A Bigger Tonnage AC Won’t Cool Your Home Better!

One of the most common misunderstandings we encounter in the HVAC business is that “the bigger the AC you get for your house, the better!” This isn’t remotely true, and unfortunately it leads to people getting an air conditioning system that costs too much and ends up not doing the job expected.

This is one of the many reasons you need to hire professionals like us when it comes to installing an air conditioning system in Mesa, AZ. We ensure that you have an air conditioner installation that is correctly sized to provide the cooling your house needs for comfort in our blazing hot summers without running into the troubles of an air conditioner with too much tonnage.

Wait, what is “tonnage?”

A good question. This is a bit of HVAC lingo that consumers may not understand, but it’s important when it comes to sizing an air conditioner, i.e. making sure the air conditioner is powerful enough without being too powerful.

Tonnage is a bit confusing because when people hear it, they think it means the weight of the system. But AC tonnage has nothing to do with weight. When our technicians talk about tonnage, it means how much heat an air conditioner can remove from a home in one hour, which we measure in BTUs (British Thermal Units). An air conditioner that is one ton is able to remove 12,000 BTUs of heat per hour. Each ton is an additional 12,000 BTUs.

Simply put, the more tonnage, the more air an AC can cool down. So…why wouldn’t you want the most powerful tonnage AC you can afford for your home?

The trouble with an oversized AC

We understand why people make the mistake of thinking it’s fine to get an overpowered AC. You can just turn it down if it gets too cold, and it will get the home cooler much faster, right? There’s nothing wrong with erring on the side of too much cooling power, is there?

Yes, there is. There are some big problems. Let’s get the “it will cool you faster!” myth out of the way first. More tonnage has nothing to do with the speed an air conditioner cools down a space. It’s a measure of capacity, the amount of heat removed within an hour.

But there are even bigger troubles with an oversized AC:

  • The AC will begin to short-cycle: If an air conditioner is too powerful for the space it’s supposed to cool, the thermostat will register too early that the air conditioner’s job is finished and shut off the compressor prematurely. It will then turn it back on a short time later, only to shut it off again … and this is repeated multiple times per hour, a problem known as short-cycling. These rapid start-ups and shut-downs create massive energy waste, and they put immense wear and tear on the system, leading to a short service life for the AC.
  • The AC won’t provide sufficient comfort: It turns out that thinking you’ll have more comfort with a bigger AC will end up delivering the exact opposite. If the AC is running long enough because it’s short-cycling, there isn’t enough time to evenly distribute cooling around your house, leading to hot spots.
  • Your home will have high humidity: Both humidity and temperature play a role in how comfortable we are. One function of air conditioning is removing humidity from the air. When a unit is oversized it typically will not run long enough to remove enough humidity from the air and your home will start to feel sticky and uncomfortable.
  • Undersized air ducts: More often than not when we run into an oversized AC unit, it was replaced where a lower tonnage air conditioner was originally installed. The dimensions of the ductwork were sized originally for the smaller unit. The outcome typically is the new unit can’t “breathe” – the technical term for this is high static pressure. High static pressure causes bigger problems than just comfort issues and high utility bills – it is an AC component killer and can cause expensive components like the compressor and indoor fan motors to fail.
  • Excessive dust in your home: An oversized air conditioner can lead to a few other “home” problems outside of the air conditioner itself that even most HVAC Companies may not consider or even realize. Because many of us here Magic Touch Mechanical are BPI Certified Building Analysts, and BPI Certified Envelope Specialists, we study and repair problems with buildings and homes that affect comfort and energy efficiency outside of the HVAC System. A common problem we see with oversized units and undersized ductwork is dust and contaminants being pulled into the home from unconditioned spaces like the attic and walls. We use special tools while conducting a home energy audit to demonstrate how this is happening, which most people find shocking when they see it with their own eyes.

Our technicians won’t make the mistake of incorrectly installing your air conditioner in Chandler, AZ. They’re highly trained to properly size an AC unit. They’ll use up-to-date Manual J load calculation protocols to see that the new air conditioner going into your home has the ideal tonnage: you’ll have comfort without wasted energy or a system that will fail on you years early.

If you have an older AC that was poorly installed by amateurs and is oversized—and this is a common problem!—put your trust in us when it comes to an air conditioning replacement in Gilbert, AZ!

Magic Touch Mechanical serves Gilbert, AZ and throughout Phoenix and the surrounding areas. Call us today to experience our award-winning customer service first-hand. We look forward to exceeding your expectations!