SEER2, EER2 and HSPF2, explained for South Florida

The short answer

SEER2 tells you how efficiently an air conditioner or heat pump cools over a whole season. EER2 tells you how efficiently it cools at full load on a 95°F afternoon. HSPF2 rates a heat pump's heating. Since 2023, every new central system is rated on these "2" versions. They come from a tougher test than the old SEER, EER and HSPF, so the numbers read lower for similar equipment. In Florida, a split-system AC smaller than 45,000 Btu/h must be at least 14.3 SEER2.

Higher numbers mean lower operating cost for the same cooling. But a rating is what the equipment can do under test conditions; how it's sized and installed decides what it actually does in your house.

What each number measures

• SEER2 (Seasonal Energy Efficiency Ratio 2) is the total heat a system removes during a typical cooling season divided by the electricity it uses over that season. ENERGY STAR describes it as total heat removed during the annual cooling season divided by seasonal energy use.
• EER2 (Energy Efficiency Ratio 2) is cooling output divided by electrical input at a single, hot operating point: 95°F outdoors. It's a snapshot of full-load efficiency.
• HSPF2 (Heating Seasonal Performance Factor 2) is the heating counterpart of SEER2 for heat pumps.

For a Broward home, SEER2 is the number most connected to the electric bill, because the cooling season runs most of the year. EER2 is a useful second look at how a system handles the hottest part of the day. HSPF2 matters very little here, because heating hours are few.

Why the numbers dropped in 2023

On January 1, 2023, the U.S. Department of Energy switched to a new test procedure. One reason the new numbers are lower is that the test now assumes the system is pushing air through ductwork with more resistance, because DOE found that's closer to real homes. For conventional ducted systems the new test uses 0.50 inches of water column of external static pressure, compared with 0.10–0.20 under the old one.

DOE set the 2023 minimums in the old units first and then translated them. From those paired values, SEER2 runs roughly 4.5 to 5 percent lower than SEER for equivalent equipment, and HSPF2 about 15 to 16 percent lower than HSPF. That's our arithmetic from DOE's published levels, not an official conversion factor, and individual products vary. The practical rule: compare SEER2 with SEER2. A 2023-era 14.3 SEER2 minimum corresponds roughly to the old 15 SEER.

The minimums in Florida

Federal minimums depend on where equipment is installed. Florida is in DOE's Southeast region, which has higher minimums for split-system air conditioners than the national level (the table below lists them). A few details are worth knowing:

• The rule follows the installation address. An outdoor unit whose certified combinations fall below the Southeast level can't be installed in Florida.
• Single-package units and heat pumps don't have a separate Southeast level; the national minimums apply.
• There's no EER2 minimum in the Southeast. EER2 minimums apply only in the Southwest. EER2 is still worth comparing; it just isn't a legal floor here.

Florida law and the state energy code tie in to these federal minimums: air conditioners sold or installed in Florida must meet them.

A rating belongs to a combination

The SEER2 printed in a brochure is for a specific outdoor unit paired with a specific indoor coil or air handler, tested together. Pair the same outdoor unit with a different indoor coil and the rating changes, sometimes by a lot.

That's why Florida's energy code requires matched systems on replacements, and why a quote should name both halves of the system. If you're replacing a split system, ask for the rating of the exact combination being proposed. (See central air conditioners and heat pumps.)

The rating is a ceiling, not a promise

A system only reaches its rated efficiency when it's sized, charged and installed correctly:

• Airflow problems alone can reduce a system's efficiency by up to 15 percent, according to ENERGY STAR.
• Refrigerant charge that's off by too much or too little makes a system less efficient.
• Installation as a whole matters: ENERGY STAR's guidance has long noted that improper installation can reduce system efficiency by up to 30 percent.

A higher-SEER2 system installed on leaky or undersized ductwork, or sized by copying the old unit, can easily perform worse than a lower-rated system installed well. The sizing guide explains why the size should come from a load calculation, and airflow and duct design covers the ductwork side.

Is a higher rating worth it here?

Often, yes. A South Florida system runs so many hours a year that efficiency differences add up faster than they do in mild climates. But the decision is specific to the house and the budget. A sensible way to compare:

1. Start from the minimum that's legal for the system type and size.
2. Compare one or two higher-rated matched combinations of the same capacity.
3. Look past the rating at what else changes between them, such as single-stage versus two-stage or variable-speed operation, noise, and the manufacturer's warranty terms.
4. Make sure the quote includes the installation details that let the system reach its rating: load calculation, duct inspection, startup readings.

The plate above is an illustrative example of what to look for on a quote, not a recommendation for any particular home.