I actually have three water heaters, each water heater flows from hot to cold and then the hot from the third goes to the house and the only one with power is the third which is the GE heat pump. The first water heater is connected to the desuperhater of the GTHP and the tank will heat up when the GTHP is on. The second water heater is connected to an external heat exchanger which is heated by the solar panels. The third is the GE heat pump which works great but in theory it does take it's heat from heated space. The 2,400 sq-ft by 9 ft ceilings of the basement is a zone set to 66 degrees/heat. The idea is that the GE doesn't heat the water much because the water is usually hot going into the tank. Since I monitor all temperatures and energy used I can see how well things are working and adjust. I can't see that the GTHP is in more because of the GE Water heater but of course it must be at least a little bit.

My point was to make DHW in the least costly way and with the GTHP and two water heaters I was using on average nearly 10 KWH per day for the electric water heater. I now use less than 2KWH per day on average.  I also neaded a little dehumidification in the basement which the GE does pretty well. In the summer it can run all it wants because it will be cooling the inside air which will cool the house.

If you use two water heaters and the second which is not connected to the GTHP I don't see why having a Heat pump water heater would make a difference. Problem is that the GTHP doesn't run enough to make hot water in the spring and fall.

The GE was $1,450 installed with a $300 rebate from the electric company and I will get a tax rebate of 30% on the $1,450. It really is a nice unit and so far so good.

John

 

 

Glad to hear of a good early review on the GE HPWH. Install price sounds fair as well.

I looked online today at the Stiebel Eltron Accelera 300 - very spiff. Highest EF of any water heater so far, but the only price I came across for it is $3500...yikes!

John,
What are your thoughts on using the GE HP water heater as the only water heater? Some of us are interested in just one heater for various reasons and it seems to me that it would be a good compromise in theory. You can have the water heater run in HP mode when the desuperheater was making lots of water and switch to the hybrid mode when it wasn't heating any water. That model looks like it gives you lots of flexibility with settings.

I called Steibel Eltron and asked for a price and the fist words out of my mouth were, "are you kidding". It does look like a nice unit but GE will ruin it for them. Next year GE will have a 80 gallon unit and if prices are where I bought mine they will sell lots of them.


John

I just don't get the point of one water heater. It makes no sense to me and the GE unit may not be rated for such use. A dummy electric water heater is nearly nothing in cost and you will really save by having two. Understand how this works. With two water heaters the GTHP will at best give you lower costs by helping heat the DHW but my data and experience shows that the GTHP can't do it all. If you turn off an element or lower the temperature you will hate it in the spring and fall. I'm in zone 5 and use lots of heat and I still spend money on DHW. Even if you're in the hot belt you'll still have days where you won't get enough DHW from the GTHP. I hate running out of hot water.

The GE unit has a Hybrid mode but does not have a HP only mode.

I'm not trying to be brash here but you have to do it right and reap years of cost savings. On the other hand if it's due to other reasons than you need to get the right people to help solve the problem. I've met few problems in my years that I couldn't solve (I'm only talking engineering here).

john

The GE does have a HP only mode, Hyrbid, or electric only

I wished I knew how to get into the diagnostic menu on the ge I bet is has all of the cool info like current water temp ect. Maybe after some of these are sold then the code will surface on the net

John, if you goto the energy menu and scroll down past the FAQ there is a diagnostic menu that is password protected by a 3 key combination. I bet all of the good info on the workings of it is in there!

< Edit I. Figured out the code :) it does show you the curent temp and all kinds of good info like when the lower or upper element is on. PM me and I will tell you the code I don't want to post it publicly GE might not like that

Is the GE HP noisy? Someone said it did make enough that it should be installed away from living areas. Is that true? Also, I'm having trouble finding it available here in the NE.The nearest seems to be in Pa. GE said it was waiting until it had trained repairpeople before it allowed distribution here. That will not be for another three months or so.

Is the space you have it in conditioned?

Mine is in my basement shop area and my basement is conditioned space. It is somewhat
loud but since it's in my shop area I don't mind. I was surprised by the noise but it seems
to be from the fan. I am in NE-PA and purchased mine through a deal with our electric
utility PPL. I think it's a nice unit and so far it has worked real well. I also have solar but
it's not been on much and I have Geothermal which also heats DHW. Anyway my costs
are less than 20 cents a day now and mostly around 10 cents. We're 10 cents per KWH.

The fans on the ge is the noisy part when they are going at full speed it sounds like a window air-conditioner on high, basically its the same thing anyway. Ours is installed in a utility room but I planed for this unit when I built my house. I insulated all of the walls and installed a supply and return air for the room. So far everything is working fine I have had it for over a month and it was just a install and use it thing no issues at all.

My home will have a geo-exchange unit with desuperheater and a set of solar thermal panels.  Currently, the plan is to use a 80 gallon tank connected to the desuperheater and also containing a heat exchanger for the the solar thermal.  This buffer tank would feed a tankless BG heater which would then provide the house with DHW.

I didn't notice anyone in this thread using a tankless NG heater downstream from a single buffer tank.  Is this not a good idea for some reason?  My builder currently plans to use a Bradford Everhot tankless system.  I understand the need for a NG system (tank or tankless) to "top-up" heat when the renewable systems don't provide enough.  I'd just like to minimize the NG usage.

@jongig Any reason that you don't have your desuperheater and solar thermal connected to the same tank?  In my climate, the desuperheater will mostly run in the winter (no need for A/C).  The solar thermal panels will be angled to maximize summer sun and not produce much in the winter.  The idea is that the two systems complement each other so I'm hoping one tank will be enough.

@jongig Any reason that you don't have your desuperheater and solar thermal connected to the same tank? In my climate, the desuperheater will mostly run in the winter (no need for A/C). The solar thermal panels will be angled to maximize summer sun and not produce much in the winter. The idea is that the two systems complement each other so I'm hoping one tank will be enough.

No major reason except that I had two 50-gallon electric tanks already with the first already connected to the desuperheater and some theories. The second water heater was connected to electric and it used a lot of electricity, nearly 10 KWh per day especially spring and fall. After adding the heat pump water heater it seemed easy to just use the one for the solar and the first leave with the desuperheater. I also considered that I didn't want 100 gallons of solar hot water storage and which would shut down the desuperheater. On a good day even in December I heated the water in the solar tank to 136f and since at 140 the desuperheater would shut down it seems to have been a good idea. I would rather see the desuperheater working. If the solar is on it brings my KWh for DHW to about .5KWH per day or lower. I can't ask for better than that. I think my decision to use two tanks makes sense and it does work. In the summer I will see the GTHP come on somewhat and I do want it heating DHW.

I can't see a better way to do it and with the data I'm keeping it supports my conclusions.

Even in your description I think you should separate the two systems. I like the idea of the first for the desuperheater and the second for Solar and then into the instant, BUT, and here it comes. I also have experience with Takagi gas systems and I would not use one in a home. I would use it to maybe to heat an exchanger in the solar tank to bring the temperature up to a point when the solar doesn’t do it but I wouldn’t use it as the main source for the house.

Things to think about. The instant water heater doesn’t heat when the electric is off, if you have tanks of hot water you don’t care (assuming on a community water system). Even if the instant can keep up with hot water it’s the head loss that will ruin a shower if you have more than one person in the house using hot water and/or cold water. As a water operator I focus on balanced flow and pressure and in my house I did the same. We can take multiple showers, flush a toilet and run the dishwasher and no one will notice. In a system where you add one high head loss part you nearly can’t do it without a lot of additional expense. I also don’t like the way they turn on and off with water flow, that works great if you always use a flow rate greater than required but they are not perfect. I am not beating up on these units because I think they are great and for a weekend cabin or a heat exchange system and where they are used as backup is great but I wouldn’t use on in a full time home, IMHO.

John

Oh, one more thing about your using NG for DHW. Consider that electric companies charge less in a resedential use in a the more you use the less it costs per KWh. If you add gas to your house you may spend more than if you used all electric. I knew this going into my system and it was the right thing to do. I am below 10 cents per KWh in the winter months which brings down the big use cost wise, the GTHP. We have propane for the cooking but that was because the wife likes gas stoves. Had we gone electric the electric company would have given us other discounts. Can't win all the time...

Very helpful comments.  Many thanks.

Best regards,

Bill