Thermal bridges can occur at various locations in the building envelope. They result in increased heat flow, which in turn causes additional transmission heat loss, lower internal surface temperatures, and possible condensation and mould problems.
The additional transmission heat loss drives up energy consumption, an especially important issue as we move towards low-energy housing and passive houses, and further in the future towards near-zero energy homes.
Indeed, research has shown that heat loss due to thermal bridges can be so high that it cannot be offset by the energy gained through solar water heating. Thermal bridges generally have a significant overall impact on heat-energy demand, driving up consumption by as much as 30%!