This sounds like a potentially bad idea.

The heater requires minimum of 700 cubic feet (10x10x7)
Therefore the closet must be ventilated in order for this to work.
A fully louvered door would probably meet that requirement.

My guess is that you are sensitive to the sound (since this is an office and you are asking about the sound).

There aren't any other real risks other than the noise and ventilation issue.

Thanks for your response.

I do not think I am that sensitive to sound, but who knows, right? I haven't heard the noise when the compressor kicks in of an actual unit live.

When I ask about risks, I mean more along the lines of, it would not be a fire hazard, would it? Is the air volume spec is just for energy efficiency? GE's documentation says having the unit in a smaller room with a 240 square inch minimum louver opening to a larger room is sufficient, but that sounds like perhaps a bit of vendor overpromise.

This post was edited by herg39458 on Thu, Nov 6, 14 at 10:46

One other thing I neglected to mention, this closet is the best location in terms of the heater being close to every place that needs hot water. The utility room where the furnace resides and which would be the best place all else being equal is about 30' away. Could the hot water out from the HPWH located in that utility room run into a (small?) tankless heater in the closet to avoid a long, water-wasting hot water wait?

I'm not saying that you have sensitive ears... I'm saying this is in an office and you are asking about sound level. That sounds like you are worried about sound levels.

Yes, you could do a small tank (5 gal) in series with the main heater to avoid a long run.

There will be two issues with putting the GE in there:
1-) Constant humming at 55 dB is more than enough to be major disturbance if it is the kind of place you are planning to do office work. Besides, 55 dB is the quitest possible rate that was measured by the manufacturer so it can turn out to be lauder than that because of the different conditions it has to work in or because it gets old and inefficient in years. You must not have a hybrid water heater in a place where you want peace and quiet.
2-) Even with the lauvered door, it is going to suck heat from the room and make it cool and dry in there. If it is a room that needs heating, putting the water heater in there is kind of defeats the purpose.
In most cases, it is best to put a hybrid in a room where it will be alone and free to make whatever noise and cool the place.

FWIW - my GeoSpring is quieter than my dehumidifier when running in the hybrid mode. And, it doesn't run constantly.

If you have a subterranean basement, do not worry about the hybrid's effect on room temperature... also, don't worry about it "drying" out the room. I have a condensate pump associated with mine, but the amount of condensate per day is about 1-2 cups. The pump cycles once every 2 or 3 days during the summer and less during the winter.

Noise may well be an issue. I operate my unit in Hybrid Mode ONLY. When on, it is as noisy as the whole house heat pump right next to it. Actually, it seems noisier.

I love my unit and the approximately $40 per month it saves me in electricity costs, but it is noisy. (Not a problem for me - unfinished basement.)

Thanks for the responses. We do have a mostly subterranean basement, it is about 4.5' below grade in the back near where the proposed WH location is, and fully below grade in the front.

Noise is something of a worry, but I have headphones on most of the time. That just seems like something that could be more annoying than I might think.

Our utility room is a better location in that it is plenty big, and the furnace is in there so the unit would probably run quite efficiently, but the downside is the added expense of plumbing that room, putting in a drain, and the resulting additional 40' of plumbing that would have to flush before getting hot water anywhere in the house. The proposed location is central to all the places that need a supply of hot water.

Instead of a drain, you could collect the small amount of condensate in a coffee can, or more professionally, a condensate pump discharging to where ever your A/C condensate goes.. or into the A/C's condensate pump.

It's a couple of cups of water a day.

Hmm, interesting. I wonder how often you would have to empty that can, as in, who wins the race between condensate coming out of the WH and evaporation out of the can. The other worry with that would be whether it would meet manufacturer and code requirements for the installation.

We live in the PacNW and do not have A/C.

Go with the closet installation and louvered doors. Sounds like the best place for it given the central location and plumbing is there.

If it ends up being too loud, you can move it later.

OK, don't use a can. Instead do the installation that I characterized as "more professional."

I hate it whe a can outsmarts us. ;-)

My GeoSpring produces less than one gallon of condensate a month. It's located underneath my house in an unconditioned space.

You don't want to have to add 40 feet of plumbing to get it in the closet.

This post was edited by jrb451 on Wed, Nov 19, 14 at 17:44

FWIW- I had to switch my Geo-Spring from "Heat Pump" to "Hybrid" yesterday as the ambient temperatures in my basement weren't sufficient to heat the water. (The temperature was 54 degrees.) The owner's manual says they're good down to 45 degrees ambient but not for me.)