Heating and air conditioning is one of the most common luxuries of modern life. Just a century ago, few homes had any type of mechanical heating or cooling system. Now, somewhere between 75 and 85 percent of all homes in the U.S. have an HVAC (heating, ventilating, and air-conditioning) system in them and spend upwards of $30 billion dollars every year to run the units.

Sometimes you hear talk of “air handlers” or air-handling units (AHU’s) and wonder, like most people do, what the difference is between an air handler and an air-conditioner or heater. It’s a good question and something people in the HVAC industry are asked about all the time. Why is it important to know about AHU’s, and why can keeping yours in top shape add to the long-term value of your home? Here are the basic concepts that address both those questions.

What Air Handlers Do

Simply put, an air handler is one part of an air-conditioning and heating system. Its main job is to “handle” the air, or circulate it through your entire home. For example, if you live in a warm area, you probably have an outdoor AC unit and an indoor unit that looks like a large metal box. The indoor unit is the air handler, and the outdoor unit is typically called the air-conditioner. The AC (outdoor) device does most of the heavy lifting of the cooling job, then the handler (located indoors) filters and distributes the cooled air into all the rooms of your home via a ventilation system.

But AHU’s do more than just that because they also have the capability to work in tandem with your AC or heater to make air cooler or hotter before it enters the ducts and travels throughout your house. Here’s a short step-by-step description of how a typical air-handler works with an air-conditioner to cool the air and distribute it:

  • Step One: The AHU pulls warm air from inside your house
  • Step Two: It removes heat from the pulled-in air by pushing it across the coils of the evaporator.
  • Step Three: The AHU then uses its fan (blower unit) to send the cooled air into the ducts.
  • Step Four: The cool air travels through the ductwork and enters all the rooms of your home.
  • Step Five: The heat that the AHU captured in Step One is sent directly outside in a process called “dissipation.”

Maybe you’re wondering how an ACU works with a heater during the winter. It’s exactly the same steps above but in reverse by pulling in cool air from the house, sending it across warm coils, and finally uses its blower unit to push it into the ducts.

What is an Air Handler?

The best way to think about air handlers is in relation to your home’s entire HVAC system. The AHU is part of a team of devices, all of which work together. If the outdoor AC unit, for example, did its job perfectly, it still would need an AHU to distribute all that cooler air. The same thing goes for winter, when your AHU sends warm air into your home, captures cooler air, and makes sure it’s “handled” properly.

Important Air Handler FAQs

Unless you’re an HVAC professional, it’s pretty difficult to get a full understanding of air handlers in just a few minutes. Most people have questions about AHU’s even after they read short articles about how the units work. Here are some of the most frequently asked questions that HVAC experts hear from customers:

  • Are air handlers furnaces? The short answer to this question is “no.” AHU’s don’t contain their own burners, nor are they able to operate on anything but electricity. Many furnaces use propane or even natural gas as their energy source. AHU’s can’t do that. Plus, they lack their own heating unit or burner.
  • Are they air conditioners? AHU’s are part of an air-conditioning system, not the whole system. For example, an air handler does not contain one of the essential components of an HVAC unit, the condenser. That’s on the outside of your house within the AC unit.
  • Are they HVAC systems? No. As noted above, the AHU is one part of a complex heating/cooling system that makes your home more comfortable in cool and warm months.
  • How many kinds of air handlers are there? There are three kinds: ceiling-mounted versions that lack ductwork and simply utilize a complex set of coils to move and distribute warm and cold air, wall-mounted AHU’s for homes that lack a large enough space for other types of AHU’s, and traditional versions that are larger and can be set up in many different ways depending on the way the house is configured.
  • Why is fan efficiency so important? There are usually only three things that have an effect on your home’s AHU, namely the outside unit, the AHU’s blower fan, and the AHU’s evaporator coil. It’s important for coils to be clean and free of unwanted buildup. Fans need to be running efficiently and not using too much electricity. The outdoor unit must be a good match for the AHU so they can work together as one giant system to get the job of heating and cooling done in the most efficient way.
  • What about the coils? Coil sizes on the AHU and the outdoor AC unit need to be well-matched. If they are not, then one of the units will be pushing the other one too hard. Think of it this way: you’d never put a race-car engine into an ordinary sub-compact passenger car. Nor would you want a tiny, four-cylinder engine in a huge SUV. Mismatched coils in an AHU and AC (outdoor) unit work the same way. You need to have similar-sized coils. Ideally, homeowners should purchase their AC unit and AHU at the same time from the same manufacturer. That way, everything is lined up well, efficiency is at its best, and service calls are timed to be done at the same time fof both units.

Keeping Your Air Handler in Good Shape

If you want to keep your air handler in excellent shape, you need to work with experts like the team at Delaware Heating and Cooling. Working with AHU’s is not a do-it-yourself project by any means. For example, in addition to replacing every few months, you want to make sure it’s catching all the bacteria, mold, and dog/cat dander from the air in your home. That means having a professional put in the exact kind of filter that matches your particular HVAC system and air handler.

Plus, HVAC experts know how often to do maintenance on the different kinds of systems on the market, what needs to be done to each one, and how to run a comprehensive checkup to make sure wiring, coils, lubrication levels, drainage, and motors are as they should be. Don’t leave your air handler’s health to chance. Feel free to call us anytime at Delaware Heating and Cooling and we’ll be glad to answer any questions you have about your home’s HVAC needs.