How much oil to heat 10 litres of water?

zarazara

our hot water is heated via the oil boiler. I do not know how much its costs. Does anyone know how much oil it needs to heat ,say,10 litres of water from cold to 65 degrees?

retire_at_50_2

It takes 4.7kWh to heat 100litres of water by 40'C. Incoming water is probably around 10'C so heating 10litres to 65'C would take 0.65kWh.

Assuming 60p per litre for kerosene and 10kWh energy content, 0.65 kWh would cost 3.9p.

However thats assuming 100% boiler efficiency, in reality its going to be between 50-90% so could be 7.8p - 4.3p.

Swipe

Incoming water is much colder than 10C at this time of year, more like about 4C. http://forum.netweather.tv/topic/66209-riccys-tap-water-temprature-thread/

grahamc2003

zarazara wrote: »

our hot water is heated via the oil boiler. I do not know how much its costs. Does anyone know how much oil it needs to heat ,say,10 litres of water from cold to 65 degrees?

To heat 10l of water from 5C to 65C requires 600Kcal, which is about 2500KJoules. The energy content of Kerosene is 35000KJ/l, so you need 0.07l or 70cc, theoretically.

If you burn it at 60% effeciency, and allow for a bit of heat loss from the heated water, then you'll need about 130cc or thereabouts.

reeac

In reality I suspect that you are interested in the cost per day/week/month of getting your hot water via an oil boiler. My rule of thumb [for two pensioners in a 3 bedroom bungalow] is that we use 50 litres/month to supply our hot water requirements alone i.e. in the summer months. As we now have a smart electricity meter and have a good data base for our daily electricity consumption I may experiment in the summer by switching to the immersion heater in order to compare.

zarazara

Thankyou all, what clever people there are on this board. All these replies are helpful, thankyou all.