MTD for Heat Pump Installers —
Grant-Funded Jobs and Your Threshold
Include the full job value, even the portion covered by a government grant, before materials and MCS costs are deducted.
- The same £50k / £30k / £20k phased MTD thresholds apply as any self-employed sole trader, this is one of the fastest-growing trades in the UK's green energy transition.
- Government grant-funded installs (such as the Boiler Upgrade Scheme) still count at their full job value, the grant changes who pays part of the bill, not your total income.
- MCS certification, specialist tools, and refrigerant costs are all standard allowable expenses.
If you're a self-employed heat pump installer, MCS-certified and fitting air source or ground source systems for homeowners, Making Tax Digital applies to you the same way it applies to any sole trader. This is one of the fastest-growing trades in the UK as households switch away from gas boilers, and grant-funded installs have a specific point worth understanding for MTD.
Are You Affected by MTD as a Heat Pump Installer?
Yes, if your gross installation income, plus any other self-employment income, exceeds the relevant threshold:
| Tax Year Assessed | Threshold | MTD Start Date |
|---|---|---|
| 2024–25 | Over £50,000 | 6 April 2026. Live since April 2026 |
| 2025–26 | Over £30,000 | 6 April 2027 |
| 2026–27 | Over £20,000 | 6 April 2028 |
Your gross income is your total job value before expenses, the heat pump unit, materials, and MCS certification costs are all deducted afterwards, not before, when checking your threshold.
Grant-Funded Jobs — Do They Count Differently?
What You Can Claim
| Expense Category | Examples |
|---|---|
| Materials | Heat pump units, pipework, cylinders, and controls |
| Certification | MCS certification and scheme membership fees |
| Specialist tools | Refrigerant handling and commissioning equipment, via capital allowances |
| Vehicle costs | Van running costs or mileage, at the current HMRC rate |
| Insurance | Public liability insurance |
Records for MCS Jobs, Grants and Subcontractors
Heat pump jobs are larger and slower than most trades, with surveys, deposits, commissioning and sometimes grant paperwork. Each stage produces a payment or a cost that belongs in the right quarter.
- Record survey fees, deposits and stage payments on the dates they are received, with the customer and job reference.
- Keep MCS certification, scheme and registration fees as their own expense lines.
- Keep supplier invoices for units, cylinders and controls matched to the job, since individual units are high-value.
- If you subcontract electrical or plumbing work, record their invoice against the job and keep their certificates.
- Keep grant paperwork and commissioning records with the invoice, and ask your accountant how any scheme payment is recorded.
Common MTD Mistakes for Heat Pump Installers
- Recording only the final payment. Large jobs mean large deposits, and a £4,000 deposit belongs in the quarter it arrives.
- Treating unit cost as reducing income. The threshold uses the job price you invoice, not what is left after the unit.
- Skipping accreditation and training costs. They are allowable business costs, but they need a receipt.
- Confusing grant money with your income. How a scheme payment passes through your books depends on how the job is invoiced, so settle it with your accountant first.
- Forgetting van stock. Pipework, fittings and consumables bought for the van still need receipts.
A Sample Quarter: What the Update Looks Like
A sample quarter for an installer completing a handful of domestic jobs.
| Q2: 6 July to 5 October 2026 | Amount |
|---|---|
| Deposits and stage payments | £14,500 |
| Completed installations (balances) | £22,800 |
| Surveys and servicing | £1,900 |
| Total income | £39,200 |
| Heat pump units and cylinders | £19,400 |
| Subcontracted electrical work | £3,100 |
| Van, fuel and insurance | £2,350 |
| MCS fees, tools and training | £1,450 |
| Total expenses | £26,300 |
| Profit for the quarter | £12,900 |
Notice how uneven the picture is: deposits for jobs that finish next quarter are already in this one. The profit shown is only an indication, since the cost of units for unfinished jobs also lands here.
Worked Example
Owen — Self-employed heat pump installer, MCS certified
Owen's £61,000 includes the full value of every job, including the grant-funded portion. His combined income exceeds the £50,000 Phase 1 threshold, so MTD already applies to him.
Frequently Asked Questions
Does the grant portion of a job count as my income?
Yes. The full job value, the portion covered by the grant plus whatever the homeowner pays, counts as your gross trading income. The grant simply changes who pays part of the bill, it doesn't change your total income from the job.
What's the MTD threshold for heat pump installers?
The same as any self-employed sole trader: over £50,000 gross income in 2024–25 means MTD from April 2026, over £30,000 in 2025–26 means April 2027, over £20,000 in 2026–27 means April 2028.
Can I claim my MCS certification costs?
Yes, MCS certification and ongoing scheme membership fees are standard allowable expenses for this trade.
Does grant-funded work count differently from privately-funded installs?
No, both are simply combined into one gross trading income total for your MTD threshold check, there's no separate treatment based on how the job was funded.
What software do I need as a self-employed heat pump installer?
Any HMRC-recognised MTD software works. The main practical need is recording the full job value accurately, including grant-funded portions, which most trade invoicing software handles well.
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