If you’re putting a BMS project or mechanical engineering package out to tender — or you’ve received quotes and you’re trying to work out what’s actually included — this is the page you need. These are the questions we get asked every week by facilities managers, M&E consultants, main contractors, and building owners. Straight answers, real numbers, no fluff.
At minimum, a BMS quote should include a points schedule (every sensor, actuator, and meter listed individually), a description of the controllers and head-end software, the GUI/graphics scope, network infrastructure, commissioning, programming, and any temporary works or access requirements. It should also state what’s excluded — that’s just as important. A good quote references the mechanical scope it’s integrating with and confirms compatibility with existing protocols. If you’re comparing quotes and one is a two-page letter while another is a 15-page breakdown, the short one isn’t cheaper — it’s vaguer. CIBSE Guide H recommends that BMS specifications clearly define the points schedule, system architecture, and commissioning requirements as the minimum basis for any quotation.
For a straightforward office BMS installation in 2026, expect to pay between £150 and £350 per point for a mid-range system (Trend, Distech, Schneider). A 200-point office fit-out typically comes in between £40,000 and £80,000 depending on complexity, protocol requirements, and how much existing infrastructure you can reuse. Retrofit projects cost more — often 20–40% more than new-build — because of survey time, legacy removal, and working around occupied spaces. High-spec environments like data centres, labs, or hospitals can push past £500 per point once you factor in redundancy, enhanced commissioning, and compliance documentation.
The most common exclusions are builders’ work (making good after cable runs), asbestos removal, network switches and IT infrastructure, power supplies to controllers, scaffolding or MEWP access, fire alarm integration (often treated as a separate package), and out-of-hours working. Watch out for quotes that exclude “third-party integration” — that can mean the BMS won’t talk to your chillers, boilers, or AHUs without an additional cost. Also check whether the GUI licence is included or an annual subscription, and whether remote access setup is in scope.
Line them up against the same points schedule. Every quote should price the same number of hardware points, the same software scope, and the same commissioning depth. If one contractor has priced 180 points and another has priced 220 for the same building, someone has read the spec differently — or one is making assumptions. Normalise the comparison by checking: are all three quoting the same protocol? Same head-end platform? Same graphics package? Same commissioning hours? A quote that looks 30% cheaper often just has 30% less scope.
A quote is a fixed price for a defined scope — the contractor is committed to delivering what’s described for that figure, subject to the stated exclusions and assumptions. An estimate is a rough indication of cost, usually given before the full scope is defined, and the contractor isn’t bound by it. In BMS work, early-stage estimates can swing 25–40% either way once the detailed design is done. Always confirm whether you’re looking at a formal quotation or a budget estimate, because procurement decisions based on estimates regularly lead to cost overruns.
It depends on the project, but it should always be visible as a separate line item even if it’s within the same quote. BMS commissioning typically accounts for 15–25% of the total BMS contract value on a new-build and up to 30% on a complex retrofit. If commissioning is buried inside an overall lump sum, you’ve got no way to challenge it, extend it if the programme slips, or assess whether adequate time has been allowed. CIBSE Commissioning Code M states that commissioning should be treated as a distinct activity with its own programme, resource allocation, and completion criteria — not an afterthought bundled into installation.
A points schedule is the line-by-line list of every input and output the BMS will monitor or control. Each sensor (temperature, humidity, CO2, pressure), each actuator (valve, damper), each meter (energy, water, gas), and each status point (pump run, fan status, alarm) counts as one point. It’s the single most important document in a BMS quote because it defines exactly what you’re paying for. If you receive a quote without a points schedule, send it back. A 200-point system and a 300-point system for the same building aren’t competing quotes — they’re different projects.
For a typical 150–250 point commercial office installation, allow 8–14 weeks from site start to practical completion, assuming access is available and the mechanical package is progressing on programme. That breaks down roughly as: 2–3 weeks for first fix (containment, cabling, back boxes), 2–3 weeks for second fix (controllers, sensors, actuators), 2–3 weeks for programming and graphics, and 2–4 weeks for commissioning and snagging. Retrofit projects in occupied buildings often take 30–50% longer due to restricted access windows. A contractor who quotes four weeks for a 200-point system either hasn’t read the spec or plans to cut corners on commissioning.
Annual BMS maintenance contracts in the UK typically range from £3,000 to £8,000 for a small to mid-size system (up to 200 points) and £8,000 to £25,000+ for larger or multi-site installations. That should include quarterly planned preventative maintenance visits, remote monitoring, software updates, and a reactive callout allowance. SFG20 sets out specific PPM task schedules for BMS equipment — if your provider can’t map their maintenance scope to SFG20 task specifications, question what you’re actually getting. The cheapest contract isn’t always the worst, but a £2,500/year contract for a 500-point system is almost certainly just someone visiting once a year with a laptop.
They should, and you need to check carefully. Programming covers the control strategies (how the BMS actually runs the plant), the time schedules, alarm configurations, and any logic sequences. Some contractors quote programming as part of the installation lump sum. Others break it out separately — which is actually more transparent. What you want to avoid is a quote that includes “basic programming” without defining what that means. If optimum start, weather compensation, demand-based ventilation, or load sequencing are required by the design, those should be explicitly listed and priced. Approved Document L requires weather compensation and optimum start/stop as standard on most commercial heating systems — your programming scope should reflect that.
Graphics are the visual interface operators use to monitor and control the building. A proper graphics package includes schematic pages for every plant room, floor plans showing zone temperatures and setpoints, alarm summary pages, trend viewers, and a site navigation structure. Some contractors include basic template graphics in their quote and charge extra for bespoke layouts. Others quote a fixed number of graphic pages. Clarify whether the graphics are web-based (accessible from any browser) or require dedicated software, and confirm whether the licence covers unlimited users or is per-seat. A BMS without usable graphics is a BMS nobody will operate properly.
This is one of the biggest grey areas in BMS quoting. The BMS contractor is responsible for the field-level network (BACnet MS/TP or IP between controllers). But the IT backbone — managed switches, VLAN configuration, firewall rules, server room patching — is almost always an IT responsibility and therefore a client cost. Make sure the quote states what network hardware is included and what’s assumed to be provided by others. BS EN ISO 16484-5 (BACnet) defines the communication requirements for BMS networks, but it doesn’t tell you who pays for the switches. That’s a coordination issue, and if it’s not addressed at tender stage, it becomes an argument at commissioning.
Most BMS quotes exclude scaffolding, mobile elevated work platforms (MEWPs), and specialist access equipment unless the contractor has been told to include them. In occupied buildings, out-of-hours access, security escorts, and permit-to-work costs are also typically excluded. This can add 5–15% to the installed cost depending on the building. If you’re retrofitting a 16-storey office block where every ceiling tile lift needs a MEWP and every floor needs weekend-only access, those costs are real and they need to be in someone’s budget. Don’t let them fall between the BMS quote and the main contractor’s prelims.
Standard BMS warranties in the UK are 12 months from practical completion for workmanship and installation defects. Controller hardware typically carries a manufacturer’s warranty of 2–5 years. Software warranties vary — some manufacturers offer ongoing support as part of a licence, others require a separate support agreement. What matters more than the warranty period is what it covers: does it include return visits to fix programming issues that only emerge during seasonal changeover? Does it cover sensor drift or actuator failure? A 12-month defects period with a responsive contractor is worth more than a 3-year warranty with a company that takes two weeks to return a call.
Start with the points schedule — check whether the contractor has priced more points than the spec requires. Then look at the controller hardware: are they pricing top-end controllers where mid-range would do the job? Check commissioning days — has the contractor allowed excessive time? Look at exclusions: a higher quote that includes network switches, graphics, and commissioning may actually be better value than a lower quote that excludes all three. Ask for a cost breakdown by element (hardware, cabling, installation labour, programming, commissioning, graphics, prelims). If the contractor can’t break their price down, that’s a red flag in itself.
A complete BMS tender package should include: the BMS specification (system description, points schedule, control strategies, network requirements), mechanical and electrical drawings showing plant locations, the building layout drawings, the preliminaries and conditions of contract, the programme, and a pricing document or bill of quantities. If you’re issuing a tender without a points schedule and control strategy descriptions, you’ll get back quotes that are impossible to compare. CIBSE Guide H states that the BMS specification should be detailed enough for tenderers to price without making material assumptions about the scope.
Start with what the BMS needs to control — list every piece of plant, every zone, every meter. Then define the control strategies: how should the AHUs run, what triggers the chillers, what are the heating setpoints, how does demand-based ventilation work? Include the points schedule, the network architecture (BACnet/IP, MS/TP, Modbus), the head-end requirements (web-based, on-prem server, cloud), and the graphics scope. State the commissioning expectations, the handover documentation requirements, and the integration points with other systems (fire, lighting, metering, access control). A scope that says “provide BMS to control all HVAC plant” is an invitation for wildly inconsistent quotes.
Allow 3–4 weeks for tender return on a standard commercial BMS project. Complex projects (hospitals, data centres, multi-site) may need 5–6 weeks. Add 1–2 weeks for tender evaluation and clarification meetings. If you’re running a two-stage tender with pre-qualification, add another 3–4 weeks upfront. Rushing a BMS tender to two weeks almost always results in either non-compliant returns or inflated prices because contractors add risk contingency when they haven’t had time to properly assess the scope.
Single-stage means you issue the full tender to all bidders at once — faster, simpler, suitable for straightforward projects under £150k where you know the market. Two-stage means you pre-qualify contractors first (checking capability, experience, financial standing) then issue the full tender to a shortlist — better for complex or high-value projects where you need confidence in the contractor’s technical capability before they invest time pricing. Two-stage adds 3–4 weeks but significantly improves the quality of returns and reduces the risk of awarding to a contractor who can’t deliver.
Score on three pillars: commercial (price, payment terms, exclusions), technical (system proposed, protocol compliance, points coverage, commissioning approach), and capability (relevant experience, team CVs, references, programme credibility). Weight technical and capability higher than price — a 60/40 or 70/30 quality-to-price split is common on BMS tenders. Check every return against the points schedule to confirm full coverage. Look for gaps: has anyone excluded integration, graphics, or commissioning? Has anyone priced a different protocol to what was specified? Clarification meetings before final evaluation are essential, not optional.
Watch for: pricing significantly below the other returns (usually means they’ve missed scope), no points schedule included in the return, vague commissioning allowances (“commissioning included” with no days or methodology), substitution of specified protocols without explanation, no named project manager or commissioning engineer, unwillingness to attend a clarification meeting, and references that are all from five or more years ago. Also be wary of contractors who won’t break down their price — a lump sum with no visibility is impossible to manage through variations.
No. BMS is one of the few building services packages where the cheapest option almost always costs more in the long run. A contractor who underprices the job will cut commissioning time, reduce programming quality, skip graphics, and deliver a system that technically works on handover day but causes problems within six months. The mid-range tender from a contractor with relevant experience, a credible programme, and a detailed commissioning methodology is usually the best value. The cheapest BMS tender we’ve seen clients accept has, without exception, led to either a variation-heavy project or a system that needed remedial work within the first year.
The M&E consultant typically writes the BMS specification, defines the points schedule, specifies the control strategies, and evaluates the tender returns. They should be your technical advisor throughout the process — reviewing contractor proposals for compliance, chairing clarification meetings, and confirming that the proposed system meets the design intent. On design-and-build projects, the consultant’s role shifts to reviewing the contractor’s design rather than specifying it. Either way, if your M&E consultant doesn’t have in-house BMS expertise, consider appointing a specialist BMS consultant separately. A mechanical engineer who treats BMS as an afterthought will write a specification that creates problems at tender.
Variations are inevitable on BMS projects because the mechanical design often changes after the BMS contract is awarded. The key is having a clear variation procedure in the contract: all changes instructed in writing, the contractor prices the variation before work proceeds, and both parties agree the cost impact. For BMS, typical post-award variations include additional points (new plant added), protocol changes (IT department mandates a different network approach), and programme acceleration (main contractor compresses the fit-out). Always get variations priced against the original tender rates where possible — day rates and ad-hoc pricing after award are always more expensive.
A compliant tender return meets all the mandatory requirements stated in the tender documents. That means: pricing the full points schedule as specified, proposing the specified protocol (or providing a fully detailed alternative with justification), including commissioning, programming, graphics, and handover documentation, submitting within the deadline, and providing all requested supporting information (method statements, CVs, references, programme). A non-compliant tender should either be rejected or the non-compliance should be clarified before evaluation. Accepting a non-compliant tender without challenge undermines the entire process and is unfair to compliant bidders.
A mechanical and electrical quote should include a full breakdown of labour, materials, plant, subcontractor costs, preliminaries, overheads and profit, and any provisional or prime cost sums. For mechanical specifically, that means pipework, ductwork, equipment (AHUs, FCUs, chillers, boilers, pumps), insulation, controls integration, testing and commissioning, and handover documentation. Every piece of major plant should be individually priced. The quote should reference the drawings and specification revision it’s based on, list all exclusions and assumptions clearly, and state the validity period. If a mechanical quote doesn’t tell you which specification revision it’s priced against, it’s not a quote — it’s a guess.
It depends on the procurement stage. At feasibility, mechanical services are often budgeted per square metre — typically £80–£200/m2 for office HVAC depending on specification level. At tender, pricing is done against measured quantities: linear metres of pipework, number of FCUs, AHU plant costs, ductwork quantities, and labour rates. Some contractors price per system (one lump for the heating system, another for ventilation, another for cooling). Per-floor pricing is common on repetitive buildings like hotels or residential towers. The critical thing is that the pricing structure allows you to identify and manage variations — a single lump sum for “mechanical services” gives you no control.
The costs that catch people out most often are: builders’ work (penetrations, fireproofing, making good), asbestos surveys and removal, access equipment (scaffold, MEWPs), out-of-hours working premiums (typically 1.5x to 2x day rates), temporary protection of installed work, coordination with other trades (time spent waiting or reworking), and design development costs on D&B projects. Also watch for “daywork” allowances — these are effectively blank cheques. A well-written quote makes these items visible. A poorly-written one buries them in exclusions and then charges for them as variations.
An FCU replacement quote should specify: the make and model of the replacement unit, whether it’s a like-for-like swap or a different unit requiring modifications, the pipework connections (including any valve replacements), the electrical connection, the controls interface (standalone thermostat or BMS-connected), drain connection, condensate pump if required, ceiling tile reinstatement, and commissioning. For a standard 4-pipe ceiling-concealed FCU in an occupied office, expect £2,500–£5,000 per unit installed, depending on access difficulty and whether the work is out-of-hours. If someone quotes you £800 per FCU including removal, supply, install, and commission — they’ve missed something.
AHU refurbishment quotes need to be very specific about what’s being refurbished and what’s being left as-is. Check whether the quote covers: fan motor replacement or just bearings, coil replacement or just chemical cleaning, filter section upgrade, damper actuator replacement, casing repairs and sealing, control panel upgrades, BMS integration, and recommissioning. BS EN 1886:2007 defines the mechanical performance standards for AHU casings including air leakage class (L1/L2) and thermal transmittance class (T2/T3) — a refurbishment that doesn’t address casing integrity may leave you with a unit that wastes 15–20% of its energy through leakage. Always insist on a pre-refurbishment survey report before accepting a price.
A chiller replacement quote should cover: removal and disposal of the existing unit (including refrigerant recovery and F-Gas certification), crane hire or rigging for getting the old unit out and the new one in, any structural modifications to the plant room or plant platform, new pipework connections (including flexible connections, isolation valves, strainers, and flow switches), electrical supply upgrade if the new unit has different power requirements, BMS integration, water treatment of the system, and full commissioning including performance testing. For a 300kW air-cooled chiller replacement in a London commercial building, budget £60,000–£120,000 depending on access constraints and whether the project requires planning or structural work.
Pipework is priced by linear metre, differentiated by pipe diameter, material (steel, copper, MLCP, stainless), and whether it includes insulation. Typical installed rates for commercial steel pipework range from £35–£60/m for 25mm to £120–£250/m for 100mm including fittings, supports, and insulation. Valves, strainers, flexible connections, and specialised fittings are priced individually. The cost drivers that catch people out are: working at height (adds 20–40%), hot work permits in occupied buildings, system drainage and refilling, and the need to maintain partial operation during modifications. Always check whether pressure testing and system flushing are included — BSRIA BG 29/2012 sets out commissioning requirements for variable flow pipework systems, and a proper flush-and-fill isn’t optional.
The building owner or client pays for asbestos management. M&E contractors will typically exclude all asbestos-related work from their quotes because they’re not licenced to handle it and the risk sits with the duty holder under the Control of Asbestos Regulations 2012. What should happen is: a refurbishment and demolition (R&D) asbestos survey is carried out before the M&E work is tendered, and any required removal is completed by a licenced asbestos contractor before the mechanical team starts. If the survey hasn’t been done and the M&E contractor encounters asbestos, work stops, costs escalate, and the programme gets wrecked. Budget £1,500–£5,000 for an R&D survey on a standard commercial floor plate, and significantly more for removal.
Access equipment is usually excluded from individual trade quotes because it’s more efficient to provide it centrally via the main contractor or a specialist scaffolding package. However, if you’re procuring M&E work directly as a client (not through a main contractor), you need to either include access in the M&E contractor’s scope or provide it yourself. MEWP hire runs £200–£500/day depending on the type and reach required. Internal scaffold for a plant room typically costs £2,000–£8,000 per erection depending on height and complexity. On a 10-storey office retrofit, access equipment can add £30,000–£60,000 to the overall project cost — it needs to be in someone’s budget.
A provisional sum (PS) is an allowance for work that’s anticipated but not yet fully defined — for example, “provisional sum of £15,000 for builders’ work in connection with mechanical services.” The contractor includes this amount in their price, but the actual cost is adjusted when the work is carried out. A prime cost sum (PC sum) is an allowance for a specific item to be selected or supplied later — typically major plant items where the exact specification is still being finalised. Both are mechanisms for managing uncertainty, but they also mean that portion of the quote is not a fixed price. Minimise provisional sums by defining scope properly at tender stage.
Out-of-hours rates in London and the South East are typically 1.5x standard rates for evenings and Saturdays, and 2x for Sundays and bank holidays. For a standard mechanical engineer, that takes day rates from around £350–£450/day to £525–£675 for Saturday work and £700–£900 for Sunday. The bigger cost isn’t just the hourly uplift — it’s the reduced productivity. A team that can complete a task in one 10-hour day shift will often take two 6-hour night shifts to do the same work, because of mobilisation time, security requirements, noise restrictions, and the need to make areas safe before the building opens. Always programme out-of-hours work realistically — a quote based on day-shift productivity at night-shift rates will overshoot on both time and cost.
“Supply and fix” means the contractor provides the equipment and installs it — they’re responsible for the whole job including getting it working. “Supply only” means they just deliver the equipment to site and someone else installs it. Supply only is typically used when a client or consultant specifies a particular manufacturer’s product and wants to procure it directly (to get a better price or ensure the exact model). The risk with supply only is that the installing contractor can blame the supplied equipment if anything goes wrong, and the supplier can blame the installation. For BMS and mechanical work, supply and fix is almost always cleaner because one contractor owns the whole chain from delivery to commissioning.
Yes — or at the very least, the mechanical quote should clearly state the controls interface requirements and the demarcation point with the BMS contractor. If a mechanical contractor supplies an AHU with an integral controls panel, their quote should include the panel, the local controller, and all wiring within the unit. The BMS contractor then connects to the AHU panel via a defined interface (usually BACnet or Modbus). If the mechanical quote excludes controls entirely, you’ll end up with a gap between the mechanical installation and the BMS that nobody has priced. This gap is where cost overruns and finger-pointing live.
Testing and commissioning should always be a visible line item in a mechanical quote. It covers pressure testing of pipework, leak testing of ductwork, air and water flow balancing, and functional performance testing of all plant. CIBSE Commissioning Code A sets out the requirements for air distribution system commissioning, including measurement accuracy, tolerances, and documentation. A proper commissioning exercise on a mid-size commercial building typically takes 3–6 weeks and costs 8–15% of the mechanical contract value. If a quote allocates two days for commissioning on a £200k mechanical package, either they don’t understand the scope or they plan to hand over an unbalanced system and deal with complaints as snagging.
When the client supplies equipment (free-issue), the contractor’s quote should clearly state: receiving and storage on site, offloading (if applicable), installation including all connections (mechanical, electrical, controls), commissioning of the supplied item as part of the overall system, and any warranty implications. The contractor should not be liable for defects in the equipment itself, but they are responsible for correct installation. The quote should include an explicit allowance for coordination — checking that the free-issue equipment actually matches the design, arrives on time, and comes with the right accessories. Free-issue equipment that arrives without valve kits, flanges, or fixings is painfully common and always causes delays.
A quote is a fixed-price offer for a defined scope of work — the contractor is committed to that price for the stated validity period. A tender is a formal competitive process where multiple contractors submit quotes against the same specification, usually under structured procurement rules. An estimate is an informal indication of likely cost, not binding on the contractor, typically provided before the full scope is defined. In construction, “tender” refers to both the process and the document submitted. You tender for work (process), and the contractor submits a tender (document). The tender document is effectively a formal quote submitted under competitive conditions.
Standard quote validity in UK building services is 30 days. For larger projects or where specialist equipment has long lead times, 60 days is common. Beyond 90 days, contractors will often add material price escalation clauses because copper, steel, and equipment prices can move 5–10% in a quarter. In the current market, some manufacturers are only holding prices for 14 days on major plant items like chillers, heat pumps, and AHUs. If you’re sitting on a quote for more than 30 days without placing an order, ask the contractor to reconfirm the price before you commit — it may have moved.
Preliminaries (prelims) are the contractor’s project-level costs that aren’t directly part of the installed work. They include: site management and supervision, temporary site accommodation, welfare facilities, security, insurance, health and safety compliance, programme management, design management (on D&B), temporary services, waste removal, and general attendance. Prelims typically represent 8–15% of the contract value depending on project duration and complexity. On a 6-month mechanical installation worth £500k, expect £40k–£75k in prelims. If a contractor’s prelims seem unusually low, either they’ve underestimated the management requirement or they’ve buried the cost elsewhere in the rates.
Formalise every change. Issue a written instruction, get the contractor to price the change before authorising the work, agree the cost impact and any programme implications, and record it as a formal variation. The worst outcome is verbal instructions followed by disputed invoices at final account. Most standard forms of contract (JCT, NEC) have built-in variation procedures — use them. On BMS projects specifically, scope changes are common because the mechanical design often evolves after the BMS is tendered. A well-managed project anticipates this and includes a contingency of 5–10% for BMS variations.
Design and build (D&B) means the contractor takes responsibility for both the detailed design and the installation. The client provides an employer’s requirements document (or performance specification), and the contractor designs the system to meet those requirements. For BMS, this means the contractor selects the hardware platform, designs the network architecture, develops the control strategies, and delivers the complete system. The advantage is single-point responsibility. The risk is that the contractor designs to minimum compliance rather than best practice unless the employer’s requirements are detailed enough. D&B works well when the client has a strong M&E consultant reviewing the contractor’s design proposals.
Three quotes is the standard minimum for competitive procurement, and it works well for straightforward BMS packages. But for specialist work — BMS upgrades on proprietary systems, complex integrations, or projects requiring specific manufacturer partnerships — you might only have two credible contractors in your area. Getting a third quote from a contractor who can’t realistically deliver the work just wastes everyone’s time and distorts the comparison. Focus on getting quotes from contractors who have demonstrable experience with your system type, your building type, and your scale of project. Two strong quotes from qualified contractors beat three quotes where one is from a domestic electrician who “also does BMS.”
Check their trade body memberships (B&ES, ECA, BSRIA for BMS specialists), manufacturer accreditations (Trend, Siemens, Distech, Schneider all have partner programmes), and whether they hold ISO 9001 (quality management) and ISO 14001 (environmental management). Ask for references on projects of similar scale and type to yours. Check Companies House for financial stability — a contractor who goes into administration mid-project is catastrophic. For BMS specifically, ask who their commissioning engineers are and what qualifications they hold. A BMS contractor whose team is entirely installation electricians with no controls engineers will struggle to deliver a properly commissioned system.
At minimum: CSCS cards for all site operatives, ECS (Electrotechnical Certification Scheme) cards for anyone doing electrical work, and the company should be registered with a competent person scheme for electrical work (NICEIC, NAPIT, or equivalent). For BMS-specific work, manufacturer accreditation with the platform they’re installing is important — it ensures access to technical support, firmware updates, and warranty coverage. BS 7671:2018 (18th Edition IET Wiring Regulations) compliance is mandatory for all electrical installation work, and the contractor should be able to provide electrical installation certificates (EICs) for all BMS wiring.
Minimum insurance requirements for a BMS contractor working on commercial projects: public liability insurance of £5–£10 million, employer’s liability of £10 million (legal minimum is £5m but most main contractors require £10m), professional indemnity of £2–£5 million (essential if the contractor has any design responsibility), and contractor’s all-risks or works insurance appropriate to the contract value. Ask for certificates of insurance, not just stated cover levels, and check the policy dates. On design-and-build BMS projects, professional indemnity is critical because the contractor is designing a system that affects building performance, energy consumption, and occupant safety.
Standard payment terms in UK construction are 30 days from invoice date, with monthly valuations based on work completed. For BMS work, structure payments against programme milestones: 10–15% on first fix completion, 15–20% on second fix and controller installation, 20–25% on programming and graphics completion, 20–25% on commissioning completion, and 5–10% retention held for 6–12 months post-completion. Avoid paying more than 70% of the contract value before commissioning is complete — commissioning is where the system either works or doesn’t, and you need financial leverage to ensure the contractor finishes it properly. Under the Housing Grants, Construction and Regeneration Act 1996, contractors have a statutory right to interim payments — you can structure the milestones, but you can’t withhold payment for completed work beyond the agreed terms.
Alpha Controls delivers BMS installation, commissioning, and maintenance across London and the South East. We work with Trend, Distech, Schneider, and open-protocol systems on commercial offices, data centres, healthcare facilities, and mixed-use developments. If you need a quote for BMS work or a second opinion on a tender you’ve received, get in touch or request a quote.
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