Duisburg
Multi-family housing
19 sites
Case study
Taking a 53-site commercial heat pump retrofit from tender to delivery in 18 weeks
Grand City Properties (GCP), a subsidiary of Aroundtown SA
53 sites delivered in 18 weeks, priced below industry average
- Client
- Grand City Properties (GCP), a subsidiary of Aroundtown SA
- Sites
- Hamm, Werdohl, Duisburg, Zeitz, Bremerhaven — 53 sites
- Usage type
- Multi-family residential (Mehrfamilienhäuser)
- Service
- Hybrid air-to-water heat pump systems
65%
renewable energy required for any new heating system in Germany
The Challenge
Grand City Properties, one of Germany's largest residential landlords, had a portfolio of occupied Mehrfamilienhäuser with ageing gas heating systems in need of replacement.
Under Germany's Building Energy Act (GEG), any new heating system must run on at least 65% renewable energy, ruling out a straightforward like-for-like swap.
GCP needed a partner who could source and vet qualified heat pump suppliers capable of delivering a multi-city retrofit programme at scale, on time and on budget, without disrupting the tenants living in these buildings.
Our Approach
1.
Assessment and Business Case
To claim Germany's federal heat pump rebate, GCP needed to know exactly which system each supplier planned to install, since only certain equipment qualifies. Suppliers don't typically share that level of detail, just a price.
We built a structured template requiring every supplier to disclose system type, performance data, and materials alongside their price. That gave GCP's board a complete picture of the upfront cost weighed against the rebate and projected energy savings.
2.
Design and Specification
At this scale, every building risked becoming its own bespoke project, slow to procure and hard to manage across five cities.
We grouped the sites into five geographically focused batches of 9 to 12 properties, and ran structured site surveys so each batch produced a scope-of-works table per address and a line-item pricing template.
Live projects
3.
Tendering
86%
faster tender turnaround
Batching also made the work commercially attractive to suppliers who wouldn't take on a single building at GCP's target price.
We identified and vetted 12 suppliers, selecting four based on technical credentials, track record, geographic reach, and their ability to meet that price point.
Key data
Industry standardCQuelWeeks
40
30
20
10
0
86% faster tender turnaround
6–8 wks
1 wk
45% faster
6–9 months
18 wks
Tender turnaround
Time to installation
Industry standard shown as the midpoint of the published range (6–8 weeks tender turnaround; 6–9 months to installation). Source: Enter.de, 'Lieferzeiten Wärmepumpe 2026: Wartezeiten', enter.de, November 2025.
4.
Delivery
70+
additional sites
We're now helping GCP roll out heat pumps across an additional 70+ sites.
As the project moves into delivery, our platform gives GCP clear, top-line visibility into when key stages are met and invoices are raised across all sites, all from a single place. Rather than GCP having to chase and rely solely on supplier updates, we proactively track progress and invoice status, so the customer always has an accurate picture of what's happening and when.
The Results
Time in tender
~1 week per batch, against a 6–8 week industry standard
Bid competitiveness
12 suppliers vetted, 4 selected
Time to installation
within 18 weeks — from initial supplier outreach to completed installation, vs 6–9 months typical for a programme of this kind
Pricing
Winning bids came in at least 16% below the range typically charged for Mehrfamilienhaus heat pump installations in Germany*
*€2,150–€4,839/kW range. Source: Luisa Ney, “Wärmepumpe Mehrfamilienhaus: Voraussetzungen, Kosten & Arten”, Thermondo, last updated 6 August 2026. thermondo.de