Split System
A split system is a type of HVAC (Heating, Ventilation, and Air Conditioning) configuration where the system is split into two main components: one part inside the building (the air handler or evaporator) and another outside (the condenser). This setup is widely used due to its efficiency, flexibility, and aesthetic appeal.
Buying a Split System in Oklahoma: What Changes
Oklahoma sits in the DOE South region, so a new split-system air conditioner installed here has to meet 14.3 SEER2 (11.7 EER2) — roughly the old 15.0 SEER. The North region minimum is only 13.4 SEER2, which means equipment that is perfectly legal to install in Ohio cannot be installed new here. Split-system heat pumps must also hit 7.5 HSPF2.
The second change is refrigerant. Manufacture of new residential split systems using R-410A ended 1 January 2025; new ducted equipment now runs R-454B and most ductless mini-splits run R-32. An existing R-410A split system is still fine to run, service and recharge.
Between a long cooling season and real winter cold, a split system here works both halves of the year. See air conditioner installation or heat pump installation.
On the split systems we open up around Washington and McClain County, the outdoor coil is usually the limiting part — red-dirt dust packs the fins and central Oklahoma hail bends them, and both show up as high head pressure long before anything actually fails.
If your split system is losing capacity, our $95 diagnostic is waived when you approve the repair that visit — see what repairs typically cost or get in touch.
Components of a Split System
- Indoor Unit (Air Handler/Evaporator): Contains the evaporator coil where the refrigerant absorbs heat from the indoor air, cooling it. Also includes a fan to circulate the conditioned air.
- Outdoor Unit (Condenser): Houses the compressor, condenser coil, and fan. Here, the refrigerant releases heat to the outside air, condensing back to a liquid.
How Does a Split System Work?
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Cooling:
- Refrigerant in the indoor unit absorbs heat, cooling the air.
- The refrigerant, now a gas, is pumped to the outdoor unit where it releases heat to the outside environment.
- After condensing, the refrigerant returns to the indoor unit to repeat the cycle. New residential split systems no longer use R-410A — its manufacture for this equipment stopped on 1 January 2025 — and now use A2L refrigerants, usually R-454B in ducted systems and R-32 in ductless mini-splits.
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Heating (in systems with heat pumps):
- The process is reversed; heat is absorbed from the outside and transferred indoors.
Advantages of Split Systems
- Efficiency: Rated in SEER2 and HSPF2, which replaced SEER and HSPF in 2023. Because SEER2 testing uses a higher external static pressure, a SEER2 number reads lower than the old SEER number for the same equipment — a "14 SEER" unit is not comparable to "14 SEER2". In Oklahoma (DOE South region), a new split-system air conditioner must meet at least 14.3 SEER2, and a split-system heat pump at least 7.5 HSPF2.
- Quiet Operation: With the noisy compressor outside, indoor units can be much quieter.
- Aesthetic Appeal: Indoor units can be designed to fit into home decor without the bulk of traditional systems.
- Zoning: Allows for more targeted heating or cooling in different areas of a building.
- Installation Flexibility: Can be adapted to various building types or retrofit situations.
Types of Split Systems
- Single-Split: One outdoor unit connected to one indoor unit.
- Multi-Split: One outdoor unit connected to multiple indoor units, allowing for zoned climate control.
- Ductless Mini-Split: A type of split system that doesn't require ductwork, ideal for spot cooling or heating.
Maintenance Considerations
- Filter Cleaning: Regularly clean or replace air filters in the indoor unit.
- Coil Cleaning: Both indoor and outdoor coils need periodic cleaning for optimal heat exchange.
- Check for Leaks: Ensure there are no refrigerant leaks, which can affect efficiency and environmental impact.
- Professional Inspections: Annual checks to ensure all components are functioning correctly.
Conclusion
Split systems offer an effective solution for heating and cooling with benefits in efficiency, noise reduction, and installation flexibility. Whether for residential or small commercial spaces, understanding how these systems work, their types, and maintenance needs can lead to better comfort, energy savings, and system longevity.