Are Electric Heat Pumps the Best Hot Water Heaters?
Anyone who has had to take a freezing cold shower will tell you how important heat sources are.
In an average home, we use hot water for everything from showering to washing dishes — so when it goes out it can be extremely disruptive.
For those reasons, among a host of others, reliable water heat control is a game-changer. Two of the most common water heating systems are the propane tankless water heater and the electric heat pump water heater. (These are often shortened to be called HPWHs.)
HPWHs are electric, which makes them sound like an attractive choice without further scrutiny. Electricity is always the eco-friendly option, right?
This is an incorrect, though common, assumption. There are a lot of great things about electricity, but it isn’t perfect, and, in fact, it’s often powered by energy sources like coal. According to the U.S. Energy Information Administration (EIA), coal was the third largest energy source for generating electricity in the U.S. in 2020. Propane releases significantly lower levels of carbon dioxide compared to electricity when you look at the big picture.
Taking its entire life cycle into account, electricity, while undoubtedly a much cleaner option than other power sources, isn’t perfect.
In fact, standard electric hot water heaters often have emissions over twice as high as tankless propane systems. Propane systems may even qualify for points under programs like LEED, Leadership in Energy and Environmental Design, a worldwide green building certification program.
Heat pump water heaters also aren’t necessarily less expensive, another reason many people inquire about electric systems.
The common understanding when it comes to HPWHs is that yes, they may be expensive up-front for installation and system conversion. But it’s said that once you’ve done that one-time fee you’ll save so much money on your energy bill that it’ll be worth it.
The problem with that comes when you factor in maintenance and longevity. That “one-time fee” isn’t only going to actually be one-time because heat pump water heaters require regular maintenance to keep them running smoothly. The nature of electric water heaters means they have more working parts that all have to do their job together than other systems do.
Another issue is how often replacement is needed. The average HPWH needs to be replaced every 10 to 20 years, which means that an expensive installation fee pops up again.
Compare that to tankless propane hot water heaters, which are practically maintenance-free, only needing annual maintenance checkups. (If you have hard water, there are even limescale systems that are inexpensive and keep hard deposits from building up in your boilers and pipework). Factor in that tankless propane heaters last 20 years at a minimum, so it’s pretty close to being a “set-it-and-forget-it” operation.
Plus, propane water heaters have better energy efficiency than their electric counterparts — Tankless systems have 3 times the flow rate of electric systems! In cold climates, electric systems just can’t keep up with the power of propane. In homes with average water use, propane is up to 30% more efficient than electricity. To think of it in real-life terms, that means you get 30% more bang for your buck by using propane.
Installation is easier and quicker when it comes to propane systems, too! They’re less labor-intensive to install, and they take up significantly less space than heat pump water heaters. HPWHs need a large at least one thousand cubic feet circumference, plus a large amount of vertical clearance. That’s a lot of space to have a water heater take up that could be better used for other things in your yard.
To recap: electric heat pump water heaters are less friendly to the environment, more expensive, less efficient, and take up more space than their tankless propane counterparts. The choice seems clear.
Electricity might have great public relations — but when it comes to the facts that will actually impact your daily life, electricity just can’t compete with propane for water heating.