Heat pump electric hot water heaters, good or bad idea?
Water heaters are generally the biggest energy drain in a home after heating. so Air-to-water heat pump water heaters are potentially a big energy saver, particularly when the main heat source in a home is an air source heat pump, as the water heater can in effect 'borrow' the efficiency of that heat pump, which on average is about 3 times more efficient than most other heat sources. See here for an article on how heat pumps work.
To be able to easily compare the performance of different heat pumps it would also be useful to read this guide on how to understand the differences between SEER v HSPF v COP (& SCOP) heat pump rating systems.
An air-to-water heat pump water heater uses the air in the house to generate hot water, so the more efficient the air heating system is, the more efficient the hot water heater will be. That's why you get the most out of it when you pair it with an air source heat pump, because they are a very efficient heat source when combined.
Heat pump water heaters are less beneficial in homes that heat with gas, oil or electric resistance heat since there really isn't much of an energy savings in winter, however in such a case the water heater can still help with summer air conditioning as it removes heat from the air to generate hot water and produces cooler air for in the home. Where there is hot humid air, which is usually the bathrooms, a heat pump water heater can recyle this air, drying it and removing the heat in one operation while heating hot water for the next bath or shower, so we think they're a good idea overall, but you may also want to consider tankless on demand hot water heaters for which there's a guide here.
Hi! Thank you for this article and for the informative video. I am currently in search of a high-quality water heater for my house. I am considering getting a water heater from these guys - http://************.com/products/water-heaters/
I am not sure if their water heaters are with the electric heat pump or not?
Hi Ben,
We don't allow brand links in the comment section, but I would recommend you contact the supplier to ask if they have a heat pump model. AOSmith for sure does (as seen in the video) and there is this heat pump water heater as well that has an exterior compressor.
Is there a short heat pump water heater for crawl spaces?
Hi Ray,
You'd be best to try by manufacturer I think. There may be, but we don't know who that might be. I would suggest starting doing a google search for 'Heat Pump Water Heater Manufacturer', and go through each company to see what models they may have.
A quick point though - heat pumps work best when placed in a warm conditioned space. If your crawlspace isn't heated you won't get a much value for your dollar. The colder it is the harder they have to work, and so the efficiency falls off. Just letting you know, they aren't cheap and so I would want to make sure you get the value out of it.
I live in the Caribbean and temperatures are usually between 24(night) and 37(day) Celsius. Would a laundry room be a good location for this type of water heater? How much space would it need?