SEER & SEER2 Ratings: What They Mean and How to Choose

SEER (Seasonal Energy Efficiency Ratio) and SEER2 tell you how efficiently an air conditioner or heat pump cools your home over a typical season. Higher number = less electricity to deliver the same cooling.

Since 2023, new equipment is rated with SEER2 (a tougher, more realistic test). If you’re comparing to an older unit labeled SEER, use the quick conversion below.

SEER vs. SEER2 (simple)

• SEER2 is the current standard. It uses higher external static pressure in testing, so numbers come out a bit lower than old SEER for the same machine.
  
  

• Fast conversion (approximate):
  
  

• SEER2 ≈ SEER × 0.95
  
  

• SEER ≈ SEER2 × 1.05
  
  

Example: A 15.2 SEER2 unit roughly compares to a ~16.0 SEER unit under the old test.

How efficiency turns into savings

Electricity use for cooling is roughly inversely proportional to the rating.
Savings % ≈ 1 − (Old Rating ÷ New Rating)

• Replace SEER 10 with 15.0 SEER2 (~15.8 SEER old) → ~37% less cooling energy.
  
  

• Replace SEER 13 with 15.2 SEER2 (~16.0 old) → ~19% savings.
  
  

• Replace SEER 14 with 17.0 SEER2 (~17.9 old) → ~22% savings.
  
  

Your actual bill depends on climate, thermostat settings, ducts, and humidity control—but this gives a reliable ballpark.

What rating should I choose?

Pick a target based on climate, comfort goals, and payback:

• Budget/solid value: 14.3–15.2 SEER2
  Great fit for moderate climates or rentals; pair with a proper coil match for reliability.
  
  

• Balanced comfort & savings (most popular): 16–18 SEER2
  Often includes two-stage or variable-speed compressors and ECM blowers for quieter operation and better humidity control—especially helpful in humid regions.
  
  

• Premium efficiency/comfort: 19+ SEER2
  Highest upfront cost; consider when electricity rates are high, you run AC many months, or you want top-tier comfort/humidity control.
  
  

Not sure where you land? Our Master HVAC Designer will model your home and climate to recommend a sweet spot with real payback.

Beyond the number: features that matter

• Compressor type:
  Single-stage (on/off), two-stage (better comfort), variable-speed inverter (best comfort, quietest, best humidity control).
  
  

• Air handler/blower:
  ECM/variable-speed indoor blowers fine-tune airflow for comfort and dehumidification.
  
  

• Coil match (AHRI):
  The outdoor unit + coil/air handler pairing changes real-world capacity/efficiency. We provide AHRI-matched combinations for every system.
  
  

• Ductwork:
  Tight, right-sized, and balanced ducts can cut load and noise. Undersized or leaky ducts can wipe out the gains from a high SEER2 unit.
  
  

• EER/EER2:
  If you experience very hot afternoons, also look at EER2 (full-load efficiency at a fixed outdoor temperature). Higher EER2 helps on peak-heat days.
  
  

• Heat pumps:
  For heating performance, look at HSPF2 (not SEER/SEER2). In mixed or warm climates, a high-efficiency heat pump can lower annual costs more than AC + furnace.
  
  

Quick comparison guide (ballpark)

Savings shown are cooling-energy only; your utility rate and climate determine dollar impact.

How we help you choose

• Climate-specific sizing based on your ZIP, home age, insulation, and windows (Manual-J style).
  
  

• SEER2/EER2/HSPF2 explained in plain English, with a simple payback.
  
  

• AHRI-matched system list you can hand to your installer.
  
  

• Humidity strategy (CFM per ton, blower profiles, and controls) so you’re comfortable on muggy days.
  
  

Next steps

• Talk to a Master HVAC Designer – free sizing + efficiency recommendation
  
  

• Shop high-efficiency AC & heat pumps – see SEER2, EER2, and features side-by-side
  
  

• Email your home details – we’ll reply with a right-sized, AHRI-matched shortlist
  
  

Furnace.Direct is an equipment supplier. For manufacturer parts warranty, follow brand registration and installation requirements. Installation must meet local codes/permits.