There is a wide range of insulation materials on the market, all with different qualities which can make a big difference to the way your building retains heat. When choosing your insulation, it is important to consider a number of factors in order to choose the insulation right for you and your home. Most materials have both pros and cons, making it vital that choosing your materials is not a rushed decision.
Dealing with water vapour
Water vapour behaves in different ways when coming into contact with different insulating materials. Hydrophobic materials will repel water, causing it to form droplets and run off the material, whilst hygroscopic material, which tends to be more natural materials, will absorb and hold water within its fibres. Water vapour in the air can be more problematic with hygroscopic materials as they are usually exposed to moisture for longer, however, hydrophobic material can also be damaged by moisture, and its ability to insulate will be hindered when wet. This makes protecting your insulation from water vapour especially important. Choose a hygroscopic insulation which allows water vapour to pass through it (vapour diffuse) or a hydrophobic product which is vapour impermeable, to keep moisture damage at bay.
The lower the thermal conductivity of your insulating material, the less you need to use, which ultimately saves time, space and resources. All packaged insulation displays a K value rating for reference when purchasing your materials. Most materials lie somewhere between 0.019 (phenolic and PIR) to 0.039 (sheep wool, wood fibre and recycled plant fibres). One of the highest performing insulation materials- Aerogel- ranks at just 0.014 and is ideal when space is limited, though this kind of high performance comes at a greater cost.
Consider your building’s needs
Every building is different, meaning that decisions over which insulating materials to use shouldn’t be made lightly, particularly if there is a high risk of exposure to water. Factors to consider include:
Living in an area that receives high levels of rainfall
Walls which face south west
Use of porous building materials ie sandstone
Older timber frame buildings
If a building is at higher risk of damage from water vapour, a more vapour diffuse insulation product such as wood fibre should be used. For a more modern building at a lower risk of moisture damage, PIR insulation should be sufficient.
Your insulation’s footprint
While good insulation helps to prevent energy wastage by retaining heat in your home, it’s important to consider the energy spent in manufacturing and transporting the insulation you use in your home. Though the levels of energy saved usually negate the levels of spent energy by far, it is worth considering using sustainable materials, as well as looking for local manufacturers to keep transport emissions low.
Image sourced: thingermejigtagsinsulation materials