More energy efficient — Heat pump water heaters are much more efficient than tankless water heaters. Since the heat comes from the surrounding air for the heat pump water heater, any heat loss can just be pumped back into the water to maintain it at a given temperature. In fact, bigger tanks kept at higher temperatures are the most efficient.

Lower carbon footprint — Gas tankless water heaters emit a puff of methane when they turn on. While they claim to reduce emissions by 22 percent compared to gas tank water heaters, tankless water heaters actually only reduce emissions by 14 percent because of this methane puff, according to NRDC. Heat pump water heaters reduce emissions by about 85 percent compared to conventional water heaters.

More immediate capacity —  Heat pump water heaters offer much more reliable hot water capacity than tankless water heaters. A 65-gallon heat pump water heater can easily handle a family of four showering in a row, especially with the addition of a mixing valve. A tankless water heater with low capacity (as measured by gallons per minute, or GPMs) will struggle to keep up with multiple showers while it will also take 1-3 minutes to heat up the water in the first place (unless you have a very expensive recirculation pump installed).

Better rebates and incentives — There aren't many tankless water heater rebates available anymore. Heat pump water heaters, on the other hand, are eligible for up to $1,750 in federal upfront rebates, depending on household income, and a 30 percent tax credit. Many states, cities and utilies provide rebates as well. Most provide incentives between $500-$1,500, but some provide incentives as high as $5,700. All of these incentives can be stacked.

Safer and healthier — Gas appliances like water heaters and furnaces are one of the leading causes of carbon monoxide poisoning. Avoiding gas appliances reduces your risk.

More energy efficient and environmentally friendly — Heat pump water heaters are the most energy-efficient option on the market today. Compared to gas water heaters, they use far less energy and emit less greenhouse gas emissions. 

Better rebates and incentives — Gas water heaters rarely have rebates. Heat pump water heaters, on the other hand, are eligible for up to $1,750 in federal rebates, depending on household income, and a 30 percent tax incentive. Many states, cities and utilies provide rebates as well. Most provide incentives between $500-$1,500, but some provide incentives as high as $5,700, sometimes making the installation essentially free for the homeowner.

Lower carbon footprint — Other than solar water heaters — which are still pretty expensive in most of the United States — heat pumps are the most energy-efficient water heater available. A heat pump water heater has about 15% of the global warming potential as a conventional, gas-powered tank water heater.

Much cheaper operating costs — Heat pump water heaters are generally 4x more efficient than conventional electric water heaters. The average household will save between $500 and $700 per year by making the switch from an electric water heater.

Longer warranty — Heat pump water heaters come with longer warranties than conventional electric water heaters thanks to their longer lifespans (up to 10 years versus 6 years).

Better rebates and incentives — The Inflation Reduction Act provides up to $1,750 in federal upfront rebates, depending on household income, and a 30 percent tax credit. Many states, cities and utilies provide rebates as well. Most provide incentives between $500-$1,500, but some provide incentives as high as $5,700. All of these incentives can be stacked.