Domestically An average 10-12 single radiator home requires one 500ml bottle of EndoTherm. If your home is larger than average (or has more radiators/underfloor heating) you will require 1 litre (2 x 500ml bottles).
Commercially 1 litre per 100 litres of system volume. Experts from Endo Enterprises can calculate exactly how much EndoTherm will be required to maximise the potential return on investment.