Someone asked us this week whether or not Micafil loft insulation is worth installing.
Micafil is different to most loft insulation in that it is loose fill – i.e. instead of coming in a big roll, this insulation comes as small particles in bags which can then be poured into the required spaces.
Micafil is made from vermiculite, which is a naturally occurring mineral. The vermiculite is heated to extremely high temperatures, and this then expands to produce ultra-lightweight aerated particles which consist of about 90% air.
How does Micafil perform?
In the following section we are going to compare Micafil to more traditional rolls of loft insulation (Earthwool).
Energy performance of Micafil loft insulation
Micafil has a thermal conductivity of 0.063 W/mK. A roll of Earthwool (which is the loft insulation more commonly used to do the loft insulation job) has a thermal conductivity of 0.044 W/mK which is a little higher. In order to reach building regulations you would require a 380mm layer of Micafil, but only 270mm of Earthwool, so while the insulating properties are very good, they are not as high as the more commonly-used rolls of loft insulation.
Price of Micafil loft insulation
The price of Micafil is approximately £20 per bag – and one bag of this will cover 1m2 to a depth of 100mm.
The price of a roll of Earthwool is £18 per roll (at B&Q) and will cover about 8.30m2 to a depth of 100mm. Therefore the Micafil loft insulation is considerably more expensive!
Ease of install of Micafil loft insulation
Obviously having read the first two comparisons, things are not looking good for Micafil, but it does have a real advantage over the rolls of loft insulation – and that is the ease of installation.
The Micafil comes in easy-to-handle bags and can be poured in to any space where it is required. This makes it incredibly easy to install. It’s fibre-free, non-irritant and safe, so there is no need to wear gloves, masks or take special precautions when handling it.
In conclusion, Micafil is the ideal product for topping up any existing loft insulation you have. It is extremely lightweight, so it won’t compress the underlying insulation, but also the small particles fill in gaps where the rolls of insulation don’t quite butt up to one another, giving you complete coverage.
It is also the perfect product if you have uneven joist gaps, but to be honest, even then the rolls of wool can be cut relatively easy with the Stanley knife!
If you are insulating your loft for the first time, we would always recommend using rolls of loft insulation due to the improved thermal performance of this type of insulation, coupled with the fact it is easier and cheaper to achieve the required depth of insulation.
Have you used Micafil to insulate your loft? Let us know what you thought below!
I am interested in using this Micafil insulation for my loft becuase of how easy it would be to install, but it does seem very expensive compared to the wool insulation. Is it resistant to vermin? We have had issues with mice in the house, so don’t want to give them a new source of food!!
micafil is well worth the extra cost,as vermin do not like it as they cannot burrow tunnels in it as it collapses as soon as they burrow. hope this helps.
I live in a dorma bungalow and the space between my bedroom ceiling and the roof is about 2ft high.
This means it is impossible to get in to insulate it.
Can loose fill be blown in with a pipe?
Very useful to know the U-value of mica as it is often used as chimney fill, thanks!