Air conditioning installation in Alicante

Alicante has old-town buildings with very thick walls, 1960s and 70s ensanche blocks, and modern PAU developments.

A 20 m² room in each of the three needs a different amount of cooling, and the difference is much larger than people expect.

Why the age of your building changes the size you need

The rule of thumb everybody quotes — around 100 to 130 watts of cooling per square metre — is a starting point that assumes an averagely insulated room. In Alicante that assumption is wrong more often than it is right, because the three main types of building here sit at very different points on that scale.

Old-town buildings have genuinely thick masonry walls and small windows. They have substantial thermal mass, they heat up slowly, and a room in one can often be cooled with less than the rule of thumb suggests. What they do instead is stay warm into the evening once they have absorbed a day of heat, which changes when you want the system running rather than how big it is.

The ensanche blocks from the 1950s to 1970s are the opposite. Thin walls by modern standards, little or no insulation, single glazing in many cases, and large windows facing whichever way the block was built. A west-facing room in one of these takes the full afternoon sun through poorly insulated fabric, and it can need substantially more than the rule of thumb — sometimes half again.

The PAU developments and newer blocks are built to modern standards with real insulation and double glazing. They hold temperature well and often need noticeably less capacity than an equivalent room in an older block. Fitting the same unit in all three because the rooms measure the same is how you end up with one flat that never gets cool and another that is clammy because the unit is oversized and short-cycles.