With decarbonization of our grid, all-electric “reach-codes”, and the proliferating move away from fossil fuels, there will be a need for cost-effective, electric domestic hot water heating for all projects, not just single family homes.
Most of our buildings today use either electric resistance water heating or natural gas water heaters for domestic hot water needs. However, there is a technology called Heat Pump Water Heaters (HPHW) that have many advantages, and even the California Energy Commission (CEC) is developing code language for it around the 2022 code cycle.
What is a Heat Pump Water Heater? You can think of a HPHW as an electric refrigerator in reverse. A refrigerator takes the heat out of the food you store inside it and puts it into the room. An HPHW takes the heat out of the room and puts it into the water stored in the tank. Because HPHWs move heat rather than create it, they are about 300-400% more efficient (for our climate) than electric resistance heaters and natural gas heaters. “But natural gas is so much cheaper!” I hear you saying. Yes, natural gas can be 3 to 4 times cheaper than electricity, but that just means we are near operational cost parity. In Fargo, HPHWs don’t work as efficiently (200%) as they do in Houston (up to 500%) because of ambient temperatures, so your climate does make a difference.
So what are the advantages?
HPHWs typically cost more than natural gas heaters, but if you’re building a new building and you don’t need natural gas, you don’t have to pay for all that gas infrastructure and metering to be installed. That’s a big chunk of savings.
HPHWs pair well with renewable energy and harmonize with the grid on demand response too. That makes them good for the environment and cuts down site carbon emissions. This could be a big benefit if carbon taxes (like House Bill 763) increase economic fines to polluters. It also attracts sustainability-minded tenants.
HPHWs do have a drawback in that it takes longer to make hot water which means you need larger tanks, or more of them to ensure you don’t run low on hot water at times of high demand.
For environmentally conscious homeowners, HPHWs are a no-brainer. Now, for multifamily developers, HPHWs are becoming a worthy point of design discussion, particularly for upcoming code cycles.
If you’d like to know more about how Heat Pump Water Heaters can be integrated into your facility (new or existing), contact Moe Fakih below. From energy modeling to installation verification, we can help.
Contributing Writer: Wayne Alldredge, Associate Director O&M, Energy, and Commissioning Services
Moe Fakih, Principal