A Complete Guide to Cellulose Insulation

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If you find your home unbearably cold or overly expensive to heat in the colder months, as well as excessively warm in summer, your property is probably thermally inefficient. Heat always moves towards colder spaces, making it flee your home to the cold outdoors in winter, and entering your home in the height of summer.

Luckily, it doesn’t have to stay that way forever. Installing effective thermal insulation can make your home more energy efficient and provide you with a comfortable indoor environment year round. Your home will require less energy to keep it warm in the winter and cool in the summer.
Insulation works by reducing the movement of heat through your walls, roof, and floors by creating an extra barrier between your home’s interior and the world outside.

But with so many types of insulation on the market, finding the right choice of insulation for your property and deciding which parts of your home to insulate can be difficult. Luckily we’re here to help.

We’ve broken down the pros, cons, costs, and considerations of one of the most popular insulation materials – cellulose. As a loose fibre insulation, cellulose is typically made from recycled newspaper combined with other paper products, and works especially well for homeowners wanting to insulate horizontal surfaces in lofts, crawlspaces, and wall cavities.

What is Cellulose Insulation?

Cellulose, sometimes known as blown-in insulation, is a type of insulation that’s perfect for use in homes and commercial spaces. This insulation has a light fluffy consistency and is often made from recycled materials, such as wood, unmixed newspaper, office paper, and cardboard.

Cellulose insulation tends to come in clumps of thousands of small pieces of recycled cellulose, meaning it can fit or be mechanically blown into confined spaces to the desired thickness much better than many alternative insulation materials. It is easy to pour and spread evenly to the desired insulation thickness and can also help with sound reduction in a property when it has an installed density of at least 40kg/m³.

Cellulose is also a common form of loose-fill insulation, which means it comes in small pieces that can fit spaces of all shapes and sizes. This makes cellulose fibre insulation suitable to insulate horizontal spaces, including lofts and floors.

Pros and Cons of Cellulose Insulation

As with any form of insulation material, weighing up the pros and cons before going ahead with installation is a must. Here are some of the advantages and disadvantages of loose fill cellulose.

Pros of cellulose insulation

Sure, in a way all insulation is eco-friendly because it helps reduce the use of fossil fuels in your home. But when it comes to eco credentials, loose fill cellulose insulation absolutely leads the way. 

More often than not, cellulose insulation is a sustainable insulation type made almost entirely of recycled materials (such as recycled paper products), which have often been recycled once before, but can be used again if you ever decided to remove your cellulose insulation. One of Europe’s leading brands is Thermofloc, which is fully CE marked, and the first cellulose insulation product to be awarded the Natureplus® mark of quality and sustainability.

Additionally, unlike some other insulation types, modern cellulose insulation product doesn’t contain an abundance of harmful chemicals. Since the majority of it (around 85%) is made from recycled materials, the remainder is additives such as ammonium sulphate and boric that give it its mineral fire retardant qualities. Alternatives like fibreglass insulation, on the other hand, can be dangerous to health if fibres are inhaled.

Obviously there’s a cost associated with every type of insulation product, but cellulose is one of the cheapest, yet still offers low thermal conductivity. When coupled with just how effective cellulose is at reducing heat loss and increasing your home’s energy efficiency, it works out as excellent value for money in the long run. The thermal conductivity of loose-fill cellulose puts it on par, or slightly better, than insulation options like glass wool or rock wool.

Installing cellulose insulation doesn’t just benefit your pocket in the next few years through reduced energy costs either – it can actually add value to your property if you opt to sell up at some point in future.

Consider that spending a few hundred to a thousand pounds on blow in cellulose insulation now will be paid back within a couple of years with the amount you save on your energy bills through high thermal performance. If you choose to insulate your loft, for example, the Energy Saving Trust estimates you could enjoy annual energy bill savings of up to £445 (based on adding 270mm of loft insulation to a previously uninsulated loft in a detached property).

There are many hazards and concerns that come with owning a home – one of which is fire safety. The good news is that cellulose insulation products are treated for preservation and fire protection, so it’s safe to have this material around light fittings and fixings, and you don’t have to worry about it increasing the risk of fire.
Cellulose insulation is around three times more dense than fibreglass insulation, making it more effective for sound reduction in your property than fibreglass batts. This offers real benefits if you are living in a property overly affected by noise nuisance.

Cons of cellulose insulation

While lo cellulose’s ability to settle and fit around any shape makes it easy to install, it can also make the insulation more likely to compact than many other common types of insulation materials, such as spray foam insulation.

When this happens, you end up with spaces or thermal bridges at the top of your insulation layer, which can make it less effective and allow heat or cold to transmit into your property.

Unfortunately, cellulose is not the most water-resistant insulation material. In fact, you can expect cellulose insulation to soak up moisture when it’s installed in areas high in condensation or lacking adequate ventilation. If the insulation material gets wet due to a leak, it can take a while to dry out.

In the long term, excessive moisture in your insulation can lead to mould problems, which damage your home and potentially affect indoor air quality and your health. In some circumstances a vapour barrier may be required with this type of insulation.

How Much Does Cellulose Insulation Cost?

How much you can expect to pay for cellulose insulation depends on the area of the country you’re in, which parts of your home you’re insulating, and how big your property is.
It’s one of the cheaper materials, coming in at between £10 and £12 per metre squared. You can work out how much the supply alone will cost by multiplying the cost per metre squared by the size of the space you’re insulating.

Labour costs will vary across the UK, but in general, insulation installers charge around £160-£250 for an installation project. Unless you’re installing insulation across various parts of your home and it’s a particularly large property, the installation process shouldn’t last more than a couple of days.

It’s not advisable to save money on your cellulose insulation by installing it yourself, but there are a few ways you can make the process cheaper. Getting all the spaces in your home insulated at once can get you bulk discounts on supplies of materials.

How is Cellulose Insulation Installed?

As its alternative name, blown-in insulation suggests, cellulose insulation is blown into space in your home such as cavities, gaps, and loft areas.

You’ll need to drill holes into plaster or drywall via blower nozzles and fill the hole with the cellulose material. In the case of lofts, you can blow cellulose insulation into uninsulated joist cavities.

Can Loose Fill Insulation be Installed as a DIY Project?

While plenty of types of insulation are suitable for insulation by homeowners, cellulose isn’t really one of them. When cellulose insulation material is blown into a small space, it’s a process that can be messy and is best carried out by a professional insulation installer who has the right experience, protective clothing and equipment (including blower) to carry out an effective installation.

Potential Problems with Cellulose Insulation

There are, however, potential problems that can occur if the cellulose insulation is incorrectly installed. Look out for these common mistakes to make sure your installation is effective.

One of the most common errors is failing to seal air leaks around wires or pipes before blowing the insulation into cavity walls or attics. If you leave any gaps in an insulated space, cellulose insulation can escape into areas you don’t want it to enter – especially with smaller insulation materials like cellulose.

As well as failing to cover wires and pipes, many installers fail to fill the entire area with insulation, either because they drill holes too low down on the wall or don’t blow the insulation far enough into the corner of a space.

If you don’t cover the entire area you’re insulating with cellulose, your layer of insulation will be uneven, and your results won’t be as effective.

Is Blown-in Cellulose Insulation the Right Option for My Property?

There’s no hard and fast rule for checking which of the popular insulation types is best suited to your property, but there are some simple things that can help you decide.

If you’re looking to insulate tight, cramped, or hard-to-access areas, opting for loose-fill cellulose insulation is a no-brainer. This type of insulation is unique in its ability to be blown into small areas, so it’s the best option for spaces such as small lofts or cavity walls.

Its eco-friendly credentials count for something, too. If reducing your carbon footprint is a priority, you’ll benefit from using loose cellulose insulation which is more often than not made from recycled and recyclable materials.

It’s not too costly, either. Before you go ahead with the installation, it’s worth checking whether the area in which the cellulose will be installed is prone to damp. If so, re-consider the type of material, as cellulose isn’t ideal for spaces that can become overly damp.

All things considered, cellulose is one of the most effective and planet-friendly insulation materials you can choose, so it’s well worth looking into for your insulation project.

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