A combi gas boiler is a versatile heating device that simultaneously provides hot water for the heating system and domestic hot water (e.g. for showering, washing dishes). This type of boiler is particularly popular in residential buildings and smaller apartments, as it offers a space-saving and energy-efficient solution.
The operating principle of a combi gas boiler
Heating function: The boiler produces hot water for radiators or underfloor heating, thus providing warmth for the home. The heating circuit moves the heating medium in the circuit using the boiler's internal circulation pump.
Domestic hot water function (DHW): When a tap is opened, the combi boiler automatically produces hot water for taps or showers.
Hot water is available immediately because the boiler uses the heat from the combustion chamber directly to heat the water.
Automatic diverter valve: In combi boilers, a diverter valve ensures that the boiler gives priority to the production of domestic hot water when it is required.
Advantages
Space-saving: Combi gas boilers have a compact design, as they do not require a separate hot water tank, making them ideal for smaller apartments and family houses.
Energy efficiency: The boiler only produces hot water when it is needed, reducing energy consumption and costs.
Cost-effectiveness: Installing and maintaining a single device is cheaper than installing a separate heating boiler and water heater.
Fast hot water production: Instant hot water production provides a convenient solution without having to wait a long time for the water to heat up.
Disadvantages
Limited capacity: In larger households where large amounts of hot water are needed from multiple taps at the same time, the capacity of the combi boiler may not be sufficient.
Water pressure dependency: The pressure of the domestic hot water depends on the network water pressure, so performance may decrease in the event of low water pressure.
Dependence on the electrical network: The boiler requires electrical energy to operate the circulation pump and the electronic control. In the event of a power outage, the device will not operate.
Combi-gas boiler vs. traditional boiler
| Characteristic | Combi-gas boiler | Traditional boiler |
|---|---|---|
| Hot water production | Immediately, without a storage tank. | With storage tank, slower production. |
| Space requirement | Compact, takes up less space. | It requires more space due to the storage tank. |
| Energy efficiency | Higher, as it only works on demand. | Lower, due to heat loss from the storage tank. |
| Expenditures | Lower installation and operating costs. | Higher installation costs. |
Summary
A combi gas boiler is an ideal choice for smaller homes where a space-saving and energy-efficient solution is needed. The instant hot water supply and efficient heating performance provide a convenient and economical solution. Although its capacity may be limited for larger households, with proper installation and maintenance it ensures long-term and reliable operation.