Do you know what size your air conditioner is? In the world of building science, you'll hear a lot of talk about why oversized air conditioners are a bad idea. Briefly, they may not dehumidify as well, short-cycling wears them out quicker, and your home will probably be less comfortable if the air conditioner is too big. But to know if your AC is oversized, first you have to know what size it is. (Note: This article is about finding the size of your existing AC, not determining what size you need.) Look for the label The good news is that most HVAC manufacturers make it easy to determine the nominal capacity of your air conditioner. It's in the model number. Go outside and find the outdoor unit, that metal noisemaker hidden away on the side or the back of the house. It'll look something like the one you see above, although maybe not quite so decrepit as that one. Then find the lable that gives the data about your AC. It'll look like the image below. Up near the top of the label, you see the model number (M/N) and serial number (S/N).

The model number is where you can find the number you're looking for. Not all manufacturers do this, but most will give you a 2 or 3 digit section that tells you how many thousands of BTU/hour your air conditioner can move out of your home. The first section in the model number gives you info about the type and efficiency of the unit you're looking at. In the case of this Lennox model (which, by the way, is not from the outdoor unit shown at the top of this article), the 13HPX tells you it's a heat pump with an efficiency rating of 13 SEER. The digits you need Just past that string of 5 characters, though, is the part that tells you the nominal size: 048. That means the air conditioner—or heat pump in cooling mode in this case—has a nominal capacity of 48,000 BTU/hour. I say nominal because the actual capacity is almost certainly going to be different. The numbers you'll see on residential air conditioners and heat pumps are: The 3 digits in the model number tell you the nominal capacity in thousands of BTU/hr.

Since each 12,000 BTU/hr is equivalent to 1 ton of air conditioner capacity, it's easy to figure out how many tons of nominal capacity your AC has. Why Is Air Conditioner Capacity Measured in Tons? 3 Reasons Your 3 Ton Air Conditioner Isn't Really 3 Tons Why an Oversized Air Conditioner Is a Bad Idea NOTE: Comments are moderated. Your comment will not appear below until approved.AIR CONDITIONING SIZE AND YEAR What year and size is the Air Conditioning system? Let me show you how YOU the Realtor can determine that on your own.  Remember that these dates are NOT installation dates, but they are the manufacture date and typically these dates are close to each other. First let us understand “Tonnage” is: Tonnage  The unit of measure used in air conditioning to describe the cooling capacity of a system. One ton of cooling is based on the amount of heat needed to melt one ton (2000 lbs.) of ice in a 24 hour period. One ton of cooling is equal to 12,000 Btu/hr.

This size of an Air Conditioning Unit is based up many factors, such as composition of the building, which way it faces, the number of windows, the amount of insulation..... Basic Principals of Air Conditioning: The basic principals of the Air Conditioning System used for Florida.An AC system is used as a dual purpose.One is to allow warm air to be pulled into the system, filter this air and then flow across the cold coils and blow cold air into the building.window ac units dealsThe other purpose is to pull the humidity out of the air.why is my ac unit not workingThis is VERY important.best window ac unitsSo with this information – BIGGER IS NOT BETTER!A house with to large an AC system will always be damp and contain that “bone chilling” cold.

If in doubt call a Professional and licensed Heating, and Air Conditioning (HVAC) contractor. How to determine the age and size of the AC unit: The age or manufacture date of an AC compressor is usually coded under the serial number portion of the data plate that is present on the side of the compressor (Outside AC portion of the AC system) The red boxed area is the Serial Number for this type of unit.The “L” indicates the month of the manufacture.“L” being the 12thletter of the alphabet and the ‘01” being the last 2 numbers of the year, thus meaning this is a December 2001 manufacture date. This is the area where the data or information from above was obtained.The exterior portion of the AC system called the compressor. Congratulations on learning how to determine the age of an Air Conditioning Compressor.The air handler’s age is determined much the same way.The air handler is located within the interior of the residence most of the time it is in a closet, garage or attic area.

This applies to the MAJORITY of AC units in SW Florida.Other types are present, but this will allow you to determine the age of many of the AC systems. How to determine the size (called tonnage) of an Air Conditioning system: First of all the size of an AC unit is called a ton or tonnage.A recap of tonnage is Tonnage  The unit of measure used in air conditioning to describe the cooling capacity of a system. The number to remember is 12,000 BTU’s or more simply 12.If 12,000 BTU’s is equal to 1 (one) ton of AC then 18,000 is equal to 1.5 tons and 24,000 is equal to 2 tons and so on. Look at the model number (Located on the data plate stamped on the actual side of the compressor) on the compressor and there should be a number divisible by 12.It should start at 18 and not be more than 60 for residential AC units.18 to equal 1.5 tons and 60 to equal 5 tons of cooling. Look at the model number below and you determine the AC compressor size. The 36 in the model number in the first picture above it means that the AC compressor is equal to 3 tons of cooling.