Energy efficient construction materials

How energy efficient materials make better buildings

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Contemporary buildings are more than just bricks and mortar. Today’s designers and builders can choose from a huge range of energy efficient materials to create buildings that combine interior comfort with lower energy costs and reduced environmental impact.

Thermal performance

When renovating old homes or planning a new development, the right combination of design and insulation can make a big difference to a building’s performance. It’s important, for example, to avoid thermal bridges which can cause condensation. Therefore, designers and builders should pay attention to the thermal performance of insulation materials they choose. The lambda value, also known as thermal conductivity, expresses how well a material insulates in perfect conditions: the lower the value, the better it performs.

Securing energy efficient constructions

However, energy-efficient construction depends on more than just insulation with a low lambda value. Will the insulation fit easily into the building? If there are even small air gaps, for example when insulating irregular shapes like an old roof or wall, this can have a dramatic impact on energy performance.

And because it’s typically 30-50 years before a building is changed or upgraded, how the material behaves over the long term is an important consideration:

Lifetime performance

Some insulation materials include gases that diffuse over time, reducing the insulation value.

Dimensional stability

Although they may show a low lambda value when purchased, certain materials can shrink or move in response to changes in temperature and humidity, reducing energy efficiency.

Vapour permeability

Moisture can accumulate in certain insulation materials, affecting energy performance and potentially facilitating mould or fungal growth. Ideally, insulation should allow moisture to pass through.

For energy-efficient, sustainable new buildings and renovations, ROCKWOOL non-combustible stone wool insulation is an ideal choice:

  • Fits easily into old and new constructions
  • Stays in place over the building’s lifetime
  • Keeps its shape and thermal performance over time
  • Allows vapour to pass through and does not accumulate moisture
  • Made from natural inorganic stone, providing fire safety, durability and excellent noise protection


Minimising impact in a new residential development

ROCKWOOL insulation products were an integral part of the Silken Park housing development in Dublin, Ireland, which was built to the demanding Passivhaus energy standard. 

Commenting on the successful project, contractor Barry Durkan said: “By combining simple wall construction, good solid windows, air tightness, ventilation, and above all, high levels of insulation, we will have a very happy customer, with a healthy home, and most importantly, very low energy bills”.