Which Type of Loft Insulation Is the Most Effective?

If you have a loft then you definitely need loft insulation. Besides cutting your carbon footprint, effective loft insulation can slash your heating bills by up to £250 a year. The problem is there are many different options for insulation. In this post, we’ll explore the different types of loft insulation and which is most effective.

Warm lofts and cold lofts

One big choice is whether you have a warm or cold loft — misleading terms, since a cold loft tends to be hot in summer and cold in winter.

For a cold loft, the only insulation needed is between the floor joists, preventing heat from getting into the loft. This has the advantage of being cheap and relatively easy to install. But it leaves the loft subject to temperature fluctuations and condensation. A cold loft would be unsuitable if you plan on storing materials sensitive to either, or if you intend to use the space for activities.

To create a warm loft, on the other hand, the insulation is divided between the loft floor and the underside of the roof. This means that some heat can get into the loft and regulate its temperature, but is prevented from escaping through the roof. A far wider range of uses are possible for a warm loft, but the process of insulating the roof is harder and more expensive than installing insulation between the joists.

Types of loft insulation

blanket insulation

Blanket Insulation

The most common form of loft insulation, this comes in rolls of rock, glass or mineral fibre (we use Earthwool by Knauf), or else foil-backed felt. It’s generally the cheapest option and good all-purpose insulation, especially for between joists. It’s the easiest type to fit but isn’t suitable for the roof.

loose fill insulation

Loose-fill Insulation

This type of insulation consists of a loose lightweight material, such as cork granules, cellulose fibre, mineral wool or even recycled newspaper. It can be used to top up existing insulation or on its own. The main downside is it isn’t very secure and can be really messy!

sheet insulation

Sheet Insulation

Firm boards of either synthetic or natural materials, this is the best solution for insulating the underside of your roof. The boards provide highly effective insulation for your loft space and can also be decorated over. The downside is that sheet insulation tends to be the most expensive type.

blown fibre insulation being installed

Blown-fibre Insulation

Loose materials of various kinds blown in between joists, this is ideal for hard-to-get-at places but doesn’t offer a full solution, especially in a draughty loft. It’s also expensive and needs to be installed by a professional.

Home insulation choices

The insulation you choose for your loft will depend largely on the use you’re intending to make of the space, as well as any specific challenges it poses.

Read more: our ultimate guide to loft insulation.

Need some advice on insulation?

Whether you need some advice on the most effective type of insulation for your home or if you would like a quote. Just call us on 0800 6128 933 or