Tellum is a systems integrator
for retrofit contractors.
Business systems — not heat pumps.
Your programmes, properties, evidence and cash live in different places — and someone has to stitch them together before every claim.
We join what you already run into one live picture.
Nothing gets replaced.
- Commusoft
- Sage
- Property tracker
- Email & WhatsApp
- +156 systems →
- Programmes — margin live
- Properties — stage by stage
- Cash — month-end builds itself
- Commusoft
- Sage
- Property tracker
- Email & WhatsApp
- +156 systems →
- Programmes — margin live
- Properties — stage by stage
- Cash — month-end builds itself
The systems your retrofit business already runs on.
If it's on this list, we've connected it before. If it isn't, we probably still have — .
You're not unusual. This is what running a contractor at this stage looks like.
“Same property, three systems, three different answers about what stage it's at.”
That's plumbing, not people. We fix the plumbing.
“A hundred and forty homes finished. Sixty lodged. The rest aren't money yet.”
Done isn't paid in retrofit — lodged and evidenced is. We track every property from survey to lodgement, with the pack building itself along the way.
“Month-end takes the FD a week and one spreadsheet nobody else understands.”
Month-end shouldn't be a build project. It should already be there.
Wherever you are with your systems, there's a version of this for you.
You're picking or replacing something.
We help you choose the tools that fit how you actually work — not the ones the salesman liked. Shortlist, trial, decision. Then we set them up properly.
You already have the tools. They don't talk, or they don't do enough.
We customise, connect and extend what you run: integrations, missing reports, automations, the layer on top. Then we keep it working and growing with you.
You have the systems. People use half of them.
We teach your team to run the tools you already pay for — properly, and with the automations that make them worth the money.
Most clients start in the middle. Some start with training and never need the rest.
Tools get you level. The layer gets you ahead.
Choosing, connecting and training put the right tools in place — the same tools your competitor can buy. The Tellum Operating Layer is ours: it sits on top of what you run and bends to how you work. A new metric lands in days, a new workflow in a week or two. Nothing gets replaced.
One live picture. Three things on it.
Every programme and wave, cost-to-date against budget — by measure and by subcontractor — measures installed against planned, milestones against the funder's programme, updated as costs land.
Nothing gets replaced. Your ERP stays your ERP. We add the layer on top.
Small first step. No migration. Nobody retrains.
We sign an NDA, then walk you through what we'd connect and how. A demo, not a sales call.
We pick the right technical approach and build a working prototype on your numbers — free, typically within 48 hours. Static data at this stage; the live connection comes with the build. You decide if it's worth going further.
Implementation, customisation, the connecting layer, training — the actual engagement begins. Your systems stay where they are; your team keeps working the way it works.
Before and after
Examples of what we can help you with — real engagements, anonymised, names and some details changed.
6 of 6 engagements
About to buy an ERP they'd have spent a year fighting.
Sage 50, a dozen spreadsheets and a WhatsApp group.
BigChange for crews and jobs, Sage kept for the books, one property tracker — live in six weeks.
Programme controls lived in an eight-tab workbook next to the ERP.
NetSuite for finance, Excel for costs by measure, milestones and subcontractor accounts.
One portal on top of NetSuite — cost per measure and per property, milestones against the funder programme, finance stays in NetSuite.
Work finished months before it turned into money.
Installs tracked in the field system, evidence in folders, lodgements batched when someone had time.
One board: every property's stage and evidence status, lodgement backlog visible daily, claims assembled from the pack — done to paid, weeks faster.
Nobody could see surveys turning into installs and installs turning into paid commissioning.
Money in QuickBooks, pipeline in HubSpot, the install schedule in a spreadsheet.
One weekly picture: survey-to-install conversion, commissioning and registrations complete, engineer utilisation, cash by client.
Occupied homes: three visits, two no-answers, and a QA photo set that was never complete.
Access attempts in the field system, resident contacts in email, QA photos across phones.
One board per property: access attempts and liaison history, QA photo sets complete or flagged, measures signed off — with safety and workforce reporting alongside.
Three acquisitions, three regions, programmes that didn't line up.
Consolidating P&L by region and wave took most of the month.
A consolidation layer on Intacct — common property and measure structure, month-end across all entities in days.
Want to see the layer itself? Same numbers, three front-ends — inside NetSuite, as a modern portal, as Power Apps.
You're probably here the way most of our clients arrive — a colleague passed our name on, or you got a note from me. Either way, good to meet you. If the page doesn't answer your question, ask me directly — I read every reply myself.
Questions we get asked
The stack we see most often in retrofit & decarbonisation: TrustMark, MCS, Elmhurst, Commusoft, BigChange, SafetyCulture — plus Excel, Microsoft 365 and WhatsApp. In total we work with around 160 systems across 21 categories, listed at tellum.works/vendors. If a system has an API, a database or an export, it can be connected.
Pick your first step.
From a free PDF to a working prototype on your own numbers in 48 hours. Pick one — the form below adjusts.