The pros we worked with thought so -- recommended this for us. (We ended up straight tankless with a demand (push button) recirc pump, so we still wait for hot water, but it's not all going down the drain.)

What about hybrid of tankless with solar hot water for pre-heating?

On our new build we were told a tankless with a recirculating pump with a timer was the way to go. It seems to me the added storage tank defeats the purpose.

Our plumber said a recirc pump on the tankless makes the tankless work sporadically and harder to feed the recirc lines. The electric tank would be for storage and be fed from the tankless heater. He said the temp is also more consistent.

We've got a 4 bathrooms and a big soaking tub so this seemed to make sense.

russbaker,

Your plumber's statement does not ring true to me. I have a tankless water heater with a built in recirculation pump. With a temperature rise of 40F it will pump through 9.5gpm of hot water. The recirculation pump does not need that much power at a time. I would be shocked if it pulled more than 1gpm. Which tankless water heater are you getting? I have a three bathroom house with one soaker tub. I have run two washers, dishwasher and several showers at a time with no issues. I have one bathroom with a thermostatic valve and another with a pressure balanced valve.

Good luck!

Fine Homebuilding has a good article on why to add a tank to a tankless system. I think the newest and most expensive tankless options are making the added tank less necessary.

Do not let your plumber install a typical recirc system unless you don't care about energy costs and increased maintenance needs. The best recirc systems use occupancy, timer or push buttons to initiate the pump as in the recirculation system highlighted in this blog.

Better yet, don't do tankless and find a good location for a large capacity heat pump water heater, especially if your home has air conditioning needs. Install an up-to-date shower head to curtail your lil rascal's wasteful showering habits.

Springtime Builders, how do the heat pump water heaters compare in cost to tankless? And in SW FL, zone 2 could they be put in the garage? Right now we had planned on a tankless.

We are in Montana and use A/C about 5 days a year. We will be on a well, so water is cheap. I am concerned about recirc waste. However a timer system seems like it might address that. We work from home and hate, hate, hate, waiting for hot water at the faucet. The bathroom that will be close to the home office is about 75' from the tank/heater. Can the recirc lines be insulated to reduce loss? Wouldn't any heat loss simply be absorbed by the house (northern climate) and count as heat?

Great links. Thanks!

--Russ

Florida is probably a perfect place for a HP HW heater. You need about a 10x10 space / air in order to feed it and it will "exhaust" cool air. So the benefit will be a cover garage - and if yours is anything like mine - bringing in a hot car can make the garage quite unbearable in the summer.

And echo the recirculating pump costs - it's crazy to keep things going "constantly" for instant hot water. You burn a lot of energy.

Solution 2 in this link was what was recommended for us. Located in north Georgia.

Recirc with timer

I agree with above. Even in drier, heating dominated climates, the dehumidifying effects help keep interior humidity at better, lower levels for health and home.

Great that you recognize the benefits of a more controlled recirculation system. They make sense to serve the needs of the ever growing trend of oversize homes and plumbing footprints. People going for recirculation are wise to include timers, occupation sensors or buttons to turn on the pump. It's true that waste heat from the pipes will help heat your house, a good thing for Russ but probably results in increased maintenance or shortened life of an expensive appliance not designed for space heating.

Costs of HPWH are amazingly low to me. In this recent electric or gas hot water heater thread we discuss these issues and Ms Lindsay says she found a HPWH GE model, retailing for $999 at $630. I would expect very fast paybacks for HPWHs in the 1k-2K range but even 3k-4k will eventually payback maybe as little as 4-7 years depending on Air Conditioning with reduced dehumidification benefits. Sorry Russ, looks like I barged in on your thread there too, and while it's probably not right for you, I'm hoping other readers benefit.

There are many hidden costs in gas heating, including water heating. For electric tanks including HPWH, infrastructure is very cheap. Standard electrical wiring and monthly, service fees from the utility provider are already being implemented anyways. I think well built building envelopes and technology like heat pumps, PV, and induction cooktops have given us a cost effective path to eliminate the gas bill entirely. Gas piping and venting costs, maintenance and risks disappear.

Even before heat pump water heaters HPWH were widely available, many energy experts still preferred storage over tankless. As long as you can find a good place for one, HPWH seem to be the preferred favorite for the vast majority of energy and ASHRAE type professionals. From what I've read, garages that don't experience freezing temperatures are a great spot for HPWHs. For the best performance and energy savings, get the biggest tank that fits or is available.

According to my builder he's had problems with the HP water heaters. He said the last one he installed lasted about 8 years before requiring a large dollar repair bill. Have they improved a lot in the past 8-10 years?

They were very rare in the states 8-10 years ago so would expect much better performance, price and availability. 8 years might have been long enough to pay back any upfront costs compared to other choices. The newer technology in play is one reason I chose the Steibel Eltron Accelera 300 for my parents with a 10 year warranty and long history of success in Germany. I think the GEs seem pretty well reviewed for how many must be out there by now. Our clients have had good luck so far with the GE geosprings and AO smith Voltex.

Springtime you might want to check your link for the Steibel Eltron. LOL

Some articles about both:

Tankless vs HP HW

Another article

Heat Pump Water Heaters

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