Can I Use a Generator to Run AC?

From June to November, the potential for tropical activity rapidly ramps up along coastal areas of the Gulf of Mexico and Atlantic Ocean. As a result, many Florida and South Georgia residents have invested in portable generators to power parts of their home during a power outage. With the power out and temperatures rising, many residents wonder, “Can I use a generator to run AC?”  

Portable generators are great for powering televisions, ceiling fans, lighting, microwaves and even refrigerators. But can a portable generator power your air conditioning system in a pinch? The answer depends on a number of factors, from the type of air conditioning or heat pump system you use to what other appliances you want to power. It may even involve a little bit of math, so make sure you have a pencil and a piece of scrap paper available if you plan on using your generator. 

Here are a few questions to ask yourself when determining if your generator can power your heating and air conditioning system. 

Is There a Safe Connection for My Generator?

Before powering anything from your generator, you should ensure that your appliances have a proper connection to your generator. In most cases, this is through your circuit breaker box. This requires the use of a transfer switch that needs to be connected to your breaker box. You can then plug a portable generator to your transfer switch connection and flip on the breakers that power the appliances you plan to use. 

You should always have a certified electrician install a transfer switch, as an improper connection could risk your life, or endanger a friend or family member or even a utility worker due to your generator backfeeding to nearby powerlines. If you need to run an extension cord from your generator to power an appliance, be sure to use an undamaged cord with the properly gauged wire. 

Does My Generator Have Sufficient Starting Watts and Running Watts for My System?

Both your system and your generator should be rated for a specific number of starting wattage and running wattage. Running wattage refers to how many watts an appliance needs to operate. However, many appliances (including heating and air systems) require a power surge to turn on, called starting wattage. 

This means that even if your generator can power a running heating and air conditioning system, its starting wattage also needs to rate higher than your system’s starting wattage (also called maximum output wattage), or your system won’t start or you could risk electrical damage. 

In general, many of the larger portable generators are rated for enough starting and running wattage to power moderately sized heating and air conditioning systems. However, if you’re using a smaller portable generator that you typically use to power a few things while tailgating, it likely won’t power your system. 

If you’re still considering purchasing a portable generator to run AC, take the starting wattage and running wattage into account before making your purchase. 

Are There Other Appliances I Need to Prioritize Over My Heating and Air? 

Prioritizing your needs is important during a power outage. You will more than likely have to sacrifice some major appliances to run others in this situation. Your heating and air system will likely take up a significant portion of a portable generator’s power output. It may be that keeping your refrigerator running, your living room lights on and your microwave available are higher priorities. Whatever your needs are, first list out your power priorities. Then make sure your generator can handle your needs before you power anything on. 

Generac provides a handy form that helps you to prioritize your power needs and includes a chart that allows you to add your appliances’ starting and running watts together to determine what your generator should be able to handle. The form also includes power estimates for several home appliances. Be sure to find the exact running and starting watts for an appliance before you power it from a generator. If you overload your generator with wattage, you could put yourself or family at risk, damage your appliances or even ruin your generator. 

Can I Use a Generator to Run AC?  

Depending on the climate and weather, your comfort preferences and any other cooling options you have, you may not need to use your home’s heating and air conditioning system. Instead, opening your windows, using a few fans, or using a less-powerful window unit may provide enough comfort for you and your family. This could free up your generator to accommodate other appliances and could also be a less expensive option. 

If you have questions regarding your heating and air conditioning system’s use with a generator, please give Barineau Heating and Air Conditioning a call at (850) 580-4029.  

Note: This article is meant for general information purposes only. Never use a generator inside and check with a professional before powering anything in your home. 

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