Heating Engineer Payment Schedule: Deposit to Final Invoice

The supplier wants the equipment order, but the quote does not say when the deposit is due or what payment unlocks. Fix the heating engineer payment schedule before the customer accepts the quote. Put every stage, amount and trigger into the quote or contract.

If the customer has already accepted terms that do not contain the schedule, stop. Agree the change in writing before issuing a stage invoice or ordering equipment. Keep the accepted contract value, invoices issued and payments received as separate totals.

Lock the replacement scope before splitting the price

Inspect the property before you write payment stages. A vague scope produces vague invoice triggers.

Record the replacement equipment, output and controls. State where each item will go and how it will connect to the existing system. Include the flue or discharge route, pipework changes, electrical work, access equipment, protection, removal, disposal, testing, commissioning and handover documents within your scope.

Write down anything you could not inspect. Existing pipework can be hidden. An electrical supply may need work. The proposed flue route may depend on access that is not available during the survey.

Do not price those unknowns as if you have seen them. State the assumption and explain what happens if site conditions differ.

Record the customer’s responsibilities beside the affected work. That might mean clearing an airing cupboard, providing access to a plant room or arranging for another trade to finish work before your start date.

Confirm the equipment option in writing. A supplier document helps your purchasing. It does not replace the customer quote.

If the enquiry has not reached survey stage, use the heating engineer call-out triage checklist to collect the property, fault and access details before booking the visit.

Choose the heating type and check who signs off the work

Do this before promising an installation date or making approval part of the final payment trigger. Start with the heating type and UK nation. A gas boiler, heat pump, oil appliance, solid-fuel appliance or electric heating system does not follow the same route.

Ask each question separately and record the answer against the job:

• Does the replacement include gas work? Check who may carry it out and the work category with the Gas Safe Register (opens in a new tab). This applies across the UK.
• Does a heat pump or air-conditioning system require work on equipment containing fluorinated greenhouse gases? Check the qualification route in the GOV.UK guidance for work on F-gas equipment (opens in a new tab).
• Does work in England need building regulations approval? Ask building control (opens in a new tab) for the installation address.
• Does work in Wales need building regulations approval? Check the route with the Welsh Government building regulations service (opens in a new tab).
• Is the property in Scotland? Ask building standards in Scotland (opens in a new tab) about the building approval question.
• Is the property in Northern Ireland? Check the approval route through Northern Ireland building regulations guidance (opens in a new tab).
• Will notifiable electrical work in England or Wales be self-certified under Part P? Check the registration route with a competent person scheme (opens in a new tab). Do not apply that route to Scotland or Northern Ireland; use the building approval route for the nation where the property stands.

Do not turn an outside approval into a payment trigger without defining it. State who arranges it, what record marks completion and what happens if the inspecting body controls the date.

Put the answer into the quote and job record. The office should not have to guess whether commissioning, customer handover or an approval record is still outstanding.

Map when the replacement starts costing you money

Build the quote before allocating payment stages. Start with the costs created by the accepted scope:

• Equipment and purchased components.
• Installation materials, fittings and consumables.
• Labour for removal, installation, testing and commissioning.
• Electrical, lifting, access or other subcontract work.
• Delivery, protection, waste removal and other direct job costs.
• Overhead recovery.
• Markup.

Keep cost and price separate. Cost is what the job consumes. Markup is what you add to cost to reach the selling price. The payment schedule controls when you bill that selling price; it does not replace the costing behind it.

Next, mark when each cost becomes committed. The equipment may need paying for before delivery. A subcontractor may require a confirmed booking. Labour builds as the crew removes, installs and commissions the system.

Use your own supplier terms, wage costs and overhead records. Do not choose a deposit because it looks normal. Choose it because you can point to the commitments it controls.

Build the heating engineer payment schedule around visible work

Start with the proposed quote total. A heating engineer payment schedule may have a deposit and final stage, or it may need a genuine progress stage between them. Use no more stages than the job needs, then include the full schedule in the quote before acceptance.

Each trigger must answer a simple question: what has happened on the job that now makes this amount due?

Set the deposit from early exposure

List every job-specific commitment due before the next payment stage. Record when it must be paid and how much of the selling price you will allocate to the deposit.

Use this worksheet. The internal commitment cost supports your decision. The customer-facing deposit remains part of the agreed selling price.

Deposit allocation worksheet

Accepted equipment or specification: [details]
Next payment stage: [named milestone]

Commitment: [equipment, materials, subcontract work or other direct cost]
Supplier or payee: [name]
Payment or commitment date: [date]
Internal cost from your own figures: [£ amount]
Selling price allocated to deposit: [£ amount]

Commitment: [description]
Supplier or payee: [name]
Payment or commitment date: [date]
Internal cost from your own figures: [£ amount]
Selling price allocated to deposit: [£ amount]

Total commitments due before next stage: [£ amount]
Total selling price allocated to deposit: [£ amount]
Deposit shown in customer quote: [£ amount]
Checked by: [name and date]

The allocated selling price must come from your quote costing. Do not copy the internal cost total into the customer quote without accounting for overhead recovery and markup.

Add a progress stage only when there is a real middle point

Use a progress stage when both parties can identify the milestone without interpreting a percentage of completion.

Equipment delivery, equipment installation and completed commissioning are different events. Pick the event your invoice actually depends on.

A progress trigger could refer to the specified equipment being fixed in its quoted position with the stage’s named connections complete. It must also say what remains, such as controls, testing, commissioning, snagging or handover.

If the middle of the job cannot be described clearly, remove the progress stage. Use the deposit and final stage instead.

Reconcile the original stages to the quote

Add the deposit, progress stage if used, and original final stage. They must return to the quote total before variations.

Do not leave an unexplained balance for the final invoice. Do not rewrite the accepted quote when a stage is billed.

Use this blank heating engineer payment schedule as the control sheet attached to the quote:

Customer: [name]
Installation address: [address and postcode]
Quote reference: [reference and version]
Quote value: [£ amount]
Accepted equipment: [make, model or agreed specification]

Deposit
Trigger: [quote acceptance / other agreed event]
Purpose: [costs or commitments controlled]
Invoice amount: [£ amount]
Invoice reference: [reference]
Payment received: [date or not received]
Equipment order authorised by: [name and record]

Progress stage, if required
Trigger: [visible installation milestone]
Work complete at this point: [scope]
Work still outstanding: [scope]
Invoice amount: [£ amount]
Evidence: [site record and photographs]

Final stage
Trigger: [defined completion and handover event]
Original final-stage amount: [£ amount]
Approved variations: [references and amounts]
Earlier invoices: [references and amounts]
Payments recorded: [references and amounts]
Balance due: [£ amount]

Issue the heating replacement deposit invoice without calling it payment

Send the heating replacement deposit invoice only after the agreed invoice trigger. Connect it to the accepted quote rather than writing a new version of the scope.

Before the office issues it, check the business record that says whether the business is VAT registered and how the advance payment is treated. Use the HMRC requirements for invoice fields (opens in a new tab), the HMRC VAT invoice rules (opens in a new tab) and the HMRC guidance for deposits and advance payments (opens in a new tab) for that decision. Then show the required customer, supplier, date, description, amount and VAT details on the invoice.

State what the deposit controls. It might control equipment ordering or a booking commitment. Do not describe it as payment for completed installation when no installation has happened.

Keep these events separate in the heating engineer payment schedule and job record:

• The customer accepted the quote and payment schedule.
• The office issued the deposit invoice.
• The payment was received.
• The payment met the agreed clearance trigger.
• The equipment order was authorised.
• The supplier confirmed the order against the job.

Cleared payment does not settle every ordering question. Before committing to equipment, check how the contract was agreed and whether the customer has a cancellation right. Use the GOV.UK rules for online and distance selling (opens in a new tab) for a contract agreed at a distance, or the GOV.UK doorstep-selling rules (opens in a new tab) for a contract agreed at the customer’s home. Record the contract route, the cancellation position and the person who authorised the order.

If cleared payment is the agreed trigger and the contract record permits the order, place it. An accepted quote is not cash. An issued invoice is not cash either.

For the document fields used across deposit, stage and completion billing, use the heating engineer invoice guide.

Bill a replacement progress invoice only at the named milestone

The new appliance is in position. Controls, testing, commissioning and handover remain. The office wants to send the replacement progress invoice.

Read the accepted trigger first. If it says equipment installed in position and names the included connections, check that work on site. If the trigger says commissioned, the invoice must wait.

Make a dated milestone record before invoicing. Identify the installed equipment, its location and every named connection included in that trigger. Record the person who confirmed the milestone and any testing or commissioning that the trigger specifically requires. Attach photographs that show the recorded work.

Do not use a delivery note as installation evidence. Delivery proves that goods reached a location. It does not prove they were fitted, connected or tested.

The progress invoice should show the quote reference, milestone reached, current stage amount, earlier invoices and stages still to come. Bill the stage. Do not recreate the whole quote as a new invoice.

Stop and write a variation when the hidden work appears

The old system comes out and exposes pipework, wiring, a flue route or an access condition outside the accepted scope. Stop before the extra work disappears behind the replacement.

Photograph the condition. Describe why the quoted work cannot continue unchanged. Price the extra labour, materials, subcontract work and programme effect. Send the variation to the person authorised to approve it.

The variation should state:

• The condition found.
• The added or reduced work.
• The price change.
• The invoice trigger.
• Any change to the programme or original stages.
• The approval record.

Keep the original accepted quote intact. An approved variation changes the current contract value. It does not alter the historical quote or pretend the extra work was included from the start.

Oak Street worked example

Oak Street is the house electrical example, but the same document control applies to a heating replacement.

R. Chen accepted Quote Q-1847 for a bathroom exhaust fan and four LED downlights at 14 Oak Street. The quote total was 1,105 sample currency units. The ceiling was lined and chasing was excluded.

Extra cable and chasing were approved on site as a 160 variation. Invoice INV-1847 therefore totalled 1,265 sample currency units. The original quote remains 1,105, while the approved variation explains the difference.

Do not calculate profit from the 1,265 invoice. The costs belonging to the 160 variation are not given. Invoice value and profit are not the same record.

Define completion before sending the final heating invoice

The installation may be working while a snag, approval record, customer instruction or included handover document remains outstanding. Read the completion trigger instead of billing from memory.

Check the accepted scope for:

• Equipment and connections installed.
• Testing and commissioning completed.
• Controls set up within scope.
• Snags completed or recorded under the agreed process.
• Waste removed and the work area left as agreed.
• Customer instruction completed.
• Included certificates, notifications or handover records supplied.

Only include an outside inspection or approval in the trigger if the accepted quote says it belongs there. Record who controls that event.

The final heating invoice should use the same terms as the quote. Show the accepted quote, earlier stage invoices, approved variations, payments recorded and remaining balance as separate lines.

An invoice total shows what has been billed. The payment record shows what has been received.

Do not hide an unpaid deposit inside the final balance without identifying it. The customer and office should be able to trace every amount back to a quote, stage or approved variation.

Close the job with payment reconciliation and cost tracking

Match each payment to an invoice. Record part payments against the document they belong to. Keep cleared receipts separate from invoices issued and from the current contract value.

Then finish the cost tracking. Enter actual equipment, materials, labour, subcontract and direct job costs. Compare them with the accepted quote costing. Include the variation costs where you have them.

Use the finished-job job-costing method to separate money billed from the profit the work produced. A paid invoice can still belong to a badly costed job.

Yes Foreman can keep the accepted quote, heating engineer payment schedule, stage invoices, variation and payment records against the same heating trade job.