How many peak sun hours do I need for solar?

When deciding whether or not going solar makes sense for your roof or location, one of the first questions you may ask is, "How many sun hours do I need for solar to be worth it?" This question is essential because there is a significant range across the country for average peak sun hours. In this article, we'll explain which states offer the best sun hour value and how much sunlight intensity in your state should impact your decision to go solar.

The simple answer to this question is that there is no simple answer because a home's suitability for solar will depend on several factors: roof angle, electricity bill cost, and available sunlight. However, looking at the best states for solar in the U.S., there is a trend: having at least 4 hours of typical peak sunlight is best for solar panels.

A necessary clarification with the term "sun hour" is that it does not refer to merely hours of daylight. While many areas of the U.S. will have practically the same total daylight, some states may only average two peak sun hours per day while others will average as many as seven.

A peak sun hour is typically defined as an hour of sunlight that offers 1,000 watts of photovoltaic power per square meter. Peak sunlight hours describe the intensity of sunlight in a specific area. Peak sun hours occur when the sun is highest in the sky. The number of peak sun hours will increase the closer an area is to the equator and, more generally, during summer months.

As mentioned above, U.S. homeowners will see significant disparity in available sunlight depending on where they live. Check out how the top states for solar power stack up in terms of average peak sunlight hours per day:

Peak sun hours by state

Source: Solardirect

There are conflicting takeaways from this table: though many top states for solar in the U.S. have higher average sun-hour values (Arizona, California), other top solar states are on the lower end for peak sun-hour averages (New York, Massachusetts). Conventional wisdom would say that the states with the highest sunlight hour averages are the best for solar. However, number of peak sunlight hours is not the only factor that influences the cost-benefit ratio of solar energy.

For example, sunshine is less plentiful in states like Massachusetts and New York. Nevertheless,  electricity prices in those states are high, and several major states' incentives make solar affordable. The energy cost can be a deciding factor for the economics of solar than available sunlight – hence why a state like Massachusetts is a much more popular place for solar energy than many of the sunny Southeastern states where the energy cost is low.

Furthermore, in the case of states with high electricity prices but low peak sunlight hours, solar-interested homeowners can install higher-efficiency panels that will generate more power from less sunlight. Solar panel efficiency typically ranges from 15 to 20 percent, but high-end solar panels like SunPower can offer efficiency levels as high as almost 23 percent and above. A lower-efficiency panel will likely do the trick in a state with strong peak sunlight. By comparison, states with fewer peak sunlight hours can be just as ideal for solar panels but will require more efficient solar equipment. For the prospective homeowner considering solar, the next step is to review our:

Three Tips for Solar Shoppers

1. Homeowners who get multiple quotes save 10% or more

As with any big-ticket purchase, shopping for a solar panel installation takes a lot of research and consideration, including a thorough review of the companies in your area. A recent report by the U.S. Department of Energy's National Renewable Energy Laboratory (NREL) recommended that consumers compare as many solar options as possible to avoid paying inflated prices offered by the large installers in the solar industry.

To find the smaller contractors that typically offer lower prices, you'll need to use an installer network like EnergySage. When you register your property on our Solar Marketplace, you can receive free quotes from vetted installers local to you; homeowners who get three or more quotes can expect to save $5,000 to $10,000 on their solar panel installation.

2. The biggest installers typically don't offer the best price

The bigger isn't always better mantra is one of the main reasons we strongly encourage homeowners to consider all their solar options, not just the brands large enough to pay for the most advertising. A recent report by the U.S. government found that large installers are $2,000 to $5,000 more expensive than small solar companies. If you have offers from some of the big installers in solar, compare those bids with quotes from local installers to ensure you don't overpay for solar.

3. Comparing all your equipment options is just as important

National-scale installers have offer higher prices – they also tend to have fewer solar equipment options, which can significantly impact your system's electricity production. Collecting a diverse array of solar bids allows you to compare costs and savings based on the different equipment packages available to you.

There are multiple variables to consider when seeking out the best solar panels. While specific panels will have higher efficiency ratings than others, investing in top-of-the-line solar equipment doesn't always result in higher savings. The only way to find your property's "sweet spot" is to evaluate quotes with varying equipment and financing offers.

For any homeowner in the early stage of shopping for solar that would like a ballpark estimate for an installation, try our Solar Calculator, which offers upfront cost and long-term savings estimates based on your location and roof type. Check out our quote comparison platform for those looking to get quotes from local contractors today.