HP To BTU/hr: Horsepower To BTU For A/C (Calculator + Chart)

In lots of cases, you see air conditioner capacity expressed in HP (HorsePower). We usually want to convert that HP to BTUs per hour. During this article, we will show you exactly how to convert horsepower to BTU per hour for an HVAC system (air conditioners, furnaces). On top of that, we have programmed an HP To BTU/hr Calculator (just insert HP, get BTU/h), complete with a chart where we converted 0.1 HP to 100 HP into BTU per hour.

Alright, let’s first address this horsepower unit we see on aircon specification sheets (Example: 1.5 HP air conditioner). There is not your regular mechanical horsepower we use for cars. Rather, in HVAC, we use a specific type of horsepower unit (that can be quite easily converted into BTU per hour, of course).

Here is a short description of these two units we use in HVAC:

  • HP or HorsePower in HVAC is a unit for cooling or heating output. This is an HVAC-specific unit that doesn’t relate to other types of horsepower units (electric, mechanic, metric, boiler). It is specifically used to denote the capacity of air conditioning systems and heating systems (like furnaces).
  • BTU/hr or British Thermal Unit per hour is also an HVAC unit for cooling or heating output. It is the energy needed to increase (or energy withdrawal to decrease) the temperature of 1 pound of water by 1 degree Fahrenheit in 1 hour.

To convert these HVAC horsepower to BTU/h, you only need to know this 1 conversion rule:

1 HP = 9,000 BTU/hr

This means that 1 HVAC horsepower is equal to 9,000 BTU per hour. Example: 1 HP air conditioner is the same as a 9,000 BTU air conditioner.

2 hp lg air conditioner is 18000 btu per hour
This is an 18,000 BTU/hr LG Inverter V air conditioner (outdoor condenser unit). You can also refer to it as a 2 HP air conditioner since 18,000 BTU = 2 HP.

We can calculate the BTUs per hour from the given HP using this formula:

BTU/hr = HP × 9,000 BTU/hr Per HP

Quick Example: Let’s say we have a 1.5 HP portable air conditioner. How many BTUs per hour is 1.5 HP? We just insert the ‘1.5 HP’ in the equation like this:

BTU/hr (1.5 HP) = 1.5 HP × 9,000 BTU/hr Per HP = 13,500 BTU

We see that 1.5 HP is equal to 13,500 BTU per hour.

You can calculate this on the back of the napkin. To help you out, we have designed a simple-to-use HP to BTU per hour calculator for HVAC (you insert HP on the AC unit, and get the BTUs per hour). We have also converted 0.1 HP to 100 HP into BTU per hour, and summarized the results in a neat conversion chart you will find below the calculator:

HP To BTU Per Hour Calculator


Here is how this calculator works:

Let’s say you want to know how many BTUs per hour is a 2 HP air conditioner. Just slide the slider to ‘2’, and you get the result immediately: 2 HP is equal to 18,000 BTU.

Here is the full all-encompassing conversion chart:

Horsepower To BTU/hr Conversion Chart

Horsepower (HP in HVAC): BTU/hr:
0.1 HP 900 BTU/hr
0.5 HP 4,500 BTU/hr
1 HP 9,000 BTU/hr
1.5 HP 13,500 BTU/hr
2 HP 18,000 BTU/hr
2.5 HP 22,500 BTU/hr
3 HP 27,000 BTU/hr
3.5 HP 31,500 BTU/hr
4 HP 36,000 BTU/hr
4.5 HP 40,500 BTU/hr
5 HP 45,000 BTU/hr
5.5 HP 49,500 BTU/hr
6 HP 54,000 BTU/hr
6.5 HP 58,500 BTU/hr
7 HP 63,000 BTU/hr
7.5 HP 67,500 BTU/hr
8 HP 72,000 BTU/hr
8.5 HP 76,500 BTU/hr
9 HP 81,000 BTU/hr
9.5 HP 85,500 BTU/hr
10 HP 90,000 BTU/hr
20 HP 180,000 BTU/hr
30 HP 270,00 BTU/hr
40 HP 360,000 BTU/hr
50 HP 450,000 BTU/hr
100 HP 900,000 BTU/hr

Now, you can just look at this chart and see how many BTUs per hour a certain amount of horsepower is. Example: Let’s say you have a 4 HP air conditioner. How much is that in BTUs per hour? As you can see from the chart, 4 HP is equal to 36,000 BTU. That is equal to 3 tons.

We hope that using this calculator and chart, you will now be able to easily convert horsepower on your AC unit into BTUs per hour. If you need our help, give us some numbers in the comment section below, and we will help you out. You can also check a similar Horsepower To BTU per minute calculator and chart here.

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