 390 watt, 72-cell panel, 3.3’ by 6.5’ panel) while lower-wattage panels tend to be smaller (such as a 330 watt, 60-cell panel, 3.3’ by 5.6’ panel). Higher-wattage panels aren’t necessarily higher-efficiency or “better” panels, they are likely simply physically larger panels.
Many solar installers, ourselves included, use smaller panels for residential installations because the smaller physical panel size allows us to rearrange panels into more configurations to better fit each roof. By using smaller panels we are actually able to fit more power production on each roof. This isn’t always the case; when the roof geometry allows, larger panels may be the right choice for your home.
There are higher efficiency panels on the market. These panels produce more energy while staying physically smaller in size. But the trade-off for efficiency is cost. For example, the REC 370-watt panel is a premium 60-cell panel that’s only 3.33’ x 5.65’ in size but costs 40% more per watt than the 3.45’ x 5.75’ Qcell 340-watt panel. Since these higher efficiency panels cost more, we only recommend them to customers with limited roof space that need to squeeze out every watt of power production they can with their limited square footage. Generally, the more cost-effective way to produce more power is simply to add another standard-efficiency solar panel rather than switching to more expensive high-efficiency panels.
Energy Production: Beware Overestimates
Every solar company needs to make several assumptions when calculating how much electricity a solar array will produce. How much shade from surrounding trees and buildings will cover your array throughout the year? How much snow will cover the array in the wintertime? How much production will be lost due to system inefficiencies, temperature fluctuations, and weather? At Drews Solar, we tend towards more conservative estimates when making assumptions. This means our estimates and quotes may show our arrays producing less power annually than our competitors. Other companies make more optimistic assumptions about how much electricity their systems will produce.
The solution? Hold the energy-production and annual-offset estimates loosely. Compare the kW size of the solar array, not the amount of power the solar company tells you the array will produce. If you receive two estimates for a 6 kW solar array and one tells you the array will produce 6000 kWh of electricity per year and the other tells you it will produce 8000 kWh of electricity per year, know that you are likely to get production somewhere in that range, but that there are too many factors for a perfect prediction to be made.
At Drews Solar we tend to be more conservative in our estimates because we want our systems to produce at least as good as we predict. While our ultimate goal is to be as accurate in our assessments as possible, we’d prefer our customers to be pleasantly surprised that their systems produced more power than their quote estimated rather than be disappointed it is not producing at the level they expected.
Quality: Look at Independent Reviews and Warranties
When trying to assess the quality of panels, inverters, and other components of your solar array we recommend looking at independent testing and data. PVEL, an independent testing group, offers scorecards for both panels and inverters that may be worth consulting when choosing your array.
Another thing to consider is the warranty offered with the inverters or panels. If your panels and inverter(s) come with a 25-year warranty, they are likely high quality, reliable components.
One note when comparing panels and other components: don’t get caught up in looking for the “best of the best.” There are a lot of quality, reliable panels and inverters on the market that will dependably produce power for you across the lifetime of your solar array. Just like cars, a Honda may not have the highest specs when compared to a BMW or an Audi but will just as reliably get your family where you need to go. We recommend high-quality panels and inverters but find chasing the highest-end specs often results in just higher prices with very little additional electricity production or reliability. The same goes with choosing consumer-name-brand panels. While customers may know the names LG or Panasonic more than they know Silfab, Qcell, or REC, within the world of solar panel production, consumer-name-brand panels are not necessarily better than name brands known only within the solar world.
Installation & Customer Service: Look at Online Reviews
Your home is likely your largest investment. You want a solar company that takes care of your home, your roof, and your electrical system. You also want to choose a solar company that will take good care of you throughout the process, making it easy to go solar without causing you headaches and confusion along the way, and will provide quick and quality service to your system if it is ever needed. There are many quality installers in Wisconsin, but we highly recommend reading online reviews before choosing your solar installer to make sure you choose one that will take good care of you and your home. The highest quality panels and components mean little if they are poorly installed or your home or roof is damaged in the process.
Return on Investment and Financing: Look at the Total Cost
Return on investment and savings over the lifetime of your solar array are both great indicators of the value of your solar array, but there are two assumptions that need to be made when calculating these numbers: (1) the amount of energy your solar array will produce each year and (2) the projected rise in electricity costs over time. As outlined above, each solar company needs to make several assumptions when calculating the amount of energy your solar array will produce each year, and therefore the return on investment and savings over the lifetime of your array may end up being overestimates or underestimates, based on the assumptions the installer made. Drews Solar tends to make conservative assumptions that may lead to underestimating the savings over time. Other companies may tend toward optimistic assumptions that may lead to overestimating the savings over time. Electricity costs also tend to increase over time. The more a solar company assumes they increase over time, the most cost effective going solar will look on paper. Drews Solar assumes the more conservative 2.2% yearly rise in electricity rates based on historical data. Other area solar companies assume electricity costs will rise at rates as much as 4% a year, which makes going solar look even more economically advantageous on paper than our 2.2% increase projection.
Some solar companies offer in-house financing. It may be the right choice for certain homeowners, but we recommend considering at least one other option, such as a loan from your own bank or credit union, when financing a solar array. You may find that your system may end up costing you double when choosing to financing through a solar company rather than paying for it outright or financing your solar array through an independent bank or credit union. We recommend considering the total costs of going solar and not just the monthly savings to see which option will be the most cost-effective choice overall.
At Drews Solar we are committed to integrity and quality. We want happy customers over the whole lifetime of their solar array, which means we are committed to the highest quality installation and materials, we sweat the details to get it right, and we communicate with honesty and integrity every step of the way. These aren’t just words- it’s who we are.
Still having trouble sorting out which contractor or system is right for you? We’d be happy to look at the other quotes you’ve received and give you our honest assessment of your choices. If we’re not the best choice, we’ll let you know which other contractor we recommend or do our best to update our quote to give you the best system at the best price possible.