Having a properly sized Air Conditioning System can bring to your home the following benefits:

• Increased Efficiency & Lower Energy Bills:

  You wouldn’t buy an 18-wheeler just to drive around town, right? That vehicle wouldn’t match the task at hand, and would cost you a lot more money to operate. The same goes for heating and cooling equipment. If your system is larger than necessary, it means that you are paying to operate larger fans and larger compressors.

  The goal is to buy one that is sized “just right.” This can be equated to highway mileage in a vehicle. If it runs steadily, without stopping and starting, it’s more affordable to operate.

• Increased Comfort:

  Contrary to popular belief, bigger is NOT always better. Over-sized air conditioners are not able to dehumidify the air inside the home. Most air conditioning units need to run for ~10 minutes before their coils get cool enough to cause condensation (this is what dehumidifies the air in your home).

  If the system is oversized, the thermostat will be satisfied before the unit is able to remove any significant amount of moisture. This creates cold, clammy conditions.

  Properly sized air conditioners should produce relative humidity levels of ~50% in the cooling season (indoor design conditions vary with climate). If your relative humidity is larger than this, you may have an oversized system that is not staying on long enough to properly dehumidify. Heating season comfort is also impacted by over-sized machinery; especially with heat pumps.

  Why you ask?
  Because heat pumps produce supply air that is roughly 100 degrees, compared to furnaces that produce supply air that is 125-135 degrees. This means that a heat pump has to move more air around the house in order to deliver a fixed amount of heat. If a heat pump is oversized, this means that there will be more air than necessary moving about the house, creating drafts, and causing comfort complaints.

  Heat pumps should be sized based on the cooling load of the house (to ensure proper dehumidification), with the rest of the heating needs delivered by the “auxiliary” heat – typically electric resistance strip heaters or furnaces.

• Improved Indoor Air Quality:

  If your system is over-sized and therefore not properly dehumidifying, you’ll have moisture problems. This may show up as strange smells, mold or mildew growing in areas that don’t receive much air flow, excessive presence of dust mites, etc. In much of the nation, humidity control is the main purpose of air conditioning systems. In order for them to control this humidity, they MUST be sized properly.