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Questions about hybrid electric water heaters + electric tankless

8 years ago

IÃ¢ÂÂve read some postings about hybrid electric water heaters stating that the heat pump functionality only kicks in if temp surrounding water heater is above 50 degrees, otherwise it runs on electric. Is this true?

I have a very old electric water heater in my garage that I need to replace. I approached Lowes about purchasing a standard electric water heater but Lowes is strongly encouraging me to go to a hybrid electric water heater vs. a standard electric water heater and when I stated the above they said it isnÃ¢ÂÂt true. IÃ¢ÂÂve read a lot of reports of reliability issues with hybrid electric water heaters so I certainly donÃ¢ÂÂt want to get one if it will almost always run in electric mode vs. heat pump mode.

My home is a daylight basement design, the water heater is in the garage which is part of the daylight basement and is very cool/cold year round (even in summer). I live in the Seattle/Tacoma Washington area.

I have two water heaters in my home, one is a natural gas tankless servicing the bathrooms, the other is this one servicing the kitchen/laundry areas so it isnÃ¢ÂÂt used often. Is an electric tankless something I should consider instead since this water heater IÃ¢ÂÂm replacing isnÃ¢ÂÂt frequently used so that normally the tankless isnÃ¢ÂÂt consuming any electricity? I wanted to install a gas tankless one to replace the electric one but between the cost to upgrade gas meter and run gas line to far end of home estimates are obscene, in the $9K range (including the tankless, upgraded gas meter and gas line) which wouldn't pay for itself for several lifetimes. It is attractive to me to not have a giant tank taking up space in the garage.

Thanks!

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Comment (1)

dadoes
8 years ago
Electric tankless will require an upgrade as well ... on the electric circuit. A typical electric tank takes a 25 to 30 amp circuit. Electric tankless can be high as 120 amps depending on the needed capacity. Capacity in tankless terms means the heating power required to raise the desired rate of water flow (gallons per minute) from the starting point (lowest tap-water temp experienced during the winter season) to the desired output temperature (typically at least 120ÃÂ°F for a kitchen with a dishwasher). If your house has a large-enough existing electric drop from the pole, then you'd only have to run a larger circuit from the breaker box. Otherwise you'd also have to upgrade the service drop from the pole.
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Is 15A 120V breaker all that is needed for the electrical requirement on a gas tankless? Or does it need to be 20A? I believe there is some open slots in my panel for a new breaker, and the panel is only about 15 feet from where the unit would go, so running a new one isn't too big of a deal. The unit would be going on the exterior wall that is part of my garage, so a new electrical run could be ran through the attic, down on the interior of the wall inside the garage, and then drilled through the wall and an electrical box placed on the exterior. Or, it can be ran through the attic and down through the soffit and ran through exterior grade conduit on the exterior wall of the house. Which one of these would be approriate? If running down the exterior wall in conduit, where does the conduit need to start? Just somewhere up in the attic, but it doesn't matter where? I know that code in this area does not require full length of electrical runs to be in conduit Lastly, is the electrical connection from the gas tankless hardwired in, or is it an actual plug? The reason I ask these questions is that I have 2 quotes and one of the plumbers doesn't do electrical so I have to source it out, and the other plumber does, but he is the one who said he'd tap the GFCI. They also wanted to charge me $300 to tap the GFCI, run 2 ft of cable, drill a hole, and mount a box, and that is just absurd, so I'd probably do the electrical myself or have my handyman do, it is far cheaper.
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Nevermind, I just learned that the main switch in my panel is only 100 amps. I would need a pretty stout electrical upgrade for the entire house. I'm back to replacing the tank.
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