Heat Loss comparisons
U-values, thermal bridging and the metrics that explain where a home loses heat.
Heat loss investigationU-values vs Thermal Bridging in Heat Loss
U-values describe heat loss through the flat area of walls, roofs and windows; thermal bridges describe extra heat loss at junctions and interruptions. You need both: improving U-values without addressing thermal bridges leaves significant heat loss — and condensation risk — at the very junctions a camera reveals.
Read comparisonDesign Heat Loss vs EPC Heat Demand
Design heat loss is a peak-power figure (watts) calculated from the building's real fabric to size heating systems and emitters; EPC heat demand is an annual-energy estimate (kWh/year) from RdSAP for rating and compliance. They answer different questions and must not be confused — you size a heat pump from design heat loss, never from an EPC. The EPC tells you roughly how a home compares; design heat loss tells you what the heating system must deliver.
Read comparisonThermal Bridging vs Air Leakage as Heat Loss
Thermal bridging is conductive heat loss through interruptions in the insulation; air leakage is convective heat loss carried out by moving air. Both are 'hidden' losses that a basic U-value or EPC misses, and both also cause condensation risk — thermal bridges via cold surfaces, air leakage via moisture transport. They need different diagnostics (thermal imaging for bridges, a blower door for leakage) and different fixes, and a serious heat-loss assessment addresses both.
Read comparisonWhole-House vs Single-Measure Retrofit
A whole-house plan models and sequences measures so they work together and do not create new problems; single-measure retrofit fits one improvement at a time without considering the interactions. Because insulation, airtightness, ventilation and heating are physically linked, piecemeal measures can shift condensation risk or lock in poor decisions. A whole-house plan can still be delivered in stages — the point is that the stages are coordinated, not that everything happens at once.
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