Is Bigger Better?

That depends on who you ask and what you're talking about. When it comes to air conditioners, though, not really.

We have recently inspected two homes with new HVAC installations. In both homes, the units were oversized for the area they needed to condition. In one case, the installer talked the homeowner into the larger unit, leading them to believe it would provide superior cooling.

The installation was poor, far from that of a skilled professional.

The home would have been comfortable with a 2 or 2.5-ton unit, and they were sold a 4-ton unit. This was a smaller, one-floor home. The installer had to leave the closet door off where the air handler is because the unit was too large and stuck out of the closet. The owner complained of feeling warm, although the temperature is reaching the goal set by the thermostat. This is a result of the unit cooling too quickly and not removing the required humidity. It acts more like a refrigerator than an air conditioner. The key word here is conditioner.

In the second case, once again the unit was severely oversized, requiring a 1.5 or 2-ton unit but having a 4-ton unit installed. I did not receive an answer as to who initiated the idea of a larger unit; I am leaning towards the homeowner. This was a small condo. They did manage to get the air handler in the closet with the door on, but they could not hook up the plenum properly above it. The top of the air handler was just placed under the plenum in the hopes that most of the air would make it up into the venting system. Obviously, it did not. When I opened the closet door with the unit running, more air was coming out of the closet than was going up and out through the vents.

A reputable HVAC company will conduct a load calculation to accurately determine the size of the unit needed for your home. Needless to say, in both of these cases, they were not reputable companies.

So many times, poor cooling is caused by issues that are not the fault of the mechanical system.

Poor installation from the beginning is usually the culprit. Ductwork that is improperly sized, or with runs (the length of the duct from the trunk) too long or too short will cause an imbalance in airflow into different areas. Another often-found issue is the returns. They should be sealed tight and never pull air from anywhere except the living space, not an attic, not from in between the walls, nowhere except the living space. This is a very common issue we find.

There are many reputable HVAC companies out there. If you are experiencing problems, reach out to one for their advice, but make sure you reach out to two or three for their advice as well, in case you have found one who does not have your best interest at hand. The HVAC units in your home are one of the most, if not the most, expensive items to operate, using large amounts of energy. They need to operate at peak efficiency.

Remember that in this case, bigger isn't always better.