Nearly 20% of residential energy bills is used to produce hot water. Much of this energy is consumed to simply maintain the water in the water heater at the desired temperature. Traditional gas water heaters have a flue in the center of the tank that is uninsulated, and allows the heat from the water in the tank to easily transfer to the air in the flue, which then goes outside.
Many homeowners have installed instantaneous water heaters to eliminate this heat loss. Instantaneous water heaters do not have a storage tank, so they have virtually no standby heat loss. Of course, by eliminating the storage tank, the water heater does not have the same response as a traditional water heater. There is a longer wait time for the hot water to arrive at the faucet, along with other issues at low flow rates and the so called "hot water sandwich" effect.
A simpler solution is available to homeowners with hydronic radiant heating. Indirect water heaters can nearly eliminate standby heat loss. Indirect water heaters use the heat from the boiler system water to heat the domestic hot water. This eliminates the need for a burner system for the water heater, simplifying the unit and allowing it to be well insulated.
The Smart Indirect Water Heater from Triangle Tube is completely encased in 2 inches of foam insulation. This minimizes the heat loss to 1/2 degree F per hour. This heat loss is so low, that it costs only $0.05 per day to keep 40 gallons of hot water ready to use (with natural gas). The Smart 40 model is the most popular model, and its unique design gives it the ability to heat water twice as fast as a traditional gas water heater. With this performance, many homeowners find that a Smart 40 delivers hot water better the traditional 75 gallon water heater it replaced.