Learn how to choose the right AC size for your St. Louis home. Discover why proper air conditioner sizing matters and when to schedule a consultation.
When summer temperatures rise in the St. Louis metro area, a properly sized air conditioner makes the difference between a comfortable home and one that constantly feels hot and humid.
Many homeowners assume “bigger is better” when it comes to air conditioning. In reality, an oversized system can cause just as many problems as an undersized one. If you’re considering AC replacement or a new HVAC installation, understanding how air conditioner sizing works can help you make the right decision for your home.
Why Proper AC Sizing Matters
Choosing the right size air conditioner is one of the most important factors in home comfort and energy efficiency.
A system that is too small will:
- Struggle to cool your home
- Run constantly during hot days
- Increase energy bills
- Wear out faster
A system that is too large will:
- Cool too quickly without removing humidity
- Short cycle (turn on and off repeatedly)
- Create uneven temperatures in your home
- Increase system wear and energy costs
Missouri summers are hot and humid, so proper sizing is especially important in St. Louis homes.
How Air Conditioners Are Sized
Air conditioners are not sized by square footage alone. They are sized by cooling capacity, measured in BTUs (British Thermal Units). Most residential systems are also described in tons of cooling capacity. Here’s how that works:
| AC Size | Cooling Capacity |
|---|---|
| 1.5 ton | 18,000 BTUs |
| 2 ton | 24,000 BTUs |
| 2.5 ton | 30,000 BTUs |
| 3 ton | 36,000 BTUs |
| 4 ton | 48,000 BTUs |
| 5 ton | 60,000 BTUs |
The “ton” rating does not refer to weight. It refers to the amount of heat the system can remove from your home.
Typical AC Sizes Based on Home Size
While every home is different, these estimates provide a general guideline.
| Home Size | Typical AC Size |
|---|---|
| 900 – 1,200 sq ft | 1.5 – 2 tons |
| 1,200 – 1,500 sq ft | 2 – 2.5 tons |
| 1,500 – 2,000 sq ft | 2.5 – 3 tons |
| 2,000 – 2,500 sq ft | 3 – 3.5 tons |
| 2,500 – 3,200 sq ft | 3.5 – 4 tons |
| 3,200 – 4,000 sq ft | 4 – 5 tons |
However, square footage alone is not enough to determine the correct AC size. Professional HVAC companies perform a detailed analysis to calculate the exact capacity your home needs.
Why Oversizing Is a Common Problem
Unfortunately, some HVAC installations skip the proper calculations and simply replace the old unit with the same size.
This can cause problems because:
- Older homes may have been improperly sized originally
- Renovations may have changed the home’s cooling needs
- New equipment operates differently from older systems
Why Homeowners Choose a Local St. Louis HVAC Company
Choosing the right HVAC contractor matters just as much as selecting the right equipment. Working with a locally owned St. Louis HVAC company ensures:
- Technicians familiar with the Missouri climate
- Personalized service
- Proper system sizing
- Reliable installation
National companies that appear local online often rely on large call centers and subcontractors. Local companies are invested in the community they serve.
Schedule an AC Sizing Consultation in St. Louis
If you’re planning to replace your air conditioner or want to confirm your system is properly sized, a professional evaluation is the best place to start. The team at Thomas Hoffmann Air Conditioning & Heating LLC provides expert AC installation and replacement services throughout the St. Louis metro area. Call today for AC service or replacement consultation: (314) 471-7625
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At Thomas Hoffmann Air Conditioning & Heating, we pride ourselves on being a locally owned and operated HVAC company. With more than 30 years of experience and a master technician and mechanical engineer as our owner, we can replace, repair, and maintain your business or home’s HVAC system.