When it comes to air conditioners, there are a lot of choices. Having choices is always a good thing for consumers, but the reality is that some consumers can get overwhelmed when shopping for air conditioners. Of course, you want to be sure you’re getting one that’s sized appropriately for your home, and you also want to be paying a good price for it. In addition, many are concerned about monthly utility bills and hope that they can find something efficient. Fortunately, you don’t have to figure everything out on your own. At Friar's Heating and Air, we offer our AC installation services to residents in San Diego. We can be a resource for you to turn to whenever you need assistance. Below, we’ve included detailed information you can use to determine what size air conditioner you need for your home.

All About BTUs

The term BTUs is very important to understand when trying to figure out what size AC to get. BTUs are British Thermal Units, and they are a measure of energy, in the form of heat. One BTU is how much energy is required to increase the temperature of one pound of water by one degree. BTUs can not only describe how much heat can be released from an object but also how much heat it can absorb. This last point helps us understand why BTUs are used to describe air conditioners. Air conditioners take heat away from a space. ACs with more BTUs can remove more heat in an hour, and vice versa.

When people discuss the size of an air conditioner, they’re not actually referring to its physical size. Instead, they’re referring to how many BTUs it has.

How BTUs Relate to Tons

Another way in which the “size” of an air conditioner can be described is by using the term “tons.” Again, it’s kind of a misnomer. A one-ton unit doesn’t weigh 2,000 pounds, and a four-ton AC doesn’t weigh 8,000 pounds, thankfully.

The reason why the term “tons” is used with air conditioners is because huge blocks of ice were sometimes used to cool buildings. The ice absorbed heat from the air, and that’s how the space was called. It was determined that one ton of ice could be melted by absorbing about 288,000 BTUs in a day. Converting that to BTUs per hour, we get approximately 12,000 BTUs. Therefore, a one-ton air conditioner has about 12,000 BTUs. A two-ton AC has about 24,000 BTUs, and so on. There are also 1.5-ton, 2.5-ton, and 3.5-ton AC units.

Which Size Is Best for My Home

Now that we have all the background information out of the way, we can move on to which size would be appropriate for your home. A very general guideline that some people use is that 20 BTUs is necessary to cool one square foot of space. Using this ratio, we see that an AC with 12,000 BTUs could cool a 600-square-foot area.

You’ll take a slightly different approach if you’re just cooling a room in comparison with cooling an entire home. A window or portable AC designed for a room would typically be described with BTUs, while a whole-home AC would be described by how many tons it is.

If you have a 1,200-square-foot home, you’d need a two-ton unit. A 2,400-square-foot home would need a four-ton unit. Again, there are 2.5-ton and 3.5-ton units in case your square footage doesn’t work out perfectly for a two- or three-ton unit, for instance.

Other Factors

All of those numbers that we just presented are still just guidelines. The exact amount of BTUs that would be ideal for your home can depend on a number of factors.

They include:

  • Layout of your home
  • How much insulation or shade there is
  • How many windows there are
  • How many people live in the house
  • Ceiling height

It makes sense that if your home is well-shaded and/or well-insulated, it can stay cooler. In this case, you might use the ratios provided above and then subtract 10% of the recommended BTUs. If there are a lot of windows from which the sun can stream in, you might need to bump the recommended BTUs up by a bit. Having more people and/or more appliances in an area also requires you to have slightly more BTUs. Finally, ceiling height is related to how many cubic feet of air you’ll have to cool, and the layout of your home can affect how easy it is for the air to flow through it.

At this point, it may seem like a lot goes into determining BTUs. That’s because the process can be somewhat complex if you’re going for accuracy. This is one reason why we suggest having a professional assess your home before you invest in a whole-home air conditioner. This is especially true since they require relatively significant investments.

What Happens If I Get the Size Wrong?

If you come close to the recommended number of BTUs, everything should be fine. If you can’t be exact, most people would agree that it’s better to have slightly more BTUs than slightly less.

However, if your calculations are off by a lot, you may find yourself dealing with unexpected issues. When air conditioners don’t have enough BTUs to cool a space, they will continually be pushed hard to remove heat. They might be operating 24 hours a day and still not be able to get your home to the desired temperature. This can lead to extra wear and tear, premature failure, and utility bills that are higher than normal.

On the other hand, an air conditioner with much too many BTUs isn’t ideal either. That’s because it will do something called short cycling. Let’s say your ideal temperature is 68. Once the temperature hits 69, your AC will kick in. It will be so good at its job that it will very quickly get the temperature down to 68, so it will turn off. Then, with the heat of the day, the inside temperature may soon rise again to 69. The process will continue repeatedly. Turning on and off again so many times can lead to problems with longevity. Plus, a unit that has more BTUs may cost more money.

Turn to Us

Friar's Heating and Air is ready to assist you. Our family-owned business has deep roots in the industry, and we’ve learned the importance of working hard, treating people with respect, and always upholding high standards. We’re proud that many of our customers have ended up referring their friends, family, and neighbors to our business. That’s a sign that we’re doing something right. Our technicians are well-trained and have extensive experience with all makes and models. We take care of installations, repairs, and maintenance for our local customers, and we work with heaters, air conditioners, ductless mini-splits, and indoor air quality components. Call us if you have any questions or would like to set up an appointment.

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