How to plan the perfect solar panel installation
Written by Chris Meehan
Updated March 31, 2020
4 minutes read
Whether you are a homeowner planning out a DIY solar panel installation or a new solar contractor winning your first solar job these tips will minimize the risk of mistakes and reduce the stress and cost involved with installing a solar power system on a home.
Solar panel installation can be tricky because of variable local permitting rules, inspections from city and utility company inspectors and variable interpretations of set back and fire code regulations.
Some of the tips below apply more to DIY homeowners but all are also things we sometimes see professional solar companies get wrong
Step 1: How many solar panels are needed to power the home and what is the objective of the installation
Most people are looking for a solar system that will produce something like 100% of their annual energy use even if it does not quite cover their whole power bill.
If you are a DIY homeowner you need to work out what your objective is.
If you are installing solar for a client you need to ask them what their objective is.
You may want a bigger system if you are planning to get an electric car or a smaller system if your kids are about to head off to college.
Regardless of the objective, you will need to work out how many solar panels would be needed to offset 100% of the electric use in the specific home.
This is a good starting point for a conversation about objectives and budget.
We have included at the top of the page a free online estimator that will convert the $ amount of the home's monthly power spend to a kWh monthly electric usage.
It can do this because it has EIA energy use profiling for each area in the US in its database and also the electric rate plans from each utility in America
The next thing the estimator does tell you how many solar panels are needed to offset 100% of power use in the home. This is invaluable information to have at your finger tips.
Step 2: Work out how many solar panels will fit on the roof of the home, where the panels should go, and how much power they will produce
Another reason we have included the calculator above is that it uses machine-learned artificial intelligence to place solar panels in the best positions on the roof of a home. This shows you a fairly accurate idea of what you can fit and it also adjusts the production to the direction and tilt of your roof.
You shouldn't rely 100% on its panel placement because it does not take into account the setback rules for your specific city. To get the setback and panel layout 100% right you really need to either speak to the city or an experienced installer in your city.
However, if the estimator shows there is plenty of spare room on the roof then it probably is safe to rely on its layout (at least initially)
Step 3: Even if you are considering a DIY solar panel installation you should seek quotes for a professionally managed installation
The only good reason to organize your own DIY installation to save you a few thousand dollars over a professionally managed job where the solar company takes care of permitting, inspections, engineering approvals and the actual physical installation of the system.
DIY solar installations don't always work out cheaper.
To see if this is the case you need to get a quote from a full-service solar company. The added advantage of this is that often you can pick their brains for tips that will help when installing on your home. Often they will prepare a compliant design which you can use as a guide even if you decide to stay on the DIY path
We don't feel bad suggesting this because when many DIY customers do this they realize it is far better to just get a professional solar company to organize the whole job.
The estimator will give you a cost estimate for the system the home needs based on the average price charged by professional solar companies in your area for that size of the system. It will also get you specific prices from between 1-4 local solar companies on the system
Step 4: Compare the solar companies' price with the cost of buying the equipment online.
This page lists all of the top websites (and current prices) that sell solar panel kits to DIY customers.
You can search this page by system size, by panel manufacturer and brand of inverter: Shop solar panel kits.
This page also gives some advice on comparing different solar kit websites to ensure you are making an apple for apple comparison.
Some websites selling solar panel kits online offer permitting and design packages as a service. These can be useful for DIY customers
Once you have the kit price you then have to add on the cost of installation. to do this you have to choose a solar installer.
Step 5: Choosing a solar installer
- Ask how long it take them to install and interconnect a solar system to the grid and whether they have a waitlist.
- Ask them what solar panels and inverters they recommend and have experience installing.
- Ask for local references form clients they have installed for.
- Ask them what accreditations and licenses they have, like NABCEP accreditation, among other things.
- Ask them what they take care of regarding permitting and inspections and what you’re responsible for in terms of the permitting, engineering and inspections processes.
Step 6: How much will solar panel installation cost for a DIY customer
The problem for DIY customers is that solar installers typically charge them a lot to install a one-off system compared to what they charge a solar company to do the same job.
This is the reason DIY projects often don't work out any cheaper for the client.
A solar installer will typically charge a solar company around 70 cents per watt to install volumes of jobs but will charge of one of DIY customer around $1.10 per watt to install a system because there is a lot more hand-holding and a greater risk of mistakes with a DIY job.
So for a standard 7kW system, the installer may charge a DIY customer $7,700 to install it even though it is only a 1-2 day job for a crew of three people (plus inspections).
Step 7: The Permitting Process Begins
Depending on where you live and what’s required, this process can take a couple of days, weeks, or months.
Certain cities and towns have been designated as Solar Friendly Communities or SolSmart Communities, which means they’ve taken additional steps to make the permitting process quicker and easier—in some of these communities solar systems can be permitted within a day of submitting applications. But the process is among one of the remaining areas where many think the costs—the so-called “soft costs” of solar panel installation —can be significantly reduced. The city should be able to tell you how long the process should take.
Step 8: Getting the Equipment and Installing the System
Finally, the big day comes when your solar contractor starts prepping your roof and house for your new solar panel system. That’s also usually when they bring the solar panels and other equipment to your home.
The actual installation will usually take between one and three days to install, depending on the size of the system and the roofing materials. The process starts by making sure the roof is sound and ready for the solar panels and racking equipment to hold them in place. At this time the installer—though sometimes the utility—may have to install a new power meter that allows for bi-directional metering of electricity, allowing for net-metering.
The installer will start installing the wiring for the new solar system. Then they’ll install racking equipment on the roof, followed by the solar panels. Finally, they’ll connect the solar panels to the inverter and your homes main circuit board.
Step 9: Interconnection—the final step
Here’s the hardest part. The system is physically installed and you’d think it was producing power for you, but there’s still a final step. Interconnection and final approval. Prior to allowing your system to go online and start providing you with energy from the sun, it must undergo a final inspection from the utility and/or local officials. The inspectors will ensure the work done by the solar installer was done safely, appropriately and to code. Once the inspectors have signed off on the solar array, the switch is flipped and the solar panels are officially generating electricity for your home.