Yes, the best place is the middle of the house if you only want one outlet. If you post your floor plan, maybe we can give suggestions. Otherwise, it's very specific to each house. We have one 60 ft. hose for 2600 sq. ft. It is just off the kitchen (which is the area that needs the hose the most,) but it reaches everywhere, including my back patio.

The outlet should have a cover, which makes it not-as-ugly. I don't see it as an uglier thing than light switches, which are basically at the same height. With that said, if the outlet bothers you, you could install a framed picture over it. If you attach the frame with a hinge, it would be very simple (and not a burden) to move the frame before you pull out the hose.

We have an outlet in the foyer as well as one in the kitchen and one on the upstairs landing. They are painted the same color as the walls and are never noticed by anyone....sadly because I would welcome the opportunity to show off the Hide A Hose! I think a home would have to be extremely minimalist for anyone's attention to be taken by a HAH outlet cover!
The center of the house is definitely the best location and it seems you have good places for each outlet. I wish we could have had just one outlet on each floor.

We have 2 outlets, both in closets. We happen to have a coat closet off the kitchen and it isn't perfectly central to the house. The only downside here is the door swing is limited by trim which is not an issue for using the closet for coats but does give the hose an extra corner to have to rub by. After we moved in, I looked into alternatives (basement was unfinished at the time), and nothing else worked. An open kitchen often doesn't have a lot of options. The face is somewhat bulky and much worse than a light switch in my opinion. A cabinet location was vetoed even though that would have been the most practical. And it isn't at light switch height on the first floor - it is closer to outlet height. You can do what ever height but on the first floor, you are pulling upward so you want to mount it lower than the second floor (assuming the hose is in the attic)

Upstairs, we have a nearly perfectly centered linen closet. Here it works perfectly. It is near the top of the stairs so it is great for the top of the stairs and hall which get the dirtiest the fastest. It is right across from the laundry room. With our fairly traditional floor plan, the upstairs is simpler to route the hose around.

Advantage for closet location is that you need to have the heads stored somewhere - so you are reaching into a closet anyway.

"You can do what ever height but on the first floor, you are pulling upward so you want to mount it lower than the second floor (assuming the hose is in the attic)"

I only have a one story... and we pull downward on our HAH...... so, it is at light switch height. David, where are your hoses installed so that you pull up? I'm confused. :)

Thank you so much, LoLauren Sis3 and David_Cary ! Exactly the feedback I needed re: location. Still uncertain about whether I should try to hide the outlet in a cabinet or closet...any chance someone could shoot me a pic of the outlet plate or its dimensions ? Also, David, wondering how big a vertical "chase" the hose requires in a closet, as our closet space is a bit tight...and I too was confused about your "pulling upward" comment...would you mind clarifying what you mean (our CV unit will originate in the basement mechanical room)

I just took these photos of my foyer. the first photo shows a close up of the Hide A Hose outlet beneath the stairs. The second is a longer view so that you can see how much of an impact the HAH cover has on the room. It's late afternoon light, the cover may be a little more apparent in bright morning light. Also my HAH was installed 6 years ago, I don't know if the covers have changed since then. I hope these photos help.

My cover (which looks like sis3's cover) is 8" x 6" ... Mine was installed a couple years ago.

The hose is stored in the pipes in the walls. At each outlet, you are either pulling up or down - although you fairly quickly just pull straight. In a typical 2 story +crawl or basement, the upper level has the hose stored in the attic so you pull it down. The lower level hose is stored in the basement so you pull it up.

Our 2nd level is at light switch level and our first level is more like outlet level but honestly a bit higher.

Every HAH is installed either as a pull down or a pull up. It is part of the design. Which way is based on where the hose is - the hose is usually easiest to do how I described but it certainly doesn't have to be. The lower level hose could be stored in between the 1st and 2nd floor but that wouldn't be the easiest install (again... usually).

You guys are the best ! The photos, measurements, and explanations have made it much more clear to me. Now that I've seen them, I think the outlets will be too conspicuous on our paneled walls so I am going to scrutinize our plans for a cupboard in which I can also store the heads. Thank you so,so much for educating me.

If you are doing paneled walls could you do a panel that looks like the rest of the wall, but when pushed it opens so you can access the outlet from there. You'd need the outlet to be a bit recessed for this as the lip of it is needed to open the cover.

OP: this is what I was talking about in my original post...

Here is a link that might be useful: http://www.thethirdboob.com/2012/01/diy-photo-canvas-alarm-panel-cover.html?showComment=1325975185156