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Open-chamber water heaters

Produce gas hot water with an open-chamber water heater using natural draught, the simplest and most economical solution for well-ventilated rooms with a flue. Ariston, Bosch and Vaillant brands available for immediate delivery.
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What is an open-chamber gas water heater?

The open-chamber water heater draws the air needed for combustion directly from the room where it is installed and vents the flue gases into a chimney thanks to natural draught. It is the simplest and most economical way to produce gas hot water, ideal when the room is large and well ventilated. Compared with sealed-chamber versions, it works more simply and its purchase price stays low, from 162 to 999 euros.

When are open-chamber water heaters allowed?

These appliances are permitted only in ventilated rooms fitted with permanent, properly sized air vents, because they draw oxygen from the room and must be able to expel the products of combustion into an efficient flue. They cannot be installed in bathrooms, bedrooms or studio flats, and they are not suited to enclosed or poorly ventilated spaces. Compliance with regulations must always be verified by a qualified installer.

Natural draught and flue

Natural draught uses the temperature difference between the hot flue gases and the outside air to draw the products of combustion up the flue, with no fan. That is why the duct must be in good condition, of the right cross-section and correctly discharging above the roof. If you do not have a suitable flue, it is better to look at sealed-chamber water heaters.

Litres and flow rate: which to choose

The choice depends on the number of water points and your consumption habits. Models with a low number of litres per minute suit a single bathroom, while higher flow rates supply the kitchen and shower at the same time. Good sizing avoids temperature swings when several taps are opened together.

The best brands available

You will find the leading manufacturers with official warranty and available spare parts: Ariston, Bosch, Vaillant, Chaffoteaux, Ferroli, Baxi, Beretta, Fondital and Riello. Ariston and Bosch are among the most requested choices for their reliability and widespread service network.

More efficient alternatives

If you are after lower consumption or a system meant for heating too, consider an electric water heater, a heat pump water heater or a condensing boiler to combine hot water and heating in a single appliance.

Prices and availability

The catalogue features 69 open-chamber models, all available for immediate delivery, with prices starting at around 162 euros. For good-value purchases, also check all the active offers on gas water heaters.

Frequently asked questions

Where can I install an open-chamber water heater?
Only in well-ventilated rooms with permanent air vents and an efficient flue. It cannot be installed in a bathroom, bedroom or studio flat, because it draws the room's air for combustion.
What is the difference between open chamber and sealed chamber?
The open chamber takes air from the room and vents the flue gases into a chimney by natural draught. The sealed chamber is isolated from the room and handles air and flue gases through a dedicated duct, so it is safer and can be installed even in enclosed spaces.
Is a flue really necessary?
Yes. The open-chamber water heater works by natural draught and needs a flue of the right cross-section and in good condition to expel the gases. Without a suitable duct, a sealed-chamber version is more appropriate.
Why does the open-chamber water heater cost less?
Because it works more simply, with no fan and no coaxial duct. In our catalogue prices start at around 162 euros, compared with sealed solutions that require additional components.
How many litres per minute do I need?
It depends on the water points. A low flow rate is enough for a single bathroom, while to use the kitchen and shower together it is best to step up the litres per minute, so as to avoid temperature swings when you open several taps.
Which brands can I choose?
You will find Ariston, Bosch, Vaillant, Chaffoteaux, Ferroli, Baxi, Beretta, Fondital and Riello, all with official warranty and available spare parts. Ariston and Bosch are among the most requested for their reliability and widespread service.
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