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##### Asked by: Delina Hanschmidt

home and garden indoor environmental quality# How many BTU heater do I need?

**BTUs**to get a general estimate. Typically, plan to purchase a

**heating**or cooling unit with 20

**BTUs**for every square foot of space you have.

Herein, how many BTU do I need to heat a 20x20 room?

Rule of thumb, of course. So the **space** you **want** to cool ( **20x20**=400) **should** be doable wih a 1 ton (12,000 BTUH) unit. But I'd bump it up to a 15,000 - 16,000 BTUH to handle the hot, humid summer **heat** of your area.

**room**, multiply the

**BTU**per square footage times the square footage of the

**room**. For example, a home located in Zone 5 with poor insulation would require 60

**BTUs**per square foot. Therefore, a

**room**that is 300 square feet will need 18,000

**BTUs**(60 x 300).

Likewise, how many BTU do I need per square foot?

To determine the number of **BTUs per square foot** that you need to heat **a** room, simply multiply the **square footage by** 20 **BTUs per square foot**. For example, if **a** room has 1,000 **square feet**, you would require 20,000 **BTUs** to heat it.

For cooler climates, a very broad estimate of furnace sizing is to select one that generates 40 to 45 BTUs per square foot. At 40 to 45 BTUs per square foot, you'd need a 100,000 to 112,500 BTU furnace to heat your **2,500**-square-foot home.