Tankless Water Heater Load Calculation

The tankless unit installed must supply the peak demand identified in this section.

Tankless water heater load calculation.

Looking to purchase a new tankless water heater but having trouble figuring out what size or model you need. Use our handy calculator to determine your needed flow rate and temperature rise then find models that match your needs. Affect the peak demand calculation in section c. 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. This hvac load calculator quickly estimates the size of your heating and cooling system in btu s. Pro size is intended to assist in selecting water heaters or boilers that best meet the specific job requirements. Smith pro size sizing program is a tool that can be used to estimate water heater requirements for many common applications.

A low flow shower head may use 1 5 gallons of hot water per minute or gpm as it is called. Most tankless units can provide up to 3 5 gallons of heated water per minute. 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. For existing dwellings the service load should be calculated using nec 220 83.

Hot water demand sizing in the fbc is by water supply fixture units wsfu. Small storage water heaters tank type. 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. Rating for output on tankless water heaters is by gallons per minute gpm.

Tiny point of use pou electric storage water heaters with capacities ranging from 8 to 32 liters 2 to 6 gallons. By both calculation methods the trutankless load is generally added to the service load at 40 of its maximum nameplate rating. Gallons per minute gpm is the key when it comes to sizing tankless water heaters. Tankless water heater efficiency is determined by the water flow rates inside your home.

Range in size from 2 5 to 19 gallons. A sink may run. Enter only those fixtures determined to be peak demand.