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An estimate of the quantity and cost of heating for the winter, from how cold your area has been over the last ten years.
A range for planning fuel purchases, not an energy audit. If you know what you burned last winter, the estimate becomes much more reliable.
For each prefecture we take daily mean temperatures from NASA POWER (MERRA-2 reanalysis), from 1991 until about a week ago, and compute heating degree days with Eurostat's definition: every day with a mean temperature of 15 °C or less adds its difference from 18 °C. A winter runs from 1 July to 30 June.
Heat demand is degree days times the home's heat loss. From the home's details we use indicative heat losses per m² for the construction era, adjusted for the type of home and how much the heating runs. If you enter last winter's consumption, the heat loss is derived from it and the assumptions are not needed.
The fuel quantity follows from the useful heat, the energy per unit and the system's efficiency, using the same values as the heating cost comparison. For heating oil, the price is prefilled with the prefecture's average delivered price from the Fuel Price Observatory.
No. It shows what you would need in an average, a mild and a cold winter from the ten most recent. No seasonal forecast reliably gives fuel quantities months ahead.
Because every home is different: orientation, windows, whether the neighbours heat, the temperature you keep, boiler maintenance. A difference of ±30% is common. Enter last winter's consumption for an estimate based on your own home.
The data is for a grid cell of about 50 km around the prefecture capital. A mountain village is colder. With an altitude we adjust each daily temperature by 0.65 °C per 100 metres of difference from the grid's average elevation.
No, space heating only. If the boiler also heats water, actual consumption will be higher, especially in summer.
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