What Size Air Conditioner Do I Need?

 

If you’re looking to install a new cooling system or are dealing with issues like short cycling or inconsistent temperatures, one thing to consider is whether you have the right size HVAC system. 

Many people don’t know that air conditioners must be correctly sized for the property. An air conditioner that is too small or too large will not cool well. It can also increase energy bills and shorten the system’s lifespan.

Why HVAC System Sizing Matters

Efficiency and Comfort

If your AC is too small, it will run continuously without effectively cooling your space. If it’s too large, it will short cycle, frequently turning on and off, creating temperature swings and uneven airflow. Proper HVAC system sizing cools your home evenly, keeping you comfortable year-round.

Energy Savings

An undersized unit runs constantly, using more electricity. An oversized unit may cool quickly, but it wastes energy cycling on and off. Choosing the right size air conditioner means your system runs efficiently, which lowers your monthly energy bills.

Longer Lifespan

When your HVAC system is sized correctly, it doesn’t have to overcompensate to reach the desired temperature. Less strain means fewer repairs and a longer lifespan. Installing the right size HVAC system is an investment that will save you money in the long run.

What Happens When Your AC Is the Wrong Size?

If It’s Too Small:

• Runs nonstop without reaching the set temperature
• Increased wear and tear, leading to breakdowns
• Higher energy bills with poor cooling results

If It’s Too Large:

• Short cycles that lead to uncomfortable temperature swings
• Poor humidity control makes the air feel damp or clammy
• Wasted energy due to frequent starts and stops

How to Choose the Right Size HVAC System

Step 1: Understand BTUs

Your AC’s cooling capacity is measured in BTUs (British Thermal Units). The general rule is to have about 20 BTUs per square foot. But that’s just a starting point. Ceiling height, how often the room is used, if it has a window, and location all affect how many BTUs your home needs.

Step 2: Use Online HVAC Sizing Tools

Plenty of online tools can help you get a rough idea of what size HVAC system you need based on square footage and location. While these are helpful, they don’t account for specific factors on your property, like insulation or sun exposure. Your best option is to get a professional opinion. 

Step 3: Schedule a Professional Load Calculation

For the most accurate sizing, trust a licensed HVAC technician to perform a full load calculation. They’ll assess everything from your home’s layout and insulation to local climate conditions. This helps determine exactly what size HVAC system will provide the best performance and efficiency for your home.

Key Factors That Affect HVAC System Sizing

Home Size and Layout

Your home’s square footage is the basis for calculating your cooling needs, but its layout is also important. Multiple levels, open floor plans, and how often a room is used all affect how much cooling power a space needs.

Insulation and Construction

Newer, well-insulated homes require less cooling power. Older homes with poor insulation or drafty windows may need more. The type of windows, number of doors, and even your roofing material all play a role in choosing the right size HVAC system.

Sunlight and Shade

Homes with lots of direct sunlight or large, uncovered windows will naturally be warmer, increasing your cooling needs. Homes that get a lot of shade from trees or north-facing windows get less heat and, therefore, require less cooling. 

Local Climate

If you live in a hot and humid area, your home needs a system to handle the extra cooling and dehumidification.

Find the Right Fit With Help From The Experts at Thornton

Choosing the right size HVAC system isn’t something you want to guess at. The team at Thornton provides expert assessments to ensure your new AC fits your home perfectly. Whether you’re upgrading an old system or installing one in a new build, we’ll help you every step of the way. 

Contact Thornton today for a personalized consultation. We’ll help you determine the best fit for your home and ensure expert installation for years of reliable comfort.