Why Sizing Matters So Much for Home Cooling November 18, 2015

Installing an HVAC system that is not properly sized for your home can lead to problems, such as poor heating and cooling performance, excessive energy usage and higher maintenance and repair costs. Sizing HVAC systems properly is essential to their performance and takes far more than a simple “rule of thumb” estimate.

Effects of Improper Sizing

Many systems are oversized to compensate for any leaks in the exterior of the home or any problems in the ductwork, such as leaks, damaged ducts or missing insulation. A system that is oversized will turn on and off frequently, which can lead to the following problems:

• Hot or cold spots between cycles
• Excessive wear and tear on the blower motor or compressor when starting and stopping
• Poor dehumidification during the summer, leading to reduced comfort
• Poor heating and cooling performance
• Increased energy usage, since HVAC systems are less efficient when cycled frequently

An undersized system will also have problems with increased part wear because it has to run constantly to keep up with the heating or cooling requirements; and even with it constantly running it will not keep your home as comfortable as a properly-sized system would.

Sizing HVAC Systems Correctly

For an HVAC system to both heat and cool effectively and efficiently, it must be sized properly for your home using a Manual J load calculation. Unlike traditional estimates, which take into account only the square footage of a home, a Manual J load calculation takes many factors specific to your home into account, including:

• Size of the home
• Number of rooms
• Arrangement of the rooms
• Number of occupants
• Indoor and outdoor temperatures
• Quality of the insulation in the home
• Heat and moisture generated by appliances

This allows the HVAC installer to get a more complete picture of your home’s heating and cooling requirements and to select the correct HVAC components, without over sizing or under sizing them.

For more information about the importance of properly sizing HVAC systems, talk to our team at Conditioned Air. We have served Southwest Florida, including the Naples, Fort Myers and Sarasota areas, since 1962.