I have solar panels installed. Why is my electric bill so high?

Do you already have solar panels on your home? Normally that’s a great thing, but maybe you’re looking at your monthly utility bill and wondering why it’s not lower.

For most people, helping the environment is one reason why people go solar, but the top reason according to market research is saving money on your electric bill. This is why it can be so frustrating if you’ve spent thousands of dollars on a solar installation or committed to a 25 year solar lease and you’re looking at a monthly electric bill that’s still pretty high.

There’s a few reasons why this can be the case: some of them are normal, but there are problematic issues that could be the cause too. This article will list some common reasons why your electric bill isn’t as low as you think it should be, and tips on what to do about it.

Solar panels don’t eliminate your electric bill

Unless you’ve gone completely off-the-grid and disconnected your home from your utility company, you will still get a monthly bill. If you financed your solar panels with a lease or power purchase agreement, you’ll actually get two bills: one from the solar company, and another from your utility company.

The vast majority of solar homes are grid-connnected, which means they can draw power from the electric grid when their solar panels aren’t producing any power.

Even if you generate more electricity in a month than your house used, with most utilities you’ll still get an electricity bill with a minimum charge. Most often this is a basic connection charge that you pay because your home is connected to the grid. On my National Grid bill in New York state, this is called a “basic connection charge”, and it’s $17.80 that I pay every month.

On your bill, what this is called and the amount you pay will be different from mine. There’s usually a few pages with your bill that explain the different charges, so read it closely to understand them better.

Your solar production will vary throughout the year

If you’ve recently added solar panels to your home and haven’t had them for a full year yet, you won’t know how exactly how much your electricity generation will vary from winter to summer.

Your solar installer probably gave you a month-to-month estimate of your solar production, but if they didn’t The Solar Nerd calculator will give you a reasonably accurate graph of your seasonal electricity generation.

Depending on your location, the difference in solar generation between summer and winter can be quite large. For this reason, if you’re looking at your solar production in the winter and you’re wondering why the panels aren’t matching your electricity use, be patient. Your energy production will increase in the spring and summer, and you might even bank credits because you generated more power than you used in a month.

If you have net metering, credits banked during the summer will be spent in the darker months of the year.

You might have a solar panel or inverter failure

While solar panels normally last a really long time, it’s still possible for you to experience a failure. If you have microinverters, this is less noticeable because you might have only one solar panel out. With a string inverter, a failure can knock out a string or the entire array, leaving you with no electricity production.

Your monitoring system will often alert you automatically, but it’s a good idea to check on your system periodically - at least once a week - to see if everything is operating normally.

With my Enphase microinverters, I get an automatic email alert to let me know if one or more microinverters isn’t producing electricity.

Are you using more electricity?

If you aren’t closely watching your electricity usage, it’s pretty easy for you to use more than you realize.

This can especially be true if you use a heat pump or central air conditioner. The weather isn’t the same every year, so if a year is hotter or colder than average, it’s easy for your heating or cooling system to use more electricity without you really even noticing.

The website Weather Data Depot is handy for looking up the number of heating or cooling days (the number of days in a year when you might need to use heating or air conditioning) in a year and comparing it to past years.

Or maybe you’ve been home more during the pandemic. Perhaps - like so many other people - you’ve taken up baking sourdough bread, and you’ve got an electric oven. If you do a little accounting by adding the amount of solar electricity you’ve generated to the total amount of kWh your utility company billed you for, you might see that you’re using more power than you realize.

Maybe your trees have grown taller?

One thing that can be easy to overlook is that the landscaping around your home might have changed since your system was installed. You might not notice a gradual change in the canopy of a tree until one day you start to see your solar production drop. Look for trees that are on or near your property that have grown taller or added branches and are now shading your solar panels.

Your solar panels might need cleaning

Many companies offer solar panel cleaning services, but at over $100 per cleaning, it’s rare that you’ll gain enough solar production from having squeaky clean panels to recover the cost of the service.

Rain will usually be all that you need to keep your panels clean. Still, with droughts becoming more commonplace, it’s possible that if you live in a dusty area and haven’t had rain in awhile, dirt on your panels might start to have a noticeable impact on your energy production.

If that’s the case, you can try to clean the panels yourself. All you need is plain water and some basic equipment.

An unscrupulous solar installer might have fudged the numbers

Like any industry with home contractors, unfortunately not every solar installer is ethical or equally skilled. When you get a solar quote, one of the key things they give you is an estimate of the amount of solar electricity you will generate over the course of a year.

This estimate should be based on the solar array’s specific conditions: its compass orientation and angle relative to the horizon, the amount of shading, and your average local climate. This is important because it determines how much electricity you can expect to generate, which determines how long it will take for your system to pay for itself. You can make a similar estimate very quickly using The Solar Nerd calculator, which uses the same software that many solar installers use.

Unfortunately some solar installers can get this wrong, either intentionally or unintentionally. Shading analysis - estimating how much shadows from nearby trees and buildings will affect your solar production - can be tricky. But an unscrupulous contractor might fudge the numbers to make the system performance look better than it will be to help close the sale.

What can you do about a badly designed solar system?

If you’ve purchased a home solar system and checked that shading, dirty panels, and equipment failures are not the problem, you might be in the unfortunate situation that your contractor overpromised and underdelivered on the system design.

The first thing to do is to check with your contractor and let them know that you think you have an underproduction issue. Give them a chance to take a look at your energy usage and assess your system. They might be able to track down the issue to one of the causes mentioned above.

If they’ve done that and you still aren’t satisfied with how the system is performing, take a look at your contract and find out if there is a production warranty. A good installer will guarantee that your system will perform within certain parameters. If it underperforms, you may be able to make a warranty claim.

What consumers can do to protect themselves

If you’re a homeowner with an underperforming solar array and you don’t have a production warranty from your installer, there might not be much that you can do about it. This is why it’s important to thoroughly vet your solar installers and understand what’s in your contract.

When you use The Solar Nerd for quotes, we prescreen installers to select the best companies in your area and exclude those with questionable practices.