An AC that's quietly getting worse usually gives you warnings before it fails — conveniently, on the hottest day of the year. Catch these five signs early and a simple service keeps it efficient, healthy and reliable. Ignore them and a cheap fix can become an expensive repair.
Brought to you by the local team behind AC Rental Lisbon — years of keeping Lisbon homes and apartments comfortable.
If you notice any of these, book a service before the summer load exposes them.
If it takes far longer to cool the room or never quite gets there, it's usually a dirty filter or low refrigerant — both fixed by a service. Left alone, it just gets worse and costs more to run.
A damp, mouldy smell when it starts up means bacteria and mould have built up inside. A sanitising clean clears it — important for allergies, kids and anyone sensitive to air quality.
Water inside or below the indoor unit usually means a blocked drain. It's easy to clear on a service, but ignored it causes damp, staining and even damage to walls and floors.
Once a year for a home, ideally in spring before summer. Units used heavily, in dusty areas or near the coast, and short-let properties, benefit from a service every 6–12 months. Regular servicing keeps it efficient, healthy and under warranty.
It's a sign of mould and bacteria growing inside the unit, which then gets blown into your rooms — not great for allergies or air quality. A sanitising service clears it. If the smell keeps returning, more frequent cleaning or a deeper treatment may be needed.
Most often a clogged filter or low refrigerant. A service — cleaning the filters and coils and checking (and topping up) the gas — usually restores full cooling. If a component has failed, we diagnose it and quote the repair clearly before doing anything.
From about €60 for a single wall unit (clean plus gas check). Multi-split systems are priced per indoor unit, and a deep sanitising clean is a little more. Homes with several units and hosts get a bundle rate — see our <a href="/ac-maintenance/">maintenance page</a>.
Usually a service fixes both — they're typically caused by dirt or low gas. If a part has actually failed (a fan, a board, a compressor), that's a repair, which we diagnose from a call-out and quote separately, only proceeding with your go-ahead.
Weak cooling, a musty smell, a drip, a noise or a bill that's crept up — tell us what's happening and the brand and we'll tell you if it's a quick service or something more. Minutes to reply on WhatsApp.
Tell us your units and we'll confirm a slot and a clear per-unit price — usually within 24 hours. Any brand, fully certified.