Heat Pump & Air Conditioner Amps & Volts Use Explained (Tonnage Guide)

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Finding out how much energy consumption you have to plan around when getting a new air conditioner (AC) or heat pump can certainly be a chore. 

While the thought may be considered annoying initially, it can worsen when terminology and lingo get thrown into the mix. So, how many amps and volts does a condenser use exactly?

On average, an outdoor condenser unit (heat pump or air conditioner) uses anywhere between 9 to 13 amps, or 9.6 amps, to be exact. The amps change because models and tonnage vary. Smaller units will use fewer amps than larger units. However, voltage numbers remain relatively the same at 208 volts on the low and 230 volts on the high side. Modern residential service is 240 volts incoming, with a voltage drop not lower than 233 volts. 

This article delves into tonnage and the size breaker you’ll need.

What is Tonnage?

Unfortunately, the word “tonnage” can worsen if you do not know its most common definition. Tonnage is often referring to the weight of cargo. However, it has another description that you can find primarily in the HVAC world.

When referring to AC-based units, tonnage essentially translates into the rough amount of heat transfer you’d need to freeze one ton of water within 24 hours. 

Most notably, this entire transfer has an electrical power equivalent of 12,000 BTU/hr (British Thermal Unit/hour). This equation is going to be very relevant later.

Before we go much further, it is worth mentioning that cooling rooms and heat pumps are not considered effective AC solutions. 

As such, there is very little in the way of effectively calculating tonnage for one. Precisely because cooling your house is considered ineffective from an electrical energy consumption perspective.

A 12,000 BTU AC unit utilizes about 1000-1500 watts. To calculate the exact number of amps used, we need to divide the number of watts by the voltage.

If we were to say our 12,000 BTU AC unit used 1,100 watts and had a voltage of 115, we would have an average of 9.6 amps. (1,100W\115V=9.6 amps)

So, a 12,000 BTU unit will draw anywhere between 9 and 13 amps by the exact measurement, so we can assume that 1 ton can equate to the same 9 to 13 amps, which is the final piece of this puzzle required. 

Because wattage and volts will vary from model to model, you will see some slight variations between the numbers, but the average numbers will remain unchanged for the most part.

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How Many Amps Does a Heat Pump or AC Need?

As with most of these questions, clarity is needed before getting any answers. Assuming your heat pump has a 2.5-ton AC pull, we would want to start by analyzing how much our bare minimum amperage would be.

The absolute smallest ampacity we can arrive at, with heat pumps being much less energy efficient than AC, would be about 19 amps, and the smallest fuse size you can get is 25. 

Keeping that same train of thought, you must account for the indoor unit and how many amps it generates. 

A safe bet would be anywhere between 3 to 5 amps upon itself. So overall, you may look at about 30 amps total from a 2.5-ton central air conditioner or heat pump condenser. 

Still, you can apply the same energy inefficiency across the board depending on brand and energy consumption settings, so there may be more wiggle room there than expected.

Something else to consider here would be that your more significant concern will not be how many amps your heat pump requires to function but more so that the heat pump itself is large enough to heat or cool all the rooms in your home sufficiently.

Amp Requirements for a 5-Ton Condensing Unit

Heating or cooling large amounts of space is nothing to scoff at, especially considering how much room you might be talking. 

A 5-ton heat pump can easily cover over 3,000 sq ft in warmer climates and about 3,700 in something more moderate. Viewing those numbers, you might wonder how many amps are required to handle such ample space.

To calculate this, we would start with how many BTUs of cooling power such a device would generate in the first place. Luckily, your typical 5-ton heat pump generates roughly 60,000 BTU. 

As such, we can infer that it will produce about as much as a 5-ton AC; said AC would make anywhere between 4,000 and 8,000 watts. 

If we took a firm standing that a 5-ton heat pump required 6,000 watts to run, and the heat pump itself was on a 240-volt dedicated circuit, we would divide the watts from the volts and arrive at 26.1 amps. 

Again, this would be your ballpark average, with a few other tidbits of information that may make that number higher or lower.

While discussing these calculations, it is worth stating if any of this math is unfamiliar to you or doesn’t quite comprehend it, you may be out of your depth. You also might require the guidance of a professional to make a sound decision on your needs.

It may cost you a bit more in the long run, but it certainly beats coming up with a wrong estimate and not having enough electrical power in your home to meet the electrical requirements. Even worse, risk starting a fire by attempting to install any of this yourself.

What Size Breaker Would I Need?

Figuring out the specific size of your breaker largely depends on how much amps of power consumption your heat pump is going to demand. 

If you are working with a 4 or even a 5-ton heat pump, you will need an electrical circuit breaker rated 45-50 A and connected with an 8-10 AWG wire. It is especially true if your heat pump produces anywhere from 197 to 253 volts. 

Once again, it would be best if you were not considering this a DIY project. In that case, you will need a professional’s advice on which sizes will fully meet your unique needs and keep things up to code.

In most cases, you will require a certificate or some manner of proving that you are a licensed professional and qualified to work on installing new HVAC systems.

Determining the Size of a Generator that Holds a 5-Ton AC Unit

As we briefly mentioned above, a 5-ton AC unit typically generates about 6,000 watts of electric power.

For that exact reason, you would want to go with a generator that can handle about 7,000 watts of power if you consider start-up electrical requirements.

As long as you meet that power requirement and leave a little wiggle room, you will not have to worry about your AC unit having insufficient power, as it will never exceed that initial start-up requirement.

Amp Requirements for a 2-Ton Condensing Unit

Another excellent question that we touched on above, a 2-ton heat pump will generate roughly 24,000 BTU, and a 24,000 BTU heat pump typically generates about 2,800 watts. 

If your standard unit is a 210, you would need roughly 13 amps as a base, but you would need to account for your indoor unit and the usual fluctuations from model to model.

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What Amp Breaker Would I Need?

Once again, the amp breaker size will change significantly depending on the specific heat pump you get and the other requirements we mentioned. You should seek advice from a licensed electrician or HVAC contractor to determine what typical size breaker you need.

If replacing a circuit breaker for an older air conditioner, check the breaker size in the breaker panel. As technology advances, the breaker amp size is often lower on the same tonnage in a newer system. For example, a newer 3-ton air conditioning unit may require a max breaker of 35 amps, while your older unit could have needed a 40 amp breaker.

In most cases, a 2-ton heat pump could use a 30 amp breaker and 10 amp wire, again for your best and safest results. You would want to consult an electrician to ensure your safety is assured and your home is protected.

1. Does a Heat Pump Use a lot of Electricity?

Asking if a heat pump uses a lot of electricity is a relatively difficult question to answer. The more space your system needs to cover, the more electricity it will require by association. 

A blatant issue when discussing energy consumption is inefficiency. In that case, electric heat pumps are not precisely the most energy-efficient HVAC solutions to begin with. 

Because of this, they will more often than not require much more electricity, in the long run, to achieve the same result as a more traditional HVAC solution. 

Yes, heat pumps will almost always utilize more electricity than a more basic HVAC solution. It is doubly true if you are in a colder environment where your heat pump will work especially hard to achieve the same result.

2. What Size Wire is Needed for a Heat Pump?

The wire size required depends on how large your heat pump is specifically and scales with that same size. 

More to the point, a more significant concern should be put onto safety than size scalings when it comes to any aspect of upgrading or installing a heat pump.

Looking for a more roundabout answer, the most common wire sizes available and used on standard heat pump installations come in either 12 gauge AWG or the slightly oversized 14 gauge AWG. 

3. What Voltage Does a Heat Pump Run On?

In almost every instance available, heat pumps and air conditioners run on 240-volt double-pole circuit breakers; this is especially true for residential areas, where a vast majority of solutions will be found.

4. What Temperature Does a Heat Pump Become Ineffective?

As temperature plummets, it becomes harder and harder for a heat pump to warm your home efficiently, and you begin putting an extreme strain on the heat pump itself and run the risk of damaging it or breaking it entirely.

When temperatures reach between 25 and 40 degrees Fahrenheit, heat pumps begin taking much more energy to keep your home warm and will require a different approach to keep your home happy and toasty.

Some of the more popular backup heating solutions in these instances come from heat strips inside your HVAC system or a gas furnace backup in a dual-fuel heat pump. It would combat the cold and stray away from your electrical bill altogether and typically at a cheaper rate.

Emergency heat ensures your system heats when needed, but at a steep cost.

In that case, you will need to exercise some diligence in your automated settings from your heat pump and whatever backup heating alternative you choose.

In this scenario, finding that sweet spot between when the temperatures drop will be the primary deciding factor in whether or not you save money or lose money when using air conditioning.

If you are getting a new home and simply considering whether or not to get a heat pump in the first place, this is something to bear in mind.

Final Thoughts

Even though the number of amps your heat pump can use will vary slightly from unit to unit, the most significant takeaway to be offered here is this is not and will never be a job you can undertake without proper training.

Not skimming lightly over a topic will prepare you for a job that can be potentially dangerous in the wrong hands, especially when dealing with something that needs as much precision as electrical work.

Having a basic understanding of terms like tonnage, amps, watts, volts, and anything relating to them is not a replacement for being formally trained and certified to handle the myriad of issues and complications that can arise throughout a job installing or replacing a heat pump.

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Hubert Miles

I've been conducting professional home inspections since 2002. I'm a licensed Home Inspector, Certified Professional Inspector (CPI), Certified Master Inspector (CMI), and FHA 203k Consultant. I started HomeInspectionInsider.com to help people better understand the home inspection process and answer questions about homeownership and home maintenance.
DISCLAIMER: The content published on HomeInspectionInsider.com is not professional advice. You should consult with a licensed professional and check local permit requirements before starting any project.
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