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Doesn't matter that much if you have excess solar available, beyond that many who do solar also tend to go to a heat pump water heater which is 400% efficient b
by SigmundA 1y ago
Doesn't matter that much if you have excess solar available, beyond that many who do solar also tend to go to a heat pump water heater which is 400% efficient bringing photovoltaics in line with solar hot water without running plumbing up to the roof and now that roof space can be used to power many things rather than just hot water.
https://www.energy.gov/energysaver/heat-pump-water-heaters https://www.energy.gov/energysaver/heat-pump-water-heaters
- ryao 1y agoThe two being equal in efficiency is true in a best case scenario, but that ignores real world effects such as inverter losses. I wonder which would be superior in a real world test. That said, in my home, I use net metered photovoltaic panels with a Rheem heat pump for domestic hot water. This was not done because I considered it to be a better solution, but because it was the only solution available to me from local installers.
- SigmundA 1y agoSolar hot water has to account for pumping losses as well, its going to be in the same ballpark but the electric heat pump hot water system is much more flexible in how the power is used and decouples production from use along with electrical vs plumbing on the roof which is simpler and dare say less prone to issues. Solar thermal heating used to make more sense but cost of photovoltaics has come down so much along with relatively cheap heat pump systems nobody is doing the former anymore it seems. I just got a large solar system installed and next up is a heat pump water heater as thats the second largest user of power next to the HVAC, plus it will cool and dehumidify my garage some where the solar inverter and batteries are located, converting some of the waste heat from the inverter into hot water at the same time.