Retrofit & Insulation comparisons
Insulation strategies and retrofit approaches compared on a fabric-first, moisture-safe basis.
Insulation retrofitInternal vs External Wall Insulation
EWI is generally the better building-physics solution because it keeps the wall warm and the insulation continuous, reducing thermal bridges and condensation risk. IWI is cheaper and sometimes the only option (for example on protected façades), but it requires expert moisture detailing to be safe. The right choice depends on the building, the budget and the constraints.
Read comparisonPIR vs Mineral Wool Insulation
PIR gives more thermal resistance per millimetre, so it suits space-constrained upgrades; mineral wool is vapour-open, fire-resistant and acoustically absorbent, but needs more thickness for the same U-value. The right choice depends on the wall's moisture strategy, the space available, and fire and acoustic requirements — not on thermal performance alone. In vapour-open or breathable build-ups, especially solid-wall retrofit, mineral wool is often the safer choice despite needing more depth.
Read comparisonLoft Insulation vs Wall Insulation
Loft insulation is usually the cheapest, easiest and highest-return measure, so it is normally first; wall insulation tackles a larger heat-loss area and gives big comfort gains but costs more and needs careful detailing. The right order depends on what is already in place and where the measured heat loss actually is — which is why a heat-loss assessment, rather than a rule of thumb, should set the priorities. Often the loft is the quick win and walls the bigger project.
Read comparisonFloor Insulation vs Wall Insulation
Floor insulation tackles cold floors and the draughts that come up through suspended timber floors; wall insulation tackles a larger heat-loss area and cold-wall comfort. Walls usually lose more heat overall, but floors can be a significant and uncomfortable loss, especially with draughty suspended floors. The right choice depends on the construction, the measured heat loss and the symptoms — and, with suspended floors, on combining insulation with airtightness to stop the draughts.
Read comparisonTriple Glazing vs Double Glazing
Triple glazing has a lower U-value and a warmer internal glass surface, improving comfort and reducing condensation; double glazing is cheaper and often adequate. Triple glazing pays off most in well-insulated, airtight homes — where the windows would otherwise be the weak point — and matters for Passive House and EnerPHit. In a less-insulated house, good double glazing is frequently the sensible choice, because the windows are not the dominant loss. Context decides.
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