Understanding water heater specs
I have some questions about tank type water heaters:
How do you compare the sizing needed for a gas tank vs. electric heat pump type tank. I read (perhaps on this site?) that heat pump type tank water heaters have much slower recovery and thus, for the same hot water demand, a house would need a larger tank with the heat pump type.
1. Is there a chart to compare needed tank sizes between gas & heat pump type tanks, including how the recovery rates of a specific tank impact this?
Regarding gas tanks, none of the gas tank direct vent (ie NON power vented) water heaters seem to be energy star rated.
2. Are there any Energy Star rated Direct Vent water heaters available in the US? (ie a direct vent gas tank that does not need electricity to work)?
3. Does anyone sell a gas vented water heater (not direct vent, but with a fan) whose fan works off the gas instead of needing electricity?
4. Can anyone explain why these two direct vent AO Smith units have different first hour ratings – ie what other factors influence this besides tank size, btu’s and energy factor?
Model G6-DVS4038NV, 40 gal, 38k btu, 0.6 energy factor, 64 gallon first hour
Model GDV-40, 40 gal, 38k btu, 0.6 energy factor, 72 gallon first hour
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