120 Volt Plug-In Heat Pump Water Heaters

Meet the Plug-in Heat Pump Water Heater that changes the game for gas water heater replacements.
The 120-volt plug-in heat pump water heater is an exciting technology that allows homes with existing gas water heaters to easily convert to efficient heat pumps for water heating. This water heater plugs into a standard 120-volt outlet and heats all the water an average home will need. 120-volt plug-in HPWHs have a couple tricks to make sure they produce enough hot water including recommended larger storage tanks and an integrated mixing valve which allows the water heater to store water at a hotter temperature but then mix in cold water thus increasing the available hot water.
120-volt heat pump water heaters hit the market in 2022 and now two brands are available from leading manufacturers. Join us for a webinar on this game changing decarbonizing technology that will explore:
- Results from the first field study with 120-volts in the nation
- Overview of available 120-volt heat pump water heater products
- Where you can buy a 120-volt HPWH
- What climates the technology works work in
-Considerations for installing and operating a 120-volt HPWH
Panelists:
Mischa Egolf, New Buildings Institute - Mischa conducts data analysis, and completes technical research for NBI projects and Initiatives, including the Advanced Water Heating Initiative. Mischa helped lead NBI’s 120-volt HPWH California field study. She earned a BS in Multidisciplinary Engineering with a focus on Environmental and Ecological Engineering from Purdue University.
Arthur Smith - A. O. Smith - Arthur Smith is a Product Manager at A. O. Smith Water Products for residential electric and heat pump water heaters. He is excited to share information about these products, including new 120V plug-in heat pump water heaters, that enable more homeowners to easily reduce energy use and save money on their utility bills.
Kevin Clark - Rheem - Kevin covers the West and Mountain regions for the Utility and New Construction segments for Rheem. This Demand Generation role engages with retail, wholesale, and utility channels to promote efficient and connected water heaters. He holds an MBA from Colorado State University.

[@twosawyers]

This is the first time I saw the backup heating elements. I know they’re weaker than a 240volt but still nice to have.

[@twosawyers]

They need to make a 120 gallon to end all fears of running out of hot water until the technology advances enough to allow faster recovery.

[@stikshifter]

If I add a skylight to the roof of my water heater closet to bring more sun in, would that help the efficiency of my heat pump water heater?

[@enbrewer]

Just wanted to point out that Massachusetts DOES have a state rebate ($750) for switching from a gas to heat pump water heater. That is, of course, in addition to the federal tax refund.

[@joelynniv2688]

Would love to see/hear/access the conversation with Barnett Plumbing installer. Can you post a link?

[@kevinfellin3335]

Is it difficult or possible to replace the anode rod with a heat pump water heater?

[@williamharrop2147]

Outstanding discussion, all. (very useful, esp. on the question of cold zone installations. Rheem's still posting misleading and incorrect "smile" chart info, esp. on the HD web site. Worse, Rheem reps assigned to respond to questions at HD give contradictory answers, some sticking to the silly smile zone guidance. (thankfully, a reader at the HD web site pointed us to this video.... Oddly enough, HD took down that answer for several weeks.... then it reappeared..... What comedy. (Thanks again for the good info here.)

[@NIAtoolkit]

50:10 For reference 700 cubic-feet is the size of a small bedroom

[@wevlcking]

I currently have a standard 50 gallon 240v electric water. I understand the differences between the 120v and 240v Heat Pump water heaters. Assuming I would run the water heater on the most efficient mode 100% of the time, is there any advantage of downgrading my dedicated circuit to 120v and going with a 120v over 240v Heat Pump water heater from an electrical consumption perspective or will I get the same performance. I will add another variable to the question, I have an 18.5Kwh solar system (no battery) on my roof. It's my understanding both could run solely on solar. The standard electrical unit I have now mostly does on good sunny days. I live in Texas.

[@ElectrifyNowUSA]

@wevlcking - I don't think there is any advantage to going with the 120V unit if you already have 240V service. In heat pump only mode - the efficiency should be identical. The real difference is the ability to go to resistance back up if needed (we never use that feature). Typically, the 240V units are lower price as well - here the price difference is significant, but that may be different in your area.

[@ericstonebraker494]

why the push to upsize these tanks 2x from original tank size? I have a 240 HPWH and didn't upsize it (yet don't use backup rods). Is this Rheem / A.O. Smith just being conservative? I can't recall which unit (rheem or A.O. Smith) but one of them has a slightly smaller compressor that may more slowly produce hot water.

[@ElectrifyNowUSA]

I think this is conservative, but it is true that the first hour rating will be lower with these units because of the slower heating from the heat pump, so the larger tank compensates to achieve a similar first hour rating as a smaller gas water heater. A gas powered 50 gal WH will have a first hour rating of 80 gallons or so. The 120 V 50 gal HPWH has a first hour rating of 55 gal, so upsizing to 80 gal gets you 72 gal first hour rating. If you are maxing out the capacity of a 50 gallon gas heater now, it would be good to upsize, but if you typically do not use a lot of hot water (no teenagers taking long showers for instance) you might be satisfied without upsizing. In our home, we have a 240V 50 Gal Rheem HPWH and we use it strictly in HP mode with no hot water shortage problems. The 120V units have the same HP compressor size as the 240V units - 4200 BTH/hr - they just don't have the back up resistance mode which increases the first hour rating for the 240V models. So theoretically you should not need to upsize if you don't use tons of hot water, but that is the manufacturer recommendation.