Most people do not think about the size of their air conditioner, even when it needs to be replaced. Rather, the focus is usually on getting a replacement similar to what you already have, with an efficiency improvement. However, an air conditioner should fit like a glove for your home, not too big or too small. Here is how you determine the size unit you should consider for your home.
How Is Air Conditioner Size Measured?
You may have heard the term BTU when it comes to air conditioners, but do you know what it means? This actually stands for British Thermal Unit and is the standard we use even in the United States. One BTU is the energy required to raise 1 pound of water by 1 degree Fahrenheit.
Being we are talking about cooling rather than heating, the BTU rating gives you an idea of the cooling capacity per hour. The higher the rating, the more that particular unit will be able to cool in an hour.
Given this definition, a common misconception is that if you simply go to a larger capacity, your system will work faster. Unfortunately, that is not the case when it comes to your central air conditioning unit.
Does Size Really Matter?
In the case of your home AC, you really want to find a unit that is just the right size, not too big or too small. When you go with a smaller system than your home needs, you will end up running longer cycles. This translates into much higher utility bills and unneeded wear on your system.
On the other hand, if your system is too big, your system ends up running shorter cycles but more frequently. This means the system never gets to dehumidify your air the way it should, leaving the air muggy. It also means your system is going through more start-up processes, which increases strain, shortening the system’s service life.
The way to get the most from your system at the best cost overall is to get the right size. So let’s look at how you determine the size needed to effectively cool your home.
Determine How Much Space You Need to Cool
If you remember buying your home, you probably remember how many square feet it boasted in the listing. That may be a good reflection of the space you need to cool, but it’s always worth double-checking.
The simple calculation for square feet is to multiply the width of a rectangle or square by the length. If your home is not a perfect rectangle or square, you may need to do some extra work to get at a good number.
Go room by room and calculate the square footage of each. Do not forget areas like hallways and closets in your calculations. Do not include spaces like your attic, garage, or basement unless there are vents serving those areas.
Going From Square Feet to BTU’s
Once you have the rough square footage you are trying to cool, it’s time to figure out how many BTUs you need. There is no specific conversion that is perfect for everyone. However, a general rule of thumb is to use 20 BTUs per square foot as a starting point.
So if your home is roughly 1,500 square feet, you simply multiply this by 20, giving you a 30,000 BTU need. Once you have this rough starting point, consider the other factors affecting your need.
Going Beyond the Rule of Thumb
Other factors include how much shade your home receives and how many occupants you typically have in your home. The rule of thumb takes into account two people. If you have more, you should increase your BTU calculation by 600 for each additional person. Be sure to consider how much entertaining you do during the hot months as you consider this factor.
Also, think about the shade you have around your home. If your home is mostly shaded the majority of the day, you can reduce your need by about 10%. However, if it is in direct sunlight all day long, you may need to increase it by the same factor.
Ultimately, the best way to know you have the right size is to work with an experienced air conditioning professional. Consider getting multiple quotes before making your decision, and then go with a company you feel like you can trust. Not only will the company do the installation, but they will provide the warranty service if something breaks down.
Hometown Heating and Air has been an award-winning air conditioning provider for people around Cedarburg since 2016. Our team is sought out for heating and cooling installation, service, and maintenance, along with indoor air quality solutions. Call to schedule your consultation with one of our expert air conditioning professionals today.
