How many watts of electricity is your central AC using? Is it going to break the budget with high utility bills?
What size generator do I need for central AC?
Those are valid questions.
Here are the answers, with full details, a calculator and chart to follow.
Your central AC uses somewhere between about 1,000 and 5,000 watts of electricity.
And you’ll need a 6kW to 20kW generator depending on the size of the AC condensing unit to handle both the starting watts (boost) and the running watts.
Good news – Split system central air conditioners from 1.5 to 5.0 tons are quite energy efficient because electricity is only used to run the compressor and fan, and the refrigerant in the system does the work of moving heat from inside your home and dumping it outside. The same is true of a heat pump.
See our Generator Size for 1-5 Ton AC table below for information to keep your system running during an outage.
Central AC Power Consumption Calculation and Table
This 1-5 ton central AC watts guide gives you accurate power consumption data with a calculator and table, so you can determine:
1. How much wattage your AC uses for cooling
2. Given the information, whether you prefer to opt for room fans, a whole-house fan or a room AC you can use to cool the main rooms you use during the heat of the day.
1-5 Ton AC Watts Calculator
This AC size to watts conversion calculator shows power consumption for residential split systems and mini split air conditioners based on size.
How many tons is a 36,000 BTU AC?
Answer: 36,000 divided by 12,000 equals 3 tons.
Here is the calculator. Instructions are found below, if you need them.
1-5 Tons AC Watts Use
Central Air Conditioner Watts Calculator
Ex. 1: How many watts does a 4 ton ac unit use?
From 2285 watts to about 5500 watts for SEER ratings from 10 to 24. A 16 SEER 4 ton AC uses about 3400 watts of electricity.
Ex. 2: How many watts does a 3 ton heat pump use?
2571 watts for a 16 SEER heat pump. Heat pumps use about the same amount of energy that central ACs use, so when calculating 10 to 24 SEER units, wattage is 1715 to 4115 watts.
Info Tip: 1 ton = 12,000 BTU. That’s useful if you know BTUs but not tons. Divide the BTUs by 12,000 for the conversion to tons.
Using the Central AC Watts Use Calculator
There are two steps to this Pick HVAC Central AC Watts Calculator.
First, enter the size in tons of your AC. Use the BTU to tons conversion if needed.
How many tons is my AC? That question is answered on the label on the AC cover/jacket or in the manual. Or you can find it online by searching the brand and model number found on the label/manual.
Secondly, enter the SEER rating. This is the efficiency rating. The more efficient the AC, the less energy it uses.
SEER can be found in the same way the size is found – label, manual or online search. ACs in use today – those 15 years old and newer – have SEER ratings from 10 to 20+.
How Many Watts Does a 1-5 Ton AC Use?
The calculator is the most accurate tool for finding watts per hour. But this table shows AC Size to Watts for 14 SEER models.
How Many Watts Does a 1 – 5 Ton Air Conditioner Use
| Central AC Unit Size (Ton) | Power (Watts) |
|---|---|
| 1 ton | 980 Watts |
| 1.5 ton | 1,470 Watts |
| 2 ton | 1,960 Watts |
| 2.5 ton | 2,450 Watts |
| 3 ton | 2,940 Watts |
| 3.5 ton | 3,430 Watts |
| 4 ton | 3,920 Watts |
| 5 ton | 4,900 Watts |
* The above table does not include the power of the blower. See the FAQs for information on how many watts a furnace or air handler blower motor uses. Based on 14 SEER.
Ex. 1: How many watts does a 5 ton air conditioner use?
4900 watts. Find 5 Ton in the left Central AC Size (ton) column. In the Power (Watts) column, you’ll see that a 14 SEER 5 ton AC uses 4900 watts.
Ex. 2: How many watts does a 3 ton AC use?
Using the same method, you’ll find that a 3 ton AC uses about 2900 watts when SEER is 14. More efficient central ACs and heat pumps use fewer watts per hour.
What Size Generator to Run 1-5 Ton AC Unit
This chart is useful for determining generator size for 1-5 ton ACs whether standard split system air conditioners or mini split air conditioners. It works for heat pumps too.
The Generator Size (kW) column is accurate for starting watts and running wattage per hour.
What size generator to run 1-5 ton ac unit?
| Central AC Unit Size (Ton) | Generator Size (kW) |
|---|---|
| 1 ton | 4 kW |
| 1.5 ton | 6 kW |
| 2 ton | 8 kW |
| 2.5 ton | 10 kW |
| 3 ton | 14 kW |
| 3.5 ton | 16 kW |
| 4 ton | 17 kW |
| 5 ton | 20 kW |
What size generator to run a 5 ton AC unit?
20kW – A 20 kilowatt generator has enough power to start and run a 5 ton AC – and anything smaller.
Why does the generator have to produce so many more watts than the calculator shows?
For example, a 2 ton AC uses around 2,000 watts, or 2kW, but the generator has to be 8kW, four times higher?
It is because starting watts and running watts are very different. Most air conditioners require about 4 times more energy to start than they do to run. This is the reason central air conditioner condensing units, the outside units, are equipped with start capacitors – a small battery-like device that stores energy while the AC is running and uses the stored energy to start the condensing unit the next time.
FAQ
How much electricity does a central air conditioner use?
From about 1500 watts for a 1.5 ton AC to close to 5000 watts for a 5 ton AC for the most common efficiency.
Using the AC Watts Calculator above, we see that units from 1.5 tons to 5.0 tons and 14 SEER to 20 SEER use around 1000 watts per hour to 5000 watts per hour.
Use the calculator at the top of the page and the data from your central AC to get the most precise information on the question – How Many Watts Does a Central AC Use?
Tip: The calculator can be used for heat pumps and mini split systems too.
How much electricity does a blower motor use?
The wattage ratings above are for the AC, aka the condensing unit or outside unit.
But your furnace or air handler blower motor consumes power too – between about 250 watts for an efficient ECM motor and 900 watts for an older-style PSC motor.
All the details on furnace blower watt usage is found on the Pick HVAC FAQ page How Many Watts Does a Furnace Use? It includes factors about size and motor type – PSC vs ECM motors – that give you accurate information to determine wattage and cost.
How Many Watts Does a Furnace Use? (With Factors) – PICKHVAC
Is there a formula for tons to watts conversion?
Yes. The average tons to watts conversion is 1 ton = 3516 watts. That is consistent with our Generator Size for AC table that shows a 1 ton AC needs a 4kW or 4000 watt generator and a 5 ton AC needs at least 17,500 watt generator, so a 20kW generator will handle both starting watts and running watts.
