SEER2 Ratings Explained: What the Numbers Mean for Your Power Bill

By Bryan Donaldson, Owner, On Time Air. 25+ years of HVAC experience in Savannah, GA.

Every AC quote you get has a number on it. 14.3. 15.2. 17. 20.

Salespeople will tell you higher is better, which is technically true and not especially useful. What you actually want to know is whether the extra three thousand dollars for the higher number comes back to you, and how long that takes.

Let me walk through it honestly, including the part where sometimes it doesn’t pay off.

What SEER2 Actually Measures

SEER stands for Seasonal Energy Efficiency Ratio. It’s cooling output divided by electrical input across a full cooling season. Think of it as miles per gallon for your air conditioner.

In January 2023 the Department of Energy replaced SEER with SEER2. The change wasn’t cosmetic. The new testing procedure raises external static pressure during the test, which is a fancy way of saying they now test equipment against realistic ductwork resistance instead of near-ideal lab conditions.

The practical effect: SEER2 numbers run roughly 4.5 percent lower than the old SEER number for the same equipment. A unit that tested at 16 SEER rates about 15.2 SEER2. The equipment didn’t get worse. The measurement got more honest.

So when you’re comparing an old quote to a new one, or a used system to a new one, make sure you’re comparing like to like. SEER and SEER2 are not interchangeable numbers.

The Minimum in Georgia

Efficiency minimums are set regionally, and Georgia falls in the Southeast region, which has stricter requirements than the northern states because we run cooling so much longer.

For split-system air conditioners under 45,000 BTU, the Southeast minimum is 14.3 SEER2. Above 45,000 BTU it’s 13.8 SEER2. Heat pumps are set nationally at 14.3 SEER2.

That means the least efficient system you can legally have installed in Chatham County today is meaningfully better than what was standard fifteen years ago. If your current unit is from 2008 and rated 10 SEER, even a baseline replacement is a real upgrade.

There’s also a regional enforcement wrinkle worth knowing: in the Southeast, it’s illegal to install below-minimum equipment, not just to manufacture it. Contractors can’t work around it with old stock.

What the Upgrade Actually Saves

Here’s the math I use with customers, and you can run it yourself.

The rough formula for annual cooling cost:

(BTU capacity ÷ SEER2) × annual cooling hours × electricity rate ÷ 1000

For a 3-ton system (36,000 BTU) in Savannah, we typically see 1,800 to 2,200 cooling hours a year. Our cooling season runs long, roughly March through October, which is central to everything that follows. Georgia Power residential rates have been running in the neighborhood of 14 to 15 cents per kilowatt hour, though you should check your actual bill.

Using 2,000 hours and 14.5 cents:

SEER2 rating	Approx. annual cooling cost	Saved vs. 14.3
14.3 (minimum)	$730	—
16.0	$652	$78
18.0	$580	$150
20.0	$522	$208

Those are estimates, not promises. Your home’s load, your thermostat habits, and your actual rate all move these numbers.

Does the Upgrade Pay for Itself?

This is where I try to be straight rather than salesy.

Going from 14.3 to 16 SEER2 typically adds somewhere around $800 to $1,500 to an installation. At roughly $78 a year saved, that’s a ten to nineteen year payback on energy alone. The equipment may not last that long.

Going from 14.3 to 18 SEER2 might add $2,500 to $4,000. At $150 a year, the energy payback is past twenty years.

On pure utility savings, aggressive efficiency upgrades often don’t pay back in this market. I’d rather tell you that than pretend otherwise.

But energy savings isn’t the only reason to buy up, and in Savannah the other reasons matter more than the arithmetic suggests.

The Reasons That Actually Justify Higher Efficiency Here

Humidity control. This is the big one. Higher-efficiency systems are generally two-stage or variable-capacity. They run longer cycles at lower output, and long cycles are what pull moisture out of the air. In a climate where summer dew points sit in the 70s, a variable-speed system does something for your comfort that a single-stage unit simply cannot, regardless of its rating.

Comfort and noise. Variable-speed equipment holds temperature within about a degree instead of swinging three or four. They’re also dramatically quieter, which matters if your condenser sits outside a bedroom window.

Longer run seasons compound savings. The payback math above uses 2,000 cooling hours. In Phoenix or Savannah those numbers are far better than in Maine. Our long season is exactly what makes efficiency upgrades more defensible here than in most of the country.

Tax credits and rebates. The federal 25C credit has covered a portion of qualifying high-efficiency equipment, with heat pumps generally treated more favorably than straight AC. Program details and amounts change, so verify current-year rules before you count on them. We keep a page on local rebates and the Inflation Reduction Act as they apply.

Resale. Not a huge factor, but a recent high-efficiency system is a line item buyers notice.

My Honest Recommendation for Savannah

For most homes in Chatham, Effingham, and Bryan counties, the sweet spot lands around 15.2 to 17 SEER2 with two-stage or variable-speed capability.

That range gets you the humidity control and comfort benefits, which are the things you’ll actually feel, without paying for the last few points of efficiency where the cost curve gets steep.

Going to the absolute top of the line makes sense if you’re staying in the home long term, you’ve had persistent humidity problems, or you’re running a large home with high cooling demand.

Staying at minimum makes sense if it’s a rental, you’re selling within a couple of years, or the budget simply is what it is. A properly installed 14.3 SEER2 system is not a bad system.

The Thing That Matters More Than SEER2

I’ll say this plainly because it’s the most important paragraph here.

Installation quality affects your real-world efficiency more than the rating on the box.

An 18 SEER2 system with an incorrect refrigerant charge, leaky ductwork, and poor airflow will underperform a properly installed 14.3 SEER2 system. Every time. The rating is achieved under controlled test conditions. Your house is not a test chamber.

Refrigerant charge off by 10 percent can cost you 5 to 10 percent efficiency. Duct leakage in an unconditioned attic can waste 20 to 30 percent of your conditioned air before it reaches a room.

So when you’re comparing quotes, weigh the contractor at least as heavily as the number. Ask whether they’ll be performing a load calculation, checking static pressure, and verifying charge by superheat and subcooling at commissioning. Those answers predict your power bill better than the SEER2 rating does.

Frequently Asked Questions

What is the difference between SEER and SEER2? SEER2 uses an updated test procedure with higher external static pressure, better reflecting real ductwork. SEER2 ratings run about 4.5 percent lower than SEER for the same equipment.

What is the minimum SEER2 in Georgia? Georgia is in the Southeast region, where split-system ACs under 45,000 BTU must be at least 14.3 SEER2. Heat pumps are 14.3 SEER2 nationally.

Is a 20 SEER2 air conditioner worth it? For most Savannah homes, the energy savings alone won’t pay back the premium within the equipment’s life. It can still be worth it for humidity control, comfort, and noise if you’re staying in the home long term.

How much can I save upgrading from an old 10 SEER unit? Substantially. Moving from 10 SEER to 16 SEER2 can cut cooling energy use by roughly a third. The older and less efficient your current system, the stronger the case for replacement.

Does a higher SEER2 rating help with humidity? Not directly. Humidity control comes from the compressor staging, not the efficiency number. Higher-rated systems tend to be two-stage or variable-speed, which is what actually improves dehumidification.

Talk Through the Options

We’ll show you what different efficiency levels cost, what they realistically save in this climate, and where the line is for your home. No pressure to buy up.

Serving Savannah, Pooler, Richmond Hill, Rincon, Tybee Island, Wilmington Island, and communities across Chatham, Effingham, and Bryan counties.

Call On Time Air at 912-210-4901 or request an estimate. Financing is available.

Related: Air conditioning services, how to determine heat pump efficiency, and is my home energy efficient?