Compare seasonal running cost for a portable AC and a fan, then judge the gap against whether you only need airflow or you need actual cooling.
Last reviewed: 17 April 2026 - UK-focused warm-weather comparison, not a cooling-system design
A fan is nearly always the low-cost answer. Portable AC only starts to justify itself when the room becomes genuinely hard to sleep in, work in, or cool with airflow alone.
This tool compares electricity cost, not comfort quality. That matters because a fan and a portable AC do not solve the same level of heat problem.
The seasonal gap changes more with hours and number of hot days than with small wattage differences between similar products.
For ordinary warm evenings, a fan is often the right first step because the running cost is low and the comfort gain can be good enough.
Portable AC is there for rooms that are genuinely overheating, not just mildly stuffy. That is why the higher cost can still be reasonable in the right room.
Portable AC only earns that higher cost when the hose setup, room sealing and heat gain are sensible enough for it to actually cool the space properly.
Use these when the cost gap is clear but the practical verdict still needs context.
Use this to model your exact fan or portable AC wattage and your own session length.
Useful when your broader room-comfort question is turning into a wider household energy decision.
Review where this page is pure cost comparison and where comfort judgement matters more than the maths.
Usually yes by a wide margin. The reason to choose it is cooling performance, not low running cost.
When the room is only mildly uncomfortable and airflow is enough to improve comfort without paying for full cooling.
When bedrooms, offices or sun-trap rooms become genuinely hard to use and you need actual cooling rather than just air movement.