Looking for a bit of advice.. I've advised my sister who is renovating her house to ditch the old copper water cylinder for a new factory insulated one with an immersion included. The one that is there has no immersion or insulation fitted. Am I right in suggesting that a new one (she has priced one for €190) would be more economical in the long run than buying a lagging jacket and an immersion for the existing cylinder? How much would you think the old copper cylinder would be worth?