Last Updated: Aug 17, 2021
The average cost of installing a residential 5 kW solar photovoltaic system runs between $10,000 and $20,000. The federal solar tax credit has allowed homeowners to deduct 30 percent of residential renewable energy systems' total cost. Unfortunately, this tax credit is slowly being phased out and should become obsolete by 2022 unless a new policy is passed.
The cost of solar energy is continuing to drop yearly - it has fallen 20% in the last five years. Even so, not every homeowner has the financial stability to dedicate $20,000 to a complete solar photovoltaic system. For those of us who want to transition to renewable energy options in the future, preparing to be "solar ready" will lower the solar panel installation cost when the time comes.
The best way to lower the cost of a complete solar panel system for your home is by taking steps today to reduce your household's energy demands.
The average residential electricity consumption in the United States is over 900 kilowatt-hours per month. You will most likely need a home PV system that averages 5 to 7 kW for this electricity consumption. The more electricity your household uses, the bigger (and thus more expensive) your home PV system will need to be.
A simple home energy audit will help you determine where the most energy is being used in your home. It will also help you to determine where you can cut back on your energy usage. Also, these home energy monitoring devices can help you discover electricity drains throughout your home. Fortunately, making your home more energy efficient does not necessarily require a huge budget. By making an effort to limit your monthly electricity demand, you might opt for a smaller PV system, which will save you money.
Suppose you are interested in retrofitting your home to become carbon zero or even carbon positive. In that case, you will need to electrify your home. Electrification entails transitioning to electric heat and appliances. The more energy-efficient your home, the less energy these electric appliances will require to heat your home without relying on oil, natural gas, or other contaminating (and expensive) fossil fuels.
One study found that if every rooftop in the United States installed solar panels, we could meet almost 40 percent of our national electricity demand. Of course, one of the problems is that not all roofs are good candidates for solar panel installation. One of the biggest mistakes a homeowner can make when investing in solar is to install a PV system on an old rooftop. Solar panels have an average lifespan of about 25 years. So, it can be very costly to remove and then reinstall a solar PV system on a roof that needs replacing. There is also the possibility that damage could occur to the solar panels during the roof renovation process. Asphalt shingle roofs have an expected lifetime of 15 to 20 years, while galvanized metal roofs can last up to 45 years before needing replacement.
An essential part of making your home "solar ready" is making sure that you have the correct type of roof. To do this, you must ensure that your roof is structurally sound and can withstand the extra weight that the solar panels will create. Most solar panel installers will not install a PV system on a roof with either slate or cedar shingles. While it can be done, it is usually riskier and much more costly.
Before embarking on your project, consider the age of your roof if it is sufficiently structurally sound and made from a material compatible with solar panels. If your roof does not meet all these requirements, you can then plan to either replace it before going solar or opt for a ground-mounted system or a solar carport.
You can prep your roof for future solar panel installation by installing an electrical conduit from the primary electrical panel location to the roof. Most building codes will require a metal conduit run inside the home. The EPA has a complete checklist of solar-ready design guidelines for both new and existing roofs.
There are some further considerations for making a solar-ready home for people who are building a new house. First and foremost, you will want to make sure that your roof is facing south (if you live in the northern hemisphere). This will allow you to maximize the amount of sunlight your solar panels receive and increase energy production. While east and west-facing roofs also work, this will decrease the amount of electricity your home PV system can produce.
You will also want to minimize the amount of rooftop equipment and vents to increase available space for the solar panels' placement. This rooftop equipment includes chimneys and vents, especially those located on the south-facing part of the roof.
Structurally speaking, you will also need to make sure that your contractor analyzes the wind loads on the rooftop solar equipment to ensure you have an adequately strong roof structure. It is a good idea to confirm that roofing warranties consent to rooftop solar installations. Another consideration is installing solar-ready wiring in advance of your solar panels, including a wired conduit to the roof panels' proposed location.
Creating a solar-ready home might also require some yard work. Take a look at the locations of trees on your lot. Is your home surrounded by large trees that cast deep shade on the south-facing portion of your roof (where solar panels would be best suited)? In this case, you might consider pruning those trees to allow for maximum solar gain. If the trees are in your neighbor's yard, microinverters or power optimizers can maximize your solar energy production, even if there is a little bit of shade on your roof.
Your home might require an upgraded electrical panel before installing solar panels. Upgrades are especially crucial for houses that have an older or outdated electrical setup. When you eventually install the panels, an inverter that works with your solar panels will be connected to your breaker. Some building codes might require a larger electrical panel for safety precautions. In most cases, a 200 amp service will be enough for a regular-sized residential PV system.
Even if you aren't ready to install a complete solar panel system, there are things you can do today to make sure your home is solar-ready. If you want to jump into solar the game quickly, check out Rise's article on solar leasing and financing options to help accelerate the process!
Tobias runs an agroecology farm and a natural building collective in the mountains of El Salvador. He specializes in earthen construction methods and uses permaculture design methods to integrate structures into the sustainability of the landscape.