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BTU and AFUE! What is a BTU? What is AFUE?
Jumping into the heating world can be an intimidating decision. There are so many buzzwords and TLA’s (three-letter acronyms) that are designed to confuse and mislead. Today we will be discussing two of the most important acronyms, the BTU and the AFUE.
BTU stands for British Thermal Unit, and in scientific terms one unit is equivalent to 1055 joules of energy. A BTU is used to describe the amount of heating power available to a fireplace or furnace. A single BTU is the amount of energy needed to increase 1 pound of water’s temperature 1 degree Fahrenheit. BTU’s are a unit of measurement used in heating as well as cooling and many Air Conditioning systems use BTU’s to measure their power. In this case the BTU’s measured are in the amount of heat removed instead of added to a room. The higher a fireplace or furnace BTU output, the more powerful the system is.
Montigo’s B34DV2 has a Max BTU output of 18,000
What does this all mean for a homeowner? Well now that you know what a BTU is, you can now find out how many BTU’s you will need in order to heat your home to your satisfaction.
Before we go into how many BTU’s you will need to heat your home, we will discuss what AFUE means. AFUE stands for Annual Fuel Utilization Efficiency. AFUE is generally reported as a ratio and is used to determine the thermal efficiency of a heating unit and is usually expressed as a percentage. For example if a fireplace has an AFUE of 90%, and it is listed at 10,000 BTU, the heating output would actually be 9,000 BTU. The loss of 1,000 BTU could be due to exhaust or heat waste. Basically the unit can output at 10,000 but only 9,000 is actually heating your home.
A Direct Vent Option has heat energy leaving the system as exhaust
To give you a ballpark figure to shoot for when looking for a fireplace or furnace we have developed this chart:
| Recommended BTU for Square Footage | ||
| Room Area | Square Feet | Recommended BTU Range |
| 10′ x 15′ | 150 sq. Ft. | up to 5,100 |
| 10′ x 20′ | 200 sq. Ft. | 6,000 |
| 15′ x 20′ | 300 sq. Ft. | 7,000 |
| 17′ x 20′ | 340 sq. Ft. | 8,000 |
| 18′ x 25′ | 450 sq. Ft. | 10,000 |
| 22′ x 25′ | 550 sq. Ft. | 12,000 |
| 25′ x 28′ | 700 sq. Ft. | 14,000 |
| 25′ x 34′ | 850 sq. Ft. | 16,000 |
| 25′ x 40′ | 1,000 sq. Ft. | 18,000 |
| 35′ x 40′ | 1,400 sq. Ft. | 24,000 |
| 40′ x 40′ | 1,600 sq. Ft. | 32,000 |
This is just a starting point on your journey to getting the perfect fireplace or furnace for your dream home. Our talented furnace and fireplace experts will be able to customize your selection by finding out the AFUE of a particular unit in order to make sure that your home is properly heated. Different venting options, chimneys, and accessories are also available to make sure you get the most out of your furnace or fireplace.
Send us a message below and we will set you up with one of our experts!
