rad202

Hi, Newbie here. I'm in the market for a water softener after growing tired of dissembling my shower thermostats to descale. I have Harveys visiting my home to give me a 'no obligation free quote' but I'm pretty certain that there is zero chance I will pay £1600-£1800 for them to fit one, given that my builder has offered to fit one free of charge, providing I buy one. To that end, what if any, is the difference between a new Harveys HV4/M3/S4 vs the older HV3/M2/S3 range? There seem to be plenty of HV3/M2 refurbished models at a third to half the price of a new one. Thanks.