Hybrid Water Heaters Part 2

I wrote once before about hybrid water heaters but figured a follow up was in order given we installed one in our new (to us) home.

We removed an 80 gallon electric tank which was oversized for our needs and was making for big energy bills – the energyguide label estimated 4773 kWh annually, or nearly $500 a year to run. To put this amount of power into context, that same amount of power would run a compact EV for nearly 20,000 miles. Pretty crazy how much energy it takes to make hot water.

We ended up getting the Rheem hybrid hot water tank which is Energyguide estimated to use 1341 kwh annually – or about $135/year.

The hybrid water heater does this with a heat pump – it moves ambient energy (heat) into the water. The system is called a hybrid because it can still use traditional heating elements to fulfill high water demand.

But they can be even cheaper…

Energyguide ratings are based on hybrid mode. But if you can run the system in heat pump only mode you can push the power use even lower – so far we’re averaging about half the estimated power use in heat pump only mode. In case you wonder how I’d know that – the tanks have an app which reports usage. Yes, that means hot water for about $84/year on grid energy. But it’s even less for us (about $30/year) since we have solar power!

Now I’ll admit there are a few catches. The unit must either be placed in an unheated space like a garage or vent to such a space. That space must be at least 37 degrees (warmer is better) and be at least 300 SQ feet. You also need a drain or pump for the condensate.

Probably the biggest challenge is the plumbing – most tanks connect water on top but hybrids do the side because the heat pump is on top. That definitely increases the effort of install as well as requiring a bit more space.

The cost, rebates, and benefits

You’ll find 50 gallon hybrids at the big box stores for about $1300 retail, $1000 on sale. I hit up a plumbing supply for mine and got a couple hundred off retail. Be sure to check with your utility for rebates – PSE paid me a $500 rebate.

While you can easily pick up an electric tank heater for $400, at about $380/year to run a new 50 gallon conventional electric tank its easy to see that over the life of the tank you’ll save thousands in operating costs, easily justifying the up front cost of the hybrid tank.

Electric TankHybrid Tank
Purchase Cost$400$1000-1300
Rebate (PSE)$0-$500
Federal Tax Credit-$300
10 Year Energy Cost$3800$840-1340
10 Year Estimated TCO$4200$1040-1840
10 Year Estimated CO2
(PSE power)

Should I Switch from Gas to Hybrid Hot Water?

This is a tough one. Gas tanks are fairly cost effective to buy and operate. Switching to a hybrid means new electrical wiring which depending on your home can be quite expensive.

From an environmental standpoint a Rheem 50 gallon gas tank will emit about 3150lbs CO2 annually (269 therms times 11.7lbs CO2/therm). A hybrid heater using PSE power should run between 850-1340lbs annually – a decent savings of CO2. On the flip side in the Midwest where coal power is heavily used you’ll have small CO2 savings doing hybrid vs gas.

Really the big win is using solar power with the hybrid tank in which case you’re basically at zero emissions. But short of that, the benefit and value will vary by situation.

Bottom Line

Hybrid hot water heaters are the real deal as far as lowering hot water cost and environmental impact when replacing a conventional electric hot water tank. For those with natural gas tanks unless you’re planning on going solar, its a tougher sell but worth considering.

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