If you’re replacing an air conditioner in Austin, you’ve probably encountered a number that wasn’t on older equipment: SEER2.
You may also have heard that Texas has stricter efficiency requirements than some other parts of the country, which raises an obvious question: what do the SEER2 requirements actually mean for your home?
Understanding the difference between SEER and SEER2 can make it much easier to compare equipment, understand your options, and choose an AC system that meets current requirements.
What Is SEER2 and Why Did It Replace SEER?
SEER2 stands for Seasonal Energy Efficiency Ratio 2. It measures the cooling efficiency of an air-conditioning system over a representative cooling season, expressed in British thermal units of cooling output per watt-hour of electricity consumed.
The higher the SEER2 rating, the more cooling the system produces for each unit of electricity under the standardized test conditions.
SEER2 replaced the original SEER measurement for equipment subject to the updated Department of Energy (DOE) test procedure beginning in 2023.
The change did not simply rename the old rating. DOE changed the testing conditions to better reflect how equipment performs under real-world installation conditions, including higher external static pressure.
How the M1 Testing Procedure Changed the Numbers
Here’s the simplest way to think about it: labs test air conditioners by pushing air through them and measuring how much energy that takes.
The old test pushed air through a little too easily. Easier than it flows through an actual duct system in your attic. The new test, called M1, cranks up that resistance to something closer to reality.
Because the test got harder, the resulting numbers came out a bit lower across the board. So if you see a unit rated 13.4 SEER2, that’s not a worse air conditioner than one that used to be rated 14 SEER. It’s roughly the same unit, just measured more accurately.
SEER vs. SEER2: What’s the Difference?
The short version: SEER and SEER2 aren’t measuring different things. They’re using different rulers. Nothing about how air conditioners cool your home changed.
What changed is that the DOE tightened up the test so the number on the label reflects what you’ll actually experience, instead of a slightly rosier lab result.
That’s why you can’t just compare an old SEER number to a new SEER2 number directly. They’re not on the same scale.
SEER vs. SEER2 Conversion Chart
There’s no single exact conversion, since the drop varies slightly by equipment type, but the DOE’s own analysis points to rough conversion factors: about 0.95 for split-system air conditioners and 0.99 for single-package units.
In practical terms, that looks like this:
| Old SEER Rating | Approximate SEER2 Equivalent |
| 13 SEER | ~12.4 SEER2 |
| 14 SEER | ~13.4 SEER2 |
| 15 SEER | ~14.3 SEER2 |
| 16 SEER | ~15.2 SEER2 |
| 18 SEER | ~17.1 SEER2 |
SEER2, EER2 and HSPF2: Understanding AC Efficiency Ratings
SEER2 isn’t the only updated metric. The DOE overhauled the whole family of ratings at the same time:
- SEER2 measures overall seasonal cooling efficiency. It’s the number most homeowners see on an AC or heat pump.
- EER2 measures efficiency at a single, high-temperature condition, which matters more in extreme heat. It’s a required rating in the Southwest region, though not currently mandated in Texas’s region.
- HSPF2 (Heating Seasonal Performance Factor 2) measures heating efficiency for heat pumps, replacing the old HSPF scale the same way SEER2 replaced SEER.
Together, these three numbers give a fuller picture of how a system performs across a full year, not just on the hottest afternoon.
Why Does the Department of Energy Divide AC Efficiency Standards Into Regions?
The DOE splits the country into North, Southeast, and Southwest regions because cooling demand isn’t uniform.
A furnace-heavy climate with mild summers doesn’t need the same AC efficiency floor as a state where air conditioners run for six or seven months a year.
By setting higher minimums where cooling loads are heaviest, the DOE targets energy savings where they’ll actually add up. This is exactly why Texas, sitting in the Southeast region for SEER2 purposes, faces tougher minimums than states in the North.
Texas SEER2 Requirements: Minimum Efficiency Ratings Explained
Texas is grouped into the Southeast region for SEER2 requirements (a separate designation from the Southwest region, which covers Arizona, California, Nevada, and New Mexico). That regional placement is what pushes Texas’s minimums above the national floor.
Split-System Air Conditioners Under 45,000 BTU
For the split-system air conditioners found in most Austin homes, generally systems up to about 3.5 tons, the minimum is 14.3 SEER2. This covers the vast majority of residential replacements.
Split-System Air Conditioners 45,000 BTU and Over
Larger split systems, the kind more common in bigger homes, carry a slightly lower minimum: 13.8 SEER2. The DOE sets this threshold a bit lower because larger equipment has a harder time hitting the same efficiency ceiling as smaller units.
Heat Pumps and Packaged Units
Heat pump minimums are set nationally rather than by region, so Texas follows the same floor as everywhere else: 14.3 SEER2 for split-system heat pumps, alongside a 7.5 HSPF2 heating minimum.
Single-package heat pumps and single-package air conditioners carry a 13.4 SEER2 minimum.
Why 14.3 SEER2 Is Higher Than the North’s Minimum
The gap between regions is easiest to see side by side:
| Equipment Type | North Minimum | Texas (Southeast) Minimum |
| Split AC, under 45,000 BTU | 13.4 SEER2 | 14.3 SEER2 |
| Split AC, 45,000 BTU and over | 13.4 SEER2 | 13.8 SEER2 |
| Split-system heat pump | 14.3 SEER2 | 14.3 SEER2 |
| Single-package unit | 13.4 SEER2 | 13.4 SEER2 |
The takeaway: on the equipment that matters most, like standard split-system air conditioners, Texas’s floor sits nearly a full point higher than the North’s. That’s because Austin’s summers put more hours on the compressor.
What Texas’s SEER2 Rules Mean When You Replace Your AC in Austin
For an Austin homeowner, the practical takeaway is fairly straightforward: if you’re replacing a qualifying split-system central AC, your contractor needs to install equipment that meets the applicable current efficiency standard.
The exact requirement depends on the equipment type and capacity, so the first step is identifying what kind of system your home needs.
Can a Contractor Still Install an Older 14 SEER Unit?
No. In the Southeast region, compliance is tied to the installation date, not the manufacture date.
That means a licensed contractor in Austin cannot legally install a new air conditioner that falls below the current SEER2 minimum, even if it’s sitting on a shelf.
This is different from the North region, where equipment built before January 1, 2023, can still be installed as long as it was manufactured before the deadline.
How AC System Size Affects the Minimum Efficiency Rating
Because the 45,000 BTU threshold splits the minimums, the size of the system you need can affect which efficiency floor applies. It’s determined by your home’s square footage, insulation, and layout.
A correctly sized load calculation from your contractor isn’t just about comfort. It also determines which SEER2 minimum your new system has to clear.
The Refrigerant Change: R-410A to R-454B and R-32
Alongside SEER2, homeowners replacing an AC now run into a second regulatory shift. Under the federal AIM Act, new residential systems manufactured from January 1, 2025 onward have moved away from R-410A refrigerant toward lower-global-warming-potential alternatives.
This is primarily R-454B and, in some ductless equipment, R-32. R-410A systems already in homes aren’t affected and can still be serviced.
Any new unit you buy today will almost certainly use one of the newer refrigerants, which aren’t interchangeable with older systems.
What Is a Good SEER2 Rating for an Austin Home?
Meeting the 14.3 SEER2 minimum keeps you compliant, but “good” and “minimum” aren’t the same thing in a climate like Austin’s.
14.3 SEER2 vs. 15.2 SEER2
A 14.3 SEER2 system meets code and will cost less upfront. A 15.2 SEER2 system, roughly equivalent to the old 16 SEER, trades a higher purchase price for lower monthly cooling costs. This tends to pay off faster in a climate that runs the AC most of the year.
Does a Higher SEER2 Rating Mean Lower Energy Bills?
Generally yes, but the relationship isn’t perfectly linear. Going from 14.3 to 15.2 SEER2 delivers a real, if modest, reduction in cooling costs.
The savings become more noticeable as you climb into higher-tier equipment, but so does the price tag. The right rating depends on how long you plan to stay in the home and how much you run the system.
What Else Affects AC Efficiency?
The SEER2 number on the box only tells part of the story. Ductwork condition, proper system sizing, insulation quality, thermostat settings, and routine maintenance all influence how much efficiency you actually see on your utility bill.
A high-SEER2 unit installed with leaky ducts or mismatched components can underperform a properly installed mid-range system.
How to Check the SEER2 Rating of Your Current AC
Look for the yellow EnergyGuide label on the outdoor condenser unit, or check the equipment’s nameplate, which lists the model number.
That model number can be cross-referenced with the manufacturer’s specifications to find the SEER2 rating.
If your system predates 2023, it will show an older SEER rating instead, which isn’t a problem for equipment already installed. But it’s worth knowing before you decide whether repair or replacement makes more sense.
Energy-Efficient AC Installation in Austin
Navigating SEER2 minimums, sizing calculations, and the refrigerant transition is easier with a local team that installs compliant systems every day.
Eco Air Conditioning helps Austin homeowners choose the right SEER2-rated system for their home and budget, and handles the installation correctly the first time, from load calculations to refrigerant compatibility.
FAQs About SEER2 Requirements in Texas
What is the minimum SEER2 rating for ACs in Texas?
For most residential split-system air conditioners (under 45,000 BTU), the minimum is 14.3 SEER2. Larger split systems require at least 13.8 SEER2.
Is 14.3 SEER2 required in Texas?
Yes, for standard-sized split-system air conditioners installed in Texas homes, 14.3 SEER2 is the current federal minimum.
Is Texas in the Southeast or Southwest SEER2 region?
Texas falls in the Southeast region, along with states like Florida, Georgia, and Oklahoma. The Southwest region is limited to Arizona, California, Nevada, and New Mexico.
Can I still install an older SEER air conditioner in Texas?
No. Contractors in Texas cannot legally install a new air conditioner that doesn’t meet the current SEER2 minimum, regardless of when the unit was manufactured.
Is a higher SEER2 rating better?
Yes. A higher SEER2 rating means better efficiency and typically lower cooling costs. The right rating for your home depends on budget, system size, and how long you plan to stay in the house.
