No. Do not install a electric tankless heater for whole house. They do not provide significant savings and they usually require significantly more electrical service than your existing water heater (as in larger panel, service from the street, etc.).

You said you were putting in solar in the Spring... what type are you talking about? PV (solar electric) or Solar thermal for hot water / heat?

What I could potentially get behind is a hybrid heat pump water heater.

Thanks and PV. I sell it and we don't push the hot water at all. Still pretty expensive and no 30% tax credit. Better to invest in whole house.

Hi bold_as_love.

I'm not sure I followed anything you said past "PV".

Ok, so let me be clear - there are cases where Point Of Use electric tankless makes sense to provide instant hot water in remote locations. There is virtually no case where whole-house electric tankless makes sense.

The amount of current required for a whole-house electric tankless can run 180 amps with at least a 300 amp service. That kind of current almost always means significant upgrades to the electric service. Even then, electric tankless will struggle to provide enough hot water.

The savings for Electric Tankless are only about 2-3% over a standard electric tank. Very little standby heat is lost through the insulation on a tank electric heater.

An electric tankless heater (or electric tank heater) is NOT something you would ever want to pair up with PV.

What is paired up with PV is the hybrid heat pump water heaters.

If you look at the energy sticker on a standard electric water heater they will show about $420-500 a year. A tankless electric will be a couple percent less.

A hybrid heat pump energy sticker will be ~$110 a year.

I just meant we aren't pushing solar hot water, because it's expensive and you don't get the Federal tax credit of 30%, like you do with a full PV system. It's smarter (if roof/shade allow) to just install the panels you need to provide the whole home's electricity.

And thanks again for the entire explanation. I'm glad I checked here first 'cause I was about to pull the trigger.

To Bruce in Northern Virginia.....great idea on the timer. That's been my whole concern, the idle time. Wife showers in the morning and I in the afternoon, except for the weekend mornings. We only run the dishwasher and washing machine at night.

bold_as_love - there is really very little heat loss through the insulation as it is. Add additional insulation if you would like. Also be sure to insulate the hot water line. I wouldn't mess with a timer -- it won't change things if you don't lose the heat in the first place.

Do check out the hybrid heat pump water heaters. Your electric utility may be offering significant rebates on them as well. They do need a basement or warm garage or other open space from which to draw heat.

I'm probably going to skip the timer. Heater is in an insulated closet and yes, hot line is insulated, but probably doesn't need to be. I'm on a slab, unfortunately. We'll really cut down on our bill with the new HVAC and upgraded insulation in the attic. 18 seer system and the previous one was probably 12? Some no-name cheapo, heat strip only system. They didn't even run trunk lines. Just one huge non-insulated plenum with flex-duct runs up to 35 feet in some cases. New system has trunk lines, insulated inside and out, plus they wrapped the returns, too. I'm hoping with the Bosch and more insulation we can cut up to 40% of our bill. My buddy's buddy owns the insulation co. and my buddy did his own attic and saw about 17% reduction in his bill.

In what part of the country do you live?

Central MO, right on I-70

Yes, the higher SEER heat pump system and the insulation will help a ton.

Note: if your water heater is in the house, all standby heat loss will go into the house - so it's not wasted. It's cheaper to provide that heat with your heat pump though.

Are your walls insulated? I did blow-in from the inside on several of my homes. It was messy, but helped a lot. Insulation is cheaper than PV.

It will be hard to do enough PV to supply your entire needs - esp with electric resistance water heater... but you can take a chunk off of your bill.

I take it that natural gas isn't available.

House is only 12 years old, so walls are sufficiently insulated. Based on our software and estimates of reduction of usage with new system and doing the soffiting and attic properly, we'll need 28 panels to offset about 88%. We always shoot for around 90% offset b/c the utility credits are wholesale rates. So in theory, you want zero credits at the end of the year. Plus I sell solar, so I am getting the system at cost plus $1k to my buddy who owns the company. Our savings will pay the payment on the system.

Gas would have to be propane here. Pretty expensive these days.

Re:Propane.... yeah, wouldn't suggest that. Natural gas is cheap but propane isn't.