How to Ensure Your AC System Matches Your Heating and Cooling Needs

Updated February 19th, 2024

Whether buying a new HVAC system or upgrading your existing unit, ensuring the size matches your energy needs is essential. Typically, the size determines the efficiency and suitability. Sizing is based on area calculations, but other factors like insulation and ductwork play a significant role. Here are a few ways to help you determine the right AC size for your home.

1. Consider the Size of Your Windows and Doors

The number, type, and size of windows can make a huge difference. Typically, a professional window installation service can help you conserve or lose heating energy, making your air conditioning system work too hard. However, the orientation of your windows can also affect energy efficiency in your home.

A home with east-west windows can have a higher load gain than a home with north-south windows. This is because the sun’s orientation can impact the heat lost or gain in your home. While doors may not be as important as windows, they can make a significant difference in some locations. Typically, wooden doors can lose more energy than metallic doors with good insulation. On the other hand, glass doors lose more energy and are less efficient.

Window-heavy patios joined to the main house can also multiply the overall footage of the property. This means the energy required to cool and heat the space is significantly higher than a typical home with the same area footage.

It’s essential to consider all the openings, like windows, doors, and patios when buying a new AC system. Ideally, a home with the right orientation and windows requires a smaller HVAC system than a house with multiple windows and features that waste energy.

2. Calculate the Area and Load of Your Home

The Manual J Load Calculation is the most accurate sizing approach, and it involves several measurements that include various parameters in your house. While square footage was the predominant method a few decades ago, it may not be accurate. The modern method looks at different parameters in your home, not just the area.

You can check more about infinity heating and air on their website. Also, it’s important to note that a bigger system does not always mean better cooling.

The process eliminates guesswork and ensures you get the perfect match for your home. Two homes with the same square footage may require different HVACs due to design and architectural differences. Unless you are an expert and understand how to perform the calculations, it’s best to have a professional make them. If you are looking for an HVAC company in North Carolina, you can check out Healthy Home Heating & Air.

3. Type of Insulation

The size of your HVAC system should match the existing ductwork. Poor ductwork sizing often leads to heating and cooling problems similar to what you’d experience with a mismatched air conditioner. Ductwork incompatibilities can stress your unit more, making it overworked and leading to higher energy costs and frequent breakdowns. Correct duct sizing depends on various factors, including airflow velocity, static pressure in the HVAC system, and the duct flow pressure loss rate.

The quality of insulation in your home determines how your rooms retain and lose heat during the cold and hot seasons. A well-insulated home requires a smaller AC since it can retain heat during winter. On the other hand, a poorly-ventilated house may require a bigger unit to compensate for the losses.


Air conditioning units are essential in every home and can determine your comfort levels. However, installation isn’t a straightforward activity since you require making calculations to match the energy needs. However, good insulation and layout orientation can minimize energy loss.

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