Esquentador, caldeira or termoacumulador: hot water in Portuguese homes
What each one is, how to tell which you have, the usual problems, gas safety and when you need a certified gas technician rather than a plumber.
Three words you will hear
Portuguese homes heat water in a few different ways, and the word on the quote tells the plumber a lot.
- Esquentador: a gas water heater that heats water instantly as it flows. Very common in flats. It runs on natural gas (gás natural) or on bottled gas (butane or propane) and needs a flue or ventilation.
- Caldeira: a boiler, usually wall-mounted, that heats water for radiators or underfloor heating and, in a combi boiler, for taps and showers too. Gas, diesel or pellets.
- Termoacumulador: an electric storage water heater, a tank of roughly 50 to 150 litres that keeps water hot with an electric element. No gas, but it can run out of hot water.
You may also find a heat pump water heater (bomba de calor) or solar panels with a storage tank, both increasingly common in newer and renovated homes.
Which one do I have?
- A small white box in the kitchen or on the enclosed balcony, with a flue pipe to the outside and a little window or display: almost certainly an esquentador.
- A larger box connected to radiators, often with a pressure gauge: a caldeira.
- A big cylinder, often in a cupboard, bathroom ceiling or utility area, with a cable and no flue: a termoacumulador.
The make and model are on a label on the front or underneath. Photograph it and add the photo to your job post: it saves a visit.
Common problems
- No hot water, or the esquentador will not light: an empty gas bottle, flat batteries in the igniter, low water pressure or a closed gas valve are the usual suspects before any repair.
- Water goes hot and cold: often low flow (a partly closed tap or a dirty shower head), scale in the heat exchanger or a worn part.
- Termoacumulador dripping from a small valve: the safety valve releases a little water as it heats. Constant dripping, or a leak from the tank itself, needs a plumber.
- Lukewarm water from a termoacumulador: a failing element or thermostat, or scale on the element in hard-water areas.
Gas safety first
Gas appliances burn fuel and must vent their fumes outside. A blocked flue or poor ventilation can produce carbon monoxide, which has no smell. Never cover air vents, have gas appliances serviced regularly (once a year is the usual advice), and consider a carbon monoxide alarm.
Headaches, dizziness or nausea when the heater is on are a warning sign: turn it off, open windows and get out. If you smell gas, do not touch switches, leave and call 112.
Plumber or gas technician?
Installing, moving or converting a gas appliance, and work on the gas supply itself, is a job for a certified gas technician. Many plumbers are certified and say so on their profile on plumbers.pt; ask before you accept a quote. Water-side work, such as connections, valves, leaks and termoacumuladores, is ordinary plumbing.
Repair or replace?
Water heaters typically last somewhere around 10 to 15 years, less in hard-water areas. If yours is old, needs a major part or keeps failing, ask for two prices in the same quote: the repair, and a replacement fitted.
When replacing, ask about the size you need for your household, the type of flue (sealed, room-sealed appliances are safer in small spaces) and the energy cost of electric versus gas in your home.
Frequently asked questions
Can a termoacumulador replace my gas esquentador?
Often, yes, if there is space for the tank and the electrical supply can take it. It removes gas from the home but holds a limited amount of hot water and raises your electricity use. A plumber can advise after seeing the space.
How often should the esquentador be serviced?
The usual advice is once a year, and before winter is a good time. The service cleans the burner, checks the flue and the combustion, and catches problems early.