Solar hot water system with oil heat, one hot water tank or two?
I’m wondering if someone could help me. I am very new to the site so I apologize if I have missed the answer to this question in the archives.
We have a solar hot water system (geothermal, installed 2007, has already paid for itself – I have read the articles on photovoltaic systems) in a house that has oil heat. [Editor’s note: Audrey later clarified these remarks by noting that the reference to a “geothermal” system is erroneous; the intended reference was to a solar thermal domestic hot water system.]
Gas heat is not an option on our street. Our hot water tank that is connected to our oil tank has finally hit the end of its life and we are unsure if we should just replace this one tank, OR, replace both of our hot water tanks with just one combination tank. It seems to us that we should keep the solar tank and the oil tank separate, but we also don’t feel qualified to make this decision.
Right now the water coming in from the street at 55 degrees is heated by our solar system in the solar hot water tank, then that warmed water feeds the main hot water tank and if necessary, is heated the rest of the way using oil. Apparently we could replace both tanks with a combined tank with two coils inside; one for solar and one for oil. My question is: which will fire first for heating, my solar or my oil? Won’t the boiler just kick on and the solar might not get a chance to work? Whereas with the two tank system we have now, the solar always gets a turn first, then the oil just fills in the rest of the way. Am I missing something? Why would I want to go to a one-hot-water-tank system? Any input would be greatly appreciated! Thank you!
GBA Detail Library
A collection of one thousand construction details organized by climate and house part