A variable-speed air handler or furnace offers efficiency and indoor climate control benefits.
This brief guide explains variable speed air handler pros and cons and why one is the right choice for most homeowners.
What is an Air Handler?
If you have a heat pump, then the indoor unit is the air handler. If you have a furnace, it’s the air handler.
The term refers to the unit housing the blower fan that draws “untreated” air into the system where it “treats” it by removing heat and humidity in summer and adding heat it in winter.
The air handler then pushes it back into your living space.
What Does Variable Speed Mean?
There are three general types of air handlers – three types of blower motors.
Single-speed blower motors, aka single-speed air handlers, run “full blast” whenever they are on. The cheapest air handlers and furnaces have single-speed blowers.
Variable speed blowers / air handlers have multiple speeds. They begin at a low speed when the system first starts.
Once it is in full swing heating or cooling the air, the speed ramps up to a higher speed. As the cycle ends, the fan adjusts to a lower speed to blow remaining treated air out of the air handler.
Variable Speed Air Handler Pros and Cons
There are two sides to air handlers with variable speed blowers. Let’s start with the cons.
How much more are you willing to pay for the benefits of a variable speed air handler?
1. Greater Expense. Better performance costs more. It’s that simple. What we mean by “performance” is outlined in the Pros. Expect to pay 12% to 20% more for a variable speed air handler depending on what options you are comparing.
But later in this post, we will show you how a variable speed system gives you equipment options that might actually cost less without sacrificing performance or efficiency.
2. Repair Costs are Higher. Variable speed blowers are more complex, both the part and the control board. When they fail, the repair bill is higher.
Here are the benefits of variable speed air handlers.
1. Indoor Comfort: Have you ever been near a heating/cooling grate when the air handler started or was shutting off? If you felt a stream of warmish air (AC Mode) or cool air (Heat Mode), the air handler was likely a single-speed model.
Those units run at full speed before and after the AC/Heat pump/Furnace is maximally treating the air. That means you get a blast of untreated air at the beginning and end of the cycle. It can be uncomfortably cool or warm.
A variable-speed unit reduces that by starting and ending the cycle on low speed. So while the air might be a little warm or cool at the start or end, it won’t be an unpleasant blast of it.
2. Better Temperature Balance: This is related to the first “pro.” When the blower is running at 100% capacity, it will blow quite a lot of untreated air into your living space. That creates greater fluctuations in temperature.
3. Efficiency – Lower Operating Cost: Any air handler blower uses less electricity when operating at a lower speed. In addition, many variable speed air handlers use ECM motors that are much more efficient than standard PSC motors, as this video explains.
4. Quieter Operation: A fan running on low speed makes less noise than one on high speed.
5. Staged Heating and Cooling: Variable speed air handlers work better with two-stage heat pumps, ACs and furnaces. When the system is operating on the lower stage, the fan runs at a slower speed. Higher stage, i.e., full-capacity, the blower runs at full speed.
6. Better Dehumidification: In hot, humid summer weather, removing moisture from the air is one of the keys to indoor comfort. If the temperature is 76F, you’ll feel more comfortable if the humidity is 35% rather than 60%. Longer, low-speed cycles do a better job condensing moisture out of the air.
This will also help lower costs. How? You can set your thermostat higher when air conditioning. That’s because you will feel just as comfortable at 78 degrees with 35% humidity as you will at 72 degrees with 60% humidity.
Plus, with a single-speed fan, the air will feel a little “clammy” at 72F and 60% humidity.
7. Better Air Filtration: Longer, low-speed cycles also move air through the filter more often, so more impurities are removed from the air you breathe.
SEER Rating – How Does Efficiency Impact your Decision?
SEER, or seasonal energy efficiency rating, measures how efficient the AC uses electricity to cool the air (i.e., remove heat from your home).
The more efficient an AC or heat pump is, the more it will cost. But, being more efficient, the operating costs/utility bills will be lower.
The hotter your climate is, the more it makes sense to choose a highly efficient AC.
Save Money with a Variable Speed Air Handler
We’ve said that variable speed air handlers cost more. They do. Here’s the explanation of how the complete system can actually cost less.
SEER and a Variable Speed Air Handler: There’s more to indoor comfort and efficiency than SEER level, and that’s where comparing the performance of single-speed and variable speed air handlers makes sense.
Here’s the key.
Performance studies on AC systems show that a lower SEER system with a variable speed air handler can actually run more efficiently than a higher SEER system with a single-speed air handler.
- The system uses the cooled air more effectively
- It dehumidifies better, so most homeowners set the thermostat higher
Discuss This With Local AC Companies
With a variable speed air handler or furnace, you can save money and be just as comfortable with:
- A 14 SEER AC compared to a 16 SEER or higher unit (northern climate)
- A 16 SEER AC or heat pump compared to an 18 SEER or higher unit (southern climate)
The bottom line is that you can spend less on the total system, save money and be just as comfortable. And your utility costs can be just as low.
Most HVAC salespeople push high performance variable speed air handlers and higher SEER units.
But with this knowledge, you can ask the right questions.
We always recommend discussing your HVAC system with at least three local installers. This will allow you to find a company your best interests in mind. Our free local quotes tool will give you up to 4 free estimates and advices from your local professional contractors.