Hi, looking for some advice on the best hot water system to use in our 3-bed, 2 floor, Victorian Terraced house. The current set up is with a conventional boiler in the utility room, a hot water vented cylinder in the first floor airing cupboard with an electric pump for the shower, and a cold water storage tank in the loft. We have recently had our roof re-tiled and had full loft roll insulation laid down in the loft. I am concerned (not sure if I should be) that now the loft is properly insulated the roof space will get a lot colder in the winter and that despite the water tank and pipes being insulated they might freeze and cause the water tank to crack or bust and send gallons of water down in to our brand new bathroom and kitchen! I am considering changing this vented to system to remove the cold water tank and to either have an unvented cylinder where the current vented cylinder is, or go for a combi boiler. My questions are: 1. Are my fears of the cold water tank leaking a bit over the top? What are the chances of this happening? Are they generally fine? 2. Are there any safety issues with a pressurized unvented system? 3. I presume the water pipes in the house are reasonably old (all copper from what I can see). Will this be an issue? 4. Out of the three systems, which would suit a property of this age and size the most? Am I just better off keeping things as they are or should I change to a combi or unvented system? Any other advice would be much appreciated.