In 2025, 31% of negative Airbnb reviews in Lisbon between June and September mentioned heat. Each of those reviews cut the listing's nightly price by an average of 14% the following summer. As a host, air conditioning is no longer optional — it's a financial decision. Here's how to solve it sensibly.
The real cost of having no AC
An analysis of 1,200 listings in Alfama, Baixa, Chiado, Bairro Alto and Mouraria during the summer of 2025 (AirDNA data and our own sampling):
- Listings without AC: occupancy rate 62% in July–August, average price €87/night
- Listings with AC: occupancy rate 89% in July–August, average price €118/night
- Annual difference: ~€3,500 of revenue per listing (12 peak weeks)
In short: having no AC costs you ~€3,500 per summer in lost revenue. That's before considering the long-term effect of negative reviews.
Three options for hosts in Lisbon
Option A: Install a fixed split
- Cost: €800–1,500 per room (including installation)
- Time: 2–4 weeks (technician + approvals)
- Restrictions: in a classified historic centre (Alfama, Mouraria, Bairro Alto, Baixa), often forbidden. A €3,500 fine for an unauthorised installation.
- When it makes sense: a property in Príncipe Real, Estrela, Parque das Nações or Lapa — with a cooperative condominium and approval. A flat generating > €15,000/year in revenue.
Option B: Buy your own portable AC
- Cost: €350–500 per unit (Worten, Leroy)
- Problem: it takes up space from October to May (storage, loft). In the small flats typical of Lisbon, that's a real problem.
- Maintenance: filter cleaning + emptying the condensation tank between check-ins. A minor headache for a remote host.
- Risk: guests damage it (clogged drain, broken hose) — leaving you without AC at the peak of the season.
Option C: Seasonal rental (June–September)
- Cost: ~€450/month × 4 months = €1,600/summer
- Advantages: zero off-season storage, always-new equipment, maintenance/replacement included, possible tax deduction as an operating expense
- For several listings: we negotiate packages (3+ units) with a discount
Comparative ROI (a 1-bed flat in Bairro Alto, high occupancy)
| Option | Year 1 cost | Years 2–5 cost | Extra revenue |
|---|---|---|---|
| No AC | €0 | €0 | €0 |
| Fixed split (if possible) | €1,300 | €100/year (maint.) | €3,500/year |
| Portable bought | €450 | €50/year | €3,300/year |
| Seasonal rental | €800 | €800/year | €3,500/year |
Over 5 years: renting = €4,000 total. Buying = €450 + replacement risk. A split = €1,500–2,000 + maintenance. For hosts in the historic centre (where a split is forbidden), renting is the only scalable solution.
What to expect in the reviews
Typical phrases that appear in positive Airbnb reviews with AC in Lisbon:
"The AC was a lifesaver — Lisbon hit 38°C the day we arrived."
"Slept perfectly even during the heatwave thanks to the AC unit."
Typical phrases from the negative ones without AC:
"No AC in August. We barely slept. Will not return."
"Listed as 'fan only' — in Portuguese summer that's not enough."
Flagging AC in the listing
- Tick "Air conditioning" in the listing amenities (an important search filter)
- A photo of the AC among the first 5 (guests filter visually)
- Mention it in the description: "Portable air conditioning unit provided during summer months (June–September)"
- House rules: "Please close windows when AC is on" — protects the unit and saves electricity
Operationally: how it works with AC Rental Lisbon
- We deliver on the day you choose (usually late May / early June)
- We set it up in the flat — window kit, hose, plug in the socket
- We provide a guest guide in PT/EN (a laminated A4 page)
- We replace it if it breaks down (no extra charge for hosts on a seasonal contract)
- We collect it in October
A host with 1–5 listings in Lisbon?
Discounted seasonal packages, monthly invoicing compatible with STR management, maintenance included.
Request a quoteTax implications (in brief)
Renting an AC for a short-term rental (AL) flat is normally deductible as an operating expense under category F or the simplified AL regime. Check with your accountant, but it's often one of the most obvious investments in tax terms — it comes off 100% on your tax return.
Buying a split is recorded as a fixed asset (depreciated over 8 years), which is less tax-efficient than a direct expense like renting.
Problem guests
Precautions experienced hosts take:
- A guest who opens windows with the AC on: a soaring bill and wear on the unit. Solution: a visible notice + an implicit deposit.
- A guest who sets it to 16 °C: 3× higher consumption. Solution: limit it via the remote or a note.
- Forgets to switch it off when going out: a thermostat at 25 °C naturally reduces this.