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Best Wall Insulation

Which type of insulation is best for your walls?

When it comes to creating an energy-efficient and comfortable home, proper insulation is key. While we often focus on insulating our attics and roofs, the walls of our homes are equally important.

According to the Energy Savings Trust, if you live in an older house with solid walls rather than cavity walls, you could be losing up to 45% of your heat through your walls.

So, insulating your walls makes a big difference in helping you maintain a consistent temperature in your home and make your living spaces much more comfortable. Plus, those savings you’ll get on your energy bills are sure to put a smile on your face.

With so many wall insulation options out there, it’s natural to wonder which one’s the perfect fit for your walls. But don’t worry, we’re here to help you make the best choice for your home and your budget.

Speaking of budget, Warma UK is here to help you get the insulation you need at no cost to you if you are eligible for one of the many grants available. We’ll walk you through the steps of applying for insulation grants and secure funding for you. Click the link below to start your insulation grant application.

See if you're eligible for Free Insulation Grant

See if you're eligible for Free Insulation Grant

What is insulation R-value?

The “R-value” stands for “thermal resistance” and is used to assess how effective insulation is at resisting the flow of heat. In simple terms, the higher the R-value, the better the insulation’s ability to keep your home warm in the winter and cool in the summer.

What are the different types of insulation?

1. Fibreglass insulation:

Fibreglass insulation is one of the most common and cost-effective options for insulating walls. It consists of tiny glass fibres and is available in rolls or batts. It’s relatively easy to install and offers good thermal resistance. Additionally, fibreglass insulation is fire-resistant and doesn’t promote mould growth. It’s a solid choice for those on a budget.

2. Cellulose insulation:

Cellulose insulation is made from recycled paper products, primarily newsprint. It’s an eco-friendly option and an excellent choice for insulating existing walls. Cellulose is dense and effective at reducing air infiltration. It’s often blown into wall cavities or attics, providing a snug fit and creating a thermal barrier. However, it’s crucial to ensure proper moisture control to prevent mould and rot when using cellulose insulation.

3. Spray foam insulation:

Spray foam insulation is known for its amazing insulating properties as it expands to fill gaps and voids, creating an airtight seal, which make it exceptionally energy efficient. There are two types of spray foam insulation: open-cell and closed-cell. Open cell is less dense and has a lower R-value but is more affordable. Closed cell is denser, has a higher R-value, and provides a moisture barrier and is often used in areas prone to moisture exposure.

4. Mineral wool insulation:

Mineral wool insulation is made from natural rock or slag (a byproduct of steel production). It’s fire-resistant, offers excellent thermal performance, and is resistant to pests and mould. Mineral wool insulation is available as batts or loose-fill. As an added bonus, it provides good soundproofing qualities as well.

5. Polystyrene insulation:

Polystyrene insulation is a great option for insulating walls and offer good thermal resistance. It’s also easy to cut and install.

Ever wondered who qualifies for the free insulation grant? Click the link to discover more!

Which type of insulation is best for you?

It’s important to remember that what’s considered “best” can vary from one home to another. The insulation ideal for your neighbour’s place might not necessarily meet your specific requirements.

At Warma UK, we’ve got a lineup of options designed to save you cash and energy while boosting your home’s cosiness. We offer insulation grants, handy energy-saving tips, and will suggest the best insulation choices tailored to your needs.

Let’s team up to make your home energy-efficient and snug without draining your wallet! Just fill out our quick application form online to see if you qualify for a range of fully funded energy efficiency improvements.

See if you're eligible for Free Insulation Grant

See if you're eligible for Free Insulation Grant

Frequently Asked Questions (FAQs)

Measuring the width of your walls is a good place to start when you’re trying to work out if you have solid or cavity walls. Anything less than 260mm is likely to mean you have a solid wall. 

Also look at the brickwork pattern. if you can see the short ends of the brick, then this means you have a solid wall. Cavity walls have an even finish, with bricks in an identical pattern. 

Heat passes through solid material at a faster speed than through a gap or ‘cavity’ – so solid walls lose heat fast. In fact, you can lose about 45% of your home’s heat through solid walls, according to the Energy Saving Trust 

No, a correctly installed insulation system doesn’t cause condensation.  

It slightly reduces room size, typically by 100mm per wall. This is because the insulation boards take up space. However, the benefits of improved comfort and energy savings often outweigh this minor reduction. 

YES. Warma UK only install fire retardant wall insulation systems. 

The right option for you depends on your property and requirements. In terms of performance, both options insulate your home to a similar extent. Internal solid wall insulation can be more cost effective, and it has the added benefit of you being able to insulate one room at a time. 

Warma UK’s installations come with ventilation and moisture control measures can prevent dampness.  

When properly installed, your new insulation can last for several decades.  

The insulation is low maintenance and considered ‘fit and forget’. 

It’s generally recommended to hire a professional installer. Proper installation is crucial to avoid issues like moisture build-up and damp. 

While insulation can help reduce condensation issues by raising the internal surface temperature of walls, it may not be a suitable solution for addressing existing damp problems, which should be resolved before insulation is installed. 

Accordion Content

Yes, but you will likely need less heating, and your home will be better at retaining warmth. 


Athira Harish