Point of use water heaters

Taz1956

Are point of use tank-less electric water heaters worth the expense, and do they last?

SWEI

Sometimes. How hard is your water? What are your gas and electric rates like?

Larry Weingarten

Hello: That's a pretty broad question! Could you tell us about your application? With that, we could likely give you a more meaningful answer. Happy New Year!

Yours, Larry

Taz1956

Sure! I plan to use one for each bathroom 2, and one for the kitchen, and one for the laundry room. These days, cleaning clothes is becoming a cold only chore so that one will not get much use. As for the kitchen with sink aerator, I don't need a high cap. unit. And as for the bathrooms, they should be a larger size. (we installed a Rheem at work, and burned out in a few days) we went back to tank electric.
Also, I will use 240vac units to reduce electric costs. Hope this helps. I do not know what JCP&L rates are as we just purchased this house. We have well water. Don't know the hardness yet. I installed Rinnai Nat. gas tankless water heater in my other home 5 years ago, and would DEFIANTLY recommend that brand and system to EVERYONE! what an incredible unit and cost savings!!!

STEVEusaPA

You better check your well water first, and treat it if/as necessary, or you'll be buying these units by the truckload.

SWEI

Check your electric rates as well. Not just the published rate, but the net cost when you divide the number at the bottom of the bill by the kWH usage. Many utilities also have tiered rates to factor in.

Powering the unit with 240V will not save any electricity over a 120V unit, though you really do need 240V for most applications.

We use them for solar DHW post-heat, which is one of the applications where they often do pencil out.

Jamie Hall

The other thing to watch on the electric rates -- some places (and some homes!) have peak demand rates; if you do, the electric on-demand heaters may well trigger them.

Rich_49

Where in JCP&L territory exactly ?

Taz1956

Lake Hopatcong, NJ...I guess I should check my rates..

JohnNY

You need 240-volt, 3-phase electric to power a unit of any significance using 3 x 40 or 50-amp breakers.
This specs from Steibel-Eltron aren't enticing.

SWEI

You can run the 3-element models on single phase -- as long as you have a 300A service.

Temperature rise is often the deal killer on these, but even a winter-starved solar tank should have 80°F water in it, which nicely doubles the capacity of pretty much any tankless.

Given your interest in efficiency and your rural location, I would give serious consideration to a small solar thermal DHW system.

Taz1956

Thanx... yea, looks like I will just keep the old electric 40 gal. job for now, then purchase a high efficiency unit, put a jacket on it, and call it a day..... after a cold beer...

SWEI

Buildings or rooms (guest bathrooms, garage apartment kitchenettes, etc.) with intermittent occupancy often make excellent candidates for point of use tankless electric heaters.

If the structure is regularly occupied and the tank you have is getting the job done, I'd probably run it 'till it drops.

Is your water at all hard? If so, take off the boiler drain that came on the heater and replace it with a full port 3/4" ball valve and a short 3/4" threaded nipple (2-1/2" usually works.) Be sure to use galvanized, stainless, or brass, and not black iron for this. Now you can easily blow down the tank from mineral build up once or twice a year, which IME roughly triples the useful life.

Taz1956

That is a good idea, I should have came up with that. I love ball valves.... best there is. full flow, no seat, lasts long. Yes work the old one till its done. Save my pennies, and look for a good double element new 50 gal job. I don't know about those fangled water heaters with the motor/circulator on top if worth the effort.

Rich_49

What kind of heating are you using up there ?

SWEI

Taz1956 said:

I don't know about those fangled water heaters with the motor/circulator on top if worth the effort.

Sounds like you may be describing a heatpump water heater (or a gas condensing tank type heater.) Both are potentially good solutions, but once again it comes down to your gas and electric rates, the climate, and the occupancy of the building.

Taz1956

OK, I am presently using oil on a Heil furnace (maybe about 15-20 years old according to one HVAC person) forced air, ducts are not done right (never happens right?) and having a open concept first floor, it is hard to run trunks to second floor on inside walls, outside walls is not smart. So, I am now thinking putting oil fired hot water baseboard and counter the cost of all new ducting into piping and radiators for hot water medium.
Your thoughts......

SWEI

A water-based distribution system gives you the ultimate in flexibility and efficiency. How tight is the building -- are you going to need/want mechanically assisted fresh air (perhaps in the future)? Is any portion of the ductwork worth keeping? It's not unusual to find beautiful 1950's sheetmetal trunking mated to cheesy flex duct hack-add-on work. You might consider a hydro-air coil for some portion of the above, or at least piping for one some later date if that is a possibility.

What are your rates for oil, electric, and LPG there?