Blog · summer · Greater Lisbon

How to prepare your Lisbon home for a heatwave before it hits.

Lisbon heatwaves are getting longer and hotter, and an unprepared flat becomes an oven — especially top floors and west-facing rooms. Most of the quick wins are free and worth doing today; when they're not enough, a properly sized air conditioner is the permanent fix (and it heats in winter too). Here's how to get ready.

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Brought to you by the local team behind AC Rental Lisbon — years of keeping Lisbon homes and apartments comfortable.

Free quick wins

Do these before the heat arrives

Small habits that make a real difference on a 38°C day:

  • Close shutters and blinds by day — keep the sun out of west- and south-facing rooms; it's the single biggest free win.
  • Cross-ventilate at night and early morning — open opposite windows when it's cooler outside than in, then shut everything up before midday.
  • Block direct sun — external blinds, awnings or even a reflective film cut far more heat than curtains alone.
  • Use fans to move air — a fan doesn't cool the room but moving air feels several degrees cooler on your skin.
  • Avoid the oven and heavy appliances midday — they dump heat into the flat; cook early or late.
  • Hydrate and shade electronics — TVs, PCs and chargers add warmth; switch off what you're not using.
When quick wins aren't enough

The permanent fix

If your flat still hits 30°C indoors and you can't sleep, it's time for real cooling.

A properly sized split

A wall-mounted split cools a room fast and holds the temperature — and because it's a heat pump, the same unit heats the flat in winter. One system, all year. See our BTU sizing guide.

Get it in before summer peaks

Demand and lead times spike in July and August. Installing in spring or early summer means you're ready before the worst heat — and not waiting in a queue during a heatwave.

Renting or short-term?

If you can't install a fixed unit, a portable AC rental delivered same-day is often the smarter call for the summer.

Good to know

Your questions, answered

How hot does it get in a Lisbon flat during a heatwave?

Outdoors, Lisbon heatwaves regularly pass 38–40°C. Indoors, a top-floor or west-facing flat with poor insulation can sit around 30°C or higher well into the night, which is why sleep suffers. Shading and ventilation help, but on the worst days only active cooling really fixes it.

What's the best free way to keep a flat cool?

Keep the sun out: close shutters and blinds during the day, especially on west- and south-facing windows, and only ventilate when it's cooler outside than in (night and early morning). External shading beats internal curtains, and fans make the air feel cooler even though they don't lower the temperature.

Is a fan enough, or do I need AC?

A fan helps you feel cooler by moving air, but it can't lower the room temperature — on a 38°C day that's not enough for many people, especially at night. If your flat stays hot after dark, a properly sized AC (which also heats in winter) is the real solution.

Should I install AC before summer?

If you can, yes. Lead times and demand rise sharply in July and August, so installing in spring or early summer means you're comfortable before the peak — rather than waiting during a heatwave. Get a free quote now and book when it suits you.

I rent — what are my options?

A fixed install usually needs the landlord's agreement, so for tenants a portable AC — bought or rented for the summer — is often the practical choice. Renting one delivered same-day avoids storing it for nine months of the year.

Questions?

Flat already unbearable? Let's cool it properly.

Tell us the room and how hot it gets and we'll size a system that actually keeps up — and book you in before the next heatwave. Minutes to reply on WhatsApp.

Beat the next heatwave — get quoted

Tell us your flat and we'll size the right AC and send an honest quote within one working day. Book the install before the peak.

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