In 2026, a home’s thermal performance is no longer a “nice-to-have” feature; it is a core component of market value. With energy costs remaining volatile and government targets for Net Zero homes becoming stricter, buyers need to understand the physical reality of a building’s efficiency beyond the superficial EPC (Energy Performance Certificate) rating.
Why EPCs Often Miss the Mark
An EPC is often based on assumed data rather than a physical inspection of every wall cavity. At Howorth, we take a more investigative approach. We look at how a building actually breathes and retains heat, identifying where theoretical efficiency meets structural reality.
Critical Energy Risks We Identify
1. The retrofit danger: Many properties are currently being retrofitted with internal wall insulation or modern rendering to improve heat retention. However, if done incorrectly, this can be catastrophic. Adding non-breathable insulation to an older solid-wall property can trap moisture, leading to interstitial damp. This can cause hidden decay in timber lintels and joists. We flag where “green improvements” may actually be structural liabilities.
2. Thermal bridging and mould growth: We look for thermal bridges — areas where heat escapes more rapidly due to structural gaps. This often occurs around modern window installations or where an extension meets the original house. These cold spots can lead to localised condensation and black mould (Stachybotrys chartarum), which is a significant health hazard in modern homes.
3. Ventilation and airtightness: As homeowners make properties more airtight to save on heating, they can inadvertently compromise the building’s natural ventilation. Without the right balance of trickle vents and mechanical extractors, indoor air quality can plummet. We evaluate whether a property has been “choked” by modern improvements, increasing the risk of long-term rot in roof timbers.
The Howorth Strategy
We don’t just tell you a house is cold — we provide actionable advice on how to improve efficiency without damaging the building’s fabric.