Replacing old aircons can save on electricity bills


Active member
I have 9 aircons in my house, provided with the house when new in 2005, wall-mounted units with outdoor condensers in the range of 18000-35000 Btu each. The main bedroom ensuite bathroom even has an aircon.

Actually, currently, 8 aircons because one died, the one preferred by our dog which is now deceased. That one was used for 8 years 24 hours a day mostly for the comfort of the dog during night hours. The repair cost quoted was 50% of the new cost with an only 6-month warranty on repair which was not economically viable. Only 2 are used daily, bedroom 8 hours a day, and living room 16 hours a day, and the rest are hardly ever used if at all.

In the downstairs kitchen-dining-living-office area I have 4 aircons but only use one in the living room area.

The old aircons have a coefficient of performance around 3.1 and current good quality new aircons have a COP of 7+. Therefore I could potentially save more than 50% of my electricity bills by replacing the 2 old aircons I use most with new aircons. The payback time is 2 years and I might even get a trade-in for the old aircon which will reduce costs further.

I am currently considering this. The replacement of the missing unit for living area is definitey good economics because that is used 16 hours a day. The main bedroom unit is arguable because its only used 8 hours a day, however, that aircon has not been as good as others and I suspect it is less efficient than COP 3.1 which it is alleged to have.

I actually did replace the broken aircon 5 years ago, but the replacement unit was much noisier (American design Daikin which had cracking noises from the evaporator when cooling started and a very noisy outdoor condenser unit particularly when it started. Americans appear to like noisy appliances) than its published brochure, particularly the condenser, so I had the Supplier take it back and refund my money. Actually, the Daikin unit did perform better from the temperature aspect but its good aircon performance was not enough to overcome the noise issue.
Last edited:


Head Honcho 💉💉
Staff member
I only use the a/c in summer, usually an hour or two a day.


Staff member
bloody ell .... I'm lucky if I use my aircon 4 times a year, and that's only when the GC summer is at it's peak. Ceiling fans are usually enough for me.