Are you building a house and you have to choose a heating solution, or do you have to change an aging boiler, and you don't know how to choose your new boiler? Gilles Waterspieler, Communication Manager at Wiessmann, answers all our questions.
What are the first questions to ask before buying a boiler?
The first question concerns the energy available: gas, fuel oil, wood in quantity or none of this? The question does not arise, however, concerning electricity, which is generally available. We will not dwell on electric boilers, marginal on the market. In terms of electricity, the heat pump represents an attractive alternative solution, particularly in new construction.
Why are electric boilers no longer relevant?
Because with this system, there is a huge loss of energy. Indeed, under the new thermal regulations applicable at the start of 2013 in new construction, it takes 2.58 KW at the source to produce 1 KW of usable energy, which excludes this type of product. On the other hand, as part of this RT 2012, the heat pumps, which also operate on electricity, are perfectly suited.
What is the principle of the heat pump?
A heat pump uses the calories from air, soil or water, such as the water table, to heat the house. By consuming 1 kW of energy, we recover up to 5 kW of heating. We therefore benefit from 4 kW of free energy.
Are oil-fired boilers still a solution to consider?
Oil-fired boilers have found a second lease of life with the condensation technique which allows very high yields to be achieved. The presence of an oil storage tank remains essential, however. Fuel oil remains a convenient energy solution if you do not have a gas connection.
What about gas boilers?
There are two types of gas boilers. First of all, the high efficiency or low temperature models. Even if they remain a solution still widespread on the market, especially in collective housing, they will soon be part of the past, in new construction in any case. RT 2012 will naturally impose the new generation, that of condensing boilers. These achieve incomparable yields, which allow them to save up to 30% of gas compared to the old models of gas boilers.
How to choose between a heat pump and a gas boiler?
It is not easy to answer because a number of parameters must be taken into account. A gas boiler generally pays for itself between 3 and 5 years. For a heat pump, it can take up to 10 years because the equipment is more expensive. On the other hand, in use, the heat pump is more advantageous than the gas boiler. However, we do not know the evolution of energy prices in the coming years. Better to get advice from an energy specialist. The technical parameter is also important: the choice will indeed also depend on the size and insulation of the accommodation, the space available to accommodate the installation or, in terms of domestic hot water, the composition fireplace.
There are also wood boilers…
Yes, and these are interesting, especially if you have access to lots of wood, free or cheap. A traditional wood-fired boiler requires having logs of the right length (30 or 50 cm depending on the model) and supplying it permanently because in general, its autonomy does not exceed 24 hours. There are also pellet boilers, which are more expensive to buy than wood boilers. These boilers have an auxiliary tank which offers up to three days of autonomy. If there is space, you can opt for a pellet boiler with storage silo, which is usually filled two to three times per winter.
Can we couple a boiler with solar panels?
Yes, and it is also a good addition of free energy, encouraged by RT 2012. Solar can either produce hot water (the solar collectors are then connected to the hot water tank) , or to contribute to the heating (the solar collectors are then connected to a buffer tank, itself connected to the heating installation).
Do some boilers benefit from a tax credit?
Condensing boilers benefit from a tax credit of 13% and heat pumps from 22 to 36% depending on the model. As for solar collectors, their tax credit is 45%. But beware, these figures are only valid until December 31, 2011. For 2012, these figures may change downwards.
In the case of an extremely well insulated new construction, can we do without a boiler?
Yes and in this case, we can be satisfied with using materials using renewable energies (solar, heat pump). There are also heat pumps specifically dedicated to the production of domestic hot water, an interesting solution when the house is heated by electric convectors and we want to reduce the cost of producing domestic hot water.