Ask the Expert: How do I add solar to an existing home?

| by Melissa Rappaport Schifman
Ask the Expert: How do I add solar to an existing home?

ProudGreenHome: How do you add solar to an existing home?

Melissa Rappaport Schifman: We installed a 3.6 kilowatt solar panel system on our roof in October 2010, and I wrote about the entire process on my blog (it was not an easy process – the title is called Solar Saga.) Since I went through the process, and I spent a few years in sales and marketing at a local solar installation company, I feel I have a pretty good grip on the challenges of adding solar energy to an existing home. (Please note: this is about solar electric, or photovoltaic panels, not solar thermal collectors that heat your hot water.)

Challenge #1 : Figuring out all of the rebates and incentives so you can understand your net cost. Since solar is an upfront investment that lowers a homeowner's electric bill, the solar investment decision is usually based upon a quick payback analysis. (As a University of Chicago-trained finance person, I actually do a discounted cash flow analysis, but payback is easier to calculate and simpler to understand.) That just means calculating the cost of the system (parts and labor), less the rebates. Then, calculate the amount you will save in electricity costs per year, and see how many years it will take to pay for itself. But how does anyone know what the rebates are? Is there one central place to go?

Solution: The best source for all of these credits is the online Database of State Incentives for Renewables and Efficiency. Right now, there is a 30 percent federal tax credit (with no cap) for installing solar on your home. That is a real credit — not just a deduction — to your tax bill, but you won't realize it until April. There are also various credits and incentives offered by both states and utilities, some with deadlines and some with specific requirements (like the installer has to be NABCEP certified). Many solar salespeople will present the total cost and let you know about all the local rebates, but it's best to check it yourself. We even found a neighborhood grant program for solar, which our installer never knew about!

Challenge #2: Deciding on the right-sized and type of system for your home. There are usually several constraints for how many solar panels you can put on your home: budget, roof size, roof orientation, shading, and the home's structural ability to hold the weight of the panels. Do you want batteries, or not? Do you want to pay more for micro-inverters, or not?

Solution: Get at least one solar site analysis performed by a reputable solar installer, and ask for a range of options — including the largest system that could be installed. That way you have comparison numbers for figuring out cost and the amount of energy that will be supplied. My personal opinion is that unless you are off the grid, you do not want batteries. By storing power, you lose some efficiency, and it's another component that requires maintenance and repair. I am also a huge fan of micro-inverters, because each panel can then perform optimally, as opposed to the entire array performing at the lowest-common denominator.

Challenge #3: Deciding on the right installer. (This is key for any home remodeling project!)

Solution: Get at least three bids, do your homework and get referrals. We had several bids, and the installer that got the business was the one that physically came over to our home and took precise measurements of the roof as well as the mechanical room, where the inverter might go. (I found it difficult to believe an installer's quote when he had not been in our home!) Make sure the company has had experience installing solar and will be around for a while, so if there are any issues, they will help.

Our particular experience in adding solar to our home was a little stressful due to the rebate deadlines and requirements, but many people are working on streamlining the process. In the meantime, good luck with being a pioneer, and congratulations to those who produce free energy from the sun!

To find out other ways to add alternative energy to an existing home, please see the features section of ProudGreenHome.

Topics: Solar Power

Melissa Rappaport Schifman
Melissa provides sustainability consulting services for businesses in the Twin Cities metropolitan area. Melissa is also the founder of Green Intention LLC, where she writes and blogs about her experience in getting her own home LEED Gold certified--and then trying to live more sustainably in the home. She chairs her congregation’s Task Force for Sustainability, has her MBA, Master's in Public Policy, and is a LEED AP for Homes. www

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