What is Efficiency ratings in HVAC?
HVAC efficiency ratings help measure the performance and energy consumption of heating and cooling systems.
In other words, efficiency ratings help measure how effectively a system converts energy into heating or cooling.
Types of Efficiency Ratings in HVAC:
Here are the key efficiency metrics used in HVAC systems:
| Efficiency Rating | Full Form | Applies To | Description | Typical Range |
|---|---|---|---|---|
| SEER | Seasonal Energy Efficiency Ratio | Air Conditioners, Heat Pumps | Measures cooling efficiency over an entire cooling season. Higher SEER means better energy efficiency. | 13–26+ |
| EER | Energy Efficiency Ratio | Air Conditioners, Heat Pumps | Measures cooling efficiency at a specific outdoor temperature (usually 95°F). | 8–14+ |
| HSPF | Heating Seasonal Performance Factor | Heat Pumps | Measures heating efficiency over an entire heating season. Higher HSPF means better heating performance. | 7.7–13+ |
| AFUE | Annual Fuel Utilization Efficiency | Furnaces, Boilers | Represents the percentage of fuel converted into usable heat. Higher AFUE means more efficiency. | 80%–98% |
| COP | Coefficient of Performance | Heat Pumps, Chillers | Ratio of useful heating or cooling output to energy input. Higher COP indicates better efficiency. | 2–6+ |
| IEER | Integrated Energy Efficiency Ratio | Commercial HVAC Units | Measures efficiency at various part-load conditions for commercial systems. | 10–20+ |
| U-Factor (U-Value) | Thermal Transmittance | Windows, Insulation | Measures how much heat is lost through materials. Lower U-factor means better insulation. | 0.20–1.20 |
1. AFUE (Annual Fuel Utilization Efficiency) – For Furnaces & Boilers
AFUE is the efficiency rating for gas, oil, or electric furnaces and boilers. It represents the percentage of fuel that is converted into usable heat.
How AFUE Works:
- A 90% AFUE furnace converts 90% of the fuel into heat, while 10% is lost through exhaust gases.
- Higher AFUE = Greater efficiency & lower energy bills.
AFUE Ratings & Efficiency Levels:
| AFUE Percentage | Efficiency Level | Common System Type |
|---|---|---|
| 80% or lower | Low Efficiency | Older gas/oil furnaces |
| 80% – 89% | Standard Efficiency | Mid-range furnaces |
| 90% – 98% | High Efficiency | Condensing furnaces |
✅ Best for: Gas or oil furnaces and boilers.
✅ Tip: Look for 90%+ AFUE for high efficiency.
2. SEER (Seasonal Energy Efficiency Ratio) – For Air Conditioners & Heat Pumps
SEER measures the cooling efficiency of air conditioners and heat pumps over an entire cooling season. It calculates the ratio of cooling output (BTUs) to energy input (watt-hours).
How SEER Works:
A SEER 16 unit produces the same cooling as a SEER 10 unit but uses significantly less electricity, leading to lower energy costs.
✅ Higher SEER = Greater efficiency & reduced energy bills.
SEER Ratings & Efficiency Levels:
| SEER Rating | Efficiency Level | Common System Type |
|---|---|---|
| 13–15 | Low Efficiency | Older air conditioners & heat pumps |
| 16–19 | Standard Efficiency | Mid-range ACs & heat pumps |
| 20–26+ | High Efficiency | Variable-speed & inverter ACs |
✅ Best for: Residential & commercial air conditioners and heat pumps.
3. EER (Energy Efficiency Ratio) – For Air Conditioners & Heat Pumps
EER measures the cooling efficiency of an air conditioner or heat pump under specific outdoor conditions (usually 95°F). Unlike SEER, EER does not account for seasonal variations.
How EER Works:
An AC with an EER of 12 uses less electricity to cool a space than an AC with an EER of 9.
✅ Higher EER = Better performance in consistently hot climates.
EER Ratings & Efficiency Levels:
| EER Rating | Efficiency Level | Common System Type |
|---|---|---|
| 8–10 | Low Efficiency | Older AC units |
| 11–13 | Standard Efficiency | Mid-range air conditioners |
| 14+ | High Efficiency | Advanced heat pumps & inverter ACs |
✅ Best for: Hot climates where AC runs at full capacity frequently.
4. HSPF (Heating Seasonal Performance Factor) – For Heat Pumps
HSPF measures the heating efficiency of heat pumps over an entire heating season. It represents the ratio of heat output (in BTUs) to electricity input (in watt-hours).
How HSPF Works:
A heat pump with HSPF 10 provides more heat per unit of electricity than an HSPF 7 system, reducing heating costs.
✅ Higher HSPF = More efficient heating & lower winter energy bills.
HSPF Ratings & Efficiency Levels:
| HSPF Rating | Efficiency Level | Common System Type |
|---|---|---|
| 7.7–8.5 | Low Efficiency | Older heat pumps |
| 8.6–9.9 | Standard Efficiency | Mid-range heat pumps |
| 10–13+ | High Efficiency | Variable-speed & inverter heat pumps |
✅ Best for: Homes using heat pumps for primary heating.
5. COP (Coefficient of Performance) – For Heat Pumps & Chillers
COP measures the efficiency of heat pumps and chillers by comparing heat output to energy input. Unlike HSPF, it applies to both heating and cooling.
How COP Works:
A system with COP 4 produces 4 units of heat or cooling for every 1 unit of energy consumed.
✅ Higher COP = More efficient performance in both heating and cooling.
COP Ratings & Efficiency Levels:
| COP Value | Efficiency Level | Common System Type |
|---|---|---|
| 2–3 | Low Efficiency | Older heat pumps & chillers |
| 3–4 | Standard Efficiency | Mid-range units |
| 4–6+ | High Efficiency | Geothermal heat pumps & advanced chillers |
✅ Best for: Heat pumps, geothermal systems, and chillers.
6. IEER (Integrated Energy Efficiency Ratio) – For Commercial HVAC Systems
IEER measures the efficiency of commercial air conditioners at varying loads, unlike EER, which only considers full-load performance.
How IEER Works:
A commercial rooftop unit with IEER 16 performs better at partial loads than one with IEER 12, reducing operating costs.
✅ Higher IEER = Better part-load efficiency & energy savings.
IEER Ratings & Efficiency Levels:
| IEER Rating | Efficiency Level | Common System Type |
|---|---|---|
| 10–12 | Low Efficiency | Older commercial ACs |
| 13–16 | Standard Efficiency | Mid-range rooftop units |
| 17–20+ | High Efficiency | Advanced variable-speed HVAC units |
✅ Best for: Commercial HVAC systems running at varying loads.
7. U-Factor (U-Value) – For Windows & Insulation
U-Factor measures how much heat is transferred through a material, commonly used for windows and insulation.
How U-Factor Works:
A window with U-Factor 0.25 insulates better than one with U-Factor 0.50, keeping buildings warmer in winter and cooler in summer.
✅ Lower U-Factor = Better insulation & reduced heating/cooling loss.
U-Factor Ratings & Efficiency Levels:
| U-Factor Value | Efficiency Level | Common System Type |
|---|---|---|
| 0.40–1.20 | Low Efficiency | Older windows & poor insulation |
| 0.25–0.39 | Standard Efficiency | Double-pane windows |
| 0.20–0.24 | High Efficiency | Triple-pane & Low-E windows |
✅ Best for: Energy-efficient windows, walls, and insulation.
Importance of Efficiency ratings in HVAC:
- Lower Energy Bills 💰
- Reduced Environmental Impact 🌍
- Improved Comfort & Performance ❄️🔥
- Longer Equipment Lifespan ⚙️
- Compliance with Regulations & Incentives 🏆
Other Courses:
Also Read: HVAC Energy Efficiency explained in youtube.
