Case study · Heating & Water Systems

A maintenance contract that sends its own reminders.

Weitblick Immobilien AG has Haustechnik Sommer service the gas boiler and the water filter at its Am Wall residential complex – once a year. We follow one complete contract cycle: from signing, through the service falling due, all the way to the invoice. And we show why nobody has to keep a single date in mind along the way.

LSLars SommerMeister (master craftsman), owner ABAnna BergerOffice JWJonas WolfJourneyman SRSabine RothProperty management, Weitblick HBMr. BrandtCaretaker
2systems in one contract
16checkpoints, 6 of them with readings
0missed service appointments
€189flat fee per service, net, travel included

The company, people and amounts are fictitious – and you’ll find them exactly like this in our „Handwerk“ (Trades) demo.

Year 1 September, site visit

First the systems, then the contract

Ms. Roth from property management would rather not have to remember it herself every year. Lars walks through the boiler room with Mr. Brandt and photographs the rating plates. Back at the office, Anna adds both units to the customer’s „Anlagen“ (Systems) records – with manufacturer, model, serial number, year of manufacture and location.

In NextRB Unternehmer
  • System records for each customer, with a photo of the rating plate attached
  • Each system type comes with its own checklist – gas boiler, heat pump, water softener, filter …
  • Notes such as „Schlüssel beim Hausmeister“ (key is with the caretaker) show up for the technician later on
haustechnik-sommer.nextrb.eu/wawi/wartung · Anlagen

Anlagen · Weitblick Immobilien AG

Anlage anlegen
Gas-Brennwerttherme
Vaillant ecoTEC plus VC 25 · SN 21184500100 · Bj. 2019
Gas-BrennwertgerätHeizungsraum Keller
Rückspülfilter mit Druckminderer
Judo PROFI-QC 1" · Bj. 2019
Filter / DruckmindererHausanschlussraum
Schlüssel beim Hausmeister, Herr Brandt
Year 1 two days later

The contract – done in five minutes

Anna selects the customer and the systems, and NextRB Unternehmer suggests the right services for each system type. A flat fee of €189 net, travel included, once a year, billed after each service. As a perk for contract customers: priority appointments when something breaks down and 10% off spare parts. The PDF goes to Ms. Roth and comes back signed – Anna sets the contract to „aktiv“ (Active).

In NextRB Unternehmer
  • Annual or semiannual interval, billed in advance or after the service
  • Term, automatic renewal and notice period set out in the contract
  • Contract as a PDF with a list of systems and signature fields
…/wawi/wartung · Vertrag WV-0002
WartungsvertragNr. WV-0002
Objekt: Wohnanlage Am Wall · Am Wall 140 · 28195 Bremen
§ 1 VertragsgegenstandGas-Brennwerttherme Vaillant ecoTEC plus · Rückspülfilter Judo PROFI-QC
§ 3 Wartungsintervalljährlich – der Auftragnehmer schlägt rechtzeitig einen Termin vor
§ 4 Vergütung189,00 € netto je Wartung zzgl. 19 % USt (224,91 € brutto), einschließlich Anfahrt, berechnet nach jeder Wartung
§ 6 Laufzeit12 Monate, verlängert sich jeweils um 12 Monate, Kündigung 3 Monate zum Laufzeitende
AuftragnehmerAuftraggeber
aktivjährlichnach WartungPDF
Year 2 late September, Monday

NextRB Unternehmer speaks up first

A year has gone by. Nobody pinned a note to the board – Anna simply sees it under „Wartung · Fällig“ (Maintenance · Due): Weitblick, in twelve days. She taps „Termin vorschlagen“ (Propose appointment), picks Tuesday at 8:00 a.m., and a friendly email lands in Ms. Roth’s inbox. Her reply: That works – Mr. Brandt will let you in.

In NextRB Unternehmer
  • Services due in the coming weeks, at a glance
  • Appointment proposals by email from your own mailbox – with the systems listed in the message
  • The customer’s reply goes straight to the office
…/wawi/wartung · Fällig
FälligVerträgeAnlagenChecklisten
Weitblick Immobilien AG
WV-0002 · Gastherme, Rückspülfilter · jährlichin 12 Tagen
Termin vorschlagenEinsatz planen
Familie Krüger
WV-0003 · Enthärtungsanlage · halbjährlichin 6 Wochen
An s.roth@beispiel.invalid
Betreff Terminvorschlag Wartung – Dienstag, 6. Oktober

Guten Tag Frau Roth,

die Wartung Ihrer Anlagen (Wartungsvertrag WV-0002) steht an: Gas-Brennwerttherme, Rückspülfilter mit Druckminderer.

Unser Terminvorschlag: Dienstag, 6. Oktober, 8:00 Uhr.

Year 2 the same day

One click turns the service into a job

„Einsatz planen“ (Schedule job) creates the service visit together with a „Baustelle“ (job site) – address, contact and everything Jonas needs to know: which systems, where they are, who will let him in. Lars puts Jonas on the schedule for Tuesday.

In NextRB Unternehmer
  • The service visit runs through the same job site as any other order
  • Systems, services and notes are already filled in under „Was ist zu tun?“ (What needs to be done?)
  • Assign technicians with a tap on their tile – the job shows up on the scheduling board, and double bookings turn red
…/wawi/baustellen

Wartung WV-0002 · Weitblick

zum Vertrag
Was ist zu tun?
Wartung lt. Vertrag WV-0002 • Gas-Brennwerttherme (Vaillant ecoTEC plus) – Heizungsraum Keller • Rückspülfilter mit Druckminderer – Hausanschlussraum Schlüssel beim Hausmeister, Herr Brandt
TerminDi, 6. Oktober · 8:00
JonasMiaLars+
Year 2 Tuesday, 8:10 a.m., in the boiler room

The checklist in hand – and last year’s notes right on top

Jonas opens the service visit on his phone. Above the checklist is what his colleague noted last year: Expansion tank diaphragm brittle – replacement recommended. He already has the right tank in his van. He works through the list item by item, enters the readings, replaces the tank and books it as material. Then the filter – four items, done.

In NextRB Unternehmer
  • A checklist for each system: OK or defect, readings with units
  • Remarks and defects from the last visit appear at the top
  • Time and materials are recorded just like on any other job site
‹ BaustellenJonas Wolf
Wartung WV-0002 · 1 von 2 Anlagen geprüft
Gas-Brennwertthermeoffen
Letztes Mal: Membran Ausdehnungsgefäß spröde – Tausch empfohlen.
Brenner und Wärmetauscher reinigen✓✗
Siphon und Kondensatablauf✓✗
Gas-Anschlussdruck20,3 mbar✓✗
CO im Abgas16 ppm✓✗
Abgasverlust1,7 %✓✗
Vordruck Ausdehnungsgefäß1,5 bar✓✗
Anlagendruck1,8 bar✓✗
Ausdehnungsgefäß 18 l getauscht, Anlage befüllt und entlüftet.
Rückspülfilter✓
Year 2 Tuesday, 9:40 a.m.

A signed service report

Mr. Brandt looks over the report on the phone – every system, every item, every reading – and signs with his finger. The PDF goes straight to property management. Ms. Roth files it with the system records, so the next time she talks to the Schornsteinfeger (the chimney sweep who carries out Germany’s mandatory flue gas checks), she has everything in one place.

In NextRB Unternehmer
  • Report PDF with every checkpoint, reading and defect
  • Emailed to the customer as soon as it’s signed
  • The next due date automatically moves forward by one year
Wartungsprotokoll_Weitblick.pdf
WartungsprotokollVertrag WV-0002
Gas-Brennwerttherme · Vaillant ecoTEC plus · SN 21184500100
Brenner und Wärmetauscher gereinigtin Ordnung
Gas-Anschlussdruck20,3 mbarin Ordnung
CO im Abgas16 ppmin Ordnung
Abgasverlust1,7 %in Ordnung
Anlagendruck1,8 barin Ordnung
Rückspülfilter · 4 Punkte · alle in Ordnung · Ausgangsdruck 4,0 bar
Unterschrieben von Herrn Brandt, Hausmeister · 9:40 Uhr
✓ An s.roth@beispiel.invalid gesendet · nächste Wartung im Oktober des nächsten Jahres
Year 2 Tuesday, 11:15 a.m.

The invoice comes straight from the contract

In the „Fällig“ (Due) tab, the service now appears under „abzurechnen“ (To be billed). One click, and the draft invoice already contains the flat fee from the contract. Anna pulls in the expansion tank and the half hour it took to replace it from the „Von der Baustelle“ (From the job site) side panel – the 10% contract discount on the part comes along automatically. The invoice is out before lunch.

In NextRB Unternehmer
  • The contract’s flat fee as the first line item
  • Materials and extra work pulled in from the job site
  • The service report is attached to the invoice as a PDF
…/wawi/rechnungen/RE-2026-0478
RechnungRE-2026-0478
Leistungsort: Wohnanlage Am Wall, Bremen
Wartungspauschale jährlich lt. Vertrag WV-0002189,00 €
Membran-Ausdehnungsgefäß 18 l
64,90 € abzgl. 10 % Vertragsnachlass		58,41 €
Tausch Ausdehnungsgefäß Geselle 0,5 Std31,00 €
Netto278,41 €
USt 19 %52,90 €
Rechnungsbetrag331,31 €
Von der Baustelle
Übernehmen
✍ Protokoll unterschrieben
And for private customers? The Krüger family

Billed in advance – all on its own

After their new bathroom, the Krüger family also put their water softener in Sommer’s hands: twice a year, €79 net, billed in advance. The moment Anna activated the contract, NextRB Unternehmer set up a recurring invoice – it goes out every six months without anyone having to think about it. If the Krügers ever cancel, the invoice stops on the same day.

In NextRB Unternehmer
  • Advance billing through a recurring invoice that follows the contract’s cycle
  • Canceling ends the contract and the recurring invoice together
  • Service visits and reports work exactly as they do for Weitblick
…/wawi/wartung · Verträge
FälligVerträgeAnlagenChecklisten
WV-0002 · Weitblick Immobilien AG
2 Anlagen · jährlich · nach Wartungaktiv
WV-0003 · Familie Krüger
Enthärtungsanlage · halbjährlich · im Vorausaktiv
WV-0004 · Café Kranich
Hebeanlage Küche · jährlichEntwurf
Wiederkehrende Rechnung Krügeralle 6 Monate
Betrag je Rechnung94,01 €
Aktive Verträge2
Wartungen in 8 Wochen2

What changes compared with the calendar and the binder

Before

  • Service dates live in the Meister’s calendar – or in his head
  • On site, the technician has no idea what came up last year
  • Readings go on a carbon-copy pad, and the customer gets the yellow copy
  • The flat fee gets forgotten – or billed twice
  • Contracts keep running even though the customer canceled long ago

With NextRB Unternehmer

  • The due list shows every service in good time – with appointment proposals by email
  • Systems, notes and last visit’s defects are right there on the phone
  • Checklist with readings, signed report, in the customer’s hands right away
  • Invoices from the contract – after the service or automatically in advance
  • Canceling ends the contract and the recurring invoice together

Click through this case yourself.

In the „Handwerk“ demo, you’ll find the contracts for Weitblick, the Krüger family and Café Kranich under „Wartung“ (Maintenance) – complete with systems, checklists and the readings from the last service. No sign-up needed – just try it out.

Open the Handwerk demo Try it free

Another case study: a bathroom renovation from first inquiry to paid invoice →