Hi, I’m completing a 630 2/1 bath house. Due to Cathedral ceiling, no attic. HVAC put air handler in mechanical room. Need 31 inches for clearance to work on unit. Remaining width from air handler to wall is 41 inches. Ceilings 16 ft. Trying to get ideas on best water heater to pass inspection. Tankless vs 30 gallon low boy. Can electric lowboy get mounted on bracket inside mechanical room opposite air handler to provide clearance to work on both or should lowboy be put in adjoining closet? Thanks --166.196.xx.xxx

You can purchase any size tanked water heater (28, 30, 40 or 50 gallons) with a direct vent, 90 degree bend then out a side wall. These units have blowers. This is one solution. --47.155.xx.x

Just follow what the fire chief will approve, they have power on electric installs because the over temp drain must go into a building drain. --184.59.xxx.xx

Actually, with a 16ft ceiling, it could be almost like a second story. Bigger than just the water heater, but enough room to climb up and stand on it and have your (plumber's)tool bag up there with you. Make sure there is a good space to put the ladder. --68.229.xxx.xxx

Please come back & tell us what you end up with - inquiring minds want to know --68.229.xxx.xxx

A demand tank less is the best option where will fit in tight area. It can be power vented through the wall for combustion and exhaust area. Had very good results with Takagi demand water heater where installed in 2005 where only cleaned not replacing a single part. Lowes will sell the Takagi under A.O Smith where is a rebranded Takagi, Ask a contractor about venting through the wall. If there is hard water then recommend a water softner. Well a demand water heater is more expensive upfront the efficiency and longer life expectancy over time is a better option. First a tank less only heats water on demand not heating water all the time where a typical direct fired hot water tank 7 to 12 degrees is going up chimney where no hot water is required. Most direct fired hot water tanks have a consumable anode where once anode rod is consumed then hot water glass wears through then rusts out where will leak. I took back the direct fired hot water gas fired tank to the rental depot which was 5 years old where the scraped the tank. Once the demand hot heater fires then continuous hot water water where can use dishwasher or front load washing machine or two showers at one time with low flow shower heads. --207.236.xxx.xxx

Keeps the water heater out of the attic so reduces risks associated with the tank leaking. Tenants will still have residual hot water during power outages, minimizing complaints. A gas tankless heater may not be permitted in such a small house because a gas outdoor tankless unit would likely be too close to a door or window (or so I've been told). --5.182.xxx.xx

Or be old school and get a tabletop hot water heater. --5.182.xxx.xxx

A demand tankless can be vented thorough the roof where in the house using the chimney which was used for furnace and gas fired hot water tank. Normally a wall vent must 3 feet from a operating window and door along a certain height above the snow line. Can not be vented near stairs or sidewalks. High efficiency demand used 2” or 3” CVPC venting pipe. Also a demand water heater can be used for heat by adding a pump for radiators if permited by town. Sooner or later there are going to more stringent efficiency standards where gas fired tank heaters will have to be condensing which will cost around $4,000 where the demand gas fired will cost less. --207.236.xxx.xxx

To save inside space , an electric water heater (40 gallons , say) can go outside perhaps, whereby you build a small enclose around it on your exterior wall. Check your city code requirements. A stand alone instant water heater under each sink can be useful , too, or a large whole house instant one hanging on an exterior wall on the side of your house can work as well. Check codes and plumbers advice. --174.211.xxx.xx