Central or remote heating: which one to promote?
There is no universal answer to this question, as the optimal solution varies according to different contexts (building, individual dwelling, housing density, etc.).
In principle, remote heating can provide better overall energy efficiency. It also allows a better control of pollutant emissions - such as nitrogen oxides (NOx), carbon monoxide (CO) or fine particles - than individual heating, when the heat comes from combustion (gas, wood, oil, etc.) in a boiler. In addition, it can use more varied energy sources than individual heating (waste, green or dry wood chips, heat loss recovery). The new generations of district heating networks aim in particular at a more advanced integration of renewable energies (wind and solar) by converting excess electricity through heat pumps.
But remote heating can be very difficult to make profitable and offers little flexibility of use. It also induces potentially significant heat losses when heat demand is low, especially in summer. In the case of cities close to lakes or rivers, remote heating at relatively low temperatures makes it possible to use the natural heat of these waters via centralised or decentralised heat pumps.
In general, remote heating is favoured in densely populated urban areas; they provide a favourable context for profitability thanks to the large number of connected buildings, their generally large dimensions and the short distance between them, which allows a better distribution of investment costs. However, attention must be paid to possible energy and economic aberrations; if a remote heating network is supplied by simple natural gas boilers and is superimposed on an existing natural gas network, then the distribution infrastructure is duplicated.
In areas with medium to low urban density, central heating (per building) is more favourable, especially if there is individual control in each room. Likewise, for dense neighbourhoods that include housing with very good insulation (therefore with minimal heat losses), central heating can also be justified.
Finally, in the case of buildings and houses scattered in very low-density areas, central heating remains the only option. It would be far too expensive to lay conduits to connect to remote heating systems.
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