Solar Hot Water Heater System Removal Before Replacing Your Roof
Updated: Oct 12
If your home has an old solar hot water heater mounted on the roof, replacing the roof underneath it is rarely straightforward.
These systems, also called solar thermal systems, were designed to help heat domestic hot water using rooftop collectors, piping, and specialized roof penetrations. Some were also intended to contribute to space heating. Years ago, they made sense for certain homeowners. Today, many of them are aging, difficult to service, and attached to roofs that are reaching the end of their life.
That creates a problem. When it is time for a new roof, the old solar hot water system usually has to be part of the conversation too.
At Sun Vault Roofing, we regularly talk with homeowners in Madison who are in exactly this situation. They are not shopping for a brand-new solar thermal system. They are trying to figure out how to replace the roof correctly, what to do with the old equipment, and whether reinstalling it is worth the trouble.
If you are specifically looking for solar hot water heater removal in Wisconsin, we offer that service as part of qualifying roof replacement projects, and we can reinstall the system afterward if you choose.
What is a solar hot water heater system?
A solar hot water heater system is different from a standard solar electric panel system.
Instead of generating electricity for the home, it uses rooftop collectors to capture heat and transfer it into a domestic hot water system. Depending on the design, the system may include collectors mounted on the roof, piping, pumps, controls, storage tanks, and multiple roof penetrations.
That distinction matters because many homeowners casually refer to these collectors as “solar panels,” even though they are not the same as modern photovoltaic systems. Photovoltaic systems generate electricity. Solar hot water systems are built to heat water.
From a roofing perspective, what matters most is that these systems add hardware, flashing details, and penetrations that have to be addressed carefully when the roof is replaced.
Why old solar hot water systems complicate roof replacement
An old solar hot water heater is not just something sitting on top of the shingles. The roof has been built around it.
Once the roof reaches the point where replacement is needed, the collectors, mounts, flashing details, and penetrations often become part of the reroofing job. In some cases, the system is still operating. In many others, it has already been abandoned but never fully removed. Either way, the roofing contractor has to deal with the equipment and the roof conditions it created.
This is one reason many contractors do not want to touch these systems. It is not just a matter of lifting off a few panels and moving on. Older solar thermal systems can involve outdated mounting details, weathered penetrations, old flashing, and extra coordination before the new roof can be installed properly.
If there are leaks around the collectors, if the system no longer works, or if the roof is simply due for replacement, removal is often the cleanest path.
Old solar hot water systems are not the only roof-mounted obstacle that can complicate reroofing. We see similar issues with satellite dish removal on aging roofs.
Should you remove or reinstall solar hot water heater system during reroofing?
In most cases, the system must be removed during roof replacement. It has to come off the roof either way; the real question is whether it goes back on.
That allows the roofing work to be done the right way instead of patched around aging equipment. Once the collectors and related hardware are off the roof, the old penetrations, flashing details, and affected areas can be rebuilt properly into the new roofing system.
This is important because old penetrations should not be caulked over and forgotten. A new roof is the right time to solve those details cleanly.
At Sun Vault Roofing, we remove and reinstall solar hot water heater systems during a reroof. If your system still works, we remount the collectors and re-flash the roof around them. Whether it is worth putting an old system back is a separate question, covered next.
Sometimes the panels are mounted sufficiently high off the shingle surface that a reroofing project can be completed without a full detach and reset. But this is a rate situation.
Is it worth reinstalling an old solar hot water heater system?
For most homeowners, no. Most of the systems we see have not worked in years, and getting one running again, including the plumbing, typically costs several thousand dollars depending on the size, complexity, and age of the system.
Take a home that heats its water with electricity and uses about 4,500 kWh a year. At 18 cents per kWh, that is roughly $800 in annual water-heating cost. A system around 30 years old has lost output to age and degradation, so assume it covers 50% of that load, the low end of what solar thermal typically delivers. That saves about $400 a year, and a five-year payback means the work would need to cost about $2,000 or less. Reviving a system like that runs about $5,000 on the high end when the plumbing still works, and roughly $2,000 more when it does not. That puts the payback at about twelve years, or about seventeen with the plumbing work, on equipment that is already 30 years old. Homes that heat water with natural gas save less, because gas is the cheaper fuel.
The math only changes with something outside it, such as an incentive that covers part of the cost or a personal goal to cut carbon.
These systems are older technology, they degrade over time, and very few companies still manufacture, service, or support them well.
From a cost perspective, reinstalling an aging solar thermal system onto a brand-new roof usually does not make sense. If a homeowner is going to pay to mount equipment on the roof, introduce penetrations, and build around that hardware again, it is usually smarter to do that with newer-generation technology that has a full lifetime ahead of it, not with an outdated system already deep into its service life.
If you are interested in getting more value from your new roof, solar photovoltaic-based solar roofing is a much more practical option to explore.
What to consider instead of reinstalling an old solar thermal system
For many homeowners, the better question is not, “How do I put this old solar hot water system back on my new roof?”
It is, “What should I do instead?”
One practical option is to pair a modern high-efficiency water heating solution with solar electric generation (i.e., solar panels). Heat pump water heaters have improved substantially and can reduce the electricity needed to heat water compared with older electric resistance units. When combined with photovoltaic solar, this can be a much cleaner and more flexible path than reinstalling an aging solar thermal system.
We have seen homeowners reach a much better long-term outcome by putting money toward modern roofing and solar electric options instead of trying to preserve outdated solar hot water technology.
How do you prepare for solar hot water heater removal before a reroof?
Before the crew arrives, decide whether the system is coming off for good or going back on, because that changes the scope and the schedule. Tell us whether it is still running, so it can be shut down properly before the collectors come off.
The rest of the prep is the same as any reroof: mowing the lawn, parking down the street, and moving or protecting items in the attic and inside the house. Our roof replacement checklist walks through all of it.
Solar hot water heater removal in Madison, WI
If your home has an old solar hot water heater mounted on the roof and the roofing system underneath is ready to be replaced, this is the time to address both issues together.
Sun Vault Roofing helps Madison-area homeowners remove old rooftop solar hot water heater systems as part of qualifying roof replacement projects, and can reinstall an existing system along with the new roof. Our focus is on helping homeowners replace the roof correctly, address outdated rooftop complications, and if desired, move forward with a solar solution that makes sense today.
If you are planning a reroof and still have an old solar hot water heater on the house, contact us to discuss the next steps.
