Sizing a New Air Conditioner

Spring is the time of year when homeowners replace their old outdated air conditioners with new ones. If your air conditioner has struggled the past few years, it makes perfect sense that you may want to get a new one installed before the summer heat starts. Doing so will allow you to take advantage of all the benefits to your new system, including improved efficiency, lower bills, and a much lower risk of a breakdown.

Those benefits depend upon a number of factors, however, not the least of which is the proper sizing your new air conditioner. By sizing, we don’t mean the physical size of the system, though that can be a factor as well. Instead, we’re referring to the power levels of the system, representing the amount of cooling power the new system generates. Arriving at that number can be a surprisingly challenging prospect.


One of the most common pitfalls homeowners step into when they install a new air conditioner is the desire to buy the most powerful unit they can. It’s a natural assumption: after all, the most powerful unit will cool the home the fastest. But that’s necessarily a good thing. In fact, it can often be the worst thing you can do with a new system.

An undersized system is a bad fit for the home for obvious reasons: it will run and run all day and never really get the home cool, which wastes energy and drives up both monthly costs and wear on the system. An oversized system, however, does much the same thing. It engages in a process known as short-cycling: turning on and running for a short amount of time, then turning off, only to turn on again just a short time later as the heat of the day warms the home up.

Air conditioners use far more energy turning on and turning off than they do simply running, which means that short-cycling can cost you a huge amount in lost energy and productivity. Ideally, you want your air conditioner to run for at least fifteen minutes at a clip in order to make the most effective use of the energy it consumes.


The best air conditioner adheres to what we like to call the Goldilocks Rule: neither overpowered nor underpowered, but just right for your system. That means the technician needs to give your home a thorough examination to determine the proper power levels your new air conditioner needs. It starts with sizing the home, but there’s more to the equation than simple square footage. For instance, the amount of insulation in the walls can have a huge impact on how well the home retains cool air, while sunlight exposure from large picture windows can warm the home up in the late afternoon. With those calculations in place, your technician can then recommend the perfect power levels for your new air conditioner.

If you need a top-notch air conditioning installation service in Newberg, OR, call the friendly pros at Western Heating and Cooling today.