In our house we have a boost button on our heating control panel. By hitting this button the boiler will come on immediately for one hour only. This got me thinking, how much does this button cost me every time I push it, or putting it another way how much does your home oil boiler cost in fuel to run every hour? Well it is relatively easy to calculate; I worked it out to be €1.20 ($1.64) per hour or €1.20 every push of the boost button!
I calculated this as follows. The typical oil boiler used for home heating injects the fuel into the combustion chamber using a nozzle. Depending on the size of the house/ boiler, this nozzle will vary in size between 0.5 and 0.9 gallons per hour, (at a typical pressure of 10 bar). In an average three or four bed-roomed sub-urban house, the boiler nozzle size is typically 0.6. Converting this to metric, 0.6 gallons per hour is approx. equal to 2.27 Litres per hour. When the boiler is operating, it will burn until the water reaches a set temperature and then it will stop burning until the hot water cools sufficiently. The hot water cools as it is pumped around the house to the radiators which heat the house. The rate at which the water cools will depend on a large number of factors, i.e. whether the house is well insulated, the external temperature, radiator sizes, radiator settings etc. Therefore during cool weather in a well insulated house, the boiler may only actually be burning oil 50% of the time it is operating. But during very cold weather in a poorly insulated house the boiler may well burn oil continuously.
Therefore if we assume that the boiler, when operating, burns oil for 65% of the time, then the amount of oil used is 1.48 Litres per hour (= 2.27L X 0.65). As the current cost of oil, including taxes, is approx. €0.81 per Litre, the approximate average fuel cost of running an oil boiler is €1.20 per hour. This figure is an approximate guide and depends on your house conditions as detailed above as well boiler efficiency etc. The cost has increased in recent times as a result of higher oil prices and green energy taxes and will probably increase further.