A Passive House (or Passivhaus) is a rigorously tested building standard that dramatically reduces the energy needed to heat and cool your home — typically by 75–90% compared to a standard UK new build. It's not a style or aesthetic; it's a performance specification.

The standard centres on five principles working together: superior insulation, airtightness, heat recovery ventilation, high-performance windows, and elimination of thermal bridges. Get all five right and you have a home that stays comfortable year-round with minimal energy input.

75–90%energy reduction

≤15 kWh/m²heating demand

≤120 kWh/m²primary energy

n50 ≤0.6air changes/hr

In Cornwall's mild but damp Atlantic climate, Passive House has a particular advantage: the humidity control built into the standard means a home that stays dry, healthy, and mould-free — a significant concern in coastal builds.

Coastal construction in Cornwall presents specific challenges that standard builders aren't equipped for: salt-laden air, prevailing south-westerly winds, exposed sites, and planning constraints in AONBs. A Passive House built for a coastal site needs to address all of these alongside the standard performance criteria.

Wind-driven rain resistance is critical — airtight construction and correctly specified membranes prevent moisture ingress that would compromise both the building envelope and internal air quality. Salt corrosion affects fixings, glazing hardware, and external finishes, so material specification matters enormously at the coast.

Warvena builds exclusively in Cornwall and understand the planning landscape, the local geology, and the material behaviour in exposed coastal conditions — knowledge that only comes from years of building in this specific environment.

Most people assume insulation is the key to a warm house. It is important — but airtightness is what separates a genuinely high-performance home from an expensive one. Uncontrolled air leakage can account for 30–40% of a home's heat loss. If your building envelope leaks, all that insulation is working against an open door.

Passive House requires an air permeability of n50 ≤ 0.6 air changes per hour — tested by a pressurisation (blower door) test. A typical UK new build achieves 3–10. This level of airtightness requires meticulous detailing at every junction: windows, doors, service penetrations, wall-to-roof connections, and anywhere two materials meet.

It's a construction discipline, not a product you specify. It requires experienced builders who understand the airtightness layer as a continuous, unbroken plane throughout the entire building envelope.

If airtightness seals the building, Mechanical Ventilation with Heat Recovery (MVHR) gives it fresh air — efficiently. An MVHR unit extracts stale, moist air from kitchens and bathrooms, recovers up to 92% of its heat, and supplies fresh filtered air to living rooms and bedrooms. The net result: constant fresh air without the heat loss of opening a window.

In Cornwall's damp coastal climate, MVHR does something equally important: it controls internal humidity. Excess moisture causes condensation, mould, and poor air quality. An MVHR system running continuously prevents this without any action from the occupant.

Correct design and commissioning is everything — poorly designed ductwork or undersized units undermine the whole system. Warvena works with Passive House-certified MVHR specifiers to ensure every installation performs as modelled.

Thermal bridging occurs wherever a conductive material passes through the insulation layer — a concrete column, a structural lintel, or a poorly detailed window reveal. These cold spots not only lose heat; they cause condensation and mould on internal surfaces. Passive House demands that every thermal bridge is identified, calculated, and either eliminated or minimised in the design stage.

Timber frame is the natural partner for Passive House in Cornwall. It's fast, precise, lighter than masonry (important on challenging coastal ground conditions), and allows insulation to be packed efficiently within and outside the structural frame. Engineered timber systems give designers the dimensional precision needed to achieve consistent airtightness details across the full build.

Sustainable materials — cork, hemp, wood fibre, sheep's wool — are increasingly being specified alongside or instead of synthetic insulation products. Beyond their environmental credentials, many have excellent hygroscopic properties: they absorb and release moisture, supporting the building's vapour management. This matters in Cornwall's damp climate where managing moisture movement through the structure is as important as resisting heat loss.