2 Air Conditioning Myths You Might Believe (And How They Could Be Hurting Your System)

As soon as you receive your first power bill as a new homeowner, you might be interested in cutting your costs — without sacrificing your comfort. Unfortunately, well-meaning friends and family members might offer HVAC tips and tricks that can actually harm your air conditioner. Here are two air conditioning myths you might believe and how they could be hurting your system:

1: Bigger is Better

If your air conditioner doesn't seem to be cutting it, you might be tempted to switch out that small system for a much larger version. After all, a bigger unit will equal more cooling power, right? Not so much. Believe it or not, air conditioners are much more efficient when they are sized properly for your house. Here are a few reasons why:

  • Your Air Conditioner And Air Handler Work Together: Although most people assume their air conditioner works on its own, the fact of the matter is that your system pumps refrigerant to the evaporator coils in your furnace or air handler, where humidity is removed and the air is cooled. Unfortunately, if your air conditioner is much larger than your air handler or furnace, the water might not condensate and fall out of the air, which will leave your home warm and humid.
  • A Larger System Might Cycle On And Off More: Unfortunately, larger air conditioners also switch on and off more, which uses more energy. Instead of staying on for a normal period of time and steadily cooling your home, that system might switch off as soon as your home hits the target temperature — rattling moving parts and putting strain on the motor.

To choose an air conditioner that is right for your home, start by looking up your home's square footage. After you have that number, multiply it by 25, divide by 12,000, and then subtract 0.5. The number that you get will equal the number of cooling tons your air conditioner should be. For example, if you have a 2,000 square foot home, you would need an air conditioner capable of delivering around 3.66 tons of cooling power. However, since this equation doesn't account for the climate in your area, newer charts might give you a more accurate idea of what you need. For example, if you live in a cooler part of the country, such as Maine or Montana, a house between 1,651 and 2,100 square feet would only require an air conditioner capable of delivering 3 tons of cooling power.

If you are concerned about choosing the right size of air conditioner, work with an HVAC professional. In addition to calculating your home's heating load, they might also be familiar with local humidity levels and heat indexes.

2: Closing Vents In Unused Spaces Boosts Cooling Power Elsewhere

Since you aren't using that spare bedroom and you don't spend much time in the kid's bathroom, you might figure that closing the air conditioning vents in those areas would save energy. Unfortunately, closing vents in unused spaces won't boost cooling power elsewhere, and it can actually harm your system.

Your HVAC system is designed to strike a delicate air pressure balance throughout your entire home. When you close air vents, it actually creates pressure in the unused area, which in turn forces your air returns to pull air through cracks around doors and windows — making your system work harder to do the same job. Since closing air vents also increases the pressure inside of ventilation lines, it can also create leaks in ductwork, pushing cooled air into floor cavities and walls.

To avoid trouble, leave your air vents open to let your system regulate itself. If you feel like some rooms in your home are hotter or cooler than you should be, ask a professional to conduct an energy audit. You might also find that you need air conditioner repairs to keep all the right areas of your home cool.

By knowing the truth about your air conditioner, you might be able to fend off system failures and keep your home comfortable.


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