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Why Does Air Conditioner Size Matter?

December 6, 2022

air conditioner size

Over 90% of the country’s homes have air conditioners installed in them.

Most places have hot enough summers that they need a quality AC unit to cool their home. We spend a huge amount of time indoors, so indoor air quality couldn’t be more important. A properly cooled home is a huge aspect of good air quality.

To properly cool your home, you need the right size air conditioning unit. Not only does this impact the unit’s ability to cool your entire home, but it impacts the overall efficiency of your HVAC unit. If you don’t want to spend big bucks on your energy bills, then you need to consider air conditioner size.

In this post, we’re going to explain the reasons why this matters so much. Air conditioner sizing can be somewhat confusing, so as the resident HVAC professionals here, we’re going to give you the best possible guide. Keep reading and you’ll be able to choose the right AC unit for your home.

AC Performance and Your Comfort

The goal of any AC unit is to cool your home to make it comfortable in hot weather. Its cooling capacity is one aspect of this and its ability to reduce humidity with the evaporator coils is another. The coils turn water vapor – the stuff of humidity – into the water that flows into your AC unit’s drain pan.

These two aspects should work in tandem to cool your home efficiently. If the system is too large, it’ll cool the air too quickly, before the evaporator coil can do its thing. This results in a cool home, but high levels of humidity, which is arguably more uncomfortable than a dry, hot home.

When this happens, many homeowners will turn up the AC to get rid of the humidity. This is going to increase the strain on your system and use far more energy in the process.

With small AC units, you just aren’t going to get the cooling power that you need to stay comfortable in your home. The unit will have to work harder on longer cycles, which will create prolonged periods of strain on your system.

On a particularly hot day, it won’t matter how hard your small AC unit works anyways. This almost always results in more wear and tear, which we’ll discuss in the next section.

AC Efficiency and Wear and Tear

To understand your AC unit’s efficiency, you need to look at the SEER rating. The Seasonal Energy Efficiency Ratio helps you determine how much energy an AC unit will use (and how much it will cost) in a given year. The higher the SEER rating, the better the air conditioner is – in theory.

What the SEER rating really does is tell you how efficiently your unit converts electricity into cooling.  The problem with looking exclusively at the SEER rating is that if your air conditioner sizing is incorrect, it won’t really help you.

A small AC unit is inefficient in that it performs long cooling cycles, while large AC units will perform short cycles. Both of these put unnecessary wear and tear on your system.

Long cycles cause your AC unit to work much harder to cool your home. If it’s constantly pushing to reach your desired temperature, problems are going to arise sooner than later.

Short cycles cause your AC unit to turn on and off with more frequency. This too causes mechanical problems from wear and tear, it’s just wearing out different parts of the unit.

The Cost of Cooling Your Home

Regardless of whether your AC unit is too big or too small, it’s going to cost you more than a perfectly matched AC unit. It’s going to cost you more because the unit is straining to keep your home at a desirable temperature, which directly results in higher energy bills.

The other way that mismatched AC units cost you is in repairs and premature replacement. These are pieces of machinery with many moving parts, any of which could falter when the unit is being misused.

It might start with a few repairs here and there. Eventually, however, a domino effect will occur and you’re going to see more expensive repairs over and over again.

Quality AC units should last between 15-20 years. If there’s a size mismatch with your home, you may end up replacing it before it even reaches 10 years.

Indoor Air Quality Matters

When you think about air conditioning, you think about indoor air quality, as well as the temperature of your home. In addition to cooling, your AC unit is filtering out dirt and debris that could lower your air quality.

One of the problems that occur specifically with oversized AC units is that they don’t end up filtering these contaminants out properly. Due to the constant short cycle, it’s not running for longer periods of time, so it’s not passing air through the filters.

Dust and debris will subsequently enter your home, which can lead to allergies and cold symptoms. In addition, the buildup of humidity that we discussed earlier can create conditions that are perfect for the development of mold.

Mold, even more than dust and debris, is liable to cause serious health problems for those in your home. At the very least, you may experience congestion, runny nose, itchy eyes, or skin rashes. In the worst circumstances, mold can cause respiratory problems.

Getting the Help You Need With Air Conditioner Size

As you can see, your air conditioner size really does matter in a number of ways. If you’re looking at getting a new AC unit or you simply want to see if yours is the right size for your home, it’s best to contact an HVAC professional to get an inspection.

At Anton’s Air Conditioning Heating & Cooling, we’ve been helping St. Louis residents with all of their HVAC needs for over 40 years. If you need AC repair, routine maintenance, or installation, schedule an appointment with us today and we’ll help you get the right one for your needs.

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