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Regulating and insulating - benefit from the straw insulation surplus!

Heating system replacement, energy-efficient house – the legislator envisages leveraging existing buildings to a minimum of their previous CO2 emissions.

For efficient building envelopes, straw is coming back into focus as an insulating material. Straw is a high-tech insulating material from nature: it has a high thermal storage capacity. During the day, heat is absorbed, which is then steadily released during the cooler evening and night hours, keeping the walls and your home as a whole warmer for longer. Compared to conventional, synthetic insulation materials, however, straw insulation can effectively block heat due to greater amplitude attenuation. The indoor climate is also influenced by its moisture-regulating capabilities.

Why renovate?

Experts assume that – based on the respective old stock – the modernization of heating systems brings energy cost savings of up to 30%. With insulation even up to 39% (basement insulation – 7%, roof insulation – 14%, building envelope -18%). The combination of renovation measures is therefore recommended.

Why insulate with straw?

Except for the low manufacturing energy and eliminated disposal costs, only straw provides delayed heat transfer and heat protection in summer. Compressed straw belongs to the thermal conductivity group 0.40 – 0.50 and thus has a good value, which is about the level of conventional rigid foam insulation boards made of polystyrene.


Insulation behavior of straw

How the wall looks after straw insulation

The renovation improves the U-value from 1.6 W/m2K to 0.146 W/m2K. This results in an average annual energy saving of about 115 kWh/m2.

Humidity: The surface temperature on the room side is 19.1 °C which leads to a relative humidity on the surface of 53%. Under these conditions, mold is not expected – a room humidity between 40 and 60% is considered optimal.

Heat protection: The wall yields an amplitude attenuation value of over 100. At a value of 10, indoor temperatures fluctuate by 2°C when outside temperatures range from 15 to 35°C, e.g. at night and in the afternoon. At 100, the room temperature remains stable.

Infographic of a 2D wall cross-section with straw insulation and only with existing wall

What to consider when dealing with straw insulation?

To achieve a certain insulation value, straw insulation may require wider building depths, depending on the nature of the insulation and the existing wall. However, this can be regulated by allowing manufacturers such as LORENZ to provide flexible building depths to achieve the optimum in energy cost savings and space.


Is straw insulation subsidized?

Depending on the region or country, renovation and modernization measures are promoted, including straw insulation. Occasionally, programs occur in which regenerative or CO2-reducing building materials are explicitly considered with subsidies. In other examples, innovative measures – which include straw insulation – are subsidized. In any case, it is worth seeking advice. This is subsidized in Germany, for example. Roughly, there are the following subsidies.

Financial aid
  • Individual programs provide grants toward the cost of renovation.
Interest rate subsidies
  • State-owned banks issue loans at better interest rates.
Tax benefits
  • Tax credits are available for energy retrofits.

What insulation solutions does LORENZ offer?

Serial and individual use - the right product for every application

CO2 storage, energy cost savings, good site handling, immediate plastering or plannability, prefabricated construction depths and sizes – LORENZ combines all this in a product portfolio tailored to the application. Your options for energy-efficient renovation with straw:

Close-up of the DTX straw insulation module from LORENZ, wooden frame with reduced wood content and straw insulation
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