How much power does a heat pump use? (1-5 ton wattage chart)


There’s one thing every heat pump owner wants to know whenever you have a power outage:

“How Much Electricity Does a Heat Pump Use?”

Knowing how many watts a heat pump uses is useful in many cases, including:

  • How much does it cost to run a heat pump? (they are considered very energy efficient)
  • How Big a Generator Do You Need to Run a Heat Pump? (start-up wattage is important here)
  • Will a solar panel system be able to provide enough electricity to power a heat pump?

Here’s the deal:

heat pump use from anywhere 802 watts to 5,102 watts, The initial wattage (relevant to generator size) may still be 3 times higher; in between 2,406 W and 15,306 W,

This is a very wide spectrum. To find out how much electricity your heat pump uses, you need to consider 3 main factors that depend on the heat pump’s wattage:

  1. size or capacity (tonnage); primary factor. The bigger the heat pump, the more power it needs to run. Example: A 4-ton heat pump will use more electricity than a 2-ton unit.
  2. energy efficiency (SEER rating); primary factor. The more efficient the heat pump, the fewer watts it needs to run. Example: 14 SEER 3 Ton heat pump consumes 3,061 watts. 22 SEER 3-ton heat pump draws 2,406 watts; This is quite a big difference.
  3. type of heat pump; secondary factor. In general, a ground-source heat pump of the same size requires less power to run than an air-source heat pump (due to the higher SEER rating).

Now, determining how many watts are required to run a heat pump isn’t all that easy. If you open a heat pump’s specification sheet, you’ll rarely see anything like “max.” Wattage = 3,000W”.

What you will always find in the spec sheet, however, is the SEER rating. We can use the SEER rating to determine how many watts and amperes you will need to run this type of heat pump. First, we’ll look at how to find the wattage of any heat pump via the SEER rating.

In addition, you will also find how many watts do 1-5 ton heat pumps use (summary in the table).

How to Check How Many Watts a Heat Pump Uses?

As you may know, wattage is not labeled on the heat pump spec sheet. Fortunately, there is a SEER rating (Seasonal Energy Efficiency Rating). We can calculate the total wattage heat pump usage from the SEER rating using these two equations:

EER = -0.02 × SEER² + 1.12 × SEER (Equation 1)

Total Wattage = Capacity (in BTU) EER (Equation 2)

In short, we convert SEER to EER (Equation 1), and we use the calculated EER to calculate the total wattage of a heat pump (Equation 2). It may sound a bit complicated but it is quite simple; You just enter the SEER rating in Equation 1 and go from there.

Here’s an example of what we get:

The 2 ton heat pump (24,000 BTU) has a 20 SEER rating. How many watts does it run on? Let’s calculate it:

EER at 20 SEER = −0.02 × 20² + 1.12 × 20 = 14.4

Total Wattage (2-Ton, 20 SEER) = 24,000 BTU = 14.4 1,667 watts

Using these two equations, we can calculate how much power a heat pump uses. We did the same and summarize the results in this table:

How many watts do heat pumps use?

Heat Pump Size: Wattage (14 SEER): Wattage (16 SEER): Wattage (18 SEER): Wattage (20 SEER): Wattage (22 SEER):
1 ton (12,000 BTU) 1,020 W 938 W 877 W 833 W 802 W
1.5 ton (18,000 BTU) 1,531 W 1,406 W 1,316 W 1,250 W 1,203 W
2 tons (24,000 BTU) 2,041 W 1,875 W 1,754 W 1,667 W 1,604 W
2.5 Ton (30,000 BTU) 2,551 W 2,344 W 2,193 W 2,083 W 2005 W
3 Ton (36,000 BTU) 3,061 W 2,813 W 2,632 W 2,500 W 2,406 W
3.5 ton (42,000 BTU) 3,571 W 3,281 W 3,070 W 2,917 W 2,807 W
4 tons (48,000 BTU) 4,082 W 3,750 W 3,509 W 3,333 W 3,209 W
4.5 tons (54,000 BTU) 4,592 W 4,219 W 3,947 W 3,750 W 3,610 W
5 tons (60,000 BTU) 5,102 W 4,688 W 4,386 W 4,167 W 4011 W

Using this table, you can answer any question about how many watts does your heat pump run on.

Example: Let’s say you have a 16 SEER 3 Ton unit. How many watts does it require to run? Just look at the table and you will see that such a 3 ton unit runs on 2,813 watts.

This is quite valuable information if you are looking for what wattage generator you need to run a 3 ton unit.

We hope this helps. If you did not find the answer in the above article, you can leave it as a comment below and we will try to help you with the calculation.

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