I try to detail the info so people can check...

The bungalow ran on LPG bottled gas for 3 years heating and hot water so I know what was used: I have used the worst 2 years:

I am using the conversion rate of  one kg of LPG gas giving about 14.091kW hours

In 2 years we used about 13277kW of LPG energy for heating and hot water. ( about 10 bottles of 47kg ) If we deduct a modest 2kW for hot water each day ( total 1460kW) that leaves about 11,817 for the 2 years.

In summary about 6000kW per year so 60kW per year per square metre of floor was what we were achieving.

The target temperature in the house is 21 degrees C generally with 10m2 of rooms at 23C.

The MVHR runs at about 6watts an hour or 52kW a year. I have a plug in meter on it.   so lets say £20 a year power.  It saves masses of heat.