The letter on the energy label is a band, not a score. A+++ in cooling starts at a SEER of 8.5 and has no upper limit, so two units can carry the same label while one is meaningfully better than the other.
SEER is the seasonal cooling efficiency: kilowatt-hours of cooling delivered per kilowatt-hour of electricity, averaged across a modelled season. SCOP is the same idea for heating, quoted at a −7 °C design point. Higher is better, and the difference compounds every hour the unit runs.
In our range that spread is easy to see. The AE Pro 12 posts a SEER of 8.5 and a SCOP of 4.6; the Forest 12, a perfectly good unit, posts 6.1 and 4.0. Over a British summer plus the shoulder heating months, that is roughly £60 to £90 a year on a room that is used daily.
The practical rule: if the unit will run a handful of weeks a year, buy on price and the label is fine. If it will run most of the year, read the SEER and SCOP figures on the spec table and let them decide — they are printed on every product page here for exactly that reason.
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Send us a photo of the room and its dimensions. We will tell you what we would fit and, just as often, what we would not.
