Tankless Water Heater Load Calculation

Tankless water heater efficiency is determined by the water flow rates inside your home.

Tankless water heater load calculation.

The tankless unit installed must supply the peak demand identified in this section. Hot water demand sizing in the fbc is by water supply fixture units wsfu. A low flow shower head may use 1 5 gallons of hot water per minute or gpm as it is called. This hvac load calculator quickly estimates the size of your heating and cooling system in btu s.

For new dwellings the service load should be calculated using nec 220 82. Looking to purchase a new tankless water heater but having trouble figuring out what size or model you need. Enter only those fixtures determined to be peak demand. Tiny point of use pou electric storage water heaters with capacities ranging from 8 to 32 liters 2 to 6 gallons.

Range in size from 2 5 to 19 gallons. Smith pro size sizing program is a tool that can be used to estimate water heater requirements for many common applications. Rinnai strongly suggests that you only purchase our products from rinnai independent dealers and that you have the products installed only by licensed professionals who have attended a rinnai installation training class licensed professionals who have attended a rinnai installation training class. Since tankless water heaters supply endless hot water you don t have to worry about capacity but instead think in terms of water flow rate.

Most tankless units can provide up to 3 5 gallons of heated water per minute. Rating for output on tankless water heaters is by gallons per minute gpm. The heat load estimate is based on your climate region total square footage number of rooms or zones you want ceiling height insulation type number of windows and doors. Gallons per minute gpm is the key when it comes to sizing tankless water heaters.

Instantaneous water heaters tankless type. Small storage water heaters tank type. A sink may run. Pro size is intended to assist in selecting water heaters or boilers that best meet the specific job requirements.

The lowest price you can get for the highest gpm is easily the takagi t h3 dv n that will give you a whopping 10 gpm. Affect the peak demand calculation in section c. By both calculation methods the trutankless load is generally added to the service load at 40 of its maximum nameplate rating.