Why Cavity Wall Insulation is so important

If your house was built with cavity walls more than 10 years ago, you may have empty cavities. Cavity Wall Insulation will be invaluable for a green home.

cavity wall insulation

If your home is made of solid walls, your options for extra insulation are relatively simple, with a choice of both internal and external wall insulation. But cavity walls have the potential to be a little trickier to insulate if the cavity is just an empty gap.

That’s where cavity wall insulation comes in. Once fitted, it can bring huge advantages. As long as your wall cavities are at least 5cm wide, any masonry is in good condition, and your walls aren’t subjected to driving rain then you should find it quite simple to get cavity wall insulation fitted.

How much cavity wall insulation will save you

You could stand to save up to £140 on your energy bills every year, as well as a possible saving of 560kg of CO². The installation cost of cavity wall insulation is a comparatively low £450 – £500, which compared to the costs of solid wall insulation is barely anything. £500 is just under 6% of what it can cost to install internal wall insulation, and just under 4% of the potential cost of external insulation. This is because it involves much less elaborate and expensive materials, which are equally effective insulators. And it only takes a maximum of four years for you to earn back the cost of installing it. What’s not to like?

What’s it made of?

Most commonly cavity wall insulation is made of mineral wool, beads or granules, or foamed insulants. All three of these materials are manufactured under strict British guidelines, and if you’re in receipt of a foam insulation system which isn’t certified by the British Board of Agrément you shouldn’t use it. It’s extremely important that you have one that is, and that it’s installed according to the relevant BBA Certificates.

How’s it installed?

Cavity wall insulation needs to be installed by a fully qualified and registered installer, preferably who’s registered either to the National Insulation Association, Cavity Insulation Guarantee Agency, or the British Board of Agrément. Unlike some other forms of insulation, you won’t be able to do it yourself unfortunately. But you won’t have anything to worry about because it shouldn’t take any more than two hours to do and the installer won’t have to take apart your wall, all being well.

They’ll drill small holes at equally spaced intervals into your cavity walls from outside (as long as your outside walls are accessible), and blow the cavity wall insulation through so that your whole wall gets insulated with minimum mess. However, there can be issues if you can’t access your outside walls, or if you have any internal or external dampness. You should get this looked at and sorted out before getting cavity wall insulation fitted.

Empty cavities make energy bills unnecessarily high and aren’t particularly useful at limiting your home’s CO² output. If your house satisfies the criteria for getting this insulation installed then you should enquire about getting some as soon as you can.

Image: Craig Bloxsome

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