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T D H Mechanical, Inc, Heating & Air Conditioning, Chicago, IL


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What Size Air Conditioner Do I Need For My House?


One of the most important questions people ask when considering an HVAC unit in their home is “what size air conditioner do I need for my house?” Whether you are looking for a window unit to cool just one room, or central air to cool the entire house, it is essential that you choose the correct size. If the air conditioner you choose is too small or too large, you will have problems cooling the room or house for which it is installed.

The Problem with Air Conditioners that are Too Small

When you ask the question “what size air conditioner do I need for my house”, most people will understand that getting an HVAC unit that is too small will cause problems, and here’s why. If the AC is not large enough for the desired cooling space, the unit is going to be working constantly to try to bring the area to the temperature you want. Clearly, this will negatively impact the performance of the air conditioner. It will wear and tear and need servicing much more often, and it will increase your energy bills because of the near constant use.

The Problem with Air Conditioners that are Too Big

While most people understand the problems with an HVAC unit that is too small, many fail to realize that a unit that is too big can cause some problems as well. Some have the idea that “bigger is better” and deliberately decide to put in a unit that is larger than needed. This common misconception comes from a general misunderstanding of how cooling systems work.

A cooling system produces a comfortable environment partly by removing moisture from the air. The problem with oversized air conditioners is that they cool the room more quickly, and consequently they don’t run as long. This has the effect of cooling the room, but failing to extract enough moisture in the process. This can leave the room more humid and far less comfortable.

Finding the Right Size Air Conditioner for your House

Now that we understand the need to install a correctly sized air conditioner, here’s how to calculate it if you are just looking for a window AC unit:

1. Take the number of square feet you want to cool and multiply it by 25BTU (British Thermal Units)

For example, let’s say the room you want to cool has 200 square feet. To answer the question “what size air conditioner do I need for my house”, take 200 and multiply by 25 (200 X 25 = 5000). So, for a 200 square foot room, you would want a 5000BTU air conditioner.

For central air conditioning systems, the determination process is a bit more complicated. Central air units usually come in the following sizes:

  • 1.5 Ton
  • 2 Tons
  • 2.5 Tons
  • 3 Tons
  • 4 Tons
  • 5 Tons

As a general rule, you would want 1 ton of BTU per 500 square feet of cooling space. So, a 2000 square foot home would probably require a 4 ton unit. However, there are factors that are unique to each individual home that can make it easier or more difficult to cool, including:

  • Type of Building Material
  • Type of Flooring Material
  • How Well the House is Insulated
  • How Much Exposure the House Has to the Sun
  • How Many Levels the House Has
  • The Air Flow and Ventilation in the House
  • If the House has any Extras like an Attic Fan

To properly determine the correct sized air conditioner based on the individual factors of your home, it is best to call TDH Mechanical, afterall we are the experts in this area. We will get the best estimate and insure that the air conditioner you choose is the right fit for your home. Call one of the numbers above to schedule a free in-home estimate.

At TDH, we carry all major air conditioning products-including Trane, Goodman and Rheem with affordable prices. When you work with us, our owner will come to your home personally and give you a clean, up front estimate of the entire cost of the job with no hidden fees. You will know in advance what the installation will cost you and we will stick to that price.


Contact Information

TDH Mechanical, Inc
1623 W Montrose Avenue
Chicago, IL 60630
Phone: 773-747-5860


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Pay your HVAC Bill Online Trane Comfort Specialist North American Technician Excellence T D H Mechanical, Inc, Heating & Air Conditioning, Chicago, IL