I've very close to installing a 5 ton GSHP in my home and have a few questions

First background.  I'm looking at a 5 ton 2 stage Tranquility 27 with a horizontal loop system.  Everything appears to be sized correctly and through an experienced installer with 5 separate trenches (1/ton) to separate out the thermal load in our VERY dry soil.

I live in Yakima, Washington, with fairly mild winters (typical nights 20-25dF and days 28-30dF) with hot summers (100-104dF during the day).  The house has had several manual Js that appeared to be well calculated averaging between 4-5 tons with each installer. House is mostly single level w partial basement, moderate well sealed and 4800sq ft.  I currently live in this house alone (ridiculous eh?)

I'm trying to figure out the DSH setup.  I AM on a natural gas line, so I have the ability to add gas water heater instead of using electric. They have spec'ed a DSH loop and a depowered electric tank as the buffer tank.  Initially the quoted an electric (powered) water heater for the final tank at $850, but it made sense to me to do gas given I have the access to NG.

The quotes for gas are obviously much higher.  The highest quote was for $3400 for a AO Smith Vertex 96% efficient unit.  Is this ridiculous overkill? This unit potentially qualifies for a 30% tax credit, but I'm not certain if I can take this in addition to the unlimited geothermal 30% (aka, can I take the 30% unlimited tax credit for the GSHP and then take the 30% capped at $1500 tax credit on the water heater?)

The other options for hot water are a EF 0.65 gas model at $2000 or a EF 0.67 model at $2500. If I can take the tax break on the Vertex it would be a very good deal!

But, question is should I just go electric since I have the DSH loop w/ buffer tank and not go crazy?!?

Thanks,
Chris

Regarding your tax issue, it would be wise to contact your accountant.

Keep in mind that gas hot water heater tanks run very inefficient (less than 65 %) and loose much heat due to their design. The advantage is that the electric tanks are much better insulated, since they do not need to be vented, and are much cheaper to install. Given that you are alone, you do not seem to use a lot of hot water, electric might be a good option. You need to shower a lot to come up with savings to be worthwhile your increased upfront costs.

Check with your local electric provider. If they offer rebates, they may REQUIRE electric tanks.

Bergy

Posted By docjenser on 23 Sep 2010 06:42 PM
Regarding your tax issue, it would be wise to contact your accountant.

Keep in mind that gas hot water heater tanks run very inefficient (less than 65 %) and loose much heat due to their design. The advantage is that the electric tanks are much better insulated, since they do not need to be vented, and are much cheaper to install. Given that you are alone, you do not seem to use a lot of hot water, electric might be a good option. You need to shower a lot to come up with savings to be worthwhile your increased upfront costs.

That is the way I'm leaning right now! That $1-2,000 would go a long way elsewhere! The incentive for qualified electric is only $50 here.

I think I would tend to lean toward the electric tank, if I were you.  I struggled with the same question for my set up.  I will have the depowered electric water heater as the buffer tank and my installer suggested an electric for the main tank.  The gas was somewhere around $1K more, if I recall correctly.  However, with four of us in the house, including two kids entering their teen years, I decided to go with NG for the main tank for the quicker recovery time.

The following websites might help you with your tax credit questions:

http://www.dsireusa.org/incentives/...&re=1&ee=1

http://www.dsireusa.org/incentives/...&re=1&ee=1

http://www.energystar.gov/index.cfm...s.tx_index

Another option is an upowered electric for the buffer and a heat pump water heater for the main. You get 30% tax credit plus possible local utility rebates for the heat pump water heater. I have this setup and it works well.

I have a similar setup and it works well. Water heating costs work out to about $5 / month in summer $10 / month in winter for a family of 4.5 people. Those costs include HPWH kwh usage and operating the DSH pump as well as an educated guess as to the cost of winter heating diverted by the DSH to domestic hot water.

Thanks engineer.

My cost for a Rheem HPWH is about $2500 (40gal) and the American Standard about $3400, but obviously both qualify for a 30% tax credit. I can also go natural gas (AO Smith Vertex condensing at 96% efficient) for about the same money as the larger HPWH at around $3400 ALSO with a tax credit of 30%.

I live in a large house, but only have 1 person living in it currently. I would think, even with a few more people in the house that a 40gal HPWH along with a DSH and buffer tank would be MORE than adequate to provide hot water for 1-5 people.....

Lowes sells 50 gal GE HPWH (whose design I slightly favor over Rheem) for about $1600

Don't hang your hat on a 40 gallon HPWH thinking the DSH will always augment it - there are typically days and weeks in spring and fall when neither heat nor AC is needed, zeroing DSH contribution. Primary water heater has to tote the whole load during those times

I have the 50 Gallon GE HPWH. I have it set to run the heat pump only (e-heat mode) and not the electric resistance elements. Now that it's fall and the desuperheater is not heating the buffer very much, if at all, I was worried about the water heater keeping up with my family (4 people) demand. I was happily surprised that it has been keeping up just fine with no loss in hot water supply. We tend to not have two showers going at once, so that is spreading out demand and helping for sure. In the deep winter, the buffer should be very well heated and the GE should not run much. This should avoid overcooling my utility area in the basement by limiting run time from the GE. Right now it is dehumidifying my basement nicely and keeps my dehumidifier from turning on down there. This is an added plus in energy savings. During the summer, my buffer was in 90 - 95 deg range most days and the GE ran considerably less than it is right now.

The GE allows you to set it so it can use the electric resistance if you need faster hot water heat up when needed (company visits, etc). It does make some fan noise when running, so I would not reccomend for living floor install next to a bedroom or family room unless you had decent sound controls. I can not hear it at all upstairs.

I had to buy another tank to provide the buffer for the geo desuperheater, so felt that after all rebates, the HPWH was a good choice. No significant rebates for the other type tanks were out there. I paid $1500 - $300 (PECO) - $450 (30% Fed) = $750. I was also considering the air tap, but I needed another tank anyway, so the GE won out.

Good to hear of a success story with the GE. I like its variable modes of operation and that it is arranged to avoid need of a circulating water pump

Well thanks for the help everyone. I signed my contract today. 5 ton Climatemaster 27 with what seems a good loop design Accuclean Air Cleaner 12 gal Trusteam Honeywell humidifer Rheem 50gal heat pump water heater DSH into a depowered 50gal buffer tank I'm very excited. I'm going from an unstable, fails frequently Lennox Completeheat going into a two air handlers to a common single air handler. Lennox is single speed and I waste a lot of electricity just running the fan on high all the time to move air around. Going to just a 2 speed system is going to help power consumption a lot. I'll let people know how it is going and of course comment on the install afterwords. Any thoughts on installation of a monitoring system/power consumption monitoring in the early part of the install?

Highly recommend the welserver for monitoring. You can install the sensors right before the put the insulation over the pipes, so pretty much at the end of the install. Otherwise people tend to accidently pull on wires etc, and then you will be spending many more hours finding the trouble with the sensor.