Know What Your HVAC Unit’s Normal Heat Output Should Be

Is your furnace generating enough heat? Is it generating too much? What’s the normal heat output for a system like yours? How do you make sure it’s operating as efficiently as possible? Here’s what you need to know.

BTU and AFUE

Your furnace’s heat is measured in British Thermal Units. One BTU is the amount of heat it takes to raise one pound of water by one degree Fahrenheit. The average furnace produces between 80,000 and 100,000 BTUs per hour.

However, that’s not how much heat you actually get from your system. For that, you need to look at your AFUE rating. Your furnace’s Annual Fuel Utilization Efficiency (AFUE), is how much of the energy used by the system is given off as heat as opposed to how much is expelled as exhaust. Say you have a 100,000 BTU furnace that meets the minimum AFUE rating of 80%. Your heat output would be 80,000 BTUs.

Manual J

That was the simplified version of your heating system’s workings. In practice, your AFUE rating doesn’t guarantee your system will always operate at that efficiency level. Rather, it’s an average of your unit’s efficiency over the course of the year. Additionally, certain things can affect your home’s heat so that even if the unit produces heat at maximum efficiency, you could still lose energy. The layout of your home, the amount of sunlight that comes through the windows, the layout of your ducts, and a variety of other factors can impact your system’s efficiency.

That’s where Manual J comes in. You may know it as the guide that helps HVAC technicians find the right-size unit for your home, but it’s more than that. It also helps them tabulate all the factors that impact your home’s heating and use it to determine the maximum efficiency for your furnace and its heat output. That way, you get the heat you need to make your home comfortable without overdoing it.

To ensure your furnace has the most efficient heat output for its energy usage, contact us at Energy 1 Heating & Air Conditioning. We keep homes efficient and comfortable in Lorain, Elyria, and Oberlin.