Glen the Plumber asked me to compare the costs of a heat pump water heater compared to a gas water heater.
I went to the Home Depot website and compared two Rheem 40 gallon water heaters model XE40t10h45U0 hybrid heat pump and XG40T12DU38U2 natural gas with exhaust vent damper. The hybrid cost $1399 and the natural gas water heat cost $949. the estimated first year energy cost was $104 for the hybrid heat pump and $189 for the natural gas.Both water heaters require electricity. A 2pole 30amp circuit breaker for the heat pump and a standard GFIC outlet for gas water heater .
The gas and electric first year cost are from the Federal energy guides (yellow label) are based on national average energy costs.
Because there are too many details to cover here that could drive up the installation cost, I suggest consulting a contractor, and consult the Installation instructions on the Home Depot or manufacturer website.
Based on equal installation costs, the heat pump would pay for itself in about 4 years. If you live in an area of very high energy costs and utility rebates the payback period could be as little as two years.
Another good resource for comparing heating costs for various fuels is us-energy-information-administration-heating-fuel-comparison-calculator. This is a spreadsheet put together by the Federal government.