After various delays, the time has come to get some heat into the house, and as there have been a few on BH that have gone down the route of Willis, thought I would give it a go as well. Hopefully others will find the blog entry also.   Background: Renovated (3G passiv-rated windows, 120mm EPS EWI, 400mm loft insul, MVHR - not tested air leakiness yet) / extended (175mm SIPs) south facing detached house, East Kent 156sqm of wet UFH in 100mm concrete (with circa 300-375mm