You're running a tender to overhaul your information system, and the same sentence comes back in every proposal: "our ERP includes a maintenance module". Your comparison matrix then raises the ritual question: ERP with a CMMS module, or a dedicated CMMS? The debate begins, the columns fill up, and nobody notices that the question itself is wrong.
It assumes that a CMMS is a small niche tool to be bolted onto the side of a large general-purpose system. For a plant maintaining its own production lines, that's a fair assumption. For a company that sells maintenance — HVAC, refrigeration, electrical, multi-technical, lifts, fire safety — it's exactly the opposite. Your value chain, from quote to invoice, is the native scope of a vertical CMMS. Here's why that changes the conclusion.
An ERP's maintenance module was never designed for your business
This isn't about the quality of the vendor. It's about original purpose, and it has very concrete consequences.
An ERP maintenance module almost always originates in an industrial context: a plant, an asset base, internal work orders, cost-centre allocation. None of that assumes you invoice a customer at the end. Yet your business starts with a quote and ends with a payment. In between there is a contract, response-time commitments, contractual preventive visits, out-of-contract works to be signed off, and hours to be valued at the right rate. That commercial thread isn't in the module's DNA — it gets added on.
The gaps are always the same ones:
- Mobile. Either it doesn't really exist, or it's a stripped-down version of the web app. The test is simple: a basement plant room, a flat roof, a boiler house. Without full offline mode — asset history lookup, report entry, photos, customer signature — the engineer walks out with a paper sheet and someone re-keys it in the evening.
- Multi-level maintenance schedules. A quarterly schedule, a six-monthly one and an annual one on the same asset family, with nested tasks: that's daily life on a full-service heating contract (P2 or P3). Few generic modules handle it without contortions.
- Contracts with recurring billing. Automatically invoicing contract fees, at the right frequency, with price indexation, and distinguishing what's included from what's chargeable as an extra.
- Scheduling. Assigning the right skill and the right certification to the right place, and optimising routes. A generic calendar is not a field service management tool.
- The customer portal. Raising a service request, tracking its progress, downloading reports and safety logbooks. Your clients increasingly ask for it in their specifications.
Every one of these gaps gets filled with custom development. That's where budgets slip and timelines stretch: not on the ERP core, which does its job very well, but on the months of configuration and development needed to recreate what a maintenance management platform does out of the box. And custom code is paid for twice — once when it's built, then again at every upgrade. The module ticks the box in the comparison matrix. It doesn't deliver in the field.
A vertical CMMS covers the whole chain, from quote to invoice
Walk through your business link by link and see where it sits.
A request comes in — through the customer portal, by email, by phone, as a ticket. It becomes a qualified service request, linked to a site, a customer and an identified asset. If it's out of contract, it generates a quote, sent, chased and electronically signed. The signed quote creates the job. If it's contractual, the contract's preventive maintenance plan generates the year's work orders on its own, with the associated task lists.
Those jobs are then scheduled: skills, certifications, geographical patches, response-time commitments, route optimisation. They're carried out on mobile, including with no signal: readings, checkpoints, before/after photos, parts used, time spent, customer signature on site, report sent immediately. They're invoiced — on actuals, on a fixed price, or on a contractual billing schedule — then tracked through to payment and chasing. And at every step, margin is calculated: by contract, by customer, by site, by engineer.
That scope is the scope of an industry-specific ERP. Not of a side tool. It's what Yuman has done as standard for ten years, across an asset base of 1.6 million items, more than 15,000 active users and around €400M invoiced each year through the platform, in over 15 countries. Groups such as Descours & Cabaud (Prolians), Engie, SKF, Groupe NGE and Emeria use it for their service operations.
Specialisation shows up above all in the areas a general-purpose module doesn't reach. The French e-invoicing mandate for 2026-2027 and Peppol are handled natively, including for job invoices originating in the field — rarely the case with a maintenance module bolted onto an ERP where only central invoicing has been brought into compliance. Security is held to the same standard: ISO 27001 certification, GDPR compliance, European hosting. And built-in AI works on precise operational cases: rewriting and validating job reports, diagnostic support, and detecting jobs completed but never invoiced. That last point alone adds up quickly in a 40-engineer business.
If you want the detail link by link, the full inventory is here: what features does a CMMS include. And to position a CMMS against technical supervision tools, see BMS and CMMS: what's the difference.
"But I still need an ERP, don't I?"
Sometimes, yes. You just need to be clear about what for.
What a CMMS doesn't do, and isn't meant to do: general ledger accounting, payroll, group consolidation, managing a trade stock with several thousand SKUs. Everything else in your operations, it carries.
Two setups work well.
- Maintenance SME, 10 to 150 engineers, single-trade activity. Yuman for all operations and invoicing, with a structured accounting export to your accountant or to a lightweight accounting package. No ERP at all. This is the most common case, and also the fastest to implement. For budget orders of magnitude, see how much a CMMS costs.
- Group, or mixed maintenance + trade + projects activity. The ERP keeps accounting, payroll, purchasing and consolidation. Yuman carries the entire maintenance flow and pushes sales documents up. The two systems talk to each other in real time through the documented REST API (the technical interface that lets two applications exchange data) and webhooks (automatic notifications sent to the ERP as soon as an event occurs in Yuman, for example an invoice being validated). Each system stays master of its own domain: the field in the CMMS, the accounts in the ERP.
Connectors already exist to the main accounting systems on the market. Integration is no longer the risk it was ten years ago.
Three questions to ask before you sign
Whoever the candidate is, ask the same three questions. They sort the field on their own.
1. "Show me the mobile app, in flight mode." Ask the vendor to switch off the phone's connection during the session, then look up an asset's history, fill in a report, take a photo, capture a signature, and reconnect to synchronise. That's thirty seconds of demo. Many modules fail this test.
2. "Demonstrate the full flow for me, without switching screens or tools." Customer request, quote, signature, work order, scheduling, mobile execution, invoice, chasing. End to end, on the same database, with the same data. If the demo breaks off with "that part is handled in the finance module" or "that point would require custom development", you have your answer.
3. "How many of your customers are maintenance contractors like me?" Not manufacturers doing their own in-house maintenance: companies that invoice their jobs to third parties, of your size, in your trade. Ask for three contactable references. The number, and the precision of the answers, tell you more than any feature grid.
Choose the tool built for your business
The real trade-off isn't between a large general-purpose system and a small specialised tool. It's between a system that already knows your value chain and a system you'll have to teach it to, line of code by line of code. For a maintenance contractor, the vertical CMMS is the core system, and the ERP — when it's needed — the accounting complement. Not the other way round.
See for yourself before you launch your tender. Request a demo: we'll walk you through the full flow, from quote to invoice, in 45 minutes.