A/C Replacement: Now's the Time to Do Your Homework Before You Choose a System

A/C Replacement: Now’s the Time to Do Your Homework Before You Choose a System

Choosing an A/C replacement involves three important steps, and you’ll get better performance if you go through each one individually. Air conditioners are complex systems, and you’ll need to size it properly, select its energy efficiency, and ready your home for its installation.


Sizing makes a difference in how well the air conditioner will work and how long it will last. Bigger is not always better, and there’s little guesswork involved because skilled HVAC contractors use a tool called Manual J to calculate a home’s cooling load, in order to determine the right size air conditioner. Each home is different, and Manual J takes into account your home’s size, energy efficiency, your preferred temperatures, home design and family size, among other factors, in order to calculate its cooling load. You can also improve insulation levels and seal air leaks to reduce the cooling load, thereby allowing you to buy a smaller A/C.

A system that’s too large will short-cycle, which drives up energy bills and increases the wear and tear on the system. Air conditioners use a lot of electricity when they first start. Those short bursts of energy create more wear on the parts than when they’re running at a more continuous but lower level. Short-cycling also leaves more humidity in the air. Systems that are too small won’t cool your home when the weather is at its hottest.

Energy efficiency

Once you know the size for your A/C replacement, you can move on to energy efficiency. In this country, new central A/Cs must have a minimum 13 SEER (seasonal energy efficiency ratio). Systems that have higher SEER ratings will lower your energy consumption. It’s a good idea to choose the highest efficiency your budget can handle, since air conditioners last for many years and you’ll immediately see the payback in lower electric bills.


The HVAC contractor needs to analyze your ductwork system before the air conditioner is installed and seal all ducts to optimize efficiency. You’ll also have to select a location for the outdoor condensing unit that’s free from landscape debris and doesn’t have a lot of exposure to the sun.

If you would like more information about an A/C replacement and what’s involved, please contact us at Ernst Heating & Cooling. We’ve provided quality HVAC services to the Metro-East area since 1954.

Our goal is to help educate our customers in Hamel, Illinois and surrounding areas about energy and home comfort issues (specific to HVAC systems).  For more information about A/C replacement and other HVAC topics, visit our blog

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