We have two. They are wall hung. One is on an outside wall and one is in a closet. It just needs to be vented to the outside. The other thing to be aware of is the vent cannot be covered on the outside...like by snow as we found out during our first heavy winter storm.

Here's a pic of the one in the closet.

If you live in an area with hard water, I would suggest either not using a tankless water heater or you could also install a water softener. The calcium buildup will destroy one rather quickly.

In the garbage!

Brian you are cracking me up! I will take your answer into consideration, though.

AnnieD, thanks for the photo. I'm in the Deep South so I don't have to worry about snow. I was thinking that these things were a little more compact than the one in your picture, does this vary with the size of the house, needs, etc? I was thinking about using the space of the regular hot water heater as a broom/mop/vacuum closet with a couple of shelves for cleaning supplies. This same closet would house the tankless hw heater. Does this seem like a possibility to you?

Quik, no hard water here but thanks for the info.

exterior wall in the south.
I've seen boxes that the twh is installed
inside of, with cover for the front.

putting them inside the house adds to
cooling load in summer.

don't have pics though.

best of luck.

It depends on the size of the closet...mine is in the closet in my craft room and I have shelving and other stuff in there too.

I have a gas tankless in the basement (for the main bathroom) and one electrical each for the secondary bathroom and the kitchen. This setup was a bit more expensive than one big central water heater but adds redundancy and because they are all within feet of the fixtures provide for instant hot water.

The gas one looks like the one from Annie's picture (same model) and is vented directly to the outside, the electrical ones are much smaller (fit inside a cabinet) and were a lot easier to install.

We put ours in the garage.

In addition, if you are on the private well - I would not recommend tankless.

We are on a well and our tankless are fine...but we also have a water softening.

Thanks for recognizing my hastily made comment was a half joke. If saving space is your main priority then the tankless is tough to beat especially in a climate where it can be located outside.

If energy efficiency is a concern you should look into heat pump water heaters. Garages are excellent locations in your climate although finding a space inside will help reduce your cooling costs with dehumidification benefits.

From an energy and water efficiency standpoint, locate the heater as close to the most used fixtures as possible. Small plumbing footprints with a close mechanical room are ideal. Much like jrldh's situation, a dedicated tankless can make sense for remote fixtures but I would also consider a recirculation loop triggered by a switch or motion detector depending on the users preferences.

Oh.. and ALWAYS insulate hot water lines!!

x2 on heat pump water heater & insulating hot water lines.

LOL Brian, the forum needs a sense of humor these days.