House still hot even with the air conditioning on?

If your house stays hot even with the air conditioning (AC) on, the problem is rarely the equipment: it is the lack of insulation in the walls. In buildings with double walls, blown-in insulation fills the air cavity and helps to keep the cool air inside, in just 1 to 3 days and without major building work.

Why does the house stay hot… even with the air conditioning on?

You have the air conditioning running all day, but the house is still stuffy. The relief does not last long. And the electricity bill goes up every month.

If this sounds familiar, you are not alone. Many homes in Portugal go through exactly the same thing, but the air conditioning is not always to blame. Very often, the real problem lies in the walls.

AC does not work miracles in poorly insulated homes

Air conditioning was designed to cool, not to make up for shortcomings in the building. If the house does not retain the cool air, the AC has to work much harder to keep the temperature stable.

And that has consequences:

• Comfort is never constant
• Energy consumption goes up
• The electricity bill rises every month

Instead of cooling the house, you are cooling the air… which escapes through the walls.

Houses with double walls: a hidden opportunity

Most houses built up to the 2000s have double walls with an empty air cavity. At the time it was seen as a natural solution, but in practice that space between the walls was left without a purpose.

Today, we know that this space is the ideal place to apply blown-in insulation, a quick and effective technique.

What is blown-in insulation?

It is a method that fills the empty space between the walls with insulating mineral wool, without major building work inside the home.

• No knocking down walls
• No disruption to your routine
• Results in 1 to 3 days
• And a big difference in thermal comfort

The benefits go far beyond summer

Good insulation is not only about keeping the house cool. In winter, it helps to stop heat from escaping quickly. In other words: more thermal comfort all year round.

It also helps to reduce outside noise and to improve the energy efficiency of the property.

According to ADENE, an energy renovation can reduce a building's primary energy consumption by, on average, at least 30%.

Conclusion: it is not the AC that is weak. It is the house that needs help.

There is no need to change your equipment. What you need is to make the house work for you, not against you.

If the house heats up quickly and takes a long time to cool down, it is time to look at what cannot be seen: the walls. Comfort starts with the building envelope, not at the plug socket.

Want to know whether your house can be insulated with blown-in insulation? Our team of engineers carries out a technical assessment of the air cavity. Phone: 210 270 937.

Frequently asked questions about cooling and insulation

Why can't my air conditioning cool the house?

Usually it is because heat gets in faster than the AC can compensate for. If the walls, ceiling or windows are not insulated, you are cooling and losing it at the same time, like trying to fill a bath with the plug pulled out.

Does wall insulation really help in the summer heat?

Yes. Insulation slows down the transfer of heat into the house, which helps to keep it cooler for longer and reduces the need to have the AC on all the time.

Which type of insulation is best for the Portuguese climate?

In houses with double walls and an air cavity, blown-in insulation (mineral wool or cork) is one of the most practical solutions. In buildings without an air cavity, capoto (ETICS) is generally the alternative.

Can I insulate my house in summer, or do I have to wait?

Blown-in insulation can be carried out at any time of year. There is no major building work and no lengthy drying time: the work typically takes 1 to 3 days.

How much does it cost, roughly?

Blown-in insulation typically costs in the region of 20-45 €/m² (materials and labour). Indicative figures, confirmed after an on-site inspection.