Heat loss house

Having been assured the house was build to a high insulation spec the cold winter of last year got me thinking something was not quite right - hence the thermal image the following winter. As you can all see there is a lot of heat loss through poor contractor workmanship and poor specification of windows and doors. So why even when we try to do things well in the building trade do we fail so miserably? Perhaps more -15 degree winters like last year would alter things.