Thermal Insulation

What is Thermal Insulation?

Heat flow is inevitable when objects of differing temperature come into thermal contact. Thermal insulation is the process or method by which we aim to prevent heat transfer between these objects. In other words, insulation acts as a barrier between the air inside a property and the air outside. Its job is to reflect thermal radiation, which, as a result, regulates the temperature and thus, thermal comfort of a property. 

The materials used to create thermal insulation are far and wide, with the most popular insulation materials on the market including rock mineral wool, fibreglass, and polyisocyanurate (PIR). 

No matter the material, the main commonality between all thermal insulation materials is their low thermal conductivity; the lower the conductivity the better. 

Insulating materials may have a wide range of applications and be constructed from equally diverse materials, but they all provide the same basic advantage: lower energy expenditure which results in increased efficiency and lower energy bills. 

Best Materials for Thermal Insulation

When producing thermal insulation, insulation manufacturers utilise specially engineered methods that trap chemicals and still air so that the material cannot effectively transfer heat. 

With the number of thermal insulating products on the market (and the many different properties that come with them), it can be difficult to choose the right material for your project.

Let's explore a few types below: 

Rockwool Insulation Slabs

Rockwool is a 3-in-1 acoustic, thermal and fire insulation suitable for a range of general building projects as well as specialist specifications such as commercial, leisure, and industrial buildings.

Despite their many benefits, these resin-bonded rock mineral wool slabs are unrivalled in their soundproofing abilities. Above all else, their primary purpose is to quell unwanted noise and keep voice leaks to a minimum within a building.

Another quality they excel in is their ability to reduce fire spread; with an A1 (non-combustible) rating on the Euroclass scale, you can rest assured that these premium-quality semi-rigid slabs are optimising the fire protection of your build - prevention is better than cure, after all.

With a thermal conductivity of 0.035 W/mK, you can rest easy knowing that it's not just your project's fire resistance they are working; they are protecting its thermal envelope in tandem.

One of the most popular manufacturers we stock rock mineral insulation from is Rockwool.

PIR Thermal Insulation Boards

PIR (a widely-used shorthand term for 'polyisocyanurate') insulation gives contractors and homeowners the best combination of affordability, availability and thermal performance in one robust material.

PIR is one of the most effective heat-reduction insulation boards on the market with an impressively low thermal conductivity of 0.022 W/mK.

PIR, along with its thermal efficiency, marries a few simple properties that make for an overall excellent insulation choice; it has a closed-cell structure (and is water-resistant thanks to this), and despite its rigidity is extremely lightweight, making it easy to handle.

To summarise, PIR insulation is a tough, durable, lightweight insulating board comprising two high-performance aluminium facings sandwiched between a rigid PIR insulation core.

Celotex is one of the most popular PIR insulation board manufacturers.

Fibreglass Thermal Insulation Rolls

Fibreglass insulation, also known as glass wool insulation (or glass fibre insulation), is as the name would suggest, made up of recycled glass fibres. Layers and layers of glass mesh are bonded together; the resulting product of which features thousands of small pockets of air that inhibit warm air from escaping.

As glass is resistant to heat, it's no wonder that fibreglass insulation makes a good insulation material choice for those seeking heat and fire resistance in one robust material. Fibreglass insulation rolls have thermal conductivity between 0.032 W/mK and 0.044 W/mK depending on the product.

Fibreglass wool insulation comes in rolls and slabs or batts. Fibreglass batts – which can also be referred to as slabs – are large, compact insulation pieces that are designed to fit between joists, rafters, and studs. Fibreglass insulation roll contains much more material and can be simply rolled out into joists and other spaces, such as pitched roofs at ceiling level.

We recommend Knauf Insulation rolls for people who want to protect their lofts, crawl spaces, and open walls.

Foil Insulation

Multifoil insulation, otherwise known as foil insulation, is made up of several layers (as hinted by the 'multi' in its name) of sheets and foils. 

Multifoil insulation is engineered to target radiation, conduction, and convection. The multi-foil's reflective layers function as an airtight barrier, helping to minimise condensation. Multi-foil also works to control the amount of solar radiation that enters a property; helping to solve the dilemma of temperature balance throughout the seasons and optimise energy efficiency. 

Foil insulation is most commonly used between rafters and timber studs in roof spaces, but some products can also be effective when applied to floors, walls, or cellars.