Hi everyone, I have a few designs ideas for a project that I want to build however I want to create it virtually first to assess roughly how it will perform. I have used sketch up and AutoCAD before and it is not the design aspect I am really interested in, more the performance.

Has anyone used any software that you can draw or put in the details of the house to work out energy usage, thermal transition etc. Not necessarily the whole house, even if it is just a piece of software to work out the walls U value I would be grateful to hear about it.

Failing that and going with the good old methods: Does anyone know of some calculations or formulas for working out heat loss, ventilation and the rest?

Any help would be greatly appreciated even if it is the simplest formula.

Many thanks