Question: I’m purchasing a backup generator for my home. How do I ensure that the generator can run my central Air Conditioning System?

Answer: We at A/C Today have been asked this question more and more as we endured an active 2017 Hurricane Season. Hurricane Irma reminded us that a) we are unhappy when we lose power and b) we’re MISERABLE when we lose our Air Conditioning. As a result, many of our customers are researching the price and installation of backup generators to deliver power to their homes during sustained power outages.

A good “rule-of-thumb”: For an average single-family home with up to 5-ton a/c, you will likely need a 15-17kW generator. For most small homes such a system will meet your sustained power needs. In general, if you need to operate a central Air Conditioning System or another large motor-driven load, you need to determine its start-up current and select a generator with proper surge capability.

However, to endure that the generator is properly-sized to meet your needs, you must take the following steps:

  1. Along with your Air Conditioning System, decide which appliances, lights, and other devices that you wish to operate simultaneously during an emergency power outage. One device that many Florida homeowners forget about is their pool pump if they own a pool. Another device that gets forgotten is the water heater.
  2. Once you’ve completed your list, have a licensed electrician measure your electric consumption when all the devices on your list are running. If you’re unsure about your Air Conditioner’s load, please don’t hesitate to contact us a t A/C Today. We’ll be happy to ensure that your load calculation properly includes your Air Conditioning System.
  3. Since powering your Air Conditioner will be your generator’s priority, research whether your generator model includes “intelligent” control to support the operation of Air Conditioning Systems. Many “best-of-breed” generator manufacturers offer automatic transfer switches with optional AC Power Control modules (ACCM) that will prioritize electrical loads. The ACCM monitors the currents in selected circuits and, if necessary, temporarily turns off lower priority lines to allow the Air Conditioner to start up. The ACCM feature may also enable you to save money by purchasing a smaller generator than you might otherwise require.

There are a few more things to consider when selecting a backup generator:

  • Connection to Home: Ensure that you have a licensed electrical contractor install a proper receptacle on the outside of your house so that you can safely connect the backup generator to your home’s electrical panel. Also, be sure to ask your electrician for the proper procedure for connecting the generator to your home’s electrical panel – following the correct steps are critical. Make sure that the procedure is readily accessible, especially when the power is out and it’s dark in the home.
  • Automatic Transfer Switch: If your budget allows, look into the installation of an Automatic Transfer Switch (“ATS”). Your generator will be connected to the ATS, which will in turn be connected to your home’s electrical panel. As the name suggests, the ATS constantly monitors your local power utility’s service to your home. If the ATS detects a loss of power, the ATS will start up the backup generator, disconnect the local utility service to your home and allow the generator to deliver power to your home. Once the ATS detects that the local utility has restored power, it will switch service back to the local power utility line and shut down the generator. Automatically.
  • Generator Fuel: If Hurricane Irma taught us anything, it was that gasoline can be a scarce commodity before, during and after a storm. Therefore, you should consider generators that utilize not only gasoline but also diesel, propane and natural gas. If your neighborhood already has natural gas service available, this should be your first choice as natural gas lines are typically unaffected by storms. This means that your generator should deliver power indefinitely.
  • Service Contract: A broken generator does you no good during a power outage. Be sure to purchase a service contract with a licensed technician to ensure that your generator will be available when you need it.

As always, feel free to contact us at A/C Today with any questions. We’re here keep you cool.