Blog · 26 September 2026 · 4 min read
Gas Bottles and Your Water Heater in Portugal: How They Work
Short answer: many Portuguese homes without piped gas run the water heater (and sometimes the hob) on gas bottles — butane or propane. When the bottle runs out you swap it for a full one at a shop or petrol station. The heater then may need a few attempts to light, because air got into the hose during the swap. If it still does not light after that, check the regulator, the batteries and the gas valve.
Butane or propane?
Both are sold in bottles in Portugal. Butane is the classic indoor bottle; propane is usually kept outdoors or on balconies and copes better with cold. The bottle and the regulator are specific to each gas and to each supplier's valve type.
Your water heater is set for one type of gas. Check its label, and always buy the same type of bottle. Do not improvise with adapters.
How to change a gas bottle safely
Turn off the heater and any gas appliance. Close the regulator on the empty bottle and remove it.
Check that the new bottle has its seal and that the rubber washer inside the valve is in place (on some systems). Fit the regulator firmly until it clicks or locks, according to its type.
Open the regulator. Check for leaks with soapy water brushed on the connection — bubbles mean a leak. Never use a flame to check.
Only then turn the heater back on.
Why the heater will not light after a swap
Air in the hose: it takes a few ignition attempts to push air out and bring gas to the burner. Open a hot tap, let it try, close, repeat a few times.
Regulator not fully open or not properly seated: remove and refit it.
Weak ignition batteries: changing bottles often coincides with batteries running low. Replace them.
A faulty regulator: they wear out. If the heater lights weakly or goes out, the regulator may not be delivering the right pressure.
If none of this works, see no hot water in your apartment.
How long does a bottle last?
It depends entirely on use. For a water heater, the biggest factor is shower length: a household that showers long every day will go through bottles much faster than one person with short showers.
Keep a spare full bottle if you can store it safely. Running out mid-shower is the classic bottled-gas experience.
The hose and the regulator: check the dates
The rubber hose between the bottle and the heater degrades with time — it hardens and cracks. Hoses have a date printed on them and should be replaced before it passes. The same goes for the regulator.
A cracked hose is a gas leak waiting to happen. If yours is stiff, cracked or older than the date printed on it, replace it.
Storage and safety
Keep bottles upright, away from heat sources and direct sun, and never in basements or below ground level — the gas is heavier than air and collects in low spaces.
Do not keep more bottles indoors than you need.
If you smell gas: close the bottle, open windows, do not operate switches, leave, and call for help from outside.
Moving away from bottles
If your building has piped natural gas available, connecting to it removes the bottle routine. If not, an electric water heater (termoacumulador) is the usual alternative — see esquentador vs termoacumulador and what size tank you need.
How to tell when a bottle is nearly empty
Bottles have no gauge. Signs that it is running low: the water heater flame gets weaker, the water is less hot than usual, or the heater lights and then goes out.
Lifting the bottle slightly gives you a feel for how much is left. Some people weigh a full bottle and compare — the tare weight is usually marked on the bottle.
Common regulator problems
A regulator that is not fully clicked in delivers little or no gas. One with a damaged or missing seal lets gas escape at the connection. An old regulator can deliver the wrong pressure, so the heater lights weakly or cuts out.
Regulators are inexpensive and specific to the bottle type. If yours is old, stiff or damaged, replace it.
Balconies, cupboards and ventilation
Bottles in a kitchen cupboard need ventilation at low level, because the gas is heavier than air and settles on the floor if it leaks. Never keep bottles in a closed space without ventilation, below ground level or near a heat source.
On balconies, protect them from direct sun and rain and make sure the hose is not stretched or kinked.
The cost of staying on bottles
Bottled gas is convenient where there is no piped supply, but it is often the most expensive way to heat water, and running out mid-shower is common. If your building has natural gas available, connecting may pay off; if not, an electric tank on an off-peak tariff is the usual alternative.
Either way, if the heater itself is failing, repairs start from 75 €.
New bottle and still no hot water? We find the fault and repair your esquentador — from 75 €.
Water heater repair in LisbonFrequently asked questions
Can I use a propane bottle on a butane heater?
No. The heater must be set for the gas it uses. Converting it is a job for a qualified technician.
Why does my heater light and then go out?
Often the flame sensor, low gas pressure from a worn regulator, or low water flow. If it persists, have it checked.
Where do I buy gas bottles in Lisbon?
At many petrol stations, hardware shops and neighbourhood stores that display the supplier's sign. You exchange the empty bottle for a full one.
Is it normal to smell gas when changing the bottle?
A brief whiff at the moment of connection can happen. A smell that continues means a leak — close the bottle and check the connection.
How often should I change the hose?
Before the date printed on it, or immediately if it is cracked or hard.
Services Lisbon plumbing team
Guides written by the plumbers who do this work in Lisbon homes every week — drains, leaks, water heaters and pipework.
