Overheat Protection

Solar water heaters are very efficient and can produce very hot water. This is a good thing! The fact that they work so well is why hundreds of millions of people have these types of systems on their roofs all over the world. 

But what if they produce too much heat?

This conversation should always start with appropriately sizing the system. In a sunny climate the 40 gallon system is appropriate for households with 1-3 people and the 80 gallon system is appropriate with households of 4+. The Sunbank produces hot water, and your hot water consumption takes heat out of the system. When this is happening, the temperature in the Sunbank typically stays between 120F – 160F in the summer – going up as the sun shines, and going down as the shower is used.

160F is too hot for a shower, you say?

Correct. That’s why every Sunbank installation should include a thermostatic mixing valve. This mechanical device is sold at every major hardware store and it automatically tempers the water down to a safe temperature.

What if you’re going on vacation or use the system intermittently?

That’s why we created both the active automatic overheat protection and the passive overheat protection of simply painting and rotating the tubes. The Sunbank is a passive solar water heater, meaning that it has no pumps or moving parts – it simply creates hot water when the sun shines.

Evacuated tube solar collectors painted to turn off

 

When you remove the consumption part of the equation and don’t use any hot water, after three or four consecutive sunny days the Sunbank will get up to boiling temperature. Before it gets there, the Sunbank temperature and pressure relief valve (T/P valve) will open to allow hot water to be pushed out of the system, protecting it from overheating.

But the T/P valve is a safety device, and shouldn’t be used for regular overheating. That’s why we recommend that people either use the automatic overheat protection for situations like AirBnBs, or spray paint half of each tube as part of their installation process if you need seasonal overheat protection and don’t mind getting on the roof to spin the tubes.

EXCELLENT
16 reviews on
nic maier
nic maier
I don't write reviews but I have to tell others about James from Sunbank! We got an 80 gallon solar water heater and installed it ourselves. It works very well in Southern California. The installation was a little challenging for us, but James helped every step of the way and was even available to give us advice a full year after we had purchased the unit. He was always quick to respond with a thorough and helpful answer! I wish all businesses were run like Sunbank with people like James!
Bob Billings
Bob Billings
James, thanks for your continued support. Our 40 gallon Sunbank water heater is the best. Installed in October of 2021 and we would not trade it. Our life off-grid has worked out well. Bob Billings
Jonathan Bishop
Jonathan Bishop
My only regret is not getting the Sunbank sooner! I installed the 40 gallon system which has been perfect for 3 people. It has a 1500 watt element to heat the tank when the sun isn't shining and because of the low power demand, we are able to run it completely off-grid. James also took time to answer any questions I had and has been excellent to work with!
Robert Thorlin
Robert Thorlin
James and the team at Sunbank are exceptionally knowledgeable and willing to help. Pre-sale and post-sale support was wonderful, even to the point of shipping a bunch of extra T-bolts I needed for my unique installation, bolts and shipping all at their cost. I would bot hesitate to work with them again on anything... 10 stars if I could... Mike
Elsa Hennings
Elsa Hennings
Living in the Mojave desert, I've wanted to "go solar" for our home's energy needs for a long time (I like free stuff). We put in a solar electric system in 2004, which has long since paid for itself, and bought a plug-in hybrid car to use our "free gas" several years ago. I finally decided to heat our water with the sun, and after looking at a number of systems, I chose SunBank Solar based on it having no moving parts (I don't like to fix stuff). I mounted it on the ground since we have no shading on the other side of the wall from our old electric water heater, which made the plumbing pretty simple. For overheating protection in the desert, I painted half of each heating tube with reflective silver paint as James recommended (see photo on right), so when we leave on vacation I just rotate each tube to prevent heat absorption, turning the system off. The instructions provided, along with some how-to videos on youtube for using pex tubing, allowed me to get it all put together with no prior plumbing experience. James was an invaluable resource when I had questions, which was often! The system has now been running for over a month, quietly generating all the hot water we need! I highly recommend not only the system but the company for the high quality materials and excellent product support!
debra covey
debra covey
Installed the Sunbank 40 water heater 12/2019. We didn’t install the controller until 8/2020 in case we needed it in the coming winter, but still haven’t needed supplemental heat in south Florida as of 4/2021. Love this thing! Works great for the 2 of us in our small (1000 sq ft) home. So glad we installed it. Company was very responsive to all questions prior to ordering through install. Highly recommend!
Jim Feldhan
Jim Feldhan
I rarely write reviews; however, I am very happy and impressed with the Sunbank solar hot water heater. It appears to be made from top quality material. I was replacing a Solarhart which was not a stainless steel tank and the heat exchanger developed a leak. I started with a 40-gallon system and installed it myself. I’m very handy with DIY projects. The Instructions online were clear, and James was very helpful with any of the questions I had. Being in Phoenix I thought a 40-gallon system would be enough. Once Witter arrived, I realized that I use more hot water than I thought and wanted to have 100% solar hot water. Thus, I installed a second 40-gallon system to boost my capacity to 80. I also install a couple of radiators to heat the master bath and home office allowing me to heater those room in the fall, winter, and spring with excess hot water. In summary, I am very happy and give Sunbank 5 stars for quality and service.
Timothy Clayton
Timothy Clayton
I installed the Sunbank and the water temp went from 50F to 101F in 4 hours the 1st day. By the 3rd day I was up to 160F. It only loses approx 5 degrees overnight. It is awesome! James at Sunbank is one of the best support guys I've dealt with. Definitely recommend buying this for solar hot water.
Cuyler Smith
Cuyler Smith
Our family purchased a 40 Gallon Sunbank Solar Water Heater just over a year ago and we are VERY pleased with its performance, ease of installation, and energy savings! We have it installed on top of our spring house roof, located about 125 ft. away from our house. When combined with the Federal Tax Credit and the savings associated with the solar offset of electrical usage for heating water, this Sunbank system quickly pays for itself and is a great investment. I was able to install the system on my own and it has performed flawlessly during its first year of use. James at Sunbank Solar has been more than helpful in responding to any questions I have, even after the initial purchase, which says a lot! I would recommend the Sunbank Solar Water Heater to anyone wanting to save money and reduce our environmental impact!
tutti hacking
tutti hacking
I recently installed two 40 gallon Sunbank solar water heaters - one on my garage and one on my ADU. They have been awesome! Water is super hot and now I don't have any qualms washing my laundry with warm, solar heated water! I have wanted a Sunbank system for almost four years now, and James has patiently helped me through the process. I used my local solar panel installer to get the job done. Took 3 days to fully install (I did need some reinforcement for 2x4 rafters) and inspection was quick and easy. James steered me to a great structural engineer to get what I needed for City Planning. It feels great to have gotten rid of my natural (fracked) gas water heaters! And the 30% tax credit, along with the California Solar Initiative rebate, really makes it affordable.

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2020 5th St #1713
Davis, CA 95616

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Sunbank SB-80G

80 Gallon Solar Water Heater $3,999 ($2,799 after tax credit)