is there a cheaper alternative to paraffin for use with a greenhouse heater?

Question

i'm using a vintage aladin blue flame heater, but would prefer a cheaper fuel as i will be growing tropical plants in the greenhouse.

Answer 1

cheapest/most efficient fuel for a heating system is a heat pump, preferably hooked up to solar pannels (thermal & photovoltaic)

the instalation cost, even if you can find and fit one is likely prohibitive.
Suggest a visit to Eden & see how they do it.
but the cheapest & greenest option would be to select tropical plants that can thrive in a temparate environment. or plant trees to off-set the Co2 from your heating.