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Accounting and invoicing for heat pump installers

Planning, grant application, delivery, installation and commissioning: heat pumps are large jobs with many parties and long lead times. Saldiqo issues stage invoices at order, delivery and commissioning, bills grant and own contribution separately and records manufacturers’ invoices.

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What comes up for heat pump installers

Large jobs with long lead times

The heat pump arrives weeks after the order. The firm advances the manufacturer’s price before the customer pays.

Grant and own contribution

Customers apply for grants, and the invoice has to show components so that the application is possible.

Servicing afterwards

Maintenance contracts secure recurring income when they are billed on time.

How Saldiqo helps

  • Stage invoices at order, delivery, commissioningQuote, stage invoices, final invoice.
  • Lines for the grant applicationUnit, installation and ancillary work as separate lines.
  • Manufacturer invoices per projectRecord invoices and assign them to the job’s cost centre.
  • Servicing as a recurring invoiceSaldiqo creates yearly servicing on schedule.

Typical invoice lines

Examples that often appear on invoices in this industry. You set the prices yourself.

  • Air-to-water heat pump, supply
  • Installation and hydraulic balancing
  • Commissioning and briefing
  • Buffer tank and accessories as per delivery note
  • Removal of the old system, disposal
  • Stage invoice 40 % on ordering the unit

Tax and invoicing in the UK

What applies to invoices in the UK, in short. As of October 2026.

VAT
Standard rate 20 %, reduced rate 5 % and zero rate 0 %. Saldiqo calculates each invoice line with the rate you pick.
VAT registration
You must register once your taxable turnover passes £90,000 over any 12 months, or you expect to pass it within the next 30 days. You can deregister below £88,000. Until you are registered, your invoices show no VAT, and Saldiqo adds up your 12-month turnover for you.
What goes on an invoice
If you are VAT registered: your VAT number, the tax point, unit prices and the VAT total in pounds. A limited company shows its registered name on every invoice, and its company number, registered office and part of the UK on letters, order forms and the website.
E-invoicing
There is no mandate today. From April 2029 e-invoicing is planned for all B2B and B2G sales that carry VAT, through Peppol. The exact date and standard are not yet in law, and the government’s roadmap follows with the Budget on 28 October 2026.
VAT returns
VAT returns go to HMRC through Making Tax Digital, usually quarterly, due one month and seven days after the period. Saldiqo shows sales and VAT per rate and exports CSV. It does not submit to HMRC, and for Making Tax Digital you need software recognised by HMRC.
Record keeping
Keep VAT records for 6 years.
Late payment
Statutory interest on late business payments is the Bank Rate (3.75 % in the second half of 2026) plus 8 points, so 11.75 %. On top comes fixed compensation of £40, £70 or £100, depending on the amount owed (under £1,000, from £1,000, from £10,000). Consumers have no statutory interest.
Getting paid
Your sort code and account number are on every invoice. Customers pay by Faster Payments or Bacs, and banks check the account name with Confirmation of Payee. There is no QR standard in the UK.

Frequently asked questions

How do I bill units with a long lead time?

With a stage invoice on order. More stages at delivery and commissioning, and the final invoice deducts them all.

Can I show lines for grant applications separately?

Yes. Unit, installation and ancillary services as separate lines. What details an application requires you clear with the funding body.

Do heat pump installers in the UK have to charge VAT?

Only once they are VAT registered. Registration is required when taxable turnover passes £90,000 over any 12 months, or is expected to within the next 30 days. Below that you may register voluntarily. If you are not registered, you must not show VAT on your invoices.

Do heat pump installers in the UK need e-invoicing?

Not today. A mandate for B2B and B2G sales with VAT is planned from April 2029, and the details were still open as of October 2026. You can keep sending PDF invoices for now.

How long should heat pump installers keep invoices?

Keep VAT records for 6 years. You can store receipts digitally in Saldiqo. The legal duty to keep records stays with you.

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Write invoices, match payments, collect receipts and send reminders: free and without a trial period.

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As of October 2026. General information, not legal or tax advice, without guarantee. For your case ask your tax adviser.