Nathan

Yes, we've installed our system. So far so good although we've not had it in long enough to comment on overall running costs. We do have a very well insulated build, better than building regs and hopefully this will keep running costs down. (We also have a wood burning stove and access to lots of cheap wood.) Underfloor heating is a total joy and very unlike standard radiators. The one thing I would say is that we went for a direct heated hot water with a solar coil only. Our rational was that if the boiler is electric, it seemed a tad pointless to heat the water indirectly through the boiler and pump it through a coil in the hot water tank to transfer the heat to the water in the tank. Why not just use a dedicated immersor - using the self same 'lectricity - to heat it directly? Seems to me to be a more efficient method. Our boiler (Trianco Aztec 9kW) supplies heat only for the underfloor heating (downstairs in concrete screed) and radiators (upstairs). Again, our research led us to conclude that underfloor heating works best buried in a material with a good thermal mass. We looked into filling the voids between the upstairs joists with dry sand laid on plywood on battens but the problems outweighed the benifits - engineers being twitchy and wanting us to beef up the timbers being the main drawback. The benefits seem to be; a greater thermal mass, greater sound insulation and no creaking from heat plates - apparently something they don't mention in the sales brochures. Before committing to an electric boiiler, check with your elctricity board - not the supplier but the guys who maintain the infrastucture - that your local substation can handle the increased load. Wiring is also an extra cost as our boiler needed a dedicated MCB and RCD.

Andy