Old stock residential
A brown-to-green transition
Tuna illustrates how a targeted energy improvement programme can transform an older residential asset from brown to green while creating attractive investment returns.
Intervention
Slättö is implementing a targeted energy capex investment in a senior housing asset in Österåker, in the Greater Stockholm region, with the objective of reducing the primary energy demand of the asset.
Measures include upgrades to ventilation systems and heating substations, as well as the implementation of smart automation and continuous energy optimisation to lower operating costs. In addition, geothermal heating is currently being evaluated as a potential next step to further improve energy performance.
As is typical for residential assets, Slättö bears the heating costs. Therefore, opex savings from lower energy bills translate directly into higher net operating income.
Impact
Old-stock residential: Tuna asset
| Key results | |
| Implemented measures | |
| Energy capex, EUR | 830 k |
| Net Operating Income, EUR | +63 k |
| Yield on Cost | 8% |
| EPC improvement | From F to C, Taxonomy aligned |
| Geothermal | |
| Energy capex, EUR | 840 k |
| Yield on Cost | 8% |
| Total | |
| Energy cost | -69% |
| CO2 | -96% |
| Asset overview | |
| Location | Greater Stockholm |
| Asset type | Senior housing |
| Number of apartments | 92 |
| Construction year | 1994 |
| Heating source before intervention | District heating |
Energy cost before and after, EUR k yearly:
This chart shows how a sequence of measures reduces the building's annual energy costs by 69%, directly translating into lower opex and higher NOI.
The first three measures already implemented — ventilation upgrade, balancing, and control system — primarily cut the building's energy demand.
The ventilation upgrade accounts for the largest single drop in demand.
As a next step, there is a planned conversion from district heating to geothermal. This will have by far the largest effect on energy cost as it removes the reliance on district heating.
Takeaway
Brown-to-green transitions can create substantial improvements in older residential assets. In many cases, ventilation upgrades are one of the most important contributors to energy savings.