Natural gas - heat pump combo?

[BlindBadger]

Does anyone make a combo water heater tank unit that can switch between natural gas and electricity via heat pump? I’d love something where I could switch modes based on how much power I have left in my batteries but I can’t really find anything that combines the two fuels into a single unit.

 

[Madcodger]

In one unit? I'd be very surprised if that exists. But very easy to put two tanks in series (HP >NG) and that gives you a very large volume of hot h2O.

 

[Zwy]

Does anyone make a combo water heater tank unit that can switch between natural gas and electricity via heat pump? I’d love something where I could switch modes based on how much power I have left in my batteries but I can’t really find anything that combines the two fuels into a single unit.

Build your own, put the water heaters in series. Small heat pump water heater and a small gas water heater.

 

[kommando]

We have these in the UK, I run 2 boilers, multifuel ie wood and coal and an oil boiler with a H2 panel.

Heating Innovations homepage

Based on an old Honeywell design it can operate where one boiler preheats the water and then it gets sent to the second boiler. Or use the boilers individually. Been running for 10 years without issue.

They have been adding to the range and now do one for ASHP and GSHP plus second boiler.

H7 control system

 

[zanydroid]

Very unlikely to find in the same unit because each needs really different hardware inside, and arguably even at cross purposes/conflict with each other.

What are the correct keywords to shop for when looking for a NG tank for this series approach? I think a cheap one would have high standby losses. You would want an insulated damper on the flue

What do folks think of having HPWH going into a bypassable NG tankless?

 

[Madcodger]

What do folks think of having HPWH going into a bypassable NG tankless?

I really like the idea, but don't want to be constantly fiddling with the bypass valve. I could automate it, but for our modest hot water needs, I'm not sure it's worth it. A gas tankless uses very little gas, overall, especially for just two people.

 

[zanydroid]

I really like the idea, but don't want to be constantly fiddling with the bypass valve. I could automate it, but for our modest hot water needs, I'm not sure it's worth it. A gas tankless uses very little gas, overall, especially for just two people.

With some tankless units water will still flow through if power is cut, it just won’t start.

 

[Madcodger]

With some tankless units water will still flow through if power is cut, it just won’t start.

That would be great! I could easily automate that based on HP heater water temp and a simple automated switch controlling power to the tankless heater. A real possibility for the new house. Will pull plug on Rinnai and try it later today. Just need to make sure unit is OK to have hot water input. Planning combo-boiler for new house so wonder about those, for the domestic water only. You’ve got me thinking. Thanks!

 

[pollenface]

Build your own, put the water heaters in series. Small heat pump water heater and a small gas water heater.

that's the way I would do it