I am getting ready to replace my current hot water heater – it is a ~15 year old tank gas water heater so I want to be prepared in case it breaks. In the summer (when I am not using gas to heat the house) I pay on average $20 per month for gas, so as a first-order approximation I pay ~$240 a year for hot water.
I also have solar panels, and currently pay nothing for electricity except for the connection fee. My electrical provider offers net metering, so excess electricity made in the summer months count towards the winter months. I haven't had the panels for a whole year so I cannot be sure that I generate a net positive amount of electricity yearly, but it is trending that way at this time. So, for the purposes of this comparison, electricity is currently either free or very cheap, but the addition of an appliance that uses a large amount of electricity could change that.
I am trying to decide whether I should replace my current tank gas water heater with a heat pump electric water heater, or with another gas water heater (of some type).
Everything I have read about electric heat pump water heaters is that they offer significant energy savings over conventional electric water heaters. I have not been able to find a direct comparison of energy used by a heat pump water heater compared to a gas water heater, so it's not clear to me if I would see any savings (either money or energy) over what I currently pay/use. In terms of potential gas water heaters, I am pretty open to any of tank, tankless, or condensing – my primary interest is saving energy and lowering monthly costs, and am OK with a large up-front cost if need be.
Taking into account that I have solar power (e.g. cheap electricity) but also have gas already set up, which of heat-pump electric or gas water heaters is likely to be the most efficient and least expensive to operate?
Update
Answers to some questions
- Current water heater is in the garage, and that is where the replacement will go
- Home heating uses gas
- I am looking at hybrid heat pump water heaters.
Basically, my question boils down to the following: it is known that going from conventional to heat pump electric means savings, and going from conventional electric to gas means savings, but it is not clear to me in what direction the savings flows when going from gas to heat pump electric.
Best Answer
If you gas to heat the hot water is only $20 a month, It would not make economical sense to change to a heat pump. The cost of a gas water heater would be roughly 1/3 or less the cost of a hybrid heat pump. The gas has low maintenance, just yearly flushing and maybe anode replacement. Gas has a fast recovery time. The hybrid heat pump would require 220 v circuit, has a shorter life cycle, very slow recovery time unless the electric elements are turned on, then it would still be slower than gas. Trying to save $20 a month with a $2000 hybrid water heater with all its short coming would not be practical.