Gas Storage Tank Water Heater

A Gas Storage Tank Water Heater holds 30 to 75 gallons in a glass lined steel tank with a burner sitting under the floor of it and a flue pipe running up through the middle. A twisted metal baffle inside that flue slows the exhaust so more of its heat crosses into the water. A thermostat with a probe against the tank wall opens the gas valve, and cold water enters through a dip tube that carries it to the bottom so it does not mix with the hot layer on top. Output is quoted in BTU per hour, the rate at which the burner releases heat: 32,000 to 50,000 covers most homes, and 40,000 BTU refills roughly 40 gallons an hour at a 90 degree rise.

Its nearest sibling, the Electric Storage Tank Water Heater, needs no flue and installs almost anywhere, but recovers at half the speed. A Heat Pump Water Heater fits the same footprint and cuts running cost by two thirds, then demands a large volume of surrounding air. Gas Tankless never runs out of hot water and never keeps a tank warm, at the cost of a larger gas line and a dedicated vent. Against all three, gas storage wins on recovery per dollar. A 40 gallon gas tank matches a 50 gallon electric one on first hour rating.

Venting decides where it can go. An atmospheric model relies on hot exhaust rising up an existing chimney or B vent, costs the least, and needs real combustion air. A common rule is 50 cubic feet of room volume for every 1,000 BTU per hour unless the space has openings into another room. A power vent adds a fan, pushes exhaust horizontally through plastic pipe up to about 40 feet, and needs a standard 120 volt outlet, so it stops working in a blackout. A direct vent draws combustion air from outdoors through a concentric pipe, which suits a tight, well sealed house. Condensing models reach a UEF above 0.80 and produce acidic condensate that has to drain.

Watch the exhaust, not the tank. Rust flakes or soot at the draft hood on an atmospheric unit mean flue gases are spilling into the room. So a carbon monoxide alarm on the same floor is not optional. Flush 2 to 3 gallons from the drain valve twice a year, since sediment on the tank floor sits between the flame and the water and makes the popping sound people mistake for normal.