Historically natural insulation materials have been considered a niche product and struggled to enter mainstream building due to the misconception that they cannot compete in the area of performance or cost.
When one considers the array of benefits natural insulation provide, the reality is that natural insulation materials often outperform many man made insulation products in both these categories.
Until relatively recently it was solely the superior environmental characteristics which separated natural insulation products from the various other forms of manmade synthetic insulation products.
Natural insulation materials feature an array of characteristics which, when used correctly, can improve the buildings performance considerably. The following are just a number of the key features and additional benefits natural insulation provides:
- Hygroscopic Performance: Unlike synthetic fibres, natural insulations have an inherent property, in that they can absorb and release moisture hygroscopically offsetting condensation risk within building elements, without effecting thermal performance. This feature can also assist in reducing the risk of mould growth within the building fabric.
- Specific Heat Capacity: In lightweight construction, and as habitable spaces in attics become more commonplace, it is important to account not only for the thermal insulation qualities of the insulation in winter, but also for potential overheating within the living space in summer months. Most natural fibre insulation materials have a specific heat capacity of over 2100J/kgK, compared with only 800J/kgK for mineral wool and 1400J/kgK for plastic insulations. Independent tests have showed that when natural fibrous insulation is used in habitable attic spaces the temperature on the warmest summer months can be up to 60C cooler, when compared to an equivalent construction insulated with mineral wool. In this way natural insulation creates a much more tolerable and comfortable living environment not only in winter but also on the warmest days of the year.
- Acoustics: Due to the combination of natural insulations high density, their fibrous nature, flexibility and ease of handling and cutting, natural insulation products again far out perform many synthetic fibrous and plastic insulation materials acoustically.
- Thermal resistance: Natural insulation products can achieve a thermal conductivity as low as 0.035W/mK, which out performs many synthetic insulation products. Many of the lowest energy buildings in both new build and retrofit, including certified Passivhaus’s and the first Enerphit retrofit projects in Ireland primarily employed natural insulation.
- Sustainability: The sustainability and the ecological attributes of natural insulation products are second to none. Many natural insulation materials not only reduce heat loss and CO2 emissions in buildings, but also may sequester CO2 even after been produced! For example for every m3 of THERMO HEMP insulation manufactured it sequesters 13kg of CO2, and that’s before it is installed to conserve energy!
In terms of cost, some natural insulation materials, such as THERMAFLEECE ECO ROLL, have become much more cost competitive with conventional insulation products such as mineral wool.
When one factors in the additional health benefits for the dwelling occupier and installer, the increasing cost competitiveness of natural insulation, their superior durability and the breathable features of natural insulation products, their advantages become more apparent.
From left to right: THERMO HEMP, GUTEX woodfibre and THERMAFLEECE natural insulations
When considering the energy efficiency of buildings one cannot under estimate the positive contribution which natural insulation materials offer on many levels. As buildings become more energy efficient, the environmental impact of the building envelope increases significantly.
It is estimated that we spend up to 90% of our lives in buildings, therefore we should appreciate the impact that many of the materials we surround ourselves with, can have on our environment.
These are just some of the reasons more people are moving towards natural insulation in their homes and buildings; not just from an environmental perspective but also for the superior technical properties these materials offer.
Niall Crosson, Technical Engineer, B.TECH. MENG.SC MIEI
View our interview with Niall Crosson, Ecological Building Systems, at the recent Smart ECO Hub sustainable building event:
Pictures and graphics provided courtesy of Ecological Building Systems Ltd.