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“In the summer I plan to drain it and let it vent.”
Photo Credit: Reddit
A DIY homeowner took to Reddit to share how a solar system based on used panels was producing hot water for their home. 
In a Reddit thread on r/DIYsolar, the original poster explained that they had purchased 14 secondhand thermal panels, of which 11 were functioning after testing. Based on a simple measurement involving a 5-gallon bucket, the OP calculated that the system was producing an estimated 60,000 BTU of heat per hour. 
According to their post, the OP measured performance by timing how long it took the system to fill a 5-gallon bucket with water that the system had heated from 45 to 120 degrees Fahrenheit. After timing each bucket fill as taking 2 minutes and 45 seconds, the poster calculated that the 11 working panels were producing about 60,000 BTU per hour, or roughly 17,500 watts of heat.
The OP achieved these results despite three of the 14 panels experiencing leaks, making them unusable for the time being.
While this Redditor’s use of panels is not exactly mainstream, just about any use of solar power is a great way to save money on home energy, and solar leases in particular can deliver hundreds of dollars in monthly savings without any upfront costs. Readers can use EasyHome to see pricing and savings from vetted installers in their area.
In the comments, the discussion centered on solar thermal equipment, not the electricity-generating panels that usually dominate consumer solar conversations. 
“Interesting install,” wrote one Redditor. “Rare that non electric systems are posted here. How do you handle excess heat production?” 
“In the summer I plan to drain it and let it vent,” the OP responded in the comments. “I may put shade cloth over it if I think it is necessary. In the spring, winter, and fall, the plan is to run extra heat into the soil under our green house.”  
With energy prices through the roof, there’s never been a better time to go solar — and EasyHome can help you find the best prices from the best installers in your area.
EasyHome takes the guesswork and headaches out of energy upgrades by showing you estimated savings from a network of vetted local partners. To get started, just enter your ZIP and share a few details about your home — seeing your estimate is really that easy.
“Brilliant,” another commenter said of the OP’s plan. 
Other users questioned why the OP had angled the panels so steeply, to which the OP replied, “I need heat in the winter, not in the summer, I also hope that steep angle will help snow slide off.”
Despite the positive test results, the OP conceded that they had work left to do on their system. For example, they explained that they were reworking the system so antifreeze would circulate through the panels and then pass heat into a 700-gallon water tank through a heat exchanger.
That stored water would then directly feed the OP’s heated floor, while a second heat exchanger that supported potable water and household plumbing would be tied into an outdoor wood boiler.
The poster added that strong winds and 200 feet of uninsulated pipe were causing major heat loss, but that this, too, would be corrected. “It will be insulated,” they wrote. 
For homeowners who want traditional rooftop solar without the complications of building a custom setup, EasyHome offers a free explorer tool that makes it easier to compare vetted installers and see local pricing. EasyHome can also help readers explore backup battery storage options. Pairing solar with a battery allows homeowners to maximize savings and power their home with solar when the grid goes down.
These articles delve deeper into the issues surrounding practical solar setups, including a low-cost solar thermal water-heating system and solar roof tiles that can run heat pumps. 
• Researchers built a solar geyser system that uses ordinary sand to store and deliver heat.
• Paxos unveiled solar roof tiles that could run heat pumps and cut heating bills.
• An Australian homeowner found a 20kW solar setup made blackouts invisible and even earned bill credits.
• Energy experts said rooftop solar panels could save homeowners tens of thousands over time.
• One rooftop array powered whole-house AC and two EVs through 90-degree summer heat.
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© 2025 THE COOL DOWN COMPANY. All Rights Reserved. Do not sell or share my personal information. Reach us at hello@thecooldown.com.

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