BTU, or British thermal units, is a unit of measurement used to calculate the heat output of a furnace. In order to accurately size a furnace for your home, you’ll need to know how much heat it needs to generate in order to maintain a comfortable temperature. The furnace’s BTU rating will tell you how many BTUs per hour it produces. For example, a furnace with a BTU rating of 60,000 can generate 60,000 BTUs of heat per hour. The higher the furnace’s BTU rating, the more heat the furnace can generate in an hour. Furnaces are available in a range of BTU ratings to meet the heating needs of different homes. Once you’re ready to investigate replacing your furnace you can consult with a furnace specialist to find the right unit for your home. With the right furnace in place, you can enjoy reliable heating all winter long.