- How a condensing boiler works
- Recover heat to save money
- Condensing boiler: an installation under surveillance
- What price for a condensing boiler?
- The different models of condensing boilers
There are condensing boilers for all needs, for all sizes of housing and for all fuels, from wood to oil to gas. Their qualities? They are efficient and they reduce the energy bill.
How a condensing boiler works
- The operating principle of "traditional" boilers, at low or very low temperature, generates heat losses. The fumes and the water vapor contained in these fumes are simply discharged into the atmosphere.
- The so-called "condensing" models recover part of the heat contained in the combustion products before their evacuation. In fact, this so-called "latent" heat is no longer removed by the flues, but is added to that produced by the fireplace. They pass through a "condenser exchanger", which cools them from 200 to 50° C (or 70° C) and transforms them into water vapor.
Recover heat to save money
This water vapor releases heat that warms the home heating return circuit. Once cooled, it condenses before being evacuated via the wastewater circuit, which requires the installation of an exhaust duct.
This recovery of calories released by the combustion allows a saving of 20 to 30% compared to a boiler of more than 15 years, 10 to 20% compared to a recent standard boiler and about 5%, compared to a low temperature boiler.
These devices achieve their best performance when combined with low temperature floor heating or "soft heat" radiators. With fewer discharges of carbon dioxide, nitrogen oxides and considerable fuel savings, these boilers respect the environment. To be completely compliant, their installation requires the same certification as for a standard boiler.
Condensing boiler: an installation under surveillance
- According to the amended Gas Ordinance of 2 August 1977, all precautions must be taken, particularly for the layout of the gas supply piping and the emergency shutdown.
- A annual maintenance of the installation must be carried out by a qualified installer, in order to maintain optimal equipment operation.
- It is also important to regularly check the chimney flues and never plug the ducts and ventilation holes that allow the supply of fresh air and the evacuation of polluted air.
- Finally, the installation of a condensing boiler makes it possible to target the labels defined by the decree of July 27, 2006, namely the label HPE (high energy performance) and the label THPE (very high energy performance).
- It is also highly valued in RT 2012.
A condensing boiler can operate from different energy sources such as gas, fuel oil, wood (logs, pellets, bricks).
The QualiGaz label, created in 1990, to carry out quality control of gas installations, provides a certificate of compliance with safety standards.
What price for a condensing boiler?
The cost of a condensing boiler depends on several factors, such as the heating needs of the housing (its surface and the desired room temperature), the power required to meet these heating needs, the production or not of hot water health and the type of energy.
- It generally varies between € 3,000 and € 6,000 before tax credit and excluding installation costs.
- The amortization period of a condensing boiler is about seven years: the tax credit makes it possible to offset the additional cost of 30% on the purchase, the State reimbursing 13% of the initial investment of the boiler.
- They also have a big advantage: with a return of up to 110%, they can reduce your bills by 20% to 35%. But be careful, the installation of a condensing boiler requires a casing of the smoke evacuation duct in renovation or a specific duct in the new one.
- To accept the cold fumes that emanate from these boilers, the duct must generally be sheathed in stainless steel (80 € / meter), which usually increases the initial price of the boiler by 1,000 €.
The different models of condensing boilers
Low power wall
Intended for heating alone, this gas condensing wall-mounted boiler is equipped with a burner ensuring a permanent modulation of the power from 0.9 to 9 kW. Many options are possible. "THRi 0.9-9", Geminox. Public price € 2,700.
HIGH POINT: allows to distribute very small amounts of heat without ever stopping.
Mixed gas + heat pump
This monobloc generator combines a modulating gas condensing boiler with a small air / water heat pump but with a COP of 3.4. It feeds the heating circuit and DHW production in instantaneous or accumulation (storage tank). "Megalis Condens Hybrid", Elm Leblanc. Public price: from 5 150 €.
HIGH POINT: 3 possible operating modes: boiler only, boiler + heat pump or heat pump and booster boiler if necessary.
This bi-energy heating system of 27.4 kW maximum consists of a gas condensing and regulation wall gas boiler, a heat pump, an outdoor sensor, a remote control and a conversion kit.. "Talia Green Hybrid", Chaffoteaux. Public price: € 6,600.
STRONG POINT: the possibility of connection with a 115 or 300 liter balloon and compatibility with a heated floor.
Condensation with fuel
Available in 3 capacities from 15 to 35 kW, this condensing oil boiler is proposed with remote control system. It is compatible with the sanitary preparers, CESI and solar panels of the manufacturer. "IcoVIT Exclusiv", Vaillant. Public price: from 5 741 €.
STRONG POINT: the large volume of water in the heating element guarantees maximum condensation.
Floor standing gas boiler
Available in four models in powers from 5.6 to 25.5 kW, this condensing gas boiler is for heating alone. It can be combined with DHW tank mixers, solar or not (100 to 200 l). Twineo, De Dietrich. Public price: from € 2,400.
THE HIGH POINT: equipped with a 3-speed heating circulator that can modulate the power according to the needs of the house.