size & venting for new w/h

[dianedebuda]

Addition to house has completely separate water & septic from existing house. This addition has kitchen (2 d/w, 2 sinks) plus seldom used 3/4 bath (for pool use) and 2 (1/2 baths). Originally was planning propane w/h, but venting of planned tank location was a problem, so changed plan to point-of-use electrics.

The addition is still in "framed" state w/o drywall or insullation, so it's not too late to make changes again. Had propane piped for cooktop. Now wondering if it would be possible/legal to put a propane w/h outside without additional venting. Saw a gas tankless unit where this is possible. Can do with a tanked unit? What size would I need?

 

[phishfood]

I generally recommend staying away from electric tankless. The electrical wiring necessary to make them usable is rather expensive.

A tank water heater outside is doable, but it will need to be protected from the elements. There are tankless models available that can be installed outside.

 

[frodo]

40 gallon, gas in a 3'x3' square building, framed, insulated with roof

 

[dianedebuda]

40 gallon

Funny thing is that the plumber who installed the propane line for the cooktop actually said a big tank would be over kill and suggested the point-of-use units. Normal use would just be a single kitchen sink & d/w plus a 1/2 bath.

I generally recommend staying away from electric tankless. The electrical wiring necessary to make them usable is rather expensive.

A tank water heater outside is doable, but it will need to be protected from the elements. There are tankless models available that can be installed outside.

Outside from the kitchen is the countertop for a covered outside kitchen. I had the outside kitchen plumbed for a countertop propane grill (which I'm not going to use now), so IF the line is the proper size, it would be easy to put a short tank under the counter with an insullated surround. Would it have to be vented in any way - like louvers or screens on the door? FWIW, the exterior wall is veneered with half-width concrete blocks.

If the line is not the right size, I think the install cost of electric vs propane here is going to be a wash. I can buy/install electrical wire; I have to hire a plumber for the propane. Long term, I'd guess a propane tank would be more cost effective than an electric one. Since the propane point-of-use units are much more expensive than the electric ones, I'm not so sure the same is true in this case. My existing w/h is a propane tank; I've never dealt with electric w/h or point-of-use units.

I used to own a 4-plex where the gas w/h tanks were in outside/attached storage units. But those had regular 2-wall vent pipes throught the ceiling. The doors had to have top & bottom vents.

Thanks for your help.