Tankless Water Heater Load Calculation

By both calculation methods the trutankless load is generally added to the service load at 40 of its maximum nameplate rating.

Tankless water heater load calculation.

A sink may run. The tankless unit installed must supply the peak demand identified in this section. Small storage water heaters tank type. Instantaneous water heaters tankless type.

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. Gallons per minute gpm is the key when it comes to sizing tankless water heaters. Rating for output on tankless water heaters is by gallons per minute gpm. Affect the peak demand calculation in section c.

A low flow shower head may use 1 5 gallons of hot water per minute or gpm as it is called. Pro size is intended to assist in selecting water heaters or boilers that best meet the specific job requirements. Enter only those fixtures determined to be peak demand. Hot water demand sizing in the fbc is by water supply fixture units wsfu.

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. Use our handy calculator to determine your needed flow rate and temperature rise then find models that match your needs. This hvac calculator is the closest estimate to the actual manual j calculation done by hvac pros. Looking to purchase a new tankless water heater but having trouble figuring out what size or model you need.

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. This hvac load calculator quickly estimates the size of your heating and cooling system in btu s. Range in size from 2 5 to 19 gallons. 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.

For new dwellings the service load should be calculated using nec 220 82. For existing dwellings the service load should be calculated using nec 220 83. Most tankless units can provide up to 3 5 gallons of heated water per minute.