Sizing an AC system

The air conditioner’s primary role is to cool the home.

A cooling system that doesn’t match the demands of the square footage will fail to maintain a comfortable temperature.

Equipment that is too small will run constantly yet be unable to keep up with the requirements. An air conditioner that is too big will drop temperature too quickly, resulting in short cycling. The frequent on and off can cause temperature fluctuation and added wear and tear to components. A properly sized cooling unit will provide best energy efficiency, comfort and overall performance. Modern air conditioners are rated by cooling capacity and energy efficiency. The BTU rating measures the cooling capacity. SEER (Seasonal Energy Efficiency Ratio) ratings provide the unit’s energy efficiency. The higher the SEER rating, the more energy efficient the air conditioner is. Energy Star rated air conditioners use at least 8% less energy than conventional models. The biggest factor in sizing the air conditioner is square footage of the living space. However, there are other variables that affect recommended sizing. Areas of the country with warmer climates rely on the air conditioner more often. The construction, type of materials used on the home’s exterior and even the color influences how much heat is absorbed or reflected. Lighter colors reflect the sun’s heat while brick absorbs and retains heat. Vinyl siding offers good insulation properties. Sun and shade are important to consider. Homes with plenty of shade experience less sun exposure and will naturally remain cooler. Sufficient insulation helps to keep heat out and cool air in during the summer and allows the air conditioner to operate more efficiently. Windows are often a source of energy escaping and can increase demands on the cooling system. The tighter the thermal envelope, the less the air conditioner needs to work, enabling a smaller unit to handle the requirements.

HVAC system

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