Best Invoicing Software for Plumbers & Gas Engineers (UK, 2026)

The average heating & plumbing business is owed over £6200 in unpaid invoices. The right invoicing software stops paperwork from eating your evenings — and stops customers from “forgetting” what they owe you.

This guide compares the best invoicing software for UK heating and plumbing businesses so you have what you need to pick the right one.

What makes invoicing software actually good for heating & plumbing

Good invoicing software goes beyond just creating the invoice itself. For heating & plumbing businesses, it often needs to sit alongside a gas certificate, link to the right job, capture parts and labour, and ideally collect payment before you’ve left the address.

The criteria worth caring about:

• Speed on-site — can you raise an invoice from your phone, or does it need to be done later?
• Connected to the job and the certificate — does the invoice know what you fitted, what you tested, and what you certified?
• Payment built in — can the customer pay there and then?
• MTD-ready — will it push cleanly into your accounting software so your accountant (or yourself) isn’t fishing through paper at year-end?

Now onto the list itself.

Gas Engineer Software (GES) — The Best Overall Invoicing Software For Heating & Plumbing Businesses

With GES, the invoice is the natural end of the job. You complete the work on-site, fill in the gas safety certificate or service record, add parts and labour, before putting together an invoice – all in one app.

An invoice is only ever as fast as the information sitting behind it. For many heating businesses, that information is scattered: The quote is in one app, the job notes are in your head, the certificate is a PDF you emailed yourself, and the parts are on a receipt in the van door. Building the invoice means going and finding all of it first. That’s the bit that eats the evening. The typing takes two minutes.

Gas Engineer Software keeps the whole job in one chain, and the invoice is simply the last link in it:

• The customer record has everything: Property, appliance, paperwork, and every job you’ve done there before, in one place.
• Existing quotes can be converted into invoices. This alone makes creating an invoice a trivial task. See how it works.
• The customer can pay before you’ve left. A Crezco payment link or QR code means bank transfer there and then, no card fees out of the margin.
• Chasing happens without you. Payment reminders go out automatically.
• The books stay current. Syncs to Xero, QuickBooks or Sage, MTD compliant without a year-end shoebox exercise.
• Next year’s job books itself. Issuing the certificate queues a service reminder — which becomes next year’s job, which becomes next year’s invoice.

Accounting Software: Xero, Quickbooks, and Sage

All of Xero, Quickbooks, and Sage offer a clean interface, strong mobile experience, and are widely loved by small to large UK businesses.

Their invoicing functionality is best-in-class when viewed in isolation, so these are genuinely good options for any business. However, using them in isolation means giving up on a more heating & plumbing specific workflow: none will connect invoices to jobs, certificates or your diary like a job management platform can.

Where these platforms shine are their integrations with job management software options for gas engineers and plumbers like GES. Invoices you create on one of these systems will sync over to Xero, Quickbooks or Sage, alongside payments and customers.

The result is a streamlined jobs-to-accounts workflow that keeps you organised and on top of your paperwork.

Learn more about the best accounting software in our comparison article.

Powered Now

A UK-built trades platform that includes invoicing alongside other job admin features. Designed broadly for tradespeople — electricians, builders, decorators, plumbers — rather than for the heating and plumbing trade specifically.

Powered Now has a fully-fledged invoicing system great for trades businesses, and integrates with the accounting software options mentioned above. It also includes SumUp payments to help you get paid faster.

While Powered Now is a solid option for multi-trade businesses, it lacks some of the more heating & plumbing specific features. Read a side-by-side comparison of Powered Now and Gas Engineer Software.

Gas App Uk

Gas App UK is a reference and paperwork app built for the individual engineer — a big boiler manual library, a fault-finding forum, gas calculators, digital forms and a diary, on one flat subscription. 

It does produce invoices, so it earns a place on the list. But the invoice is where it stops. There’s no way for the customer to pay it — no payment links, no QR codes — and nothing chases it, so an unpaid invoice sits there until you notice. 

The structural difference is that there’s no job underneath. In Gas App Uk, the certificate is the unit of work, and the status lives on the form, so the quote, the invoice, the photos and the notes for one visit don’t sit together anywhere.

There’s a full side-by-side on the Gas App UK vs Gas Engineer Software page.

ServiceM8

An Australian platform with UK pricing, well-regarded among trades businesses and genuinely good at the quote-to-invoice basics. It’s priced differently to the other options here in that you pay by jobs per month rather than by user, and every paid plan includes unlimited users.

That pricing model is the first thing to work out. Starter is £25/month but caps you at 50 jobs. If your week is services, breakdowns and landlord certs — lots of small jobs rather than a few big ones — you’ll be on the £59 or £119 plan faster than you’d expect.

One consideration for gas work is how certificates happen. The Electronic Forms module only appears from the Growing plan up, and it’s a form builder: you build your own compliance documents, buy pre-made ones from their Form Store, or pay a partner to design them. A CP12 isn’t something that ships with the product and gets maintained as requirements change — it’s something you assemble and then own the upkeep of. There’s a full breakdown on the ServiceM8 vs Gas Engineer Software page.

BigChange

An enterprise-grade field service platform aimed at larger fleets, with invoicing as one feature within a much wider back-office system. BigChange integrates with Xero and Sage, and helps facilitate the payment process for customers.

The trade-off is fit. BigChange is built for businesses with vehicles, dispatchers and back-office staff coordinating engineers from a central office — closer to commercial M&E contractors than to a sole trader or a small plumbing team. The invoicing feature is capable, but the rest of the platform is overkill for most heating and plumbing businesses, and the price reflects it.

Tradify

A cross-trade job management platform originally built in New Zealand, now used by UK trades.

Tradify invoicing is very capable and includes invoice reminders, credit card payments, and more. However, heating and plumbing-specific pieces — gas certificates, service records, landlord paperwork — aren’t part of the core. If your business runs on those documents, you’ll either bolt on another tool or live with workarounds. Read more about Tradify vs Gas Engineer Software.

At-a-glance comparison

How to choose – questions to ask yourself

The right pick depends less on features and more on a few honest questions about your business. 

• Are you squarely focused on heating and plumbing? If most of your week is services, breakdowns, gas safety certs and landlord work, you need software that understands those documents — not a generic trades or accounting tool you have to bend into shape.
• Are you spending evenings sending and chasing invoices? If the bottleneck is paperwork after the job rather than the job itself, prioritise on-site invoicing and built-in payment links over fancier reporting features.
• What does your accountant already use? Whatever invoicing tool you pick, your books still end up in Xero, QuickBooks or Sage. Save yourself a fight by making sure the two talk to each other cleanly.
• How many engineers will be raising invoices? A sole trader can get away with a simpler setup. Once you’ve got two or more engineers in the field, you want everyone in one system so nothing falls through the cracks and the office can see what’s outstanding in real time.
• Do you want to be paid on the day? If yes, look for payment links and bank-transfer collection built into the invoice itself
• Is your business mostly in the UK? UK-based support, UK pricing without FX surprises, and a platform that understands gas regulations and MTD rules will save real friction.