Is a 3-Ton System the Right Size for Your Home?
R-32 Sizing Tips & Furnace Pairing with Goodman’s 15.2 SEER2 + 96% AFUE Combo
Why Sizing Matters More Than the Brand Name
When folks shop HVAC equipment, they usually get hung up on brands and efficiency numbers. Goodman, Trane, Carrier—it’s like picking Ford vs. Chevy. But here’s the hard truth: if you don’t size your system right, none of that matters.
Buy too small, and you’ll sweat through July and freeze in January. Buy too big, and you’ll deal with short cycles, higher bills, and a unit that croaks years earlier than it should.
The Goodman 3 Ton 15.2 SEER2 R-32 air conditioner condenser with vertical coil and 96% AFUE 100,000 BTU natural gas furnace is a solid system. But before you pull the trigger, let’s talk about whether it’s the right size for your home.
What a 3-Ton AC Really Means
In HVAC, a “ton” doesn’t mean weight. It means 12,000 BTUs (British Thermal Units) per hour of cooling capacity.
So:
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3 tons = 36,000 BTUs per hour of cooling.
That’s how much heat this Goodman condenser can pull out of your house on a hot summer day.
Rule of Thumb Sizing (and Why It’s Not Enough)
The back-of-the-napkin rule says:
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1 ton = 400–600 sq. ft.
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3 tons = 1,200–1,800 sq. ft.
But this is a dangerous shortcut. As the U.S. Department of Energy points out, square footage alone ignores:
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Ceiling height
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Insulation levels
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Windows and shading
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Sun exposure
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Your local climate
I’ve seen 1,500 sq. ft. homes that ran fine on 2 tons and 2,000 sq. ft. homes that needed 3 tons just to keep up. That’s why the real answer depends on more than floor area.
Climate Zone: The Real Game-Changer
Your zip code changes the math more than your square footage.
Hot & Humid (Florida, Texas, Georgia)
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High cooling loads because the AC fights both heat and humidity.
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A 3-ton system may only cover 1,200–1,400 sq. ft. here.
Moderate (Midwest, Mid-Atlantic)
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Balanced heating and cooling needs.
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3 tons usually handles 1,500–1,800 sq. ft. comfortably.
Cooler North (Minnesota, Maine)
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Shorter cooling season and lower summer loads.
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3 tons could stretch to 2,000+ sq. ft. in a well-insulated home.
👉 Jake’s Tip: Don’t size your AC based on what your cousin in Florida bought. A 3-ton in Michigan goes a lot further than a 3-ton in Houston.
Want to know your zone? Check the Energy Star Climate Zone Map.
The Furnace Side: 100,000 BTUs at 96% AFUE
Now let’s talk heating.
This furnace cranks out 100,000 BTUs of heat per hour at 96% efficiency. That means for every dollar you spend on gas, 96 cents heat your home, and only 4 cents go up the flue.
How Much Home Can It Heat?
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Mild climates: 2,500–3,000 sq. ft.
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Cold climates (Midwest, Northeast): closer to 2,000–2,400 sq. ft.
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Drafty old homes: 100k BTUs may just keep you even.
That makes this furnace a little oversized for smaller homes (under 1,400 sq. ft.), but spot-on for medium-to-large homes in northern states.
The Cooling/Heating Balance Problem
Here’s the tricky part: cooling and heating loads don’t always match.
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Cooling is sized by heat gain in summer.
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Heating is sized by heat loss in winter.
Example:
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A 1,500 sq. ft. Michigan home might need a 3-ton AC but only a 70k furnace.
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A 2,400 sq. ft. Texas home might need a 4-ton AC but only a 60k furnace.
This Goodman combo hits the sweet spot in 1,500–2,200 sq. ft. homes in the Midwest and North, where cooling and heating needs line up.
Common Mistakes Homeowners Make
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Oversizing “just in case”
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Leads to short-cycling, clammy air, and higher bills.
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Ignoring insulation and windows
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Drafty homes need more tonnage; tight homes need less.
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Forgetting ceiling height
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1,800 sq. ft. with 8-ft ceilings ≠ 1,800 sq. ft. with cathedral ceilings.
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Not thinking about future renovations
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Adding a sunroom or finishing the basement? Plan ahead.
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👉 Jake’s Rule: Size for the home you’ll actually live in—not just what the realtor’s brochure says.
Why R-32 Matters in 2025 and Beyond
The refrigerant inside your AC is just as important as the tonnage.
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R-410A (old standard): being phased out under the EPA AIM Act.
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R-32 (this system): more efficient, lower global warming potential, and future-proof.
If you’re buying new equipment now, R-32 is the smart play.
Jake’s take: Buying R-410A in 2025 is like buying a diesel SUV the day before gas prices spike—it’ll run, but you’ll regret it.
Real-World Examples
Example 1: 1,800 sq. ft. ranch in Ohio
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3-ton AC = perfect for Midwest summers.
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100k furnace = plenty of power for January.
✅ Great match.
Example 2: 2,200 sq. ft. new-build in Minnesota
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AC handles mild cooling season.
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Furnace shines in sub-zero winters.
✅ Smart pairing.
Example 3: 1,400 sq. ft. bungalow in Georgia
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Furnace barely used.
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AC undersized for hot, humid summers.
❌ Wrong system.
Manual J: The Right Way to Know
A Manual J load calculation is the only reliable sizing method. It factors in insulation, windows, occupancy, and climate.
Quick Midwest Example (1,800 sq. ft. home)
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Cooling: 20 BTUs/sq. ft. × 1,800 = 36,000 BTUs → 3 tons.
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Heating: 50 BTUs/sq. ft. × 1,800 = 90,000 BTUs → 100k furnace is right on target.
It’s not guesswork—it’s math. Most contractors can do it in under an hour.
Energy Savings: What SEER2 and AFUE Mean for Bills
Cooling Efficiency: 15.2 SEER2
Compared to older 14 SEER units, this is 7–10% more efficient. Over 15 years, that adds up to thousands saved. Try the Energy Star savings calculator for local estimates.
Heating Efficiency: 96% AFUE
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Old-school furnaces: 80% AFUE.
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This Goodman: 96%.
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That’s ~$160 saved per $1,000 of gas burned. In cold climates, the difference is huge.
Jake’s take: Don’t just look at the sticker price. Think about the lifetime operating cost. This is where high efficiency pays back month after month.
Maintenance: Keeping It Running for 15–20 Years
Even the right size system will flop if you don’t maintain it. At minimum:
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Spring: clean outdoor coil, check refrigerant, replace filters.
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Fall: inspect burners, blower, flue, and swap filters.
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Year-round: filters every 1–3 months.
For a seasonal checklist, see Energy Star’s maintenance guide.
Jake’s Final Word
The Goodman 3 Ton 15.2 SEER2 R-32 system with a 100,000 BTU 96% AFUE furnace is a workhorse. For 1,500–2,200 sq. ft. homes in moderate or northern climates, it’s just about perfect.
But don’t guess. Spend the money on a Manual J calculation. You’ll save yourself from buyer’s remorse, clammy summers, or cold winters.
Think of it like buying boots: the wrong size will rub you raw no matter how nice they are. Get the right fit, and you’re set for years of comfort.
In the next blog we will learn about SEER2 and AFUE
