Mechanical and electrical (M&E) consulting engineers sit at the heart of almost every building project in the United Kingdom. The decisions a building services consultancy makes about heating, ventilation, electrical distribution, public health (water and drainage), fire safety, building management systems (BMS) and vertical transportation directly shape how a building performs, whether it complies with Building Regulations, and what it costs the end client to operate over its life. When something goes wrong — a system that does not meet design intent, an energy model that does not stand up to scrutiny, or a fire-safety strategy that fails on review — the financial consequences fall to the consultancy that signed off the design.
Professional indemnity insurance (PI) is the policy that responds when a client alleges negligent design, an error or omission in a report, or breach of professional duty. For M&E firms with members of the Chartered Institution of Building Services Engineers (CIBSE), the Institution of Mechanical Engineers (IMechE) and the Institution of Engineering and Technology (IET), PI is also a precondition for chartered practice and for tendering on most public-sector and major commercial frameworks.
The PI environment for building services engineers has shifted significantly in recent years. The Building Safety Act 2022, the post-Grenfell tightening of fire-safety expectations, and the net-zero retrofit programme have all expanded the risk profile of the work. The right cover should reflect not only the projects you deliver today but the long tail of liability that sits behind them.
What does PI insurance cover for building services consultants?
A building services PI policy is designed to respond to civil liability arising from the professional services the firm provides. In practical terms, that means defence costs and damages awarded against the consultancy where a client alleges:
- Negligent design of HVAC, electrical, public health, fire-safety or BMS systems
- An error or omission in a report, specification, calculation, energy model or commissioning record
- Breach of professional duty of care, including misstatement in advice on Building Regulations compliance (Part L energy efficiency, Part F ventilation, Part B fire safety, Part O overheating, Part S electric-vehicle charging)
- Defects in coordination between disciplines that result in remedial works
- Breach of confidentiality or the unintended release of client information
- Loss of, or damage to, client documents and data in the consultant's custody
- Unintentional infringement of intellectual property, for example in a standard detail or methodology
Most modern wordings are arranged on a "civil liability" rather than a narrower "negligence" basis, which broadens the response to include innocent misrepresentation and certain contractual liabilities. Cover is almost always written on a claims-made basis, so the policy in force when a claim is first notified is the policy that responds — not the policy in force when the work was done. That is why run-off cover, which extends notification rights after the firm ceases trading, is so important. The Defective Premises Act limitation periods, extended by the Building Safety Act 2022 to 15 years prospectively and 30 years retrospectively for certain dwellings, mean that exposure to building-related claims can stretch decades beyond practical completion.
Sub-limits, exclusions and conditions vary between insurers. Common areas to review include cover for fire-safety design (some markets now sub-limit or exclude cladding-related work), cover for higher-risk buildings (HRBs) under the Building Safety Act, the position on net-contribution clauses, and whether the policy provides an aggregate or each-and-every-claim limit.
Common building services consultant PI claim scenarios
Real claims rarely look like the textbook examples. They tend to arise where energy expectations, programme pressure and complex multidisciplinary coordination collide. The following anonymised scenarios are typical of the type of allegation a UK M&E consultancy may face.
- Heat-pump system undersized on a new-build estate. A consultancy designs the heating strategy for a residential development using air-source heat pumps. After occupation, residents report inadequate heating performance in cold-weather conditions. The developer alleges the design did not properly account for fabric heat-loss assumptions and seeks the cost of remediation across multiple plots. Defence and settlement costs reach a six-figure sum.
- Part L SAP / SBEM modelling error. An energy model submitted to support Building Regulations sign-off is later challenged. A reviewer finds an input error that, when corrected, takes the building below the required Part L performance threshold. The consultancy faces a claim for the cost of retrofit measures to bring the building into compliance and for the impact on the building's EPC rating.
- Smoke ventilation strategy fails design review. A smoke vent design on a residential block is found, on post-installation review, not to meet BS 9991. Remediation involves opening shafts and replacing dampers in occupied flats. The PI insurer defends the firm and contributes to a substantial settlement.
- BMS strategy results in energy overspend. A building management system is commissioned in a way that overrides the design intent for night-time set-back. The occupier sees energy bills materially above forecast and argues that the consultant's commissioning advice and witnessing were negligent.
- District heating heat-loss assumptions wrong. A district heating scheme underperforms because pipework heat-loss assumptions in the original model were optimistic. The end-user energy company alleges the design was not fit for purpose and seeks the cost of additional plant.
- Water hygiene advice on Legionella control. A consultancy advises on water-system design under the Approved Code of Practice L8. A subsequent Legionella outbreak triggers an HSE investigation and a civil claim that the design and risk-assessment advice was inadequate.
Choosing the right cover for your building services firm
The right PI limit reflects the contracts you sign, the largest realistic exposure on a single project and the expectations of the clients and frameworks you work with. As a general guide for UK M&E consultancies:
- £2m–£5m is common for smaller and mid-sized firms working on standard commercial and residential projects
- £5m–£10m is frequently specified for larger commercial developments, major refurbishment programmes and public-sector frameworks
- £10m or more is typical for higher-risk buildings (HRBs) under the Building Safety Act, complex healthcare and education projects, and major net-zero retrofit programmes — sometimes arranged through project-specific PI
Net-contribution clauses are a critical area for building services firms. Without them, the consultant can be held jointly and severally liable with other consultants and contractors for the whole of a loss, even where the firm's share of fault is small. We work with clients to align their PI wording with the contract clauses they are being asked to sign.
Other points to test when comparing wordings include the breadth of the "professional services" definition (does it capture Principal Designer duties under the Building Safety Act, Construction Design and Management (CDM) coordination, or expert witness work?), the position on cladding and combustible materials, the treatment of sub-contractors and associates, and the availability of long-tail run-off cover. Where you provide energy modelling, embodied carbon assessment (for example using CIBSE TM65 and TM65.2), or net-zero retrofit advice, the insurer's appetite for those activities should be confirmed in writing.
Why work with Apex as your building services consultant PI broker
Apex Insurance Brokers Limited is an independent broker based in Bristol, specialising in professional indemnity for UK professional services firms. We are authorised and regulated by the Financial Conduct Authority (FCA firm reference 724952) and have access to a panel of insurers active in the construction professional indemnity market, including specialist Lloyd's syndicates.
Working with an independent specialist means your renewal is not tied to a single insurer's appetite. We can present your firm to the markets most likely to engage with your service mix, your turnover profile and the projects you take on — whether that is small commercial fit-out, residential development, healthcare, education, or higher-risk buildings under the Building Safety Act. We take time to understand the appointment documents and net-contribution wording that drive your insurance requirement, and we provide claims advocacy — supporting you through the notification, defence and resolution of any claim or circumstance.
We do not pay or receive inducements, and we are transparent about how we are remunerated. Our aim is to arrange cover that is appropriate for your firm and well-matched to the engineering you actually deliver.
Frequently asked questions
Does CIBSE require members to carry PI insurance? CIBSE expects chartered practitioners and registered practices to hold appropriate professional indemnity cover. Most CIBSE-aligned firms carry limits proportionate to their projects and clients; £2m–£5m is common for general M&E work, with higher limits for major or higher-risk building projects.
How does the Building Safety Act 2022 affect my PI cover? The Building Safety Act has extended limitation periods for claims relating to dwellings, introduced new duty holder roles (including Principal Designer under the BSA), and created a tougher regulatory regime for higher-risk buildings. Insurers consider these factors carefully when underwriting, and some impose sub-limits or conditions on HRB work. We can review your activity and confirm where your existing policy responds.
Do I need separate cover for fire-safety design and cladding work? The insurance market has tightened sharply on fire-safety and cladding-related work since 2017. Many policies now contain specific exclusions, sub-limits or conditions for cladding, external wall systems and combustible materials. If your firm carries out this work, the wording must be reviewed carefully.
What is run-off cover and how long should I buy it? Run-off cover extends the right to notify claims after a firm ceases trading or sells. Because PI is claims-made, without run-off there is no policy to respond to a late-emerging claim. Six years is a common minimum aligned to the standard contractual limitation period in England and Wales, but building services firms should consider longer periods reflecting the extended Building Safety Act and Defective Premises Act limitation periods.
Are net-contribution clauses important? Yes. A net-contribution clause limits the consultant's liability to a fair share of the overall loss rather than joint and several liability for the whole. Insurers strongly prefer net-contribution wording in appointments, and absence of one can affect both premium and limit availability.
Will my PI cover energy modelling and net-zero retrofit advice? Most policies cover energy modelling and decarbonisation advice as part of professional services, but performance-based guarantees or warranties (for example, contractual guarantees of a measured energy outcome) may not be insurable. We can review specific wordings and contract clauses on request.
Do I need separate cyber insurance as well? Most PI policies include limited data and confidentiality wordings but are not a substitute for a standalone cyber policy. Firms running cloud-hosted modelling tools, BIM environments and shared project data should consider cyber cover alongside PI.
Get a quote
If you would like to discuss your PI arrangements, request a review of your current wording, or obtain terms for a new policy, please get in touch. Call 0117 325 0027, email info@apexinsurancebrokers.co.uk, or request a quote online. Full contact details are available on our contact page.
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About Apex Insurance Brokers — Apex Insurance Brokers Limited is authorised and regulated by the Financial Conduct Authority, FCA firm reference 724952. Registered in England and Wales, Companies House 07014570. Last reviewed: May 2026.