The clever air-con upgrade that’s cutting Costa del Sol electricity bills, room by room

If your villa cools every room whether anyone’s in it or not, you’re wasting money every day. A technology most local installers already use quietly fixes that.

Here’s a scene most Costa del Sol property owners will recognise. It’s July, the air conditioning is running flat out, and there are people in exactly two rooms of the house. The guest bedrooms, the dining room, the study, all being cooled to 22°C for nobody at all.

It happens because most ducted air-con systems installed on the Costa del Sol treat the whole house as one unit. The thermostat reads one room, usually the hallway, and the compressor responds accordingly. Every grille opens, every room cools, and your Endesa bill climbs whether anyone is there to feel it or not.

Zoning changes that. The technology has been around for years, but a Spanish system called Airzone has made it practical and affordable for standard residential ducted installs, the kind found in most Costa del Sol villas built after 2005.

Airzone fits on top of your existing ducted system without replacing the outdoor unit or the ductwork. It adds motorised dampers to each branch, a small wireless thermostat in each room, and a central controller that ties them all together. From that point, each room controls its own temperature independently. The bedroom gets 24°C, the living room gets 21°C, and the rooms no one is using stay closed, saving the energy it would have taken to cool them.

The savings vary by property, but in a typical six-room Costa del Sol villa running air conditioning from May to October, the reduction in wasted cooling is significant. Rooms that go from always-on to only-when-occupied can account for 25–40 per cent of total runtime on a ducted system.

There is a second reason the system is popular here, and it matters particularly for owners who rent or split their time between Spain and elsewhere. Airzone connects to your home Wi-Fi and gives you full remote control through an app. Before guests check in, you can pre-cool the house. When they check out and you’re still back in the UK, you can switch everything off. If a guest complains the bedroom is too warm, you can adjust it from your sofa without getting on a plane.

Longer-stay owners use the same feature differently: holiday mode locks the thermostat to a fixed 26°C while the property is empty, keeping the unit ticking over enough to prevent condensation and mould without running a full cooling cycle all summer.

Installation on an existing ducted system typically takes one day and does not require replastering or major building work. The Airzone installer connects the dampers in the plenum, wires the thermostats flush to the wall, and commissions the whole system before leaving. In most cases the existing outdoor unit and indoor air handler stay in place.

For anyone considering it, Agua Therm, an Airzone-certified installer based in Marbella, has published a complete guide to Airzone smart zoning for Costa del Sol properties Agua Therm that covers which system suits which type of home, real installation examples from the area, and the questions to ask before committing. It is free to read and written without the sales language.

If your property has ducted air conditioning and you want to know whether zoning is feasible, Agua Therm also offer a no-obligation site survey and written quote for Airzone installation across Marbella and the Costa del Sol. No deposit is required until you decide to proceed.

In a climate where air conditioning runs for six months of the year, cooling the rooms you’re actually in seems obvious once someone points it out. The technology to do it has been sitting in the ductwork all along.

Ben Hayden is an English-speaking electrician and independent energy advisor based in Marbella, with over 15 years of electrical experience across Europe. He provides independent energy and electrical checks for overseas property owners across the Costa del Sol. His writing has appeared in the Euro Weekly News, ExpatArrivals, BuildingTalk and pv magazine. ben-hayden.com