Hi. I am just about to start designing a house. (Approx 2750 sq ft) and have really started to think about all the decisions I have to make before commencing. I’m meeting the architect later this week to discuss my preferences for features and design. From reading countless posts on here and studying several magazines and websites, in addition to initial discussions with the architect, I have more or less decided on going for timber frame with block walls on interior and exterior with above average insulation to keep my heating bill to a minimum. I am also going to go for an airtight structure with heat recovery ventilation. A wood pellet burner with underfloor heating downstairs and rads upstairs with a mixer system to regulate the water temperature. Also probably will go for a pellet stove in open plan living area. I am also considering a pressurised water system for showers etc. as I will have 3 possibly 4 showers in the house. I think that just about covers all the major basic specification decisions I have to make. Does anyone think this is a good spec to go for? Or am I missing something? Just interested to hear some opinions on it. Thanks. Also when it comes to the insulation, what is the best type to use?