Along with better keeping the heat in and lowering your energy bills, loft insulation can even increase the value of your property, potentially by 5% to 15%.
Insulating a loft usually involves a professional adding material to keep the heat in, limiting cold air seeping into a property and warm air escaping via the loft. The material is fitted between and above the joists for the ceiling below at the loft’s floor level.
Loft insulation is not simply for keeping the attic space warm. It also acts as an effective way to limit heat loss for your property overall. It can lower your home’s heat loss by 20-30% while lowering your bills similarly due to improved energy efficiency.
This measure will make your home more energy efficient, making for a more comfortable space that can stay warmer for longer, which can be particularly helpful in the winter. Let’s dive in!
Key Points:
- Loft insulation can reduce heat loss by 20-30%, leading to significant energy savings and lower heating bills.
- The average household can save between £200 to £400 per year, depending on the home’s size.
- Blanket insulation is a popular and cost-effective option, usually made from mineral or sheep’s wool. Costs range from £400 to £850 for typical installations.
- Loft insulation reduces a household’s carbon footprint by 100 to 800kg of CO₂ annually, contributing to sustainability.
- Some types can be installed DIY, but professional installation is often recommended, especially for materials like spray foam or blown-fibre insulation.
- UK residents may be eligible for insulation funding schemes like ECO4 or the Great British Insulation Scheme, offering up to 100% cost coverage for some households.
Types of Loft Insulation
Note: A professional will usually be required to install loft insulation. In some cases, a DIY approach may be possible, but only for certain types of loft insulation, assuming all steps are correctly taken (especially safety steps), and you use the right tools, equipment, measurements and materials. If in any doubt, consult with a professional.
While offering reduced heating bills and improved energy efficiency generally, the average cost and precise benefits of loft insulation can vary depending on the type you opt for. Here, we’ll look at the pros, cons and typical applications for several types of loft insulation.
Blanket Insulation
Firstly, blanket insulation, usually in the form of rolls, tends to comprise glass, rock or mineral fibre.
Besides being low-cost, blanket insulation is one of the most popular forms of loft insulation in 2024.
Blanket insulation is often installed between joists, though is sometimes fitted over loft rafters or as under-floor insulation. However, it is not suitable for roof installation.
This type of loft insulation costs about £25 to £50 per roll or £5 to £30 per square metre.
The price variation largely depends on the type of blanket insulation used (e.g. mineral wool or sheep wool).
The total cost, including supply costs and the price of labour (i.e. around £250 per day), an average loft insulation with mineral wool blanket will land around £400 to £850, with the figure reaching £1,000 to £2,850 in the case of sheep’s wool blanket.
Blanket insulation is ultimately a practical and cost-effective option. However, it may not work as well as other types of loft insulation.
Also, some blanket insulations can irritate the skin. In these cases, the need to wear protective equipment/clothing emphasises the importance of understanding the safety needs of loft insulation.
Loose-Fill Insulation
Loose-fill insulation is an insulating material that the installer pours or compacts loosely. Unlike solid, pre-made options like blanket or sheet insulation, installers use an insulator blower to blow loose-fill insulation into place.
Loose-fill insulation costs around £10 per m² in supply-only expenses, with options including mineral wool, cellulose fibre, cork and fibreglass loose-fill loft insulation.
Factoring in the cost of supplies and labour, the average combined cost of loose-fill loft insulation is about:
- £550 to £650 for a small loft space of 30m² to 40m²
- £650 to £850 for a medium loft space of 40m² to 60m²
- £850 to £1,050 for a large loft space of 60m² to 80m².
Loose-fill insulation is often a great option if your loft features unevenly-spaced joists or ones awkwardly spread apart. Further, loose-fill insulation is quicker to install.
However, loose-fill insulation can compress over time, becoming less effective at keeping the heat in. It is also at a greater risk of soaking up water, which can cause mould.
Sheet Insulation
Sheet insulation is also a solid option, though it is firmer with sheet insulation comprising rigid sheets. Board insulation is a similar and often overlapping choice (more on that below).
The two primary categories of sheet insulation are those made with synthetic and natural materials.
Synthetic sheet insulation options include polystyrene and polyisocyanurate or PIR; the former is usually cheaper, but the latter offers more insulation. Natural sheet insulation includes those made with mineral wool.
Depending on what type you opt for, sheet insulation will often cost somewhere in the region of £500 to £1,200.
Board Insulation
Again, while sheet insulation and board insulation types can overlap, giving board insulation its section is valuable and informative.
Across the board (pun not intended), insulation boards are often used above or below the roof rafters. Alternatively, however, they can be installed between ceiling joists.
The average total cost of board loft insulation is around £150 to £800 for a 30-40m² loft space, £200 to £1,200 for a 40-60m² loft space or £300 to £1,600 in the case of a large, 60-80m² loft space.
PIR and PUR Board Insulation
Along with polystyrene and polyisocyanurate (PIR) sheets/boards, polyurethane (PUR) insulation boards are another option.
Standout aspects of PIR are its strong flame- and smoke-resistance qualities. However, PIR and PUR board insulation offers a high capacity to slow water absorption.
This is important to help keep a property dry, thus limiting the danger of mould growth, water damage and specific hazards (e.g. water coming into contact with electricity).
PIR boards are usually cheaper than PUR boards and often less expensive than polystyrene insulation boards.
Polystyrene Insulation
Returning to the more familiar material mentioned here, ‘Polystyrene’, you can choose between EPS and XPS insulation boards.
Both are great choices. However, the latter, known more often as XPS insulation boards, offer more durability and greater insulation potential. These boards are known for their use where load-bearing is concerned.*
*You should still verify any of these details with a professional to err on the side of caution.
Blown-Fibre Insulation
This type of insulation involves the installer adding many loose materials to joists. This way, blown-fibre insulation can be blown in a place where other options may be too difficult to add.
Blown-fibre insulation differs from loose-fill in that blown-fibre tends to involve the use of heavier materials while also offering firmer, more effective insulation.
Blown fibre may not be suitable in some cases, though, as (among other reasons) it may be too heavy, causing a hazard if your loft’s ceiling lacks the load-bearing capacity needed.
Blown-fibre insulation is generally costlier than loose-fill at about £650 to £1,300 for an average loft.
Spray Foam Insulation
A less common choice is spray foam insulation. While it has many benefits, it is a more controversial option since it has various risks and downsides.
Spray foam is a high-quality option and a liquid form of insulation that can be applied using a spray gun. Once applied, it expands before setting in place.
To have spray foam insulation added to a loft, it will cost about:
- Small Loft Space – £1,050 to £1,850
- Medium Loft Space – £1,450 to £2,650
- Large Loft Space – £1,800 to £3,450
Spray foam has various upsides, such as an airtight seal along with no gaps or joints and ease of installation (for professionals*).
*Professionals need to deal with this type of loft insulation.
Multifoil Insulation
Foil or multifoil insulation is another alternative. Multifoil insulation can reflect heat into the room thanks to its reflective and insulating layers.
The materials used help to keep the space warm and provide greater heat insulation for the property overall.
You can expect to pay around £550 to £1,000 to have a professional add multifoil insulation (including labour and supply costs). While offering good value for money, it needs cleaning every so often to rid it of dust.
Costs of Loft Insulation
As the above subsections show, loft insulation prices can vary greatly. For instance, blanket loft insulation often costs several hundred pounds.
However, sheet insulation generally costs closer to £1,000 and spray foam insulation tends to cost between £1,400 and £2,800.
Loft insulation costs can differ based on the insulation type, size, and accessibility of the loft space, and the quality of the loft insulation product.
Here is how the different forms of insulation listed above compare:
| Type of Insulation | Average Costs | Average R-Values* |
|---|---|---|
| Blanket Insulation | £400 to £1,500 | 2.5 to 4.5 |
| Loose-Fill Insulation | £650 to £850 | 2.4 to 3.3 |
| Sheet Insulation | £500 to £1,200 | 2.5 to 4.5 |
| Board Insulation | £200 to £1,200 | 2.6 to 6.5 |
| Blown-Fibre Insulation | £650 to £1,300 | 2.2 to 4.3 |
| Spray Foam Insulation | £1,400 to £2,800 | 3.6 to 5.6 |
| Multifoil Insulation | £550 to £1,100 | 2.5 to 2.8 |
*The R-value measures how much a material can resist heat transfer at a given thickness.
Benefits of Loft Insulation
While the pros and cons can vary depending on the type of loft insulation in question, some broad advantages can apply to most, if not all, forms of insulation.
Energy Savings
The main draw of loft insulation is its energy-saving capacity. By trapping heat, loft insulation can make it easier to heat your home and allows your heating system to work less.
The extent of loft insulation’s energy savings can vary significantly depending on factors like the size/type of property, the household’s heating needs and the type of insulation used.
The average annual energy savings loft insulation offers is about £200 to £300. Smaller households may save around £150 to £200, whereas semi-detached homes are likely to save between £175 and £250. Larger households may save up to £400 or more annually.
Increased Comfort
By limiting heat transfer, loft insulation can help keep rooms in your home toastier for longer on cold days and nights.
Loft insulation limits heat transfer in and out of the property via the roof, which can also help keep the heat out on hot summer days. This way, your home can also stay cooler and more comfortable on hot days.
Environmental Impact
Loft insulation’s energy savings can also lower your carbon footprint. This, of course, assumes you are not using a low- or zero-carbon source of household heating.
Here are some key points to consider for loft insulation’s environmental upsides:
- Loft insulation can reduce a household’s carbon footprint by somewhere in the region of 100kg to 800kg of carbon dioxide per year
- The figure may reach or even surpass 1,000kg in the case of large homes (e.g. detached properties).
- Various factors will determine how much loft insulation lowers a household’s carbon footprint
The abovementioned figures indicate a household carbon footprint reduction of around 5% to 15%.
Long-Term Value
Another notable upside of loft insulation is its potential to increase the value of your home. Of course, this may not always apply (e.g., spray foam insulation may even lower property value). In general, though, loft insulation can increase a property’s value by about 10%-or-so.
Beyond that, loft insulation can extend the lifespan of your roof by helping to protect it from the elements, potentially adding many years to the roof’s life expectancy or/and prolonging how long before roof repair work is next needed.
Lastly, loft insulation usually pays for itself with time and can be many times over according to a GOV.UK release. Factoring in the type and quality of insulation used and how effective it lowers your heating bills, it will often pay for itself after 2 to 5 years. In some rarer cases, it could take around 7-10 years.
Disadvantages Of Loft Insulation
Along with the many upsides to loft insulation, it’s still important to weigh these with some notable downsides.
Cost of Installation
While loft insulation can lower energy bills and pay for itself over time, the upfront cost is still quite an expense in the short term.
As discussed earlier, loft insulation may cost several hundred pounds, but it can cost thousands in other cases.
Blanket insulation generally costs a few hundred pounds or somewhere between £1,000 and £2,000 for more expensive options. However, board insulation usually costs less, while spray foam insulation is costlier.
That said, it is still worth noting that some households may be eligible for grants or funding from the government or local authorities (e.g., the Great British Insulation Scheme or the ECO4 Scheme). If unsure about your potential eligibility, contact your local council for clarity.
Here’s a quote from David MacMichaels, an EPC expert, on loft insulation in UK properties:
“Loft insulation is one of the most effective ways to improve energy efficiency in UK homes. Properly installed, it can reduce heat loss by up to 30%, making homes warmer and reducing energy bills significantly. With current government incentives like the ECO4 scheme, many households can install loft insulation at little to no cost, making it an essential upgrade not just for comfort, but also for long-term financial savings and reducing carbon footprints.”
Space Usage
To one degree or another, loft insulation can make storing items in your attic difficult after the installation. Of course, this can differ depending on your loft’s layout and the insulation used.
Suitability for Older Homes
Another issue is that it may not be possible to add some forms of loft insulation to older or listed properties, whether for practical, safety or legal reasons (with the latter potentially applying if you have a listed property).
*To add what types of insulation may not work for older homes.
Ventilation Issues
Incorrect installations can also result in condensation or damp issues, which is one of many risks associated with adding loft insulation DIY.
Without correct ventilation, rainwater, melted snow, and ice can seep through the insulation, ultimately causing dampness with possible damage and higher condensation levels in your home.
It’s also worth noting that it’s even possible for too much loft insulation to result in more condensation. In summary, too little ventilation can cause problems, but so can too much in some scenarios. Hiring a reliable professional will minimise the risk of these issues arising.
Access and Installation Challenges
Depending on your budget (and hence the type and quality of loft insulation used) and the layout of your attic, accessibility and installation difficulties could prolong the work required.
As a result, the labour costs may be higher in these scenarios due to the longer time frame involved in the work. Access and installation challenges could also limit what types of loft insulation you can opt for.
Savings and Energy Efficiency
When opting for loft insulation, improved energy efficiency and reduced heating bills go hand-in-hand. Let’s discuss energy savings and payback periods in more detail.
How Much Can Loft Insulation Save?
On average, here is how much different types/sizes households may save on bills:
- Terraced House – £150 to £200 per year
- Semi-Detached House – £175 to £250 per year
- Detached House – £300 to £400 per year
The savings can also differ based on the insulation used and its quality. Spray foam insulation takes the crown as the most effective option to reduce heating bills. This is thanks to its airtight seal with no gaps or joints.
Other top choices for lowering heating bills are sheet and board insulation. That said, while more affordable, options such as loose-fill and blanket insulation are not as effective, so they are unlikely to save as much on heating bills.
The average annual energy savings loft insulation offers is about £200 to £300. Smaller households may save around £150 to £200, whereas semi-detached homes are likely to save between £175 and £250. Detached bungalows and detached homes will probably save closer to £300 to £400 each year.
Payback Periods: How Long Before It Pays For Itself?
The time it takes for loft insulation to pay for itself (i.e. save more on your energy bills than it costs to install) can vary significantly.
Loft insulation can pay for itself in more optimal scenarios in 2 to 3 years. This is more likely to occur when choosing high-quality insulation or/purchasing loft insulation at good value for money.
On average, it takes 2 to 5 years for loft insulation to pay for itself. In less effective scenarios, it will take closer to a decade.
Available Loft Insulation Funding and Grants
Depending on where in the UK you are located and a range of eligibility criteria, you may be eligible for funding or a grant toward your loft insulation.
Options Available Throughout the UK
| Funding/Grant | Application Window | Key Eligibility Criteria* | Estimated Savings |
| Great British Insulation Scheme | Sept 2023 to March 2026 | EPC Rating of D to G, Annual Gross Income Below £31,000 | 50% to 100% off the Installation Cost |
| ECO4 Scheme | April 2022 to March 2026 | EPC Rating of D to G, Claim income-related benefits | Usually 100% of the cost is covered |
| ECO4 Flex** | July 2022 to March 2026 | Flexible and can vary from one local council to another | 70% to 100% – Should cover at least most of the costs but less likely to cover 100% than ECO4 more broadly |
*Other forms of eligibility criteria can apply, but the above are some of the most notable examples. You may not need to meet all criteria listed as it can vary over time and by scheme. If in doubt, consult with your local authority.
**ECO4 Flex, a.k.a., LA Flex, is a part of the ECO4 scheme more broadly. This scheme within a scheme allows local authorities to expand and make broader the eligibility criteria for securing funding for energy efficiency upgrades. This is to help prevent some households from falling beneath the cracks.
Both the Home Upgrade Grant (HUG) and Local Authority Delivery (LAD) schemes are closed to applications; however, new phases of either or both may open in the future.
Regional Funding/Grants
| Region | Funding/Grant | Application Window | Key Eligibility Criteria* | Estimated Savings |
| Scotland | Home Energy Scotland Loan | December 2022 to Present | You own and live in your home that is your primary residence | 30% to 100% off the cost (£500 to £1,500) |
| Wales | Warm Homes Nest Scheme | April 2018 to Present* | You own and live in your home which is your primary residence | Usually at or close to 100% cost reduction |
| Northern Ireland | Affordable Warmth Scheme | Sept 2014 to Mar 2026 | Own or occupy the property that is your main home, have a total annual gross income under £23,000 | Generally 100% off the cost |
**As for the EPC rating, you are eligible for the Warm Homes Nest Scheme if your home has a rating of E, F, or G or D through G if you or a household member has an eligible health condition.
Installation: DIY vs. Professional Installation
While it is sometimes possible to add loft insulation alone, you’ll need a professional in some scenarios. Of course, you should not attempt this DIY if you are unsure what is required.
Other scenarios where you’ll require a professional include the loft having ongoing damp problems, your home having a flat roof, or you opting for the likes of spray foam or blown-fibre insulation.
Adding Loft Insulation DIY
Adding loft insulation DIY is best suited to easier installation options, such as blanket, sheet, or board insulation.
As mentioned above, you should only add loft insulation DIY if you know exactly what is required, such as the equipment and materials needed, how to keep it safe during the process and how to install the insulation correctly and effectively.
Key safety steps to keep in mind are:
- Make sure that your loft is lit properly
- Ensure there are minimal tripping hazards*
- Look out for asbestos, loose wiring and pipes before starting
- Consider vacuuming your loft space
- Make sure there is proper ventilation in the loft
- Remove existing loft insulation in a safe and effective manner
*While you may not be able to remove all trip hazards, addressing some (e.g. moving boxes with stored items to reduce the chance of falling over them) can help lower the risk of injury.
Safety is essential when adding loft insulation DIY. Beyond that, make sure to have a clear plan, know exactly what is required and choose the right type of loft insulation for your home, budget and needs.
In summary, here are the positives and negatives of adding loft insulation DIY:
| Advantages | Disadvantages |
| You’ll likely save around £200 to £300 without labour expenses | Safety risks involved with a range of potential hazards |
| With a successful installation, you’ll be in a strong position to ‘top it up’ once you know what is needed | Risk of a poor installation that could be ineffective, require a professional to fix it or/and pose safety hazards |
| Not all forms of loft insulation are suitable for a DIY job |
Professionally-Added Loft Insulation
Hiring a professional is generally the best course of action and, in many cases, is required, as mentioned above.
While it can cost more (generally £200 to £300 extra to cover labour), this extra cost offers security, peace of mind and certain guarantees.
Of course, hiring a suitable professional with the right experience and knowledge is essential for a solid outcome.
Here are the pros and cons of hiring a professional:
| Advantages | Disadvantages |
| A high-quality loft insulation job | Higher cost, generally £200 to £300 more |
| Safe and secure installation work | |
| Professionals needed either way for complex jobs like spray foam and blown-fibre insulation |
To find reputable installers, looking around and using reliable services is important. From there, you can compare quotes or contact suitable and knowledgeable professionals and, where applicable, decide who is best for the job.
Loft Insulation Maintenance and Aftercare
While loft insulation will often last for decades, it’s important to consider maintenance, professional inspections and aftercare to make the most of it.
Maintenance and Causes of Damage
To make your loft insulation last, it’s important to safely look out for any roof leaks coming through the insulation/ceiling. Otherwise, water damage can accumulate with time, degrading your insulation, the below-level ceiling and more of your property’s infrastructure.
Beyond that, ensuring your loft remains ventilated over the years is key, as ventilation can wear down or become blocked. This will lead to a build-up of moisture in the loft space and damage the loft insulation and other aspects of the attic.
Having a vapour barrier fitted beneath loft insulation by a professional can also protect the insulation over time, even when the ventilation is well-maintained. Please note that a vapour barrier may not always be an option, depending on the type of loft insulation.
Importance of Professional Inspections And Repairs/Replacement Work
Whether due to safety concerns with moving about your loft or/and for more extensive or professional evaluations, you should hire a professional to look at your loft insulation every few years.
However, you should have this done at least every five or so years, as even high-quality loft insulation will eventually decline over time. This may not be apparent initially, but after enough time, a professional evaluation can spot issues ahead of time.
With enough time, your loft insulation may need repairs before eventually requiring a replacement. In some cases, loft insulation may outlive us all if sufficiently high quality and maintained well.
Loft Insulation Case Studies and Examples
Here are some examples of loft insulation used to significantly improve heat retention and/or resolve other needs.
Knauf Insulation Retrofits Housing Project For High Efficiency
Global company Knauf Insulation has 40 years of experience and is known for its innovative, high-quality insulation products.
Both Knauf Insulation and Knauf Energy Solutions provided a modern solution for the Trafford & Eccles Housing Projects.
Knauf’s high-quality mineral wool insulation and advanced sensor technology allow construction companies to install top-notch insulation and accurately determine its effects on a property’s energy efficiency.
In what was, according to Knauf, the largest real performance retrofit project in UK history, Knauf Insulation and Knauf Energy Solutions upgraded 28 homes from 1970s standards to modern mineral wool insulation.
The results included the following:
| Factor/Aspect Improvement | Trafford | Eccles |
| Avg. Fabric Energy Improvement Per Home | 31% Increase | 17% Increase |
| Avg. Reduction In Residents’ Bills | £411 | |
| Notable Improvement For One Home | 51% Improvement | 28% Improvement |
Rockwool Loft Insulation in Greater Manchester
Multinational company Rockwool is known for its high-quality, fire-resistant mineral fibre insulation.
In one case study, Rockwool provided insulation for a large regeneration project to feature 2,215 new homes.
The project’s developer, Scarborough Group International or SGI, needed insulation to retain heat while complying with fire regulations. Rockwool’s loft insulation was a suitable fit with qualities such as meeting Euroclass A1 non-combustibility classification, high-quality heat retention and noise reduction capacity.
Summary
Loft insulation may be an investment at first. Still, along with keeping you and others in your home warmer, it can reduce energy bills, often by hundreds of pounds and ultimately pay for itself with time.
As today’s guide shows, there are many types of loft insulation and various factors to remember when deciding what option might work best for you and your loft.
Be sure to carefully weigh your options and only install DIY when it is safe, suitable and practical.
With effectively installed loft insulation, you can enjoy a cosier home that stays warmer for longer and ultimately saves more than you initially spent once the loft insulation has paid for itself through energy bills!