How Does Loft Insulation Reduce Heat Loss?

Insulation Prevents Heat Loss

A poorly insulated property can lose significant heat. Typically, around 25% of heat loss goes through an uninsulated roof, so imagine how much difference you can make to heat retention and energy bills with proper insulation. In this post, we explain how loft insulation can reduce heat loss and help you decide which type of insulation material is best for you.

Heat Loss in UK Homes: Overview

Let’s talk science for a moment: the way heat flows is that it moves from the warmer object to the cooler one. As such, a heated-up room can easily lose all its warmth quickly — provided your heat source is off and it’s rather cold outside.

The solution can’t be to just crank up your heating and waste money on high energy bills when a more cost-effective option is available to you. Loft insulation efficiently reduces this heat loss and saves you up to 40% on heating bills. In numbers, that can amount to as much as £445 in energy bill savings per year (according to the Energy Saving Trust and based on a detached property adding insulation to a previously uninsulated loft).

How Can Loft Insulation Reduce Heat Loss?

Loft insulation, in short, is the process of insulating the floors and roofs of your home’s loft. The insulation involves adding an extra layer of insulating material onto those areas. 

Those layers then act as barriers, preventing the heat from escaping into the cold atmosphere outside. Instead, the heat bounces back into your home, thus, ensuring that your living space remains cosy and warm in cold or chilly weather.

Naturally, the thicker the material used for insulation, the more heat is trapped inside the house. The insulation also keeps the cold from entering your home, too.

That said, let’s look into the two main mechanisms loft insulation manages to keep heat in.

Eliminating Heat Convection (Heat Transfer)

Heat convection is the process of heat transfer we mentioned before – how it moves from hot to cold atmospheres. After all, air is a poor conductor of heat, and without insulation, the air in your home won’t remain warm on its own.

With loft insulation, the hot air in your house will be trapped inside the insulation material’s fibres. This barrier that you’ll create disrupts the scientific way air or heat circulates in the house.  

Stopping Radiative Heat Loss

Radiative heat loss makes up a small fraction of total heat loss in your home. It usually includes the heat that radiates from your furniture and other ‘warm’ objects in the living space.

Loft insulation ensures that even that slight percentage of heat isn’t lost either. It’s how you keep your rooms pleasantly warm for longer.

Can Loft Rolls Prevent Heat Loss?

We use loft rolls to insulate the loft floors. Insulation companies install them in the floor joists to achieve the same desired effect of loft insulation. So, yes, they do prevent heat loss as well.

Loft rolls can be either glass or mineral. Both insulation materials will effectively trap the heat in the rooms under your loft. As such, you won’t need to keep your heaters on for too long just to achieve those cosy temperatures.

With that, let’s take a look at how the two loft roll materials work to reduce heat loss:

How Glass Wool Traps Heat

Glass wool is commonly known in the industry as fibreglass. Here’s how the material is made: 

Manufacturers subject glass and sand to incredibly high temperatures so that it melts. After that, they quickly spin the glass and use resin to bind the material together.

In the end, small air pockets get trapped inside the loft roll. And that’s what gives the wool its thermally insulating properties. 


  • An eco-conscious option since it’s made of recycled glass
  • Made of inorganic material so it’s fire-resistant
  • Insects and other microorganisms are repelled by the material 


  • Not suitable for damp or humid areas as the glass loses effectiveness when wet

How Mineral Rolls Trap Heat

While not as common in the UK as glass rolls, mineral rolls prove just as effective. They’re often called stone, rock, or slag wool insulation rolls as well. 

From the name, you can guess how these rolls are made. Manufacturers pick from a selection of raw minerals, such as stone or rock. 

Similar to how glass rolls are processed, companies then melt these materials at high temperatures before binding them with oil and resin.


  • Light-weight and blanket-like, making it easy to install
  • Since it’s three times denser than fibreglass, it also has soundproofing qualities
  • The material is hydrophobic and fire-resistant


  • More expensive, irritates the skin, and is harder to find in small sizes

How to Choose the Best Loft Insulation for You

There’s no one-size-fits-all loft insulation out there. You need to consider a few factors before settling on a loft insulation type that suits you. Let’s learn what they are below:

Loft Type and Size

It goes without saying, but your loft type and size play a big role in your decision. When assessing your loft, ask yourself questions like:

  • Do you only use the loft space for storage?
  • Is it of standard size or does it have awkward spaces and obstacles?
  • How many tricky-shaped spaces, filled with beams or pipes, does the loft have?
  • Are you planning on building an attic soon?

Pick an insulation type based on the answers. For example, standard loft spaces benefit best from sheet or blanket insulation.

Cost and Budget

Your overall budget is the second and most important factor to keep in mind. Loft insulation, while costly, is a great, long-term investment. It boosts the property’s value and guarantees you a warm space for years to come. 

You can try cutting costs by opting for DIY installation. However, not all loft insulation types are DIY-friendly. If anything, you might end up paying more for protective gear or specialised equipment. 

Frustrated? Don’t be. Fill out a form with us today and get a quote on any insulation type you’re interested in. 

Environmental Considerations

Believe it or not, some insulation types take more of a toll on the environment than others. And if you’re an eco-conscious person, you’d want to know about them. Even if you’re not, having an eco-friendly home is an excellent selling point if you plan on putting it on the market later.

That said, sheep wool and cellulose insulation are not only good for the environment, but also for your lungs. Recycled paper in loose-fill insulation is an equally great option, too.

On the other hand, mineral wool, polystyrene, spray foam, and some sheet foams have high embodied energy – meaning, it takes more CO2 gas to make them. This has a direct effect on climate change and the atmosphere.

Humidity Levels

Finally, consider how humid the area you live in is as well as how damp your loft gets throughout the year. Bear in mind that some insulation types, especially expensive ones, lose their effectiveness when wet.

So, if this case applies to you, go for hydrophobic (or water-resistant) insulation types. Those include rigid fibre or fibrous wood insulation made from fibreglass or mineral wool.

What Type of Loft Insulation Should You Pick?

Let’s not confuse you with all the technical lingo regarding insulation types. To make it easier for you to decide, here’s a table summarising the details upfront:

Insulation TypeOverviewAdvantagesDisadvantagesBest ForCost
Spray FoamExpensive foam applied to the roof’s underside– Excellent air sealing – High thermal performance – Long lifespan – Moisture resistant– Potential health risks during installation- Requires a professional handLofts with uneven surfaces or draughty atticsModerately expensive
SheetRigid boards made from insulating materials (PIR, polystyrene…etc.)– Creates a flat loft floor- Easy to install- Good thermal insulation– Less space-efficient than other types- Can be more expensiveStorage or conversion loftsExpensive
BlanketRolls of sheep, mineral, or glass wool laid between the loft joists– Affordable- DIY-friendly- Good thermal insulation-Is itchy and dusty to handle- Won’t fit awkward spaces wellMost loftsInexpensive
Loose-FillGranular or flaky material (cork, recycled paper, mineral wool) poured into the loft space– Budget-friendly- Easy to top an already-existing insulation– Poor air sealing- Might lose effectiveness- Is messy to installLofts that already have insulation and need topping upHighly expensive
Blown-FibreA machine blows cellulose or mineral wool fibres into the spaces– Good Thermal Performance- Fills awkward spaces- Can be DIY installed– Requires specialised equipment- Will settle over timeLofts with irregular spaces, obstacles, or floorsModerately expensive


To sum up, loft insulation should be on your home renovation list. It barricades heat and stops it from flowing outside, while also preventing the cold from creeping in. 

And if that wasn’t enough, the right loft insulation can soundproof your walls and increase the value of your home, too. 

Convinced but not sure where to start? Let Insulation Advisor help you figure it out. Get your free quote on loft insulation today.


How safe is loft insulation?

Taking into account the necessary precautions, building regulations, and proper handling, loft insulation is more than safe. Seek our services and we guarantee to put you through to only the best!

That said, the dangers of loft insulation include the build-up of asbestos, dust, and moisture – all of which are avoidable with the right contractor.

What is the cheapest way to insulate my loft?

Loft insulation can be hefty, especially if you’re going for thicker layers or will be insulating the entire loft (roof and floor). However, cost-effective loft insulation options exist.

Those include classic cold loft insulation, fibreglass insulation, and spray foam insulation — which is the most common and the easiest type to install.

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