How Much Does It Cost to Run Air Conditioning?
One of the most common questions we get isn't about installation price, it's about what a system will cost to run day to day. The honest answer depends on your electricity tariff, how often the unit runs, the temperature you set it to, and how efficient the unit itself is.
Modern inverter-driven splits from Panasonic, LG and Midea are a world away from older on/off units. Instead of switching fully on and off, an inverter compressor modulates its output to hold a steady temperature, which uses noticeably less electricity than cycling a fixed-speed compressor repeatedly.
What affects running cost
- How many degrees below outdoor temperature you're asking the unit to achieve
- How well insulated and shaded the room is
- Unit efficiency rating (SEER for cooling, SCOP for heating if used as a heat pump)
- How often doors and windows are left open while it runs
- Whether the system is sized correctly — oversized and undersized units both waste energy
Inverter vs fixed-speed
A fixed-speed unit runs at full power then switches off once the room reaches temperature, causing the room to drift and the compressor to restart repeatedly. An inverter unit ramps down to a low, steady output once it's near the target, which is both more efficient and quieter.
Nearly everything we install now is inverter-based, and it's the main reason running costs have come down significantly over the last decade even as unit capabilities have improved.
Sensible ways to reduce running costs
- Set a realistic target temperature rather than the coldest setting — each extra degree of difference costs more
- Keep filters clean so the unit isn't working harder than it needs to
- Use timers or scheduling rather than leaving units running unattended
- Have the system serviced so it stays at its rated efficiency
How we help you keep costs down
At survey stage we size the system to the room rather than over-specifying, because an oversized unit short-cycles and wastes energy. We'll also talk through heating mode running costs if you're considering the system as a supplementary heat source in shoulder seasons.
FAQs
Common questions
Is it cheaper to leave AC running all day at a low setting?
Usually not — modern inverter units are efficient at maintaining temperature, but leaving them running with no one in the room simply wastes energy.
Does air conditioning use more electricity than heating with gas?
Direct comparisons depend on your tariffs and the system, but inverter heat pump-style units can be efficient for supplementary heating, particularly in shoulder seasons.
Do bigger rooms always cost more to cool?
Room size matters, but insulation, glazing and sun exposure often have a bigger effect on running cost than square footage alone.
How much does servicing affect running costs?
A dirty filter or low refrigerant charge makes a unit work harder for the same result, so regular servicing helps keep running costs close to the rated efficiency.
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