It was with great interest when I noticed a new solar install going in up the street – for the first time I’ve seen locally, they were installing the PV panels on a low-sloped roof here in Krisana Park! Every time I had stopped at one of those solar booths and inquired about installation, all of them asked the question: “What is your roof slope?” When I noted that they are 1 ½” per foot, they would shake their head and say that anything under 4/12 slope won’t work.
Namaste Solar had their sign up in the yard and I immediately called them up to chat about how they are doing the installations. They confirmed what I wanted to hear: The panels can be installed about eight to ten inches above the roof AND at the same angle as the roof!
I then asked for a quote so we could see what would be possible on our roof. They asked a series of questions and then for kicks did a comparison for me to show that based on my yearly power needs (about 11,000 kilowatt hours a year) that I would only lose about 150 kwh when positioned at the lower angle. This is negligible for sure. What has a bigger impact is shade, especially from evergreens, so make sure they come out to view your house and analyze the locations of the trees around your property and your adjacent neighbors.
I think one of the reasons most solar companies don’t want to bother with low-slope installations is that it requires poking a lot of holes in the roof which will need special patching to seal it back up properly. For a typical 20 to 30 panel installation, you are going to have about two penetrations per panel, so upwards of 50 holes cut into your roof! On commercial roofs this is done all the time, so there are proper ways to do it. Usually a collar or “boot” is installed around the support post which helps provide a good seal at the base and up the post. The type of boot and patching around it will be specific to the roof material (asphalt roll roofing versus a rubber membrane like EPDM or TPO).
Some other items to keep in mind:
There isn’t going to be any short-term payback, so this is about doing what’s good for the environment vs. saving a lot of money. If you plan to stay in your home for the next 20 years, your payback will become significant (a typical loan is 12 years).
For a rough number on a system, a 2,000 SF house using 11,000 kilowatt hours, a 8-9 kW array will run you about $22,000 after a 30% rebate. Note that the rebate not taken off up front, it’s just tax credit.
If you want to charge a hybrid or plug-in electric car, you will need to purchase it first as you can’t up-size your array prior to purchasing the vehicle.
Xcel will only allow you to install an array that provides up to 115% of your average yearly use, so keep this in mind – if you plan to expand your home, you might want to go through with that first prior to claiming what your typical use is.
Xcel will install a second “Net” meter next to your existing meter, so you will need some space near your existing meter.
In addition to the net meter, a shut off for firefighters is required, plus an inverter for converting the DC to AC current (all included in the install price).
We are so happy that you can now access totally free power from the sun, while your MCM home will still look great from the street without the ugliness of panels sticking up at the 45 degree angle!
Note: We appreciate Namaste providing us with a quote and answering all our questions, however, we have no financial relationship with them. If you know of another installer that will work with low slope roofs, please let us know in the comments below.