Rooftop solar in the United States is growing rapidly. The industry grew 30% in 2021 when more than 4.2 gigawatts of residential solar was installed (there are now 121 gigawatts of solar power nationwide) from the sunny southwest to regions less well known for their cloudless climates. While inflation and an uncertain economy may slow things down, the federal tax credit remains at 26% for the rest of the year. That means, it could be another big year for solar.

No two roofs are alike, because of angle or shading. States and municipalities offer different incentives. Net metering deals vary from place to place.

Even so, there are enough regional similarities (like electricity costs, solar costs, climate) to make a bigger picture view worthwhile. New England, despite having less sun than other places, has strong incentives throughout the region and some of the highest solar adoption in the United States. The east coast of the United States has strong enough solar potential to make solar panels worth it. Depending on the state, there are incentives beyond the federal tax credit.

The cost of electricity

For this exercise, we're calling the east side of the United States south of New England. That comprises Delaware, Florida, Georgia, Maryland, New Jersey, New York, North Carolina, Pennsylvania, South Carolina, Virginia, West Virginia and Washington, D.C. This group includes the Energy Information Agency's Middle Atlantic and South Atlantic regions, which is one reason not every state included sits nicely within the East Coast.

Electricity rates in these states range from $11.27 per kilowatt hour to $18.36 in New York, according to the EIA. The cost of electricity typically increases from year to year. Last year, prices increased by 4.3%, the largest jump since 2008.  The average monthly electricity bill ranges from $88.89 in Washington, D.C. to $138.16 in South Carolina. The other states in the region—Delaware ($117.06), Florida ($128.64), Georgia ($129.92), Maryland ($124.50), New Jersey ($109.54), New York ($110.47), North Carolina ($118.44), Pennsylvania ($144.90), Virginia ($131.72), and West Virginia ($124.09)—slot in between.

The cost of solar panels

Comparing costs for solar panel installations is a bit tricky. The total cost can vary based on local rebates available, the cost of labor in an area, supply chain issues and more. The total value to a homeowner varies due the price of electricity from their utility, the amount of it they use, and the suitability of their roofs. The cost of solar panel installations vary widely depending on the size of and how many solar panels go on a roof.

To get around some of these differences, the solar industry measures costs in price per watt, or the system's total cost divided by the total capacity of a solar system in watts. 

According to the consulting firm Wood Mackenzie, the national average cost of solar panel installation is $3.28 per watt. Depending on your source, averages by state vary. According to EnergySage, solar prices on the East Coast range from $2.44 per watt in Florida to $3.41 in Washington, D.C., which is a bit of an outlier.

The average prices per watt from roughly north to south: New York ($3.16), Pennsylvania ($3.01), New Jersey ($2.79), Delaware ($2.62), Maryland ($2.92), Washington, D.C. ($3.41), Virginia ($2.85), North Carolina ($2.75), South Carolina ($2.78), Georgia ($2.99), Florida ($2.44). West Virginia doesn't have an average listed. (Solar cost information varies by source. In EnergySage's estimate, only D.C. exceeds Wood Mackenzie's average.)

Solar's price is affected by federal, state and local incentives, including tax credits and net metering. Regardless of where in the United States you live, if you install solar in 2022, you can get 26% of the cost back as a credit on your federal income taxes. In 2023, the credit drops to 22% and in 2024 and beyond it goes away altogether. The credit could be extended by the U.S. government.

State and local incentives exist in the form of tax exemptions, cash incentives and net metering. You can find a comprehensive list of the incentives available to you by visiting the Database of State Incentives for Renewables and Efficiency and entering your ZIP code. (Be sure to vet the list that gets kicked back to you. Some may have lapsed or be programs that are no longer accepting new applicants.)

There are a wide range of incentives offered at the state and municipal level, but it is again variable: States like New York have multiple tax incentives and parts of Pennsylvania have rebates for solar panels on top of tax incentives. On the other end of the spectrum, West Virginia offers net metering but no other incentives for residential solar customers. Overall, incentives along the East Coast are not quite as strong as those found in New England, though most states offer local incentives and smaller jurisdictions (like counties and cities) offer rebates or tax credits more frequently than in New England.

Every state has net metering laws on the books. Florida's net metering rules were the focus of a recent political fight in the state that saw Gov. Ron DeSantis veto a bill that critics said would gut net metering benefits.

Florida, New Jersey and New York have provisions waiving sales tax on solar purchases. Maryland, New Jersey, New York, North Carolina, South Carolina, Virginia and Washington, D.C. all have temporary property tax exemptions for the increased value of rooftop solar or allow municipalities to make those exemptions. Governments and utilities in New York, North Carolina, South Carolina and Philadelphia, Pennsylvania (among others) offer rebates and tax credits on top of the federal tax credit.

A solar customer's ability to sell solar renewable energy certificates, or SRECs, can also affect the long term financial calculation for solar panels. SRECs represent the environmental benefits of solar panels, which create one SREC for every megawatt of electricity they produce. Delaware, New Jersey, Maryland, Pennsylvania, Virginia, Washington, D.C. and West Virginia all have markets for SRECs. SRECs' value is determined by supply and demand within the market. Their price (at the time of this writing) varies from $5.75 in West Virginia (which participates in Ohio's SREC market) to $370 in Washington, D.C. Delaware SREC transactions occur through long-term contracts. North Carolina allows SRECs from all 50 states, which means the price will remain low. New Jersey's market is robust, too.

The solar potential of the East Coast

Solar adoption up and down the East Coast also varies a lot. West Virginia and Georgia sit in the bottom five states for solar installations per capita, according to data from the Solar Energy Industry Association. At the same time, Maryland and Washington, D.C. sit just outside the top ten.

The decisions home owners make that drive those different adoption rates are influenced by a variety of factors, including solar's potential to fit the energy needs of their daily lives. One way to measure that is looking at how much of a house's energy use can be offset by solar by solar. According to the National Renewable Energy Laboratory, rooftop solar on the east coast has some of the lowest potential to offset the average household electricity consumption.

At the top end of the list, the average New York home could offset 100% its energy consumption with rooftop solar. New Jersey (90-100%), Florida (80-90%) and Pennsylvania (70-80%) come next before a chunk of states where the average offset would be between 60 and 70%: Delaware, Georgia, Maryland, North Carolina, South Carolina and Virginia. The average West Virginian house could offset less than 60% of its energy consumption with rooftop solar.

These are averages, so there are West Virginian houses which rooftop solar could offset 100% of its electricity consumption. And, 60% of a very high electricity bill, could still be more than enough to make solar worth the investment.

This also doesn't mean that solar doesn't work on the east coast. Some of those southern states use more air conditioning than in New England. Even though the solar potential of the East Coast lags behind that of New England by some measures, in plenty of situations it will still make financial sense to adopt solar.

The information here give a bird's-eye view, though to know for sure how solar will work on your roof, you'll need to explore the options specific to you. Experts recommend getting multiple quotes, including from regional and local installers when possible.