Hey there, I’m Jake Lawson. If you’re staring at a bunch of PTAC units wondering which one to pick, you’re not alone. Most folks get stuck right here: size. Too small, and your unit's working overtime. Too big, and you're paying more upfront and monthly than you need to.
So let me break it down for you—no fluff, just what you need to know to make a smart choice.
🔢 What’s a BTU, and Why Should You Care?
A BTU, or British Thermal Unit, is just a fancy way of measuring how much heat an air conditioner (or heater) can move around. More BTUs = more power. But here’s the catch: more isn’t always better.
If you oversize your unit, it cycles on and off too often, which means more wear and tear, uneven temps, and wasted energy. Too small, and it just can’t keep up.
📏 Basic PTAC Sizing by Square Footage
| Room Size (sq. ft.) | Recommended BTU Range |
|---|---|
| Up to 300 | 7,000 - 9,000 BTUs |
| 300 - 500 | 9,000 - 12,000 BTUs |
| 500 - 700 | 12,000 - 15,000 BTUs |
| 700+ | 15,000+ BTUs |
Now before you go shopping, let’s fine-tune that number.
⚖️ Adjustment Factors That Actually Matter
1. Sunlight: If your room gets full sun most of the day, add 10% to the BTU total.
2. People: If more than 2 people use the space regularly, add 600 BTUs per person.
3. Kitchen Use: For rooms with appliances or kitchen equipment, add 4,000 BTUs.
4. Ceilings: Got vaulted ceilings or more than 8 feet? Add 10%.
5. Insulation: Poorly insulated walls or windows? Bump it up another 10%.
Keep a calculator handy, and use this quick math to make adjustments.
⚡ Voltage Matching Matters
Don’t forget to match your PTAC’s voltage to your electrical setup. Most come in 208V, 230V, or 265V. If you plug in the wrong voltage, you're not just breaking the unit – you’re also risking a fried circuit or worse.
Read the full guide on that here: PTAC Electrical Requirements Demystified: 208v, 230v, or 265v?
✨ Jake’s Quick Checklist Before You Buy
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Before you hit “Add to Cart,” make sure you’ve got these checked off:
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📐 Measure Room Size – Grab a tape measure and calculate square footage (length × width).
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☀️ Adjust for Sunlight – Add 10% BTUs for rooms with heavy sunlight.
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🧍♂️🧍♀️ Count People – More than 2 people in the room regularly? Add 600 BTUs per extra person.
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🍳 Check for Appliances – If it's a kitchen or includes heat-producing equipment, add 4,000 BTUs.
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🏠 Account for Ceiling Height & Insulation – Add 10% BTUs if you’ve got high ceilings or poor insulation.
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⚡ Verify Voltage – PTAC units come in 208V, 230V, and 265V. Match your power supply before buying.
Nail these six, and you’ll avoid buying a PTAC that’s either too weak or way more than you need. Smart sizing = smooth operation and better energy bills.
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📊 Final Thoughts: Measure Smart, Shop Smarter
A well-sized PTAC runs quieter, lasts longer, and keeps your electric bill in check. Don't wing it—use your numbers, factor in the details, and make your investment count.
Ready to browse? Start here: Shop R-32 PTAC Units – The Furnace Outlet
Got questions? Drop me a line or talk to the team at The Furnace Outlet. We’ll help you get it right the first time.
— Jake
