Replacing a roof with solar on it - is this a $$$ or $$$$?

May 31, 2016 4:35 PM

I'm considering buying a home with a shake cedar roof which has "roughly five years" left in it (if we ignore the wildfire risks, which I won't) and has solar mounted on top. I assume replacing this roof, particularly with the solar mounted on top of it, will be very expensive. How much will removing and reinstalling the solar add to the roof cost?

First time buyers considering buying a home with solar mounted on top of shake cedar. We know roofs are very, very, very expensive. How much more will it cost since there is already a solar panel mounted on the roof? (Solar is about 10x20 or 14 squares [not sure which measurement matters], roof is about 32x48, location is the west in a fire-prone area that gets modest snow and rain).

We were thinking of asphalt tiles, which we've priced at roughly $10-16k (we're open to other options). Solar is from 2014. I know that is relatively new, but if you think it would be cheaper/more cost efficient to remove the 2014 solar and replace with more modern solar we're open to that as well.

Thanks for any advice you might have!

posted by arnicae to Home & Garden (10 answers total)

This depends on whether the homeowner owns and maintains the panels, or a solar company does. Under our particular contract, we have to pay $500 for the panels to be removed, stored, and reinstalled on a new roof.
posted by amro at 4:37 PM on May 31, 2016

I would recommend a metal roof. Fire proof, long lasting.

But, the solar part is pretty easy, $500-1000 most likely. Find out who did the original install and call them.

Lots of the initial cost is electrical permitting, running conduit, sizing the panels to the roof, etc. The actual mounting on the roof is a small part.
posted by flimflam at 5:03 PM on May 31, 2016

Don't replace the solar, 2014 models will be good for a couple decades probably. Shouldn't be expensive to take down, it's just bolting and unbolting stuff.

It's hard to recommend a roofing material without knowing more (snow shedding issues, wind loads, cathedral ceilings, pitch etc) but overall there are a lot of fireproof roof materials now so ask around and shop around a bit. You can always call the fire department, they will send someone to help fireproof the house and can give you somewhat unbiased info.
posted by fshgrl at 5:18 PM on May 31, 2016

If you're leasing the solar panels, you may be able to replace the roof and reinstall the original panels but you won't be able to just upgrade them.
posted by praemunire at 5:22 PM on May 31, 2016

Response by poster: Hi - these are not being leased, they were purchased outright. No contract. Also, no battery (or other storage) and no connection to a utility company, so from what I can tell they are great if we're using energy while the sun is shining, but not so great if we aren't.

Our only friends with solar are in bigger cities with either contracts/leases or connected to a public utility - if you have any advice on making these solar panels more useful (e.g. by adding a battery?) I'm all ears!
posted by arnicae at 6:11 PM on May 31, 2016

The problem of a really useful battery for solar power is unfortunately at least a few years away from being solved.
posted by praemunire at 6:16 PM on May 31, 2016

I'd replace the shakes with standing seam metal. Any roof structure that was suitable for shakes will work fine with standing seam metal. 50 year warranty. Best roof for rain water collection. Fireproof. Way cheaper than a shake installation.

arnicae: "if you have any advice on making these solar panels more useful (e.g. by adding a battery?)"

Does your electrical supplier allow grid tieing? If so this is far and away the easiest, most cost effective way to go.
posted by Mitheral at 7:14 PM on May 31, 2016 [2 favorites]

Does your electrical supplier allow grid tieing?

Called "net metering" where I am — wouldn't have installed my system without it. I agree that this should be a priority if you can make it happen.
posted by exogenous at 7:01 AM on June 1, 2016 [1 favorite]

Good lord, of course you should keep the panels - they're practically new. Solar panels are rated to last a minimum of 25 years. Prices have dropped since 2014 but efficiency has not gone up so much it would be worth scrapping that investment. Just call the contractor that installed them and tell them you're going to replace your roof. They'll come out, remove the panels, set them aside somewhere on your property, then come back when the new roof is installed and reinstall the solar panels. This is a routine operation, and the price my solar installer quoted was roughly $1000.

Do you have net metering? You need net metering, if it's available. Then it doesn't matter whether you're using power at the same time you generate it - all that matters is the difference between the total amount of power you generate and the total amount of power you consume.
posted by crotchety old git at 10:58 AM on June 1, 2016

Do you know the wattage of the panels? Is the house in an area prone to power outages?

Given that the installation is new, covers only about half of the available roof area and isn't tied to the grid, I wonder if you might be well served by having it available for power generation if there's a storm. Once it's tied into the grid, it will shut down and won't be available to you during a power outage.

Can you ask the current owners, their installer, or even the electric utility, why they didn't maximize the available roof space, or net meter?

Either way, even if they're Coleman panels from Menard's, it could be worth it to reinstall them. You would just run your high-energy-using appliances only when the sun shines, like it's the 70s and you're an early solar adopter.
posted by mgar at 7:35 PM on June 1, 2016