In HVAC, you will sometimes have to convert BTU per hour to horsepower (HP). This conversion is frequently used for air conditioner, furnace, or heat pump capacity. We are going to explain exactly how to calculate HP from BTU per hour. On top of that, we have also prepared a simple-to-use BTU/hr To HP Calculator (just insert BTU/hr, and get horsepower immediately). To top it off, we have converted 1,000 BTU to 72,000 BTU into HP, and summarized the results in a neat conversion chart.
Let’s first look at the two units we are converting:
- BTU/hr or British Thermal Unit per hour is a unit for cooling or heating output in HVAC. We have, for example, 5,000 BTU/hr, 12,000 BTU/hr, 24,000 BTU/hr air conditioners, are so on (it also applies to furnaces). 1 BTU/hr is an energy flow that will heat or cool 1 pound of water by 1 degree Fahrenheit in 1 hour.
- HP or Horsepower in HVAC is also a unit for the cooling output of air conditioners or the heat output of furnaces or heat pumps.
How to convert BTU/hr to HP easily? To convert these British Thermal Units per hour to horsepower, we only need to know this relation:
- 1 HP is equal to 9,000 BTU.
That means we can write the BTU/hr to HP conversion formula like this:
HP = BTU/hr / 9,000
Basically, 1 BTU/hr is equal to 1/9,000 HP or 0.000111 HP.

Quick Example: How many horsepower is a 12,000 BTU/hr air conditioner? We just insert 12,000 into the equation like this:
HP (12,000 BTU/hr) = 12,000 / 9,000 = 1.33 HP
12,000 BTU is equal to 1.33 horsepower. ?
This is just one example. To convert any number of BTU per hour to HP, you can use the following calculator. Below this online calculator, you should also consult the conversion chart where we have converted 1,000 BTU to 72,000 BTU HVAC capacities into HP. Here is the calculator:
BTU/h To HP Calculator
Here’s how easy it is to use it:
Let’s say you have an 8,000 BTU window air conditioner. How many HP is that? Just slide the slider to ‘8000’, and you get the result: 8,000 BTU is equal to 0.89 horsepower.
You can find a similar (in reverse) HP to BTU/hr calculator here.
Here is the full conversion chart that illustrates well the most common BTU per hour to HP conversions:
BTU/hr To HP Conversion Chart
BTU/hr: | Horsepower (HP): |
1,000 BTU/hr | 0.11 HP |
2,000 BTU/hr | 0.22 HP |
3,000 BTU/hr | 0.33 HP |
4,000 BTU/hr | 0.44 HP |
5,000 BTU/hr | 0.56 HP |
6,000 BTU/hr | 0.67 HP |
7,000 BTU/hr | 0.78 HP |
8,000 BTU/hr | 0.89 HP |
9,000 BTU/hr | 1.00 HP |
10,000 BTU/hr | 1.11 HP |
11,000 BTU/hr | 1.22 HP |
12,000 BTU/hr | 1.33 HP |
13,000 BTU/hr | 1.44 HP |
14,000 BTU/hr | 1.56 HP |
15,000 BTU/hr | 1.67 HP |
18,000 BTU/hr | 2.00 HP |
20,000 BTU/hr | 2.22 HP |
21,000 BTU/hr | 2.33 HP |
24,000 BTU/hr | 2.67 HP |
25,000 BTU/hr | 2.78 HP |
27,000 BTU/hr | 3.00 HP |
30,000 BTU/hr | 3.33 HP |
36,000 BTU/hr | 4.00 HP |
48,000 BTU/hr | 5.33 HP |
60,000 BTU/hr | 6.67 HP |
72,000 BTU/hr | 8.00 HP |
As you can see, you can now just read the BTU/hr to HP conversion of this chart like this:
Air Conditioner Example: How many HP is a 5,000 BTU/hr window air conditioner? You can see that 5,000 BTU is equal to 0.56 HP.
Furnace Example: How many HP is a 30,000 BTU/hr gas furnace? We see that 36,000 BTU/hr is equal to 3.33 HP. That means that a 30,000 BTU/hr furnace is the same as a 3.33 HP furnace.
We hope that you can readily use the calculator and this chart to figure out how many HP is in any number of BTU/hr. If you need any help, give us some numbers in the comments below, and we will help you out.
It helps me lot to guide how to determine and design the cooling needed in a building requirements.