An 18th-century farm has been transformed into energy-efficient homes

Stenberg farm is located near Hudiksvall in Hälsingland in eastern Sweden, where Klas Boman worked up until a few years ago. Now, after a major transformation of the site, the farm has been transformed into housing.

– "For 40 years, the farm served as a workplace for my former company. But when we sold it in 2017, we had 800 square metres standing empty. We then decided to create housing out of the old office spaces," explains Klas Boman, owner of Boman & Compani.

Today there are eight apartments, three of which are brand new and four that have been completely renovated. Klas Boman and his family live in apartment number eight. There is a total of 1,254 square metres of living space, with the largest apartment measuring 243 square metres and the smallest 116 square metres.

All apartments were sold as cooperative housing and have been occupied since March 2022.

Recycling and the Passive House Standard

The goal of the Stenberg project is to show how to build and live with a low carbon footprint – and that it is actually possible to build homes that can last another 300 years. All materials are therefore selected from a life cycle perspective, and the homes are built according to the Passive House standard.

'Passive House' stands for low-energy homes that are very well insulated, so that they can be heated with solar heat and energy generated by the residents themselves.

This also means that the contractors had to be trained to build according to environmental and climate requirements, as well as in the selection of materials.

– "We started by training the contractors who would be active on the building site. Before training, they had to answer questions so we could make the training as effective as possible.

As much material as possible was recycled in the project. For example, the oldest house on the farm – a timber-framed building from the mid-18th-century, has had its wood reused for a new facade."

Focusing on energy optimisation

Klas Boman explains that the choice to build with less environmental impact should also apply to the property’s energy solutions. The long-term goal at Stenberg is to be energy self-sufficient, with the current level of self-sufficiency at around 60 per cent.

– "Stenberg is a living experiment. The aim of the entire project is to show what's possible. The project is our 'payback' to the environment for the amount of CO2 we have used. We have 270 square metres of solar panels that generate 65 kWp, corresponding to just over half of our total consumption. In addition, we have several battery solutions providing us with almost 500 kWh of storage capacity."

kWp stands for Kilo Watt Peak and is an expression of the maximum capacity of the photovoltaic system.

– "The total capacity means that we will be self-sufficient for several days if the power goes out. Energy storage allows us to swap expensive electricity for cheaper electricity. We top up the batteries when energy is cheap and use it when power is expensive. This results in big savings," says Klas Boman, adding:

– "Stenberg is unique from many perspectives. The ambition to build for another 300 years is accompanied by a cutting-edge energy solution.

In the summer of 2023, Stenberg received eight shared electric cars, which are part of the energy solution for the entire property. The cars’ batteries are actively used to store solar energy and to purchase power when the going rate is at its lowest. This solution is the first of its kind in Europe."

Monitoring the homes' consumption

All apartments are heated with a heat pump. Underfloor heating is installed in six of the apartments, while another two apartments use underfloor heating in combination with radiators. In addition, there is shared hot water production.

– "Our energy solution gives us great opportunities to save energy, also thermally. Energy prices are set for the following 24 hours. Knowing that makes it possible to adjust the temperature of the hot water tank, for example," says Klas Boman.

The aim is to orchestrate all resources optimally:

– "It means that we monitor everything possible and automatically decide on measures depending on the season, weather and energy price. The system will be self-learning, which means that it will continuously improve in terms of optimisation."

Troldtekt is effective and aesthetic

Troldtekt acoustic panels were chosen for the interiors of six of the eight apartments. Good sound absorption is important, as the ceiling heights are between 3.4 and 6.5 metres and the floors are concrete and oak. Here, Troldtekt excels at absorbing sound very effectively.

–"The Troldtekt line design solution in natural grey nicely matched our birch plywood walls and grey concrete floors. Simplicity, straight lines and a clear design can be found in all the apartments. The clean lines are actually a common denominator," says Klas Boman, referring to the Troldtekt line longitudinal grooves. He adds:

– "Troldtekt is fantastic in several ways. The Cradle to Cradle concept that Troldtekt follows is impressive and inspiring, and together with its great product properties and quick and easy installation, the choice was obvious," says Klas Boman.

See more pictures of Stenberg in Hudiksvall