5 Ton vs 4 Ton AC Systems: When to Go Big or Size Down

🧊 Size Wars: Why Getting This Wrong Costs You Big

Let’s start with the basics: one ton of AC = 12,000 BTUs of cooling. So:

• A 4-ton system = 48,000 BTUs

• A 5-ton system = 60,000 BTUs

That’s a 25% difference in cooling power, and the gap is wider than most folks think.

The problem is, people either overestimate how much AC they need (“Bigger must be better!”), or they undershoot to save money—both choices lead to hot, humid, uncomfortable homes.

Jake’s mission today: help you pick the right size without blowing your budget or your comfort.

📐 Step One: Know Your Load, Not Just Your Square Footage

The rule of thumb most HVAC techs start with is:

20 BTUs per square foot of conditioned space

So:

• 2,400 sq ft = ~48,000 BTUs = 4 ton

• 3,000 sq ft = ~60,000 BTUs = 5 ton

Sounds simple, right? Well, not quite.

Real load depends on way more than square footage. According to ACCA Manual J (the gold standard for load calculations), here’s what else matters:

• Ceiling height

• Window size & orientation

• Roof material & attic insulation

• Shade from trees or surrounding buildings

• Infiltration (air leakage)

• Internal heat gains (people, appliances, electronics)

That’s why a 2,800 sq ft house in Florida with single-pane windows might need a 5-ton system, while a 3,200 sq ft home in Colorado with spray-foam insulation might only need 4 tons.

Want a better estimate? Use this Modernize AC sizing calculator for a regionally-adjusted load guess.

🏠 When a 4-Ton System Might Be Enough

Jake doesn’t believe in overselling. If a 4-ton AC unit fits your house and budget, go for it—especially if:

✅ Your home is 2,200–2,600 sq ft
✅ You’ve got tight ductwork and spray foam insulation
✅ Your ceilings are standard height
✅ You live in a mild climate (northern states, coastal areas)
✅ You run ceiling fans or use shade to reduce load

That said, you still need to check your return air volume and blower CFM—even the best 4-ton unit will fall short if your ducts are strangling it.

Need a match? Check out Goodman’s 4-ton R-32 systems, which balance lower cost with eco-friendly refrigerant and solid SEER2 ratings.

🏗️ When to Size Up to a 5-Ton System (Jake’s Checklist)

Here’s where 5 tons is not overkill—it’s bare minimum:

✅ Home is 2,700+ sq ft
✅ Open floor plan with high ceilings
✅ Big south- or west-facing windows
✅ Poor attic insulation or leaky envelope
✅ You’re in a hot-humid zone like Texas, Florida, Georgia
✅ You have 4+ people home during the day

In other words, if your house cooks in the afternoon sun and the AC has to battle high humidity all day, you need that extra horsepower.

Jake’s top pick: the Goodman 5 Ton 14 SEER2 R-32 System. Built for big homes, tough summers, and long days. It’s Jake-tested, homeowner-approved.

💨 Don’t Forget the Ductwork

Oversizing your AC but forgetting to upgrade your ducts? You just flushed money.

A 5-ton system moves 2,000 CFM (cubic feet per minute). If your return is sized for 1,600 CFM (like it would be for a 4-ton), here’s what happens:

• Static pressure builds up

• The coil freezes

• Your system short-cycles

• You end up with humidity problems and high energy bills

According to the U.S. Department of Energy, improperly sized ducts reduce efficiency by up to 30%. So if you size up your system, size up your ductwork, too.

Minimum duct sizes for 5-ton systems:

• Return: 20” round or 18×30” rectangular

• Supply trunk: 18” round or 20×25” rectangular

🌡️ Dehumidification: Where Oversizing Gets You in Trouble

Let’s say your house is borderline between 4 and 5 tons. You figure, “Better safe than sorry,” and get the bigger one. Problem solved?

Not quite.

Here’s the catch: oversized systems cool the air too fast. That means:

• They don’t run long enough to remove humidity

• You feel clammy even when the thermostat says 72°F

• Mold risk increases, especially in basements and crawl spaces

• Air quality tanks

You end up running a dehumidifier all summer just to fix the problem your new AC created.

If your house has high humidity but low heat gain (shaded lot, few occupants), Jake actually recommends going with the 4-ton and making sure it runs longer at a lower speed.

🧪 Real Efficiency Comes from Balance

It’s not just about the number on the box. Efficiency is how well the system cools your home using the least energy possible.

That means:

• Matching tonnage to load

• Matching airflow to duct layout

• Matching compressor speed to runtime

A 4-ton system sized correctly will outperform a 5-ton system that’s choking on undersized ductwork or cycling every 8 minutes.

According to HVAC.com’s SEER2 explainer, systems are rated at steady-state performance—so short cycling destroys efficiency.

Jake's tip: When in doubt, size based on Manual J, not just your neighbor's install.

🛠️ What If You’re in Between Sizes?

Let’s say your house needs 52,000 BTUs. Now what?

Here’s what Jake considers:

Option 1: Go 5-Ton, Add Dehumidifier

• Pros: Comfort in extreme heat

• Cons: May short cycle in spring/fall without zoning or multi-speed blower

Option 2: Go 4-Ton, Tighten House

• Pros: Longer runtimes = better humidity control

• Cons: May fall behind on 100°F days unless home is sealed tight

Option 3: Install a Dual Stage or Variable Speed System

• Best of both worlds—but it costs more. These adjust output between ~70% and 100% as needed.

Unfortunately, most 4- and 5-ton units at the budget level (like Goodman’s 14 SEER2 line) are single-stage. So unless you’re going top-shelf, you’ll need to make the call based on your climate + house construction.

💸 Let’s Talk Numbers: What’s the Cost Difference?

Install cost depends on ductwork, line set length, electrical upgrade, and labor rates. Adding a return or upsizing ducts can add $500–$1,000+.

If you need zoning or staging, that jumps another $1,200–$2,500 depending on brand.

For more accurate estimates, check Remodeling’s 2024 Cost vs. Value HVAC report

🧠 Final Jake Verdict: Know Your Home, Then Pick Your System

Jake doesn’t care what the neighbor says. He wants your system to run clean, cool, and without drama.

So here’s his take:

✅ Go with a 4-ton if your home is well-insulated, 2,200–2,600 sq ft, and in a mild or shaded climate.
✅ Step up to 5 tons if you’re over 2,700 sq ft, in a southern zone, or have sunlight pouring in and insulation that’s seen better days.

If you’re going 5-ton, do it smart with a system like the Goodman 5 Ton 14 SEER2 R-32 AC. It delivers power without fluff, and with R-32, it’s already aligned with where the industry’s heading.