Tankless water heaters provide just the hot water you need and only when you need it. Unlike conventional storage-tank water heaters, with a tankless system there’s no tank holding gallons of hot water in reserve. Because water in that tank continuously cools and requires re-heating, storage heaters are not the most energy-efficient alternative. Water heatingtypically accounts for about 25 percent of a home’s energy expenses, and gas-fired tankless heaters tend to be about 22 percent more energy efficient than storage models. However, they have a higher upfront purchase price, and installation costs can be steeper than a conventional heater as well. Before deciding on a tankless water heater, you’ll need to take two factors into consideration:
Flow rate is the gallons per minute of water a heater can supply at a specific temperature. It’s included in the manufacturer’s specs of every water heater. The flow rate should exceed the expected amount of hot water demand in your house at any given time by about 10 percent. You can estimate demand by combining the gallons-per-minute of all hot water outlets running at once. So, total maximum demand of a typical household might be the sum of a kitchen faucet plus a bathroom shower plus a washing machine.
Temperature rise refers to the temperature variance between cold water in your plumbing pipes as it reaches the tankless heater and the heated water coming out the other side of the heater. If the water temperature at the inlet is 65 degrees and the heater outputs 98-degree water, the unit produces a 33-degree temperature rise at maximum flow rate. Should the household’s gallons-per-minute demand for hot water exceed the maximum flow rate, the temperature rise will decrease and you’ll get lower-temperature water.
Shortfalls in a tankless unit’s flow rate may be minimized by installing low-flow shower heads and faucet aerators throughout the house. Another option is to place an additional dedicated tankless heater to serve a high-demand spot such as a laundry room or kitchen.
Comfort Systems offers Wichita-area homeowners full household comfort services including heating, air conditioning and plumbing. Contact us for additional information about saving money with a tankless water heater.