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Sealed chamber water heaters

Instant hot water in complete safety, even in internal bathrooms and kitchens: the sealed chamber isolates combustion from the room and vents the flue gases through the wall. Find the best gas brands available for immediate delivery, with installation and dedicated support.
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What is a sealed-chamber water heater?

The sealed-chamber gas water heater is an instant appliance in which combustion takes place in a sealed chamber, separated from the room where it is installed. The combustion air is drawn from outside and the flue gases are expelled through a coaxial wall outlet, without consuming the room's oxygen. That is why it is the safest solution when the water heater must stay indoors, in the bathroom or the kitchen.

Why choose the sealed chamber over the open chamber

In open-chamber models the combustion air is taken from the room, so a well-ventilated space is needed. The sealed chamber, instead, fully isolates the process: no air drawn from the room, no risk linked to the products of combustion and the option to install even in small rooms. It is the same safety logic you find in modern condensing boilers.

How many kW you need for the water flow

In instant water heaters performance is measured in kW of power, which determine how many litres of hot water per minute you can draw. The higher the power, the more taps you can supply at the same time:

  • Low power: ideal for a single draw-off point, such as the bathroom basin.
  • Medium power: covers the shower plus the sink with no drop in temperature.
  • High power: supplies several outlets at once, suited to large families.

Unlike electric models, the gas water heater produces hot water only when you open the tap, with no tank to heat up.

Energy class and consumption

Instant water heaters also show the energy class on the label: the most efficient models modulate the flame according to demand, avoiding wasted gas. Choosing a high class means lowering consumption at the same comfort, a criterion worth comparing alongside the current offers.

Installation and wall outlet

Installation requires a qualified technician, because it involves the gas connection and the fitting of the coaxial duct for the wall outlet. The sealed chamber allows short, flexible flue runs, so it is often simpler to position than natural-draught systems. For heating rooms, instead, look at the solutions dedicated to heating.

The best brands available

You will find the leading manufacturers in the sector, with official warranty and available spare parts: RINNAI, Ferroli, Bosch, Vaillant, Ariston and Riello. Prices start at around 320 euros and go up to the highest-performing solutions, with almost the whole catalogue available for immediate delivery.

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Frequently asked questions

Can I install a sealed-chamber water heater in the bathroom?
Yes, that is precisely its main advantage. Because combustion is isolated from the room and the flue gases exit through the wall outlet, it can be installed even in the bathroom or kitchen, where an open-chamber water heater would not be allowed without specific ventilation.
What is the difference between sealed chamber and open chamber?
In the open chamber the combustion air is taken from the room, which must be well ventilated. In the sealed chamber the air comes from outside and the flue gases are expelled outside, so the process is entirely isolated from the room and safer.
How many kW do I need for the shower?
To supply a shower with a good flow you need a medium power, which guarantees a constant flow of hot water. If you want to use the shower and sink together, it is best to step up to a higher power, so the temperature stays stable even with several taps open.
Does a gas water heater use more than an electric one?
It depends on the cost of energy, but for the same amount of hot water produced, gas is often cheaper than electric. In addition, the instant water heater heats the water only when you open the tap, without keeping a tank warm.
Do I need a qualified technician for the installation?
Yes, the installation must be carried out by a qualified technician, because it includes the gas connection and the fitting of the coaxial duct for the wall outlet. It is a mandatory step for safety and for the validity of the warranty.
Does the energy class matter for an instant water heater too?
Yes, instant models show the energy class as well. The most efficient models modulate the flame according to draw-off and reduce gas consumption, so choosing a higher class lowers costs at the same comfort.
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