Wrapping a house with insulation—more commonly known as external wall insulation (EWI)—is gaining attention for good reason. Rising energy costs, a push for better efficiency, and financial support through grants have put this retrofit solution on the radar for homeowners. But is it worth it?
This article explores the real benefits, potential drawbacks, costs, installation process, and long-term value of wrapping your home with insulation. Whether you’re looking to save on heating bills or improve indoor comfort, this guide will help you decide.
What Does It Mean to Wrap a House with Insulation?
External wall insulation involves applying a layer of insulation to the outside of a home’s walls. The insulation boards—typically made from materials like expanded polystyrene (EPS), mineral wool, or phenolic foam—are secured to the wall using adhesive and mechanical fixings. They’re then covered with a base coat, a reinforcing mesh, and finished with a durable render.
This “wrap” adds an extra layer of protection, helping the home retain heat more effectively and blocking cold air from seeping through the walls.
Main Benefits of External Wall Insulation
1. Lower Energy Bills
The most immediate and measurable benefit of wrapping your home in insulation is energy savings. For properties with poor insulation, external wall insulation can reduce heating demand by up to 35%. Over time, this can mean significant reductions in energy bills—often hundreds or even thousands in savings per year, depending on house size and local climate.
2. Greater Thermal Comfort
Homes with EWI maintain a more stable indoor temperature. It reduces cold spots, eliminates draughts around exterior walls, and helps the building retain heat during colder months. This consistency means you won’t need to rely as much on heating systems, and your home will feel warmer for longer after the heating is turned off.
3. Acoustic Insulation
Another underrated benefit is noise reduction. Mineral wool-based insulation, in particular, helps dampen sound from outside. If you live near traffic or in a densely built-up area, external insulation can make your living space noticeably quieter.
4. External Aesthetic Upgrade
Wrapping a home with insulation provides a chance to refresh the external appearance. A new rendered finish can modernise the façade, cover unsightly brickwork or old pebbledash, and even increase kerb appeal. Many systems offer different colours and textures to suit architectural preferences.
5. Protection Against Moisture and Weather
High-quality EWI systems also act as a barrier against rain and wind. When installed properly, they reduce the risk of water ingress and damp, particularly in older properties where wall materials may have started to degrade.
6. Increased Property Value
A well-insulated home that meets or exceeds energy standards tends to sell faster and at a better price. With more buyers now paying attention to energy performance ratings, homes upgraded with EWI stand out in a competitive market.
How Much Does It Cost to Wrap a House?
The cost of wrapping your house with insulation varies based on several factors, including the size and type of home, the insulation material used, and the type of finish selected. Here’s a rough guide based on recent averages:
|
Property Type |
Estimated Cost (Before Grant) |
Average Grant (Where Available) |
Approx. Final Cost |
|
Apartment |
€11,000 – €14,000 |
€3,000 |
€8,000 – €11,000 |
|
Mid-Terrace |
€11,000 – €14,000 |
€3,500 |
€7,500 – €10,500 |
|
End of Terrace |
€17,500 – €21,500 |
€6,000 |
€11,500 – €15,500 |
|
Semi-Detached |
€17,500 – €21,500 |
€6,000 |
€11,500 – €15,500 |
|
Detached |
€25,000 – €30,000 |
€8,000 |
€17,000 – €22,000 |
These figures assume full-wall coverage and standard finishes. More elaborate render designs, custom textures, or additional works (like new sills, soffits, or moving utility boxes) can increase costs.
Are There Grants or Support?
In some countries, financial aid is available to help cover the cost of EWI. Ireland, for example, offers SEAI grants of up to €8,000 depending on the property type. Check with local energy authorities or sustainability agencies in your region for eligibility.
Many grant programmes require certified installers and pre/post retrofit energy assessments to qualify for funding. These schemes are worth investigating before starting any work.
When Is External Insulation Worth It?
Wrapping a house makes the most sense in certain situations:
- – Solid-wall homes with no cavity to insulate
- – Older properties with deteriorated or non-existent insulation
- – When renovating or upgrading windows, roofs, or rendering
- – Homes with poor energy ratings (E, F, or G)
On the other hand, if your home already has well-insulated cavity walls and modern energy systems, the return on investment may not be as dramatic unless part of a broader retrofit.
What Are the Drawbacks?
1. High Upfront Cost
The biggest barrier is the initial expense. Even after grants, many homeowners find the upfront cost difficult to absorb without financing options. However, it’s a long-term investment that starts paying off immediately through energy savings.
2. Planning Considerations
In some regions, adding external insulation increases the thickness of walls beyond allowable limits under permitted development rules. If the new render increases the property’s width by more than 25%, you may need planning permission.
This is particularly relevant for homes in conservation areas or those with unique architectural features.
3. Disruption During Installation
Although most homeowners can remain in their property during works, the process is noisy and can take two to three weeks. Scaffolding is required, and there may be temporary access restrictions to parts of the garden or driveway.
4. Not Suitable for All Builds
Homes with timber frames, steel structures, or older properties with “breathable” walls (like lime render or stone) may not be suitable for EWI. These buildings require specialist approaches using vapour-open materials or internal insulation.
How Is External Wall Insulation Installed?
The installation involves multiple layers:
- Cleaning and Preparation – Removing loose render or dirt and fixing any surface cracks
- Insulation Board Fixing – Securing the chosen insulation boards to the wall with adhesives and fixings
- Reinforcement – Applying a base coat with embedded mesh to add strength and prevent cracking
- Primer and Finish Render – Applying a decorative and protective top coat, typically silicone or acrylic render
The system must be installed by trained professionals following manufacturer’s specifications to ensure performance and eligibility for grants or warranties.
What Materials Are Used?
– EPS (Expanded Polystyrene)
- Affordable and widely used
- Lightweight and easy to work with
- Good thermal insulation
– Mineral Wool
- Fire-resistant and excellent for noise insulation
- Breathable
- Slightly more expensive than EPS
– Phenolic Foam
- Very high thermal resistance
- Slimmer boards are needed to achieve target U-values
- More costly
Each material has its own pros and cons depending on the home’s needs and budget.
How Long Does It Take?
On average, installation takes between 10 and 20 working days, depending on property size and weather conditions. Larger detached homes or complex façades may take longer.
Delays may also occur if the project involves moving external pipework, vents, or meters. These must be factored into the project plan and budget.
Can External Insulation Be Combined with Other Upgrades?
Yes, and this is often the most cost-effective approach. Combining EWI with:
- – Triple-glazed windows
- – Roof insulation
- – Airtightness improvements
- – Mechanical ventilation with heat recovery (MVHR)
- – Heat pump systems
- can bring your home to near-passive standard. The total upfront cost is higher, but when done together, labour and material efficiencies reduce per-unit costs.
Long-Term Value and ROI
When considered over 20–30 years, the return on investment from wrapping your home can be impressive. Not only will you save on annual energy bills, but you’ll also reduce the workload on your heating system, extend the life of your property, and cut carbon emissions.
Insulation improvements also shield you from future price shocks in energy markets and help meet sustainability standards that may become mandatory in the future.
Conclusion
Wrapping your home with insulation is a proven way to improve energy efficiency, increase comfort, reduce noise, and enhance property value. It isn’t cheap, and it’s not for every building type, but for many households, it’s a solid investment with real long-term benefits.
If your home is poorly insulated and you’re looking for meaningful improvements, external wall insulation is well worth considering. For expert advice, quick installations, and full support with SEAI grants, Osber is ready to help. Serving Dublin, Kildare, Meath, and Wicklow, Osber offers top-quality insulation solutions tailored to your home’s needs. Contact us today to book a consultation or learn more about available grants.
FAQs
1. What is external wall insulation?
External wall insulation involves fixing a layer of insulating material to the outside walls of a property, then covering it with render or cladding. It helps reduce heat loss and improve energy efficiency.
2. Is it worth wrapping a house with insulation?
Yes, in many cases. Wrapping a house with insulation (external wall insulation) can significantly lower heating bills, enhance comfort, reduce damp issues, and improve the overall energy efficiency of your home.
3. How much can I save on energy bills?
Savings vary depending on the size of your home and current insulation levels. On average, external wall insulation can save up to £400–£600 per year on heating bills in the UK for a detached house.
4. Does external wall insulation improve property value?
Yes. Improved energy performance, reduced heating costs, and enhanced appearance can all contribute to an increase in property value.
5. Can I install external wall insulation myself?
While technically possible, it’s highly recommended to use professional installers. Proper installation ensures optimal performance, moisture protection, and compliance with building regulations.