Category: Sustainable buildings · Reviewed by Amy Price, Account Executive · Last reviewed 2026-06-10
EnerPHit insurance is the package of property, liability, professional indemnity and latent defects covers arranged for existing buildings undergoing deep retrofit to the EnerPHit standard — the Passivhaus Institut’s certification scheme for existing buildings, which permits a relaxed energy performance target reflecting the constraints of retrofitting.
Category: Sustainable buildings Also known as: Passivhaus retrofit insurance, deep retrofit cover, EnerPHit-certified building insurance Typical UK market form: contractors’ all risks during works + property all risks once complete + PI for designers + latent defects for retrofit elements Related concepts: Passive house insurance, Green building insurance, Latent defects insurance
EnerPHit is the Passivhaus Institut’s certification standard for retrofits of existing buildings. It permits a higher space heating demand than the Classic Passivhaus standard — typically up to 25 kWh/m² per year (climate-zone dependent) — and an airtightness result of no more than 1.0 air changes per hour at 50 Pa, recognising that achieving Classic Passivhaus values in an existing building is often technically impossible or economically prohibitive. There are two routes to certification: a demand-based route using the same metrics as new-build Passivhaus (with relaxed thresholds), or a component-based route specifying minimum performance for each retrofitted element.
EnerPHit insurance covers the entirety of a project’s risk life-cycle: from desktop survey and design (PI), through construction (contractors’ all risks, public liability, contract works), to occupation (property all risks, latent defects for the retrofit interventions). The retrofit context creates particular risks that distinguish EnerPHit insurance from new-build Passivhaus cover.
EnerPHit was first published by the Passivhaus Institut, Darmstadt, in 2010. Certification is awarded by accredited Passivhaus Certifiers and verified through the Passivhaus Planning Package (PHPP). UK certification bodies operate under BS EN ISO 17025 accreditation and are coordinated through the UK Passivhaus Trust. The component-based route allows step-by-step retrofit (one element at a time) with components certified to the EnerPHit component standard.
EnerPHit retrofits commonly intersect with other UK frameworks. The RICS Whole Life Carbon Assessment for the Built Environment, 2nd edition (September 2023) is increasingly used to demonstrate that deep retrofit delivers better whole-life carbon outcomes than demolition and new-build. The LETI Climate Emergency Retrofit Guide and Climate Emergency Design Guide provide complementary targets. The UK Net Zero Carbon Buildings Standard, Pilot Version 1.0 (September 2024) explicitly recognises EnerPHit as a route to compliance for existing buildings. PAS 2035:2023 (Retrofitting dwellings for improved energy efficiency) often runs alongside EnerPHit on domestic schemes.
Property all-risks rating for completed EnerPHit retrofits depends heavily on the pre-existing construction. A late-19th-century brick terrace retrofitted with internal wall insulation and triple-glazing carries different exposures from a 1960s concrete-frame office. Internal wall insulation in particular has been associated with interstitial condensation and consequential timber decay claims, and insurers will typically require hygrothermal modelling (WUFI or equivalent) before binding cover. UK insurers active in this space include Aviva, Zurich, Allianz and specialist mutual providers.
Latent defects and structural warranty issues are central to EnerPHit work. The 10-12 year warranty market for retrofit is more restricted than for new-build. Premier Guarantee, Build-Zone and ICW offer retrofit warranties, but NHBC’s Buildmark is generally limited to new-build. Where MMC retrofit components are used — pre-fabricated insulated panels, off-site manufactured window cassettes — these go through the same NHBC Accepts process as new-build MMC. The warranty typically covers the retrofitted elements only, not the pre-existing structure, which creates evidence-of-loss complications.
Professional indemnity for retrofit design teams carries materially higher exposure than for new-build, principally because of moisture-related claims. PI insurers in the London market — including Beazley, Markel, Travelers and RSA — increasingly require evidence of hygrothermal modelling and a written moisture-management strategy as a condition of cover. The PAS 2035:2023 Retrofit Coordinator role carries its own PI exposure. The Insurer Wider Buildings (IWB) inspection regime for retrofits places particular emphasis on the airtightness test certificate, MVHR commissioning and any monitoring sensors installed under PAS 2035.
The Building Safety Act 2022 (Royal Assent 28 April 2022) and the Building Safety Regulator (established within the HSE in October 2023) apply equally to retrofit of Higher-Risk Buildings — residential of at least 18 metres or 7 storeys — under the Building Safety (Higher-Risk Buildings Procedures) (England) Regulations 2023 (SI 2023/909). Many large-scale EnerPHit projects (social housing tower-block retrofits) fall squarely within this regime. Section 135 of the Act extended the Defective Premises Act 1972 limitation to 30 years retrospective and 15 years prospective, which now reaches back well before EnerPHit-style retrofits were common practice.
Approved Document L (2021 edition, operative 15 June 2022) sets the minimum standards for existing dwellings where retrofit triggers it. Approved Document F (ventilation, 2021) and Approved Document O (overheating, 2021) interact with EnerPHit MVHR and overheating analysis. The Construction Products (Amendment etc.) (EU Exit) Regulations 2020 and the UKCA marking regime apply to retrofit components. Listed buildings (Planning (Listed Buildings and Conservation Areas) Act 1990) and conservation area constraints often require derogation from elements of EnerPHit (e.g. external wall insulation on a listed façade) — and the insurance file should record this clearly.
Owners commissioning EnerPHit retrofit should engage both warranty provider and PI broker before signing the design appointment. Mid-project changes to insulation type or window specification are the most common cause of EnerPHit certification failure and warranty exclusion. For listed and conservation-area properties, derogations should be evidenced by Local Planning Authority correspondence kept on the insurance file. Where the retrofit will be tenanted on completion, the Energy Performance Certificate (EPC) regime under the Minimum Energy Efficiency Standards is engaged separately.
A registered provider retrofits a 1970s 14-storey residential block in Manchester to EnerPHit standard in 2026 using a closed-panel external wall insulation system from a manufacturer on the NHBC Accepts list. The works are insured under a £30m contractors’ all risks policy with a £5m public liability section. The design team carries £10m PI with a £3m aggregate sub-limit for retrofit-related moisture claims. Premier Guarantee issues a 12-year retrofit warranty for the EnerPHit interventions. The Building Safety Regulator’s Gateway 2 consent is conditional on a fire-engineering statement for the external wall system, evidenced in the policy file.
This entry is part of the Apex Insurance Wiki. Last reviewed by Matt Bartlett on 2026-06-10. Next review: 2026-12-10.
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