There are many ways to make a home more energy efficient, and one of the best to tackle first is to simply reduce the amount of heat lost by improving home insulation. Adding improved insulation to any home will make it easier and cheaper to heat, saving money and reducing your carbon footprint.

Retrofitting your home with new insulation in the attic, walls, or under the floor can tackle the problem of where heat is being lost unnecessarily.

Home insulation

Key Takeaways

  • Up to 30% of a home’s heat can be lost through the roof, the walls can see another 35% lost, and up to 10% of a building’s heat can be lost through the floor

  • Consider the following: Attic insulation / Cavity insulation / External wall insulation / Internal wall insulation / Floor insulation

  • Receive up to €8,000 in grant funding

Benefits of Home Insulation

Many homes people live in may have been top-quality construction when they were built, but today fall behind in terms of comfort, energy efficiency, and the sheer cost of heating them. There are multiple benefits to having a home retrofitted with insulation for your wallet and the environment.

Up to 30% of a home’s heat can be lost through the roof, the walls can see another 35% lost, and up to 10% of a building’s heat can be lost through the floor. Tackling any one of these can deliver huge dividends in comfort and savings.

Adding insulation to the attic or walls of a home can save hundreds of euros each year on heating bills. With the price of oil and electricity as high as it is the cost of buying insulation can be offset in as little as 1 or 2 years.

Having a good BER is an increasingly important factor for any property owner to consider. Homes with a rating of E1 will have a much harder time attracting buyers or renters. Insulation is an easy way to drastically improve the BER of a home, and bump up its value.

Properly insulating your home will drastically reduce the amount of electricity or oil used in home heating, making your property much friendlier for the environment.

Everyone wants to be cosy in their home, and it is much easier to get a house toasty and warm with good insulation.

On top of its thermal protection, insulation also offers another layer of protection against noise travelling from outside. This is a great benefit for anyone who lives in an urban area and doesn’t want to be kept up at night. 

Adding a layer of insulation to your home will act as another barrier against weather-related issues such as damp causing wear and tear to walls and rafters.

Benefits of Home Insulation

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Types of Home Insulation

There are multiple ways to insulate your home to reduce heat loss, with different types of insulation available for walls, the attic, or underfloor. Depending on where a person is insulating they will also have different types of solid or liquid insulating materials.

Attic Insulation

Attic Insulation is perhaps the easiest and most effective way to insulate your home and drastically cut down on the amount of heat being lost. Up to 30% of your home’s heat can be lost through the roof, making this the biggest individual target for someone looking to save money.

Attic Insulation tackles two main areas, the floor of the attic where the roof of the rooms below are, and the rafter of the building’s roof.

Insulation for the floor of the attic will typically consist of rolls of wool materials laid down in the gaps between the joists, or blown cellulose which can be used to get into small hard-to-reach spaces.

For insulating the spaces between the rafters it is common to use a spray foam or blown cellulose insulation. Boards of rigid Polystyrene can also be affixed between joists and rafters.

What type of insulation is best for your attic will depend on its design and layout, and the result the homeowner wishes to achieve.

Cavity Wall Insulation

Cavity Wall Insulation involves insulation installed into the cavity between the inner and outer walls. Doing so prevents air from circulating in the cavity, and drawing heat out of your home. There are different types of cavity insulation, and which is of use to you will largely depend on the nature of the project and the budget.

Solid polystyrene cavity insulation blocks can be inserted into the gap between walls as long as the space is regular. This is more common in new builds, as doing so for any existing property would involve extensive construction work to remove one side of the wall to expose the cavity.

For retrofit projects, it is more common to use a bonded bead or spray foam insulation. Holes are drilled into the wall at intervals and the insulation is injected into the cavity at high pressure.

External Wall Insulation

External Wall Insulation, also known as a Wrap, consists of multiple layers of material, with the insulation boards attached directly to the walls of the house, and other layers on top of that which will provide protection against the weather and an aesthetically attractive finish.

External insulation is more common with older people which might not be suited for cavity insulation. On top of its insulating effects, it provides a facelift to the appearance of the house and helps protect against weather.

As the wrap goes on the exterior walls of the house, it is easier to cover much of the building and does not affect the size of the internal space.

Internal Wall Insulation

Internal insulation, also known as dry lining, works much the same way as external insulation. Rigid boards of insulation are fixed to the internal walls of the house and covered with plasterboard or another finishing material.

This will make rooms warmer and cosier, but will also reduce the internal space of the room. In the case of rooms such as a kitchen or bathroom with many fixtures, it will also require extensive refitting.

Floor Insulation

It is also possible to install insulation beneath the ground floor of a house depending on the design of the floor. In a suspended timber floor it can often be possible to install rigid insulation boards between the floor joists.

Insulation Materials

The type of insulation which will be used in your home depends on the area of the house which is being worked on, and can also depend on how much you are willing to spend on the quality of materials.

The most common and easiest to apply type of attic insulation. Rolled Wool insulation consists of layers of glass wool (fibreglass), wood wool, rock wool, or sheep’s wool which is rolled out, as the name suggests. Different materials will have different levels of thermal conductivity. 

Fibreglass and Rock wool also have the advantage of being very fire-resistant.

The most important factors to take into consideration are the density of the material being used and the thickness of the layers being set down. Both of which will affect how much insulation is provided.

An environmentally friendly, efficient and cost-effective method of insulation, Cellulose is made of recycled paper products which are cut down into tiny fragments and then made into a fibrous material which can be blown into small spaces.

The advantages of cellulose insulation include that it can be used over flat surfaces, but also in small spaces and niches to ensure complete protection with no gaps or air pockets.

Polyurethane is a sprayable foam that is excellent for insulating areas with lots of small spaces or otherwise in hard-to-reach areas such as attics or cavity walls.

Easily usable in new or old buildings, polyurethane is also completely airtight and has excellent thermal performance minimising heat loss. The water-resistant seal provided by the spray foam insulation also protects from rain and dampness. Spray Foam insulation will also expand as it dries and hardens, filling every crevice.

Polystyrene Insulation is a type of thermoplastic foam which comes in the shape of rigid boards. This is popular as a form of insulation due to its adaptability, ease of application, and excellent protection against heat loss and noise.

Different from regular polystyrene boards, Bonded Bead or Cavity Bead insulation consists of small beads of polystyrene which are injected into the cavity space in a wall together with an adhesive bonding agent.

The small nature of the individual beads allows them to fill the entirety of an inaccessible space, and fill it with a solid mass once the adhesive sets.

Insulation Materials

Home Insulation Grants

The Sustainable Energy Authority of Ireland provides grant funding for many types of energy efficiency improvements to homes.

Speak with Energy Efficiency to find out how much you can save with Home insulation grant funding.

Home Insulation Grants
Insulation Type Grant Value
Attic Insulation Apartment (Any) – €800
Mid-Terrace House – €1,200
Semi-Detached/End-Terrace – €1,300
Detached House – €1,500
Cavity Wall Insulation Apartment (Any) – €700
Mid-Terrace House – €800
Semi-Detached/End-Terrace – €1,200
Detached House – €1,700
Internal Insulation (Dry Lining) Apartment (Any) – €1,500
End-Terrace House – €2,000
Semi-Detached/End-Terrace – €3,500
Detached House – €4,500
External Insulation (The Wrap) Apartment (Any) – €3,000
End-Terrace House – €3,500
Semi-Detached/End-Terrace – €6,000
Detached House – €8,000

One Stop Shop

The One Stop Shop Service is an SEAI service for homeowners who want to have multiple property upgrades carried out in one large retrofit. This takes more of the work out of the property owner’s hands and sets a specific target of a BER of B2 or better upon completion.

The One Stop Shop also offers a wider array of grants, including for insulation. On top of all those listed above, it also contains grants for rafters and floor insulation.

Insulation Type Grant Value
Rafter Insulation Apartment (Any) – €1,500
Mid-Terrace House – €2,000
Semi-Detached/End-Terrace – €3,000
Detached House – €3,000
Floor Insulation €3,500

Many of these grant values can be higher if an Approved Housing Body is the one applying.

Some homeowners on low income may also qualify for energy efficiency improvements to their homes which are fully funded by the government.

How Much Does Insulation Cost

The cost of retrofitting a home with new insulation can vary wildly depending on the size of the property, what areas are being insulated, and what insulation materials are being used. The price must factor in the material used and the labour costs of having it installed. Labour costs are hard to price without having your home assessed. 

When looking at the cost of insulation the main factors to keep in mind are:

  • Property Size
  • Materials Used
  • Accessibility
  • Labour

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For Rolled Wool insulation the cost will depend on the area being covered, the density of the wool material, and how many layers of insulation are being put down in the attic.

Rigid Polystyrene boards of insulation will also vary in cost depending on the thickness of the boards being chosen, as well as the total area being covered.

Spray Foam insulation is often the most costly option, though increasingly favoured for its excellent thermal, noise, and damp insulation. Its price relies on how deep a layer of insulation is being set down, along with the area to be covered.

Some approximate costs of common insulation materials per square metre are:

  • Mineral Wool/Fibreglass: €20 – €30
  • Polyurethane Foam: €30 – €60
  • Polystyrene Board: €10 – €20

Prices can vary greatly. Cavity wall insulation might cost roughly €1,000 for a four-bed detached house using bonded bead insulation, while a three-bed semi-detached home pays roughly €2,000 for using pumped foam insulation. 

It is important to consult with a builder about what materials will best suit your needs and goals with this retrofit project.


Depending on the scale and location of the proposed works, along with the nature of the property planning permission may be required to have insulation installed. This may be the case if carrying out external works on the house; if it is a protected structure; or located in an architectural conservation area.

While it is of course possible to buy all the materials and equipment required for a DIY job, installing insulation yourself can have severe consequences if done incorrectly. Not only may you not get the desired benefits, but you could also end up damaging your home.

Fibreglass or cellulose insulation should probably be inspected after 15 years or so, at which point it may be replaced. However other materials such as mineral wool, polystyrene boards, or spray foam can be good for up to 100 years if installed correctly.

Get in Touch

Get in touch to hear more about how Home Insulation can improve your home life today. Speak with the experts to get a recommendation and quote on what home improvements will suit you best. 

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