Variable-Speed vs Single-Speed: Which Is Best for My Florida Home?

April 10, 2018

If you’re in the market for an AC upgrade, you’ve probably come across the terms “variable-speed” and “single-speed”.

Wondering which one is better?

Our answer: If you can afford the higher upfront price, a variable speed AC is the “better” option because it offers precise temperatures, better humidification and lower energy bills.

In this article we’ll show you the 2 big differences between variable-speed and single-speed ACs:

  1. How they work

  2. How much they cost

But first, it’s important to understand that “variable-speed” can actually refer to 2 different components in your air conditioner: The blower motor and/or the compressor.

Let’s take a closer look at why this is so important...

Just want to know about cost? Skip to the cost section or reach out to get a free quote.

The 2 types of “variable-speed” motors in your AC system

Like we mentioned, variable-speed technology can refer to 2 different motors in the AC:

  1. The blower motor, which is responsible for blowing air through your home’s ductwork.

  2. The compressor, which pumps refrigerant (the liquid/gas that absorbs heat from your home’s air) throughout the AC system.

compressor and blower motor in central AC diagram

Your blower motor is located inside in the air handler, and the compressor is located inside the outdoor unit.

Why is this important? Well, when a tech or manufacturer refers to an AC as “variable speed”, it could mean any of the following:

  1. Only the AC’s blower motor has variable-speed technology

  2. Only the AC’s compressor has variable-speed technology

  3. Both the AC’s blower motor and compressor have variable-speed technology

The bottom line: Knowing what “variable speed” is actually referring to is important for your wallet and your comfort.

So how do you know when a tech/manufacturer is talking about one motor vs. the other?

If the tech/manufacturer is talking about a blower motor, you may hear/see these keywords:

  • “Indoor unit”
  • “Air handler”
  • “Single-speed”
  • “Air flow”

If the tech/manufacturer is talking about a compressor, you may hear/see these keywords:

  • “Outdoor unit”
  • “Single-stage”
  • “2-stage”
  • “Refrigerant”

Now let’s look at how variable-speed technology works compared to single-speed technology...

How it works: Variable-speed vs. single-speed

  • A single-speed/single-stage motor only runs on 2 speeds:
  1. ON (100% capacity)

  2. OFF (0% capacity)

Think of a single-speed blower motor like a regular light switch; it just turns on or off with nothing in-between those 2 settings.

  • A variable-speed motor continuously adjusts its speed to operate at anywhere from 10% to 150% capacity, depending on the amount of cooling needed.

Think of a variable-speed blower motor like a car’s gas pedal. The gas pedal precisely controls the speed of the car, allowing it to ramp up or down to the exact speed needed: 32 mph, 57 mph or 100 mph—and any speed in-between.

Benefits of variable-speed technology

  • Improved efficiency/lower energy bills: Because variable-speed technology allows the motors to continually adjust its output, the system only ever works as hard as it absolutely needs.

    For example, if you only need to cool your home a couple of degrees, your compressor and/or blower motor can compensate its speed accordingly so it doesn’t overexert itself by running at 100% when it only needs to run at say, 30%. This allows the system to consume less electricity which lowers your monthly power bills.
  • Better comfort: Unlike single-speed ACs that blast cold air at 100% then quickly shut off, variable-speed systems run longer at lower speeds. And the longer your AC runs, the more evenly cool air is distributed and the more humidity is extracted from the home.
  • Ideal for zoning: “Zoning” allows you to control the temperature in separate areas via different thermostats. Because they lower their speed when needed, variable-speed motors prevent overpressurization in the ductwork and noisy registers.
  • Quieter operation: Since a variable-speed motor often runs on a lower setting, it doesn’t make as much noise when it’s running. Plus, when you start up your AC, a variable-speed blower motor gradually comes up to speed so you don’t hear a loud “boom” at startup.

How much it costs: variable-speed vs. single-speed/stage

Note: Before you purchase just a new compressor or blower motor, you’ll want to contact a professionalto make sure the upgraded motor is compatible with your current HVAC system.

Blower motor cost

  • Single-speed blower motor ranges from $375 to $900*

  • Variable-speed blower motor ranges from $1,300 to $2,700*

Compressor cost

  • Single-stage compressor ranges from $1,500 to $2,500*
  • Variable-speed compressor ranges from $2,800 to $4,000*

For a middle-priced option, you can also choose a 2-stage compressor, which has 3 speeds: ON (100%), OFF (0%) or LOW (60%–70%). A 2-stage compressor ranges (without installation) ranges from $2,000 to $3,000.

Cost of an AC with both a variable-speed blower motor and compressor

  • $1,000–$3,000 more than a single-speed/stage AC (single-speed blower motor paired with a single-stage compressor)*

*Prices listed above do not include labor fees for installation.

Ready to buy a new compressor, blower motor or AC system?

Give us a call and we’ll schedule a time for one of our techs to visit your home and give you an honest quote—whether you need new compressor, blower motor or a new AC system.

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