DIYbanter - View Single Post - Converting from domestic (tank) to tankless water heater

Robert Gammon

wrote:
Model Energy Factor Cost to Operate* Annual Savings¹ Annual Savings²
250SX/SXO 0.85 $250 $110 $151
125B/BS 0.69 $308 $52 $93
125HX 0.80 $266 $95 $135
125FX 0.78 $273 $88 $129
40-gallon tank 0.59 $361
75-gallon tank 0.53 $410

Note the stated savings. In the winter the extra gas used helps heat
your home If the heating season lasts 6 months then divide the savings
by ONE HALF.

Now the largest savings bosch lists is $153 divide by 2 it saves about
76 bucks a year. Thats nice BUT the install costs several times the
cost of a standard tank.

Tank type Gas water heaters are not allowed, by building code, in many
locations to be inside the heated/cooled space. Tankless can be, if
combustion air is brought in.

So energy losses by a gas tank type water heater do not add to building
heat, not always.