around £900 a year extra in diesel(it used to be £40 a month using cold water now its around £120 per month).diesel heater with smart charger,controller,batteries,etc plus fitting and VAT cost me £4,500 ......i fully expect the system to last me at least 10 years so over that time it would work out at £450 per year
diesel........£900
system.....£450
so an extra £1350 per year..........£112-50 per month,£26 per week........
servicing/parts etc i cant calculate as not needed to yet,some diesel heater users have had their systems over 4 years and have not had them serviced at all or replaced any parts......