When I first started learning about HVAC, I assumed the outdoor unit—the condenser—was the “main event.” But over the years, I’ve learned that the indoor coil is just as important when it comes to getting efficiency, comfort, and reliability.
One of the most common questions I hear from homeowners is: “Is a 3.5–5 ton coil the right size for my system?” That’s exactly what we’re going to cover today.
4 Ton Upflow/Downflow Goodman Cased Coil - CAPFA6030C3
I’ll explain what coil tonnage really means, how it matches your system, and how to figure out whether the Goodman CAPFA6030C3 3.5–5 ton cased A-coil is the right fit for your home.
🧩 1. What Does “3.5–5 Ton” Mean?
First, let’s clear up some jargon.
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In HVAC, tonnage is a measure of cooling capacity—not weight.
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1 ton = 12,000 BTUs per hour of cooling capacity.
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So:
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3.5 ton = 42,000 BTUs
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4 ton = 48,000 BTUs
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5 ton = 60,000 BTUs
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When you see a coil labeled 3.5–5 tons, it means it’s designed to handle systems in that range. The Goodman CAPFA6030C3, for example, can be paired with condensers from 42,000 to 60,000 BTUs.
👉 Mark’s Take: Think of the coil as the “bridge” between your furnace and condenser. It has to match both, or the whole system won’t run right.
📖 Learn more from the U.S. Department of Energy
🌬️ 2. How the Coil Impacts Efficiency
It’s not enough to just match tonnage—you also need to match performance.
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Your condenser is rated for efficiency using a specific coil.
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If you use the wrong coil, your system may not reach its SEER2 rating.
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In fact, efficiency can drop by 10–20% if the coil is mismatched.
That’s why you’ll often see coils like the CAPFA6030C3 listed in AHRI certification directories. These certifications confirm that a coil + condenser combo has been tested to achieve the advertised efficiency.
📖 Check matches at the AHRI Directory of Certified Product Performance
🏠 3. How Home Size Affects Coil Sizing
Here’s a rough guide many installers use for cooling capacity vs. home size:
| Home Size (sq. ft.) | Typical Tonnage |
|---|---|
| 1,500–2,000 sq. ft. | 3.5 tons |
| 2,000–2,500 sq. ft. | 4 tons |
| 2,500–3,000 sq. ft. | 5 tons |
👉 Mark’s Rule of Thumb:
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If your home is around 2,200 sq. ft. in a moderate climate, a 4-ton coil is usually right.
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In hotter climates (like Texas or Florida), you might lean toward 4.5 or 5 tons for the same square footage.
📖 The Energy Star Cooling Size Guide explains more about matching capacity to home size.
🧮 4. Manual J: The Gold Standard for Sizing
The best way to size HVAC equipment isn’t guesswork—it’s called a Manual J load calculation.
This calculation takes into account:
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Home size and layout.
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Climate zone.
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Insulation levels.
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Windows and doors.
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Air leakage.
An oversized or undersized coil can wreck efficiency and comfort, which is why pros lean on Manual J to get it right.
👉 Mark’s Tip: Even if you DIY most of your system, get a pro to run a Manual J before you buy. It’s worth the small fee.
📖 More at ACCA Manual J Residential Load Calculation
⚠️ 5. What Happens If You Oversize or Undersize?
Here’s what I’ve seen first-hand when coils are mismatched:
❌ Oversized Coil (too big)
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Short-cycling (system turns on and off constantly).
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Poor humidity control.
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Higher energy bills.
❌ Undersized Coil (too small)
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System runs constantly but never cools enough.
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Frozen coils due to strain.
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Reduced system lifespan.
✅ Properly Sized Coil
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Even comfort across rooms.
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Full SEER2 efficiency.
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Lower monthly energy bills.
📖 More on why sizing matters from HVAC.com
🛠️ 6. Matching the Coil to Your System
When deciding if a 3.5–5 ton coil is right, check three things:
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Condenser Tonnage – Look for the model number. (Example: a unit labeled “048” = 4 tons).
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Furnace or Air Handler Compatibility – The coil cabinet must fit your furnace width (the CAPFA6030C3 is 21").
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AHRI Match – Confirm the coil + condenser combination is certified.
👉 Mark’s Story: When I upgraded my Goodman system, I checked my outdoor unit (a 4-ton), matched it with the CAPFA6030C3, and confirmed it in the AHRI directory. No guesswork—just confidence it would work right.
💰 7. Cost of a 3.5–5 Ton Coil
Here’s what you can expect:
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Equipment Cost: $600–$1,200 (Goodman CAPFA6030C3 falls right in this range).
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Installation Cost: $800–$1,500 for professional install (includes refrigerant handling).
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DIY Potential: Limited—EPA requires a licensed pro to handle refrigerant, though you can install the cabinet and prep ductwork yourself.
🧹 8. Maintenance for Long-Term Performance
No matter what size coil you choose, keeping it clean and maintained is key:
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Change filters monthly in summer.
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Inspect drain lines to prevent clogs.
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Schedule professional coil cleaning every 2–3 years.
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Keep ducts sealed for proper airflow.
📖 More tips from Energy.gov – Air Conditioner Maintenance
📊 9. Quick Reference: When a 3.5–5 Ton Coil Fits
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✅ 3.5–5 ton condenser (42,000–60,000 BTUs).
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✅ Home size 1,800–3,000 sq. ft. (depending on climate).
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✅ Furnace cabinet width = 21”.
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✅ Verified AHRI match for SEER2 efficiency.
✅ 10. Final Takeaways
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The Goodman CAPFA6030C3 coil is designed for systems from 3.5 to 5 tons (42,000–60,000 BTUs).
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It’s versatile but still needs to match your condenser, furnace, and ductwork.
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A Manual J calculation is the best way to confirm your home’s true cooling needs.
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Oversizing or undersizing will cost you in comfort, efficiency, and lifespan.
👉 Mark’s Last Word: Don’t just guess at coil sizing. Match your condenser, check AHRI certification, and verify with your furnace dimensions. Do that, and a 3.5–5 ton coil could be the perfect fit for years of reliable comfort.
In the next topic we will know more about: Installation Guide: What to Know Before Swapping Your Old A-Coil
