💨 Ventilation (MVHR) in Lisbon · Free written quote, in English · System sized to your flat
Ventilation (MVHR) in Lisbon — stop the winter condensation, mould and stuffy air.
Streaming condensation and black mould in the bedroom corners every winter? A flat you keep shut against the noisy street that always smells stuffy? An old Graça or Alfama building where the walls "sweat"? A part-year flat that arrives musty? Air conditioning does not bring in fresh air — it just recirculates it. Ventilation is what renews and filters the air, clears the damp and stops the mould. (Expats call it MVHR — mechanical ventilation, often with heat recovery.)
🦠 No more winter condensation & corner mould🏛️ Discreet fixes for heritage flats🌬️ Fresh, filtered air (HEPA option)💰 From €890 + VAT
Get a quote — ventilation, Lisbon
Free written quote · No-obligation survey, in English
🛡️ 3-year equipment warranty📧 Part-year owners: coordinated remotely✅ Site survey, in English
What is ventilation (MVHR), and why a Lisbon flat needs it — air conditioning doesn't bring in fresh air
Mechanical ventilation (MVHR) is a system that renews the indoor air continuously: it removes the damp, stale air from the bathrooms and kitchen and brings fresh, filtered air into the bedrooms and living room. Here is the key thing most people get wrong: air conditioning recirculates the same indoor air — it does not bring in or filter fresh outdoor air. So a Lisbon flat can have good AC and still feel stuffy, stream with condensation in winter and grow mould in the corners. The reason is simple — there is no central heating, you keep the windows shut against the noisy street and traffic dust, and the moisture from cooking, showers and just living has nowhere to go. Ventilation is the separate job that fixes that.
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Continuous fresh air, without opening windows
It runs 24/7, quietly (around 22 dB), and keeps a steady air change. You get fresh air without opening the windows to the noisy street or letting in traffic dust — and without losing the warmth in winter.
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Stops condensation and corner mould
It pulls the moist air out of the wet rooms at the source, before it settles on cold walls. That is what stops the streaming windows and the black mould that keeps coming back in the same bedroom corners every winter.
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Fresh, filtered air — not recirculated
The incoming air is filtered (standard or HEPA), so it removes city pollen and fine dust before it reaches your rooms. Air conditioning only recirculates; ventilation actually renews the air, which matters when you keep the flat closed.
Which problem do you have? See which system solves it
Ventilation isn't one-size-fits-all — the right system depends on your problem. Here's a straight match between what you're experiencing in your Lisbon flat and the system that suits you.
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Streaming windows in winter, black mould in the bedroom corners
→ Single-flow extract (from €890 + VAT). The classic city-apartment problem — windows shut against the street, no central heating. It removes the moist air continuously so the mould has nowhere to settle. For flats in Príncipe Real, Estrela, Campo de Ourique, Alvalade, Parque das Nações.
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Old building, walls that "sweat", musty smell — and you can't touch the façade
→ Discreet double-flow MVHR (from €2,490 + VAT). A lasting fix instead of the annual lime-wash, with nothing visible on a protected façade. For heritage flats in Alfama, Graça, Mouraria.
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Part-year flat that arrives musty, mould on the bathroom ceiling
→ Single-flow extract on a humidity sensor (from €890 + VAT). Runs gently and safely while you're away, with no windows left open, so the flat is fresh when you land. For the Cascais–Estoril line, coordinated remotely with your key-holder.
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Renovating — and the ceilings are open right now
→ Double-flow MVHR with heat recovery (from €2,490 + VAT). The cheapest moment to run the ducting properly. Whole-flat filtered fresh air that keeps the warmth in the mild-damp winter (about 90% heat recovery). For renovations near Estrela, Campo de Ourique, Parque das Nações.
Why a Lisbon flat is stuffy and damp — four reasons
Lisbon is a city of apartments, not villas, and that changes everything. Four realities here make mechanical ventilation genuinely useful in a flat.
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No central heating + windows kept shut = winter condensation
A Lisbon flat has no central heating, and you keep the windows shut against street noise and traffic dust. The moisture from cooking, showers and just living settles on the cold walls and windows — so you wipe streaming condensation every morning and the black mould keeps coming back in the same bedroom corners. It is a ventilation problem, not a "water in the walls" problem, and that is a different (and cheaper) fix.
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Old heritage buildings with single walls that "sweat"
In the heritage centre (Alfama, Graça, Mouraria) the old buildings have single stone walls that "sweat" in winter, and many owners just lime-wash every year. These are protected buildings, so nothing can show on the façade — which is exactly why a discreet, internally-ducted system is the right answer instead of a visible box on the wall.
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Part-year flats that sit closed and arrive musty
Many owners keep a flat (often on the Cascais–Estoril line) and use it only part of the year. Shut for months with no air movement, it smells musty and grows mould on the bathroom ceiling — and there is no realistic way to air it from abroad. Gentle ventilation running unattended keeps it fresh between visits.
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Renovations — the one cheap moment to do it properly
A lot of Lisbon flats are being renovated, and a renovation is the one moment when the ceilings are open and you can run MVHR ducting properly instead of bolting it on later. Done then, the finished flat has filtered fresh air and keeps its warmth through the mild-but-damp winter, with about 90% heat recovery.
Four real enquiries from this week
How they reached us, and what we replied. Names and personal details changed for privacy.
City apartment · winter mould
WhatsAppPríncipe Real · 2-bed flat
Hi. I have a renovated apartment in Príncipe Real. Every winter the windows stream with condensation in the mornings, and black mould keeps coming back in the same bedroom corners — I clean it off and it's back in three weeks. The flat smells stuffy because I keep the windows shut against the street noise. I don't even know if I need a small fan or a whole system. Can you advise in English, and do I need the building's permission?
09:42
Hi Megan. This is the classic city-apartment problem — no central heating, windows kept shut, so the moisture has nowhere to go and settles in the cold corners. The right fix is a single-flow extract unit from €890 + VAT, running quietly 24/7.
It removes the moist air at the source so the mould can't take hold, and you get fresh air without opening the windows. Usually it's all internal with just a small discreet grille — we'll tell you up front if anything touches the façade and give you a note for the condominium. Fatura with your NIF, of course.
10:18
Site survey booked · single-flow quote from €890 + VAT, in English · short note prepared for the condominium.
Good afternoon. We are British, we own a top-floor flat in an old building in Graça. The walls "sweat" in winter and there's a musty smell, and a neighbour told us to lime-wash every year. We'd like a proper modern fix — but it's a protected building, so nothing can show on the façade. Can you advise in English what works in an old apartment like this?
14:30
Hi Ian. For an old single-wall building like yours, the right answer is a discreet double-flow MVHR from €2,490 + VAT, with the ducting run internally and the unit on an inner terrace or light-well — nothing added to the protected façade.
It gives you a lasting fix instead of the annual lime-wash, with about 90% heat recovery so you keep the warmth in winter. We confirm the discreet routing on the survey, deal with you in English throughout, and give you an honest answer if a simpler system would do.
15:12
Survey booked to confirm discreet internal routing · double-flow quote from €2,490 + VAT · nothing on the façade.
Good morning. I'm German and I keep a flat on the Cascais line that I use a few months a year. Every time I arrive it smells musty and closed-up, and there's mould on the bathroom ceiling from being shut for months with no air. I'd like ventilation that runs gently while I'm away in Germany so the place is fresh when I get back. Can you fit it while I'm not there and email me the invoice?
11:08
Hi Sabine. Yes — this is exactly what it's for. A single-flow extract unit from €890 + VAT on a humidity sensor runs gently and safely while the flat is closed, with no windows left open (a security risk), so it stays fresh between visits instead of arriving musty.
We can fit it while you're abroad, coordinate with your key-holder, and email you the photos and the fatura with your NIF. You can pay by transfer. Simple and clear, in English.
11:55
Coordinated remotely with the key-holder · single-flow quote from €890 + VAT · unit left running on a humidity sensor · fatura by email.
Hi, I'm Dutch. I'm renovating an older apartment near Estrela and the ceilings are open right now, so I want to put in a proper heat-recovery ventilation system (MVHR) while I can run the ducts. I want filtered fresh air and to keep the warmth in winter. Can you size it for the flat, work with my builder, and explain the heat recovery in English?
19:22
Hi Joost. The renovation is the right moment — running the ducts now is far cheaper than bolting it on later. We'd size a double-flow MVHR from €2,490 + VAT to the flat, confirm the ducting fits the ceiling void, and coordinate with your builder so it goes in at the right stage.
It recovers about 90% of the heat from the outgoing air, so the fresh air comes in already tempered for the mild-damp winter. We give you the heat-recovery figure and the running cost in writing, in English, with a fatura and your NIF.
20:08
Sizing done from the renovation plans · double-flow MVHR quote from €2,490 + VAT · coordinated with the builder · figures in writing.
Reconstructed from real enquiries. Names and personal details changed for privacy.
Ventilation systems available in Lisbon
Three typical setups. On the site survey we match the right one to your flat, the building, and how you use it (lived-in, heritage, part-year, renovation).
Most popular for city apartments
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Single-flow extract — for condensation & corner mould
from €890 + VAT
starting price, equipment + full installation (up to 80 m²)
Quality units, humidity-controlled, energy class A
For a lived-in city flat with winter condensation and black mould in the corners — and for part-year flats that arrive musty (runs unattended on a humidity sensor)
Removes the moist air at the source from the wet rooms; fresh air comes in naturally through the bedrooms
Continuous fresh air without opening windows to the street, very quiet at night (≈22 dB), tiny running cost (€40–60/year)
Installed in one day, internal ducting in discreet trunking, no structural walls drilled · 3-year equipment + 1-year labour warranty
starting price, design + installation · up to 120 m²
Heat-recovery units that recover about 90% of the heat from the outgoing air
For a renovation (fitted while the ceilings are open) and for heritage flats in Alfama, Graça, Mouraria — discreet, with nothing visible on a protected façade
Keeps the warmth in the mild-damp Lisbon winter, so you can ventilate without losing heat · optional carbon filters for traffic fumes · ducting run discreetly
Whole-flat filtered fresh air from one system · the heat-recovery figure and running cost given in writing
We coordinate with your builder · 3-year equipment + 1-year labour warranty
starting price, design + installation · up to 150 m²
Double-flow units with HEPA H13 filters that capture about 99.95% of pollen, fine city dust and other fine particles
For central Lisbon flats where you keep the windows shut against traffic dust, or where someone in the home has allergies — filtered fresh air, especially in the bedrooms
Built-in air-quality sensor that varies the ventilation automatically · app control
Brings in fresh, filtered outside air instead of recirculating it, and keeps the warmth with heat recovery
A filtration upgrade on the double-flow MVHR, not a separate machine · 3-year equipment + 1-year labour warranty
In a Lisbon flat the return shows up mainly in damage avoided, warmth kept and peace of mind — not in dramatic energy bills. A rough guide for the four typical situations.
Yearly cost/saving, without vs with ventilation
Typical Lisbon situation
Yearly cost/loss without it
With ventilation (saving)
City apartment · Príncipe Real · repainting the mouldy corners every 18–24 months + cleaning
€450–650/year
−€350 to −€500/year + no more black corners
Heritage flat · Graça · annual lime-wash + heat lost airing the flat the manual way
€680–980/year
−€500 to −€720/year (heat recovery)
Part-year flat · Cascais line · emergency cleans on arrival + ruined textiles + a wasted first day
€500–900/year
−€400 to −€700/year + arrives fresh
Renovation · Estrela · cost of retro-fitting ducting after the ceilings are closed
€1,500–3,000 one-off
A fraction of that, done while open
Typical payback
City apartment 2–3 years · heritage flat 4–6 years · part-year 2–3 years · renovation: cheapest done now (the warmth and comfort come first)
* Indicative figures based on Lisbon customer cases 2024–2026. We calculate your own on the site survey.
Ventilation we've installed in Lisbon
Ducts, fans and air handling units — the type of equipment we install in mechanical ventilation systems in Greater Lisbon.
Full coverage across Greater Lisbon — from central Lisbon and the heritage centre to the Cascais–Estoril line and the surrounding towns: Cascais, Sintra, Oeiras, Amadora, Loures, Mafra.
Parque das NaçõesMarvilaBeatoOlivaisLumiarAreeiroPenha de FrançaAlfama (Santa Maria Maior)Mouraria (Sta. Maria Maior)Graça (São Vicente)Bairro Alto (Misericórdia)Intendente (Arroios)Campo de OuriqueEstrelaBelémAjudaAlvaladeAvenidas NovasSanto AntónioCarnideSão Domingos de BenficaBenficaCascaisSintraOeirasAmadoraLouresMafra
Ventilation in Lisbon: common questions
Yes. From the first message to the survey, the quote and the report, we deal with you in English. Most of our ventilation customers in Lisbon are expat apartment owners, so this is normal for us. You get a written quote in English and an official fatura with your NIF for your records.
This is the most common case in a Lisbon flat: windows stream with condensation in winter and black mould keeps coming back in the same corners, because the flat has no central heating and you keep the windows shut against street noise and traffic dust. A single-flow extract unit from €890 + VAT, running quietly 24/7, removes the moist air at the source and keeps a steady air change, so the humidity has nowhere to settle. If you want the whole flat covered and the warmth kept in, the next step up is double-flow MVHR with heat recovery. On the site survey we tell you honestly which one fits.
No — this is the most common misunderstanding. Air conditioning heats or cools, but it recirculates the same indoor air; it does not bring in or filter fresh outdoor air. So a flat with the AC on but the windows shut still feels stuffy, builds up humidity in winter and traps dust and CO₂. Ventilation is a separate job: it removes the stale, moist air and brings in fresh, filtered air continuously. That is why a flat can have good AC and still smell musty and grow mould in the corners.
Usually yes, if anything goes through an external wall or shows on the façade, that is a shared part of the building and the condominium has to agree. We keep this simple: most of the time the ducting runs internally and the only outside trace is a small, discreet grille. We tell you up front what (if anything) touches the façade, and we give you a short written description you can take to the condominium so they can approve it. It is a practical step, not a wall of paperwork.
Yes. In the heritage centre (Alfama, Graça, Mouraria) the old single-wall buildings "sweat" in winter and many owners just lime-wash every year. We fit a discreet system: the ducting runs internally in slim trunking and the outdoor unit can sit on an inner terrace or light-well, so nothing visible is added to a protected façade. It suits an old single-wall flat and gives a lasting fix instead of the annual lime-wash. We confirm the discreet routing on the survey before you commit.
Single-flow extract: one fan pulls the moist, stale air out of the wet rooms (bathrooms, kitchen) and fresh air comes in naturally. It is simpler and cheaper (from €890 + VAT) and is the right fix for condensation and corner mould in a flat. Double-flow MVHR (from €2,490 + VAT): two fans plus a heat exchanger that recovers about 90% of the warmth from the outgoing air, so the fresh air coming in is already tempered. It keeps the warmth in the mild-but-damp Lisbon winter and covers the whole flat — best for a renovation or a heritage flat where you want comfort and fresh air from one system.
Yes, that is exactly what it is for. If you keep a part-year flat (for example on the Cascais–Estoril line) it tends to smell musty and grow mould on the bathroom ceiling after months shut with no air movement. The system runs gently and safely on its own, on a timer or a humidity sensor, with no windows left open (a security risk), so the flat stays fresh and arrives ready instead of musty. We can fit it while you are abroad, coordinate with your key-holder, and email you the photos and the fatura.
Yes. Lisbon winters are mild but damp, and a flat with no central heating loses warmth fast if you ventilate by opening windows. A double-flow MVHR unit recovers about 90% of the heat from the air it removes, so it brings in fresh air without throwing the warmth out with it. In practice that means you can keep the flat properly ventilated through winter without the heating cost of constantly airing it the manual way. Single-flow does not recover heat, so for the warmth benefit you want the double-flow MVHR.
Yes, and a renovation is the cheapest moment to do it — while the ceilings are open you can run the ducting properly instead of bolting it on later. For a renovation we size a double-flow MVHR (from €2,490 + VAT) to the flat, confirm the ducting fits the ceiling void, and coordinate with your builder so it is done at the right stage. You get the heat-recovery figure and the running cost in writing, in English, and a fatura with your NIF.
Yes. A double-flow system can be fitted with HEPA H13 filters, which capture about 99.95% of pollen, fine city dust and other fine particles before the air reaches your rooms — useful in central Lisbon where you keep the windows shut against traffic dust, or if anyone in the home has allergies. This is a filtration upgrade on the double-flow MVHR (premium HEPA from €3,990 + VAT), not a separate machine. We can advise whether you need it on the survey.
Yes — every job comes with an official fatura showing your NIF, and we can email it to you, which matters if you are abroad or want it for your records. Prices on this page are quoted + VAT. If you are coordinating remotely for a part-year flat, we send the quote, the photos and the fatura by email and you can pay by transfer.
