If you are currently searching for a new heating or cooling unit, you may have seen the abbreviation BTU. Getting a unit with the appropriate BTU for your home is important because it is measurement of a HVAC system’s capacity and is used to calculate the amount of energy a unit can deliver.
What is a BTU?
BTU is an acronym for British Thermal Unit. Although its name seems to suggest otherwise, it is no longer commonly used in the United Kingdom. BTU is a unit of measurement for energy. One BTU is equal to the amount of energy used to raise the temperature of one pound of water one degree Fahrenheit. In most applications the BTU has been replaced by the joule, but BTU remains a popular measurement of heating and cooling equipment.
How does it apply to heating and cooling equipment?
In a heat pump or furnace, the BTU number refers to the heat output of the particular unit. The higher the number the more heat the unit can produce. Air conditioners are a little different. The BTU number on cooling equipment refers to the amount of energy used to remove the heat from the air.
Even small heaters or air conditioners have high BTU numbers. Typically, whole house units range from 60,000 to 80,000 and above. The larger your home, the higher the BTU you will want because it means the heating or cooling unit will be able to produce more heated or cooled air. BTU is a good way to compare the capacity of similarly priced units.
How many BTU’s do you need?
Every heating and cooling need is different, so there is not a one-size-fits all approach. The power you need for your home is going to depend on several factors.
- Size of your house
- Type and quality of insulation
- The type and size of your windows
- Location of home
- Height of your ceilings
If you are having difficulty, a professional HVAC company can be a great help in determining the appropriate size unit for your home.
A note on efficiency
Typically, BTU measures the capacity of the system’s output. For energy efficiency compare a furnace’s AFUE (Annual Fuel Utilization Efficiency). A high AFUE number on a furnace means that it wastes less energy and is more efficient.
For air conditioners and heat pumps, the SEER (Seasonal Energy Efficiency Ratio) measures the efficiency of the cooling process and the higher the SEER number, the more efficient the unit. All new products in the U.S. must have a rating of at least 13.0 but many go up to 21 and higher.