The shabby house with warm air heating is advertised for the same asking price as a very similar house on the same road in a much better condition plus central heating install. The latter, from the experience, should go for the asking price. I want to make a fair offer for the shabby house, but obviously want to deduct the cost of removing warm air unit (possible asbestos), installing boiler/radiators (gas already there) and making up (will need new flooring, boxing pipes, repainting etc). What would be a fair deduction? I am thinking towards 10-15k but don't want to play offers, so need the final good offer. I am in a chain so cannot compete with unreasonably low cash offers (if any)... Thanks!