Humidifier Sizing for Optimum Performance

Calculate your home’s cubic footage for proper humidification.

Since many of today’s homes feature high or vaulted ceilings, air volume can be increased by 30-to-60 percent over traditional homes with 8-foot ceilings.

Calculate a home’s cubic footage:
length x width x average ceiling height
Using this formula to calculate the total area of a 40 x 50 foot home with 8-foot ceilings, total cubic feet (CF) can be determined:
40 x 50 = 2,000 x 8 = 16,000
In this case, humidification for a 2,000 square foot home must be adequate for an area of 16,000cf.

Calculate a humidification output:
Use this formula to calculate humidification output required:
CF x 6.615 / 7000 = GPD (Gallons per Day)
16,000 CF x 6.615 = 105,840 / 7,000 = 15.12 GPD
This formula does not take into account number of occupants, exhaust fans, outside air supplied, use of a fireplace, HRV (heat recovery ventilator) units, etc.

By cross-referencing cubic footage and gallons per day with type of heating unit in the Skuttle Humidifier Capabilities Comparison Chart (below), humidifiers that should be considered for the home in question are identified by type and model. To narrow the options further, it is important to estimate where the house falls on the Loose – Tight cubic footage range for the humidifiers selected.

Humidifiers should not be oversized, although they are frequently undersized. The humidistat (included with all Skuttle humidifiers), in conjunction with the humidifier’s built-in volume limitations, is designed to prevent excessive humidification. Installing a humidifier (other than steam) that will generate enough humidity while the furnace blower is on will satisfy the cubic-foot requirements of the home.