Heat Pump Water Heaters (HPWHs)

Robert O'Brien

you have warm air or hydronic heat?

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Bill Allen

Heat Pump Water Heaters (HPWHs)

Pardon the intrusion. I'm not an HVAC or plumbing professional, just an inquiring homeowner.

I've been educating myself on what the alternatives currently are to replacing my old fuel oil-fired Bock water heater with Beckett oil burner. My current WH is just old (roughly 17 y.o.) and we frequently have to poke and repoke the reset button (sometime many repeats) to get it to heat water in a sustained way. (Yes, it gets regular periodic maintenance.)

Of course, I could replace it with the same thing, maybe get a Riello burner. My plumber and my furnace guys name-drop solar hot water heat, but the payback periods (as I see it) are not as quick as I'd like and I would still need backup heating when the solar heating falls short.

I've looked into tankless hot water heating (electric would be my preference but propane doesn't really change the equation much (no access to natural gas)) and the principle is attractive but the bottomline is not (both the upfront cost and the operating costs).

I've done extensive investigation into heat pump water heaters (HPWH). Based on the 4 surviving manfuactures' own literature I favor Applied Energy Recovery Systems (AERS) E-Tech Model R106H. This is an "add-on" unit that requires a standard electric heater to function. The combined HPWH-WH configutration is rated with a COP of 3.4 when raising 58 deg water to 125 deg, at a rate of 23 gph. While powered by electricity, the manufacturer claims the unit to save 40%-70% over straight direct heating.

I spoke to my local plumber about estimating the installation of this HPWH-WH combination and I met resistence. They are unfamiliar with the unit and the manufacturer, which actually is a reasonable concern. Lacking any knowledge of what I'm trying to accomplish they paint a picture of how incredibly unsubstantiated the manufacturers claims COULD be. Then there is the unkown risk exposure for down-range maintenance of the HPWH once it is in service. I don't dismiss nor do I embrace every point my plumber makes but they are right that better, objective third-party information needs to be found to verify the true value of such heat pump water heaters.

I have been successful in locating a number of blogs where satisfied customers of E-Tech HPWHs have discussed their experiences over the last 20 years. I live on Long Island (NYC suburbs, and oh BTW we "enjoy" $0.20 KW rate) and I have been unable to find anyone else who has installed an E-Tech HPWH anywhere in my region, nor have I been able to find anyone who has experience installing these units.

Are there any readers here who have opinions, good or bad, about heat pump water heaters in general or about specifically E-Tech HPWHs or their current competition, or have any knowledge of professionals with experience installing/maintaining these units in Suffolk County/Nassau County NY?

Bill Allen

I guess I forgot to mention, my house is 2-zone oil furnace (2 actual 3 ton Lennox furnaces to achieve 2 zones) forced air heating. Hot water comes from a standalone water heater, presently Bock 60 gallon water heater, Beckett burner.

The house has 3 full baths, 1 half bath under construction, dishwasher, clothes washer; and a Jacuzzi tub in Master Bath (counts in addition to the normal shower in the bathroom, but everything still counts as part of the 3 full baths).

We are currently a family size of 3 but there would rarely be more than 2 hot water sources used at any one time.

Mike T., Swampeast MO

I wouldn't give up on solar DHW quite yet. Yes, I know that "payback math" gets VERY dicey--especially with solar--but both "old-time" installers with 1970s experience and manufacturers both agree that for most structures in most climates, solar DHW is presently the most cost-effective use.

Materials have improved and lessons have been learned and a number of fairly inexpensive solar DHW systems are available that really do have reasonable chance of not only achieving payback, but continuing to provide [almost] "free" energy over their reasonable service life.

As long as the installation is not complicated by the design/orientation/placement of your home, I suspect that a well-designed solar system will provide reasonable payback.

As to the backup source? Since you currently use fuel oil for space heating, I would [probably] use the same for DHW.

Robert O'Brien

I

think the reason there aren't any on LI is the 20c KWH rates we enjoy courtesy of LIPA.Even at 50%less electrical consumption than a standard electric HWH it would cost the same to operate as an oil fired unit at $4/gallon.
Bock will have available a 2 stage modulating oil burner in the near future

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Cosmo_3

water heater heat-pumps

A few years ago I had a call to estimate to install one of these heat-pumps. Unfortunately I did not get the job, he had mentioned that he got a more economical estimate. He had a similar situation of oil-fired furnace. I like any good wethead also talked to him about a boiler install.....!!

I have thought of calling to ask if he did have the water heater heat-pump installed, and whether he has saved anything in operating costs.

Have any wallies installed one, or have any experience?

I just wonder how long the unit works before needed maintenance/etc. Or some third-party testing of energy efficiency.

Cosmo

Dave Belisle

Heat pump Water Heater

I installed a Nyle heat pump water heater in my house about a month ago.... I also installed a tempature gauge and a watt hour meter so I can see for myself if the claims made by the manufactures are correct..

It came with everything to install the unit.....

You remove the drain on the bottom of the water heater and install a 3/4 brass nipple with a 3/4 Brass Tee then you install a 1/2 inch dip tube into the 3/4 brass Tee .... A simple way to get an in and out through one connection..... that is the only plumbing connection made to the electric water heater....

The unit came pre wired with a wip of Greenfield that ties into water heater... Two wires to the 240 volt. a Green wire for ground , and a forth wire in series with the bottom element and bottom Thermostat.........
The bottom T stat runs the unit ....


This unit is producing water temps of 140 degrees ... It draws 2.8 amps and produces 8,000 BTUs....

That is a COP better than 3 !!!

A gallon of #2 fuel oil should produce about 150 gallons of hot water to 130 degrees in a 85% efficiant appliance

A heat pump water heater powered by $.20 KWH power should cost around $2.20 to heat the same 150 gallons to 130 degrees....

One thing to keep in mind that the heat pump is taking heat from the air where the heat pump is located... You want it in a large area and if that area is cold it will be a lot colder....
Water is running through the unit so it has to be in a area where it can't freeze.......

It will be great for in the summer , as you can duct the cool air off and use the cooling somewhere else ...
It is also dehumidifying while it is running.....

DCB in NH

Bill Allen

Heat Pump Water Heaters (HPWHs)

Thanks for describing your experiences with the Nyle Nyletherm 1. I had considered that model as I investigated everything that's out there currently. I consider it to be among the top tier units for residential use AND Nyle is currently offering a healthy discount price on the unit.

For me, I'm still commited to AERS's E-Tech R106H, a shelf-mounted unit (actually a similar configuration to the Nyle). The manufacturer's performance specs rate it higher and more powerful than the Nyle and, naturally, you pay for that.

By your description, you sound like you self-installed your HPWH. Since I'm not a pro, just a motivated amateur, I'm still trying to find a plumber or HVAC person in the Long Island area who is experienced or willing to take on the installation. My discussions with one plumber just the other day were rather defeatist, that no plumber on LI would take this job because they wouldn't want to be in the position to provide post-installation maintenance and repair. Basically, I was told I should proceed ONLY if I was an engineer myself (nope) or had one handy, or I was willing to take this on as my own little science project.

It's clear this one plumber wanted no part of my install job but an HPWH shouldn't be that daunting or, if it is, it deserves to be marketed to only engineers and gearheads. I'm trying to get some info from the manufacturer about plumbers/dealers/reps in my area that might give me a leg up on finding someone to do the job. All I've been told so far is that I need a plumber with a number of years experience, not a recently trained plumber.

I would gladly welcome further comments from anyone here with anything to say about HPWHs, installation, that sort of thing.

Unknown

if it can only do 23 gph (barely over a third of a gpm?), then it's only good for maintenance demands or long term recharge, which means you'd need enough tank to meet your whole demand and then let it recharge afterwards, basically.

maintenance demands, if you figure a 40 gallon tank loses 1 deg hour (which is high, typically), that's 40 x 8.4 =336 lost BTUs/hr, 8064/day, 2943360/year; that's 862kwH/yr. if you were generous and gave the heat pump a COP of 4, you save about 650kWH on that, and save $130/year. less generous, COP of 3, you save $50 to $60. If it works as advertised. and doesn't fail.

Now, if you try to size storage to allow this unit to recharge your tank after your ONE eight minute 1.5 GPM low flow showerhead morning shower., and you keep the tank at 120 so as not to wreck your COP, and you shower at a typical 105 (not pink skinning!):

you Need 1.5 x 8 x 8.4 x 47 = 4737 stored BTUs.

To do that with a 120 degree tank to supply a 105 degree shower, you need:

4737/15/8.4= about a 40 gallon tank. and it will take 20 to 25 minutes to recharge (including the 8 minutes you are in the shower, so an additional 12 to 15 minutes).

However operating it in this manner increases your savings 50% over my "standby loss" calc per shower successfully reheated by the heat pump.

obviously more showers, longer showers, higher flow, higher temps all change the figures.. but if you play your cards right and it works advertised and isn't too expensive, might not be a bad idea.


Of course, you can do solar DHW AND this together...