AI tendering for plumbing and heating engineers

Price a plumbing and heating tender from the equipment schedules and schematics: kit at your buying price, pipework measured from the layouts, labour by days per dwelling or per plant item, then commissioning, notifications and certificates as their own lines. First decide whether you're installing someone else's design or designing it. AI reads the schedules; you own the price.

What makes plumbing and heating tenders hard to price?

The schedules look complete, but they rarely are. A heating package for a housing association or a small commercial job usually arrives as equipment schedules, a schematic, some floor layouts with pipe runs drawn indicatively and a performance spec. What's missing is usually what costs you.

The problems that come up on most packages:

• Design responsibility. Performance specs ("system to achieve 21°C in living rooms") put the heat loss calculation and sizing on you.
• Pipe runs. Shown schematically, so lengths and routes are guesses until you measure.
• Unvented cylinders. Notifiable work with its own competence and paperwork.
• Commissioning and water treatment. Flushing, inhibitor, balancing and paperwork for every system.
• Long-lead kit. Boilers, cylinders and heat pumps with lead times that don't match the programme.
• Provisional sums. Items the client can't define yet, which you must price but can't control.

That was about tenders. Firms that run well on reactive and domestic work often find a tender pack a different language: schedules, schematics, preliminaries and a form of tender. The method below turns it back into what you already know, which is days per house and kit per house.

How do you price a heating tender per dwelling?

Price one house fully, then multiply, and add the items that only happen once. Repeat dwellings are where a per-house build-up beats a rate per item.

Half a day per house for commissioning and paperwork looks generous until you count it: flushing and inhibitor, balancing, the cylinder checks, the commissioning record, the customer handover in an occupied home and the notification. Leave it out and eight houses lose four days.

Approved Document G applies in England. Wales, Scotland and Northern Ireland have their own building regulations; check with the local building control body if you're tendering there.

Is this a design-and-install or install-only tender?

Read the spec, not the title. If the spec states performance (temperatures, flow rates, heat outputs) and the drawings are "indicative", you're being asked to design. If it gives sized equipment and pipe sizes on a schematic, you're installing.

What should a plumbing and heating tender clarify?

Commissioning, water treatment, design and builder's work, in that order. Then long-lead kit and anything priced as a provisional sum.

Tender: project name, mechanical (plumbing and heating) package
Our price: £amount excluding VAT, dated date

Design
1. Installed to the consultant's design: drawings numbers and revisions, schedules references. Design responsibility, including heat loss and sizing, remains with the designer. Or: design included to [standard] for [scope].

Commissioning and certification
2. Commissioning, flushing and balancing included for our installation, with commissioning records and handover to the occupier.
3. Unvented cylinders installed and notified under our competent person scheme registration scheme name.
4. Commissioning of controls by others (BMS, smart controls) excluded.

Water treatment
5. Cleaning and inhibitor dosing included. Water treatment beyond this, sampling and analysis, excluded unless listed.

Builder's work
6. Builder's work in connection, lifting and relaying floor coverings, making good and decoration excluded.
7. Asbestos survey, removal and associated delays excluded.

Kit and programme
8. Boilers and cylinders priced on manufacturer quoted lead time of weeks weeks. Delays from changes to specified kit are not at our cost.
9. Provisional sums: items to be valued on instruction at our schedule rates.
10. Price valid for number days; kit subject to manufacturer price changes after that date.

Payment
11. VAT and CIS applied as HMRC rules require. CIS deducted from the labour element only, not from materials we pay for directly.

On public and housing association tenders, check the instructions to tenderers before adding clarifications: many say qualified bids will be rejected, and raising questions before the deadline is safer. See qualifications and exclusions, and for how quality answers are scored, quality vs price scoring.

What can AI do on a heating tender, and what can't it?

AI is good at turning schedules and specs into a priced list; it can't tell you what's under the floor or how an occupied home will behave on install day.

What it does well:

• Schedules to price lists. Reading equipment schedules and pricing them from your merchant prices.
• Spec reading. Picking out design wording, water treatment, named kit and testing clauses.
• Gaps. Drawings listed but missing, schedules that disagree with schematics.
• Drafting clarifications from your standard list.

What still needs you:

• Days per house. Occupied homes, access and the existing system decide the labour.
• Pipe routes that the schematic doesn't show.
• Design judgement, if you're asked to verify sizing.
• Sign-off on the price, the clarifications and the programme.

Which plumbing and heating tenders should you bid?

Repeat dwellings with a clear design and a sensible programme suit small firms best. Use the 10-minute tender read and walk away from performance-spec packages with no design fee, or programmes that need kit you can't get in time. For how Nexley works for heating firms more widely, see the gas and heating trade page.

Common questions