How to prepare your Lisbon flat for a heatwave

Lisbon flats, especially in areas like Alfama, Mouraria, Bairro Alto and Graça, were not built with extreme heat in mind. Thin walls, uninsulated roofs, large south-facing windows. When a heatwave arrives, the indoor temperature can easily exceed 32 °C. Before switching on the air conditioning — or if you don't yet have one — there are nine things you can do today to drop several degrees at once.

1. Close the windows and blinds before 9am

The most common mistake in Lisbon: opening the window "to let air in" during the day. When it's 36 °C outside, you're letting a sauna in. Keep everything closed until the end of the afternoon — windows, shutters, blinds. The light-coloured aluminium exterior blinds (typical in Lisbon) block up to 70% of direct solar radiation.

If you have south- or west-facing windows with no blind, consider an opaque curtain on the inside. Even a white sheet held up with clips makes a difference.

2. Open everything between 10pm and 7am

The night-time temperature in Lisbon in July/August usually drops to 19–22 °C. Take advantage of it. Create a cross-draught — open kitchen window + open bedroom window — and let the home "breathe" through the night. In the morning, close everything before the sun hits the walls.

3. Switch off anything that produces heat

Every device that's on releases heat. Computers on standby, the router, the TV on standby, chargers left plugged in with nothing charging — they all contribute. During a heatwave:

• Don't use the oven between 12pm and 8pm (have cold meals or use the microwave)
• Switch off the tumble dryer (hang clothes outside at night)
• Don't iron during the day
• Swap incandescent bulbs for LEDs (they release 75% less heat)

4. Use the bathroom/kitchen fan as an extractor

Almost every Lisbon flat has an extractor fan in the bathroom or kitchen. In the late afternoon, switch it on with a window open in another room — it will draw cool air through the flat. It costs pennies per hour and is surprisingly effective.

5. Hang damp towels in front of the windows

An old trick, still effective: hang a wet (not dripping) towel in front of a window where you feel a breeze. Evaporation cools the incoming air by 2–4 °C. It works best in areas like Belém, Parque das Nações or Almada where there's more airflow.

6. Hydrate before you're thirsty

This isn't a tip for the flat — it's a tip for you. During heatwaves, drink 250 ml of water every 1–2 hours, even if you're not thirsty. The feeling of heat drops dramatically when you're well hydrated. Lisbon's hospitals are full in August because of this.

7. Take lukewarm showers (not cold)

Counterintuitive, but the science is clear: a cold shower makes the body "reheat" to compensate. A lukewarm shower (32–34 °C) lowers your body temperature in a sustained way. Do it at the end of the day, before sleeping.

8. Switch to light-coloured cotton bedding

Linen or white/beige cotton sheets absorb less heat and breathe better. Put away the duvet and dark sheets until October. Extra tip: put your pillowcase in the freezer for 10 minutes before bed — you'll sleep far better.

9. If nothing's enough — rent a portable AC

There's a limit to what these tricks can do. If you work from home, have young children, or simply want to sleep well through 3–4 days of extreme heat, a portable air conditioner solves the problem completely.

Buying a fixed split costs €600–1,300, requires landlord approval in rented flats, and sits idle 10 months a year. Renting costs €210/week, arrives the same day, and disappears when the heat passes.

Summary: the right order

If a heatwave is coming (check IPMA), follow this order in the days before:

1. Wash all your sheets and towels (you'll want fresh bedding)
2. Do a cold-food shop (you won't want to open the oven)
3. Get the blinds/curtains ready for a quick close
4. Identify the coolest room in the flat (north-facing or interior)
5. If you work from home, book a portable AC before the heatwave — at peak times, availability in Lisbon sells out within hours

"In Lisbon, surviving the summer is a mix of old tricks and new technology."