| Central Split Air Conditioner |
18,000–60,000 Btu/h
(1.5–5 tons) |
Approximately 55–75 dBA near the indoor air handler; the outdoor condenser is commonly about 55–75 dBA. |
Approximately 10%–30% when ducts are located in attics, crawlspaces, garages, or other unconditioned areas. Well-sealed ducts inside the conditioned envelope have much lower losses. |
Uses SEER2 and EER2. ENERGY STAR qualified split systems generally meet a current minimum of about 15.2 SEER2 and 12.0 EER2, subject to equipment configuration and regional requirements.
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- Provides whole-home cooling.
- Works with existing forced-air heating systems.
- Offers a wide range of capacities and two-stage or variable-speed options.
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Requires ductwork and professional sizing. Best for homes that already have a suitable air-distribution system. |
| Packaged Central Air Conditioner |
24,000–60,000 Btu/h
(2–5 tons) |
Approximately 60–75 dBA near the outdoor cabinet, depending on fan speed and installation. |
Approximately 10%–30% if supply and return ducts run through unconditioned spaces. |
Uses SEER2 and EER2. ENERGY STAR qualified single-package systems commonly meet approximately 14.3 SEER2 and 11.7 EER2 minimum thresholds, with details depending on the certified configuration.
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- Combines the compressor, condenser, evaporator, and air handler in one cabinet.
- Saves indoor mechanical-room space.
- Suitable for homes with existing ductwork.
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Usually installed outdoors or on a roof. A single failure can disable the complete heating and cooling package. |
| Ductless Mini-Split Air Conditioner |
6,000–36,000 Btu/h
(0.5–3 tons per outdoor unit) |
Indoor units are commonly about 19–40 dBA on low speed; outdoor units are often about 45–60 dBA. |
Usually below 5% because refrigerant lines replace long air ducts. Short condensate and airflow paths still require correct installation. |
Uses SEER2, EER2, and sometimes combined heating metrics. ENERGY STAR qualified ductless systems commonly publish SEER2 values around 16–30 or higher; exact qualification depends on the product type and current specification.
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- High efficiency at part-load operation.
- Individual room temperature control.
- Useful for additions, renovated rooms, and homes without ducts.
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Indoor wall, floor, or ceiling units are visible. Multiple rooms may require several indoor heads or a multi-split design. |
| Ductless Multi-Split System |
18,000–60,000 Btu/h total
(1.5–5 tons) |
Approximately 19–45 dBA indoors; outdoor sound is commonly about 45–65 dBA. |
Usually below 5%; distribution occurs through refrigerant piping rather than extensive supply ducts. |
Uses system-level SEER2 and EER2 ratings. Qualified configurations may reach roughly 16–28 SEER2 or more, but the rating depends on the outdoor unit, indoor-head combination, and controls.
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- One outdoor unit can serve several indoor zones.
- Allows room-by-room control.
- Generally quieter and more efficient than ducted distribution.
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Capacity balancing and piping design are important. A fault in the outdoor unit can affect multiple zones. |
| Variable Refrigerant Flow or Variable Refrigerant Volume System |
24,000–96,000 Btu/h
(2–8 tons for many residential applications) |
Approximately 25–45 dBA indoors; outdoor units are commonly about 50–70 dBA. |
Approximately 5%–15% for ducted indoor units; ductless indoor units can reduce distribution losses further. |
Performance is reported with SEER2, EER2, IEER, or manufacturer-specific combination ratings. There is no single universal residential ENERGY STAR threshold for every VRF configuration, so the complete matched system should be checked in the official certification database.
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- Excellent zoning and part-load control.
- Can serve many rooms from one or more outdoor units.
- May support heat recovery and simultaneous zone operation.
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Higher design and installation complexity. More common in large homes or projects requiring many independently controlled zones. |
| Air-Source Heat Pump in Cooling Mode |
18,000–60,000 Btu/h
(1.5–5 tons) |
Approximately 45–75 dBA outdoors and 55–70 dBA indoors for ducted systems; ductless indoor units are generally quieter. |
Approximately 10%–30% with conventional ducts in unconditioned spaces; below 5% for ductless designs. |
Uses SEER2 and EER2 for cooling and HSPF2 for heating. ENERGY STAR qualified split heat pumps commonly meet approximately 15.2 SEER2, 12.0 EER2, and 8.5 HSPF2 or higher, depending on the certified configuration.
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- Provides both cooling and heating.
- Can reduce the need for separate heating equipment.
- Variable-speed models can maintain stable indoor temperatures.
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Cold-climate performance, backup heat, electrical service, and local operating temperatures must be evaluated before installation. |
| Ground-Source or Geothermal Heat Pump |
24,000–72,000 Btu/h
(2–6 tons) |
Approximately 40–60 dBA indoors; outdoor compressor noise is minimal because the heat-exchange equipment is usually indoors. |
Approximately 5%–15% for properly sealed ductwork. Ground loops do not create air-distribution losses. |
Cooling efficiency is commonly expressed as EER rather than SEER2. ENERGY STAR geothermal requirements vary by loop type; a representative closed-loop threshold is about 17.1 EER, while open-loop requirements are higher.
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- Stable ground temperatures can produce high efficiency.
- Low outdoor noise.
- Provides heating, cooling, and often domestic hot-water support.
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Drilling or trenching creates high initial costs and site requirements. A qualified designer must evaluate soil, groundwater, and available land. |
| Evaporative Cooler |
3,000–25,000 Btu/h of nominal cooling effect, depending on airflow, humidity, and outdoor conditions |
Approximately 50–70 dBA near the fan and cooler cabinet. |
Approximately 5%–20% for ducted models; losses depend on duct placement and air leakage. |
Does not use SEER2 or EER2 because it cools by water evaporation rather than a vapor-compression refrigeration cycle. It is not directly comparable with ENERGY STAR refrigerated air-conditioner ratings.
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- Low electricity use in dry climates.
- Introduces filtered outdoor air while cooling.
- Generally has a simpler refrigeration-free design.
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Performance declines sharply in humid weather. Requires water, regular pad maintenance, and adequate exhaust or open windows. |
| Window Air Conditioner |
5,000–25,000 Btu/h
(approximately 0.4–2 tons) |
Approximately 50–65 dBA indoors, depending on compressor operation, fan speed, and window mounting. |
There are no long ducts, but leakage around the window panel can reduce performance and increase outdoor-air infiltration. |
Uses CEER, which includes operating and standby energy. ENERGY STAR qualified room air conditioners must meet current capacity-specific efficiency requirements; efficient models commonly show CEER values of approximately 11–15 or higher.
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- Low purchase and installation cost.
- Useful for one room or a small apartment.
- Easy to replace without modifying central ductwork.
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Limited whole-home coverage, reduced window access, and possible security concerns. Correct sizing is important to avoid short cycling. |
| Portable Air Conditioner |
8,000–14,000 Btu/h using the newer seasonally adjusted rating method; older labels may show higher ASHRAE capacity figures |
Approximately fifty-five–70 dBA indoors, with compressor and fan noise in the occupied room. |
Exhaust hose and window-panel leakage can cause meaningful losses. Single-hose units can also draw warm outdoor air into the room; dual-hose designs generally reduce this effect. |
Capacity may be listed under both DOE seasonally adjusted Btu/h and older ASHRAE Btu/h methods. Portable air conditioners generally do not have a universal ENERGY STAR room-air-conditioner qualification category, so compare the current DOE energy label and measured energy-efficiency information.
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- Requires no permanent wall or window-unit installation.
- Can be moved between rooms.
- Suitable for temporary cooling or rental housing.
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Usually noisier and less efficient than window or split systems. The exhaust hose must be sealed carefully, and condensate management is required. |
