15.3 EER, SEER, ARI Listings & Cost Effectiveness

15.3 EER, SEER, ARI Listings & Cost Effectiveness

Trade Area A also tests whether you can discuss EER and SEER with owners and architects: the calculations, Florida energy codes, the Florida Building Energy Rating System, ARI listings, and cost analysis. The exam references still say ARI because the CILB outline is older than the 2008 merger that created AHRI (Air-Conditioning, Heating, and Refrigeration Institute). On a 2026 job you will pull an AHRI Certificate of Product Ratings from the Directory of Certified Product Performance. The physics did not change; the test procedure and the name did.

Quick Answer: EER (and EER2) = cooling Btu/h ÷ watts at 95°F outdoor. SEER (and SEER2) = seasonal cooling Btu ÷ seasonal watt-hours. Florida split air conditioners below 45,000 Btu/h must meet 14.3 SEER2; 45,000–65,000 Btu/h splits meet 13.8 SEER2. Ratings count only on the AHRI-matched indoor and outdoor pair.

EER versus SEER — the calculations

Energy Efficiency Ratio (EER) is a steady-state full-load snapshot:

(\text{EER} = \dfrac{\text{net cooling capacity (Btu/h)}}{\text{total power input (watts)}})

AHRI 210/240 publishes that snapshot at AFull conditions: 95°F outdoor dry-bulb, indoor air about 80°F dry-bulb / 67°F wet-bulb (50 percent relative humidity at that dry-bulb). EER2 is the same ratio under the newer Appendix M1 test (higher external static). EER is the number that matters at 2 p.m. in July in Tampa, when the machine is sitting on the 95°F point for hours. Window units and many commercial full-load tables are still discussed in EER; Florida owners in hot-humid climates should hear both EER2 and SEER2, not SEER2 alone.

Worked EER: expanded or test data show 36,000 Btu/h net cooling at 95°F while the unit draws 3,000 watts (compressor + condenser fan + indoor blower as the test includes them).

(36{,}000 / 3{,}000 = 12.0 \text{ EER})

Because 1 watt is 3.412 Btu/h, that EER of 12 is a COP of (12 / 3.412 \approx 3.52).

Seasonal Energy Efficiency Ratio (SEER) is not one afternoon:

(\text{SEER} = \dfrac{\text{total cooling delivered over a cooling season (Btu)}}{\text{total electrical energy over that season (watt-hours)}})

AHRI 210/240 and DOE Appendix M build SEER from a set of indoor/outdoor tests and a climate-weighted bin model (part load, cycling, and for two-stage/variable units the intermediate ratings). SEER2 is that seasonal number under Appendix M1. You cannot convert a field-measured EER into a legal SEER2 with a napkin factor and stamp a permit. A rule of thumb sometimes seen in older shops (EER ≈ 0.875 × SEER) is not a compliance calculation and is not how AHRI lists equipment.

HSPF2 (Heating Seasonal Performance Factor 2) is the heat-pump heating analog of SEER2, Btu of heat per watt-hour over a heating season, reported for Region IV in the AHRI certificate.

SEER2 / EER2: what actually changed in 2023

On January 1, 2023, DOE's Appendix M1 (10 CFR 430 Subpart B) replaced Appendix M for rating residential central air conditioners and heat pumps. AHRI 210/240 was aligned to that procedure. The headline change: external static pressure used in the test rose from about 0.1 in. w.g. to about 0.5 in. w.g. (up to five times, depending on capacity), closer to real ductwork. Coil, fan, and cycling details also moved. The same hardware therefore prints a lower SEER2 than its old SEER. Nothing “got worse”; the ruler got stricter. Do not tell an owner that a 14.3 SEER2 unit is less efficient than last decade's 15 SEER — 14.3 SEER2 in the Southeast was set as the successor to a 15 SEER regional minimum.

AHRI 210/240 covers factory-made unitary AC and air-source heat pumps below 65,000 Btu/h. At 65,000 Btu/h and above, you are in AHRI 340/360 (and IEER/EER language in FBC Energy commercial tables). That 65,000 Btu/h line is 5.4 tons — still inside Class B's 25-ton cap, but the rating standard has already changed.

Florida energy-code and federal minimums

FBC Energy R403.7.1: new or replacement heating and cooling equipment shall have an efficiency rating equal to or greater than the minimum required by federal law for the geographic location where the equipment is installed. Florida is in DOE's Southeast region (10 CFR 430.32). Effective January 1, 2023, those residential central air-conditioner installation regional standards (single-phase, <65,000 Btu/h) include:

• Split-system air conditioners < 45,000 Btu/h: 14.3 SEER2
• Split-system air conditioners ≥ 45,000 Btu/h: 13.8 SEER2
• Single-package air conditioners: 13.4 SEER2 (national package floor; Southeast does not add a higher SEER2 package number the way it does for splits)
• Split-system heat pumps: 14.3 SEER2 and 7.5 HSPF2 (national heat-pump standard)
• Single-package heat pumps: 13.4 SEER2 and 6.7 HSPF2

A 3.5-ton (42,000 Btu/h) split AC and a 4-ton (48,000 Btu/h) split AC therefore sit on different SEER2 floors. That is an exam trap and a counter trap. FBC Energy 2023 commercial Table C403.2.3(1) (electrically operated unitary air conditioners) prints the same post-1/1/2023 SEER2 figures for three-phase and non-U.S. single-phase products in the <45,000 and 45,000–65,000 rows (14.3 and 13.8 SEER2 for splits; 13.4 SEER2 for single package), tested to AHRI 210/240. Larger commercial equipment in that table moves to EER/IEER under AHRI 340/360. Do not use the 9th Edition (2026) FBC Energy numbers on this exam — the 2026 Air Conditioning reference list is the 2023 Energy Conservation volume.

ARI / AHRI listings

Certified ratings live in the AHRI Directory of Certified Product Performance. The downloadable Certificate of Product Ratings lists the outdoor model, indoor model (coil or air handler), optional furnace as indoor section, SEER2, EER2 (AFull), cooling capacity at AFull, and HSPF2 for heat pumps, with an AHRI reference number. Only that combination is certified. Mixing a 3-ton condensing unit with a 4-ton indoor coil from a different family, or with a furnace that is not on the matchup sheet, voids the listed SEER2. Energy code, ENERGY STAR, and many rebate programs want that certificate in the permit packet. FBC Energy R403.7.1.1 separately warns you: the AHRI total capacity on that certificate is still a nominal rating-test value — use expanded performance data at design temperatures for Manual S sizing.

Florida Building Energy Rating System and cost effectiveness

The Florida Building Energy-Efficiency Rating Act, F.S. 553.990–553.998, creates a statewide uniform building energy-efficiency rating (not a second SEER sticker). Ratings must account for climate, construction practice, and building use, stay compatible with federal rating systems and the Florida Building Code, and provide a way to compare buildings at sale. F.S. 553.996 requires that a prospective purchaser be notified, at or before contract, of the option to obtain an energy-efficiency rating. FBC Energy R401.3 (mandatory) requires an Energy Performance Level (EPL) display card, certified by the builder, before final approval; F.S. 553.9085 requires that EPL card as an addendum to the sales contract for new residential buildings. Commission-approved software (historically EnergyGauge and other approved tools) produces residential performance-path and Energy Rating Index compliance; HVAC efficiency is one input among envelope, ducts, and water heating. When you talk to an architect about “the rating,” you are talking about that whole-building number, not the condensing-unit carton.

Cost analysis the exam expects is simple and honest. Seasonal kWh for a given cooling load scales inversely with SEER2:

(\text{kWh} \approx \dfrac{\text{capacity (Btu/h)} \times \text{equivalent full-load hours}}{\text{SEER2} \times 1{,}000})

Illustration only, not a utility tariff: a 36,000 Btu/h system with 2,000 equivalent full-load hours uses about 5,035 kWh at 14.3 SEER2 and about 4,500 kWh at 16.0 SEER2 — roughly 535 kWh saved. At a sample $0.14/kWh, that is about $75 per year. If the 16.0 SEER2 match costs $900 more installed, simple payback is about 12 years, before maintenance, duct leakage, or a time-of-use rate. A leaky attic duct or an unmatched coil can erase that $75. The cost-effective recommendation is often code-minimum or modestly above-minimum equipment plus a duct and envelope that EnergyGauge can see, not a 20 SEER2 outdoor unit on a 0.1-inch-static fantasy and a dirty filter.

Florida HVAC scenario

An Orlando (Climate Zone 2) owner wants to reuse a pre-2023 “14 SEER” 3-ton condensing unit from the shop loft with a new 3.5-ton indoor coil “because it will be more efficient.” Three failures: (1) Southeast installation of a split AC under 45,000 Btu/h now requires 14.3 SEER2 on a certified match, not a leftover 14 SEER carton; (2) the mixed coil is not an AHRI listed combination, so you have no SEER2 to put on the EPL card or the energy calculation; (3) even if a listed 3.5-ton match existed, R403.7.1.1 still forbids sizing from the AHRI nominal column — Manual J might be 28,000 Btu/h, and a 3.5-ton expanded-data total could blow the 1.15 cap and the latent problem. The conversation with the architect is: listed 14.3 SEER2 (or better) match, expanded-data capacity inside 1.15, ducts that make the M1 static look realistic, and an EnergyGauge/EPL package that reflects what will actually be installed.