💬 From Savvy Mavi:
“I used to think bigger was better—until my oversized AC left me sweaty and broke. Trust me: sizing is where your cooling journey really begins.”
📏 Why Proper AC Sizing Matters
An oversized unit will cool your space fast—but leave you with:
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High humidity
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Short cycling (on/off constantly)
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A shorter lifespan for the system
An undersized unit will:
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Struggle to cool your space
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Run constantly
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Spike your utility bills
Just like Goldilocks, you want one that’s just right.
🧮 The Gold Standard: Manual J Load Calculations
The pros use something called a Manual J calculation. It factors in:
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Square footage
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Number of windows and doors
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Sun exposure
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Insulation levels
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Number of people in the home
🔗 Manual J Load Calculation Explained – Energy Vanguard
🔍 Need a Quick Estimate?
For a general idea, you can use a BTU per square foot chart. The average recommendation is:
| Area (sq ft) | Approx. BTUs |
|---|---|
| 500–600 | 12,000 |
| 1,000–1,200 | 24,000 |
| 1,500–2,000 | 30,000–36,000 |
🔗 BTU Calculator by Room Size – PickHVAC
Note: These are just rough guides. Manual J is still the most accurate method.
🧰 Handy Tools You Can Use
🔗 AC Tonnage Calculator – HVACDirect
Plug in your square footage and get a quick estimate.
🔗 DOE: Sizing Heating and Cooling Systems
Straight from the Department of Energy, this guide offers best practices for right-sizing your HVAC system.
🧠 Bonus Tip: Think About SEER2 Too
Once you have the right size, don’t forget about efficiency. A 2.5-ton unit with a 14.5 SEER2 rating gives you balanced cooling without excess energy waste.
🔗 Goodman 2.5 Ton 14.5 SEER2 R-32 AC and Air Handler System
❓ Common Sizing Mistakes to Avoid
🚫 Guessing based on your neighbor’s system
🚫 Basing it just on square footage
🚫 Forgetting insulation, ceilings, and orientation
🚫 Oversizing “just to be safe”
💡 Mavi’s Smart Moves
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Ask your installer if they’ll run a Manual J—don’t be shy!
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Don’t size based on your old unit’s specs. Homes and climates change.
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Bigger is not always better. (Seriously.)
🏁 Final Word from Mavi
If you want long-term comfort and savings, sizing your air conditioner right is where it all begins. Don’t wing it—use the tools, trust the data, and shop smarter.
