What is a Variable Speed Heat Pump?

What is a variable speed heat pump or air conditioner

and why is it more efficient than people think?

Variable speed controls a motor’s capacity, much like your gas pedal does in your car.

The technology has been around for awhile, but it’s use is just now becoming more and more prevalent. Today, variable speed technology is changing air conditioning, IN A BIG WAY!

Traditionally, contractors would size an air conditioning and heating system based on the hottest days and the coldest days. These are the times when your heating or cooling needs to run continuously . These few hours per day, on the few most extreme days, your equipment is running as designed. The rest of the time you are oversized. Is that a problem? It absolutely is, and for many reasons.

  • Shortened equipment life
  • Higher utility bills
  • Higher humidity
  • Mold growth
  • Hot/cold spots
  • Excessive noise
  • Uncomfortable house

These problems are all related to the frequent on/off cycles a single-speed air conditioner goes through. Consider a standard efficiency house in Fort Worth, Texas on a 90 degree day. A normal system will run 50% of the time to keep up with the high cooling demand by turning on and running for about 15 minutes, then shutting off for a bit. This is inefficient and results in excess wear to the system. Think of it as city miles.
Until now, our best way to combat these problems was two-speed equipment. While two-speed technology was an improvement over past models, it only lessened the issues.

True variable speed systems are capable of controlling their speed to precisely match the needs of your home at any given moment.

Why Are Variable Speed air conditioners and heat pumps so much more efficient?

Imagine driving your car on a long road trip, but on this trip you have to put the pedal to the floor for 15 minutes then slam on the brake to come to a complete stop. Next you wait 15 minutes and do it again. You repeat this process until you arrive at your destination. This would be an uncomfortable journey. It would be very hard on your vehicle and incredibly inefficient.

Starts and stops are bad for mileage and air conditioner electricity usage.

A true variable speed air conditioner represents the way you would actually drive, or better yet, the way cruise control would drive for you during your voyage. Think of it as highway miles.
When using cruise control, you set the speed you need to go and the car handles the rest. As road conditions change , such as going up or down a hill, your car will automatically speed up or slow down as needed.

If given the same conditions as above, on a 90 degree day, but then applied them to the variable speed equipment, the system would be able to precisely match the capacity needed at any given time. Therefore, it could actually speed up on the hotter days, and slow down during cooler evenings (saving you money & keeping you more comfortable).
Be careful! Some manufacturer’s “variable speed” systems are only capable of running at a few speeds. This is not what I call “true variable speed.”

If you are considering replacing your heating and air conditioning system please give the variable speed air conditioners and the variable speed heat pumps a good look.
Use only quality contractors with training and experience in these high-end systems. If your contractor doesn’t complete a load calculation, consider looking for a better one.

  • Look for the variable speed system with the lowest minimum speed.
  • Look for a variable speed system with the most precise speed control (600-700 possible speeds).
  • Look for 10 year parts warranty.
  • Understand that SEER ratings don’t necessarily reflect the potential utility savings of variable speed systems.

Check out Poe Air for all your variable system needs.