Warm front


With another year of rising energy costs on the cards, now’s the perfect time to insulate your home and improve its energy efficiency before the cold weather returns next winter.

Insulating your home properly has always been prudent, but, let’s face it, pretty dull when you’d rather spend the money on a new sofa. But now, with energy costs soaring, there’s nothing boring about investing in insulation that could drastically reduce your fuel bills. And not only will your house feel warmer inside, you will too after taking a chunk off your carbon footprint.

The National Insulation Association (NIA) estimates that 20 per cent of the heat lost in the average home escapes through the walls, and 25 per cent through the roof. However, one of its recent polls shows that a massive two thirds of householders in the UK are not aware of these facts and, therefore, the savings that could be made by properly insulating their homes. ‘If the average property’s loft and cavity walls are uninsulated, or insulated to insufficient levels, the owners might as well be burning their own cash,’ says Neil Marshall, chief executive of the NIA. ‘It takes a very short time to recoup the original outlay for insulation; most insulation measures will pay for themselves within four years and some sooner than that. In addition, once fitted, home insulation can be forgotten about, leaving the householder to enjoy not only lower bills year-on-year, but a warmer and cosier home.’

The two ways to make a real difference to existing properties are insulating the loft and the outside walls, the latter by cavity wall or external insulation. New-builds can reduce heat loss from day one by highly insulating the roof, ceilings and walls as part of the building design.

The result is a home that’s warmer in winter, and cooler in summer. But it’s not easy to decide which solution is best for your house, your pocket, and your timescale. Laying extra roof insulation may be quick, and at under £500 relatively cheap, but the fuel savings will be far less than that yielded by a larger investment in, say, foam spraying the underside of your roof, or the most expensive option, over-cladding your house, which can produce around three times the cost savings of cavity wall insulation or loft insulation. Throw into the mix the array of grants available towards insulating costs and the choice becomes even more complex.

Because there’s no one simple answer, it’s too easy to do nothing, according to the NIA, which recommends getting a free survey from one of its members who can advise on solutions and funding. The Energy Saving Trust and Insulated Render & Cladding Association (INCA) are also useful contacts.

Adequate loft insulation can save up to 15 per cent of a home’s heating costs according to the NIA. The two approaches are insulating at roof level to create a warm, usable roof space or at ceiling level.Loft

Adequate loft insulation can save up to 15 per cent of a home’s heating costs according to the NIA. The two approaches are insulating at roof level to create a warm, usable roof space or at ceiling level.

Top-up insulation is usually laid in slabs or as a blanket at ceiling level, but can also be blown in loose. Government recommendations are for at least 270mm of insulation if using glass wool (250mm for rock wool, 220mm for cellulose).

The conventional material is mineral wool, which is manufactured from molten glass or rock. DIY stores stock a wide range, such as Knauf ’s Space Blanket, which is claimed to pay for itself in a year. But there are other, more unusual material options: Warmcel 100 is a cellulose fibre loft insulation made from recycled waste newspaper and costs approximately £300-£400 for a 45sqm loft. Thermafleece is made from sheep’s wool and has a life expectancy of more than 50 years. Prices are £9.36 per sqm for 100mm thickness. Another natural option is Isonat, made from hemp. The NIA recommends using experts to get the best results, and has a list of approved members.

Cavity walls

Cavity wall insulation is injected into the cavity between the inner and outer brickwork from the outside of the house. It’s incredibly easy to have doneCavity wall insulation is injected into the cavity between the inner and outer brickwork from the outside of the house. It’s incredibly easy to have done: small holes are drilled in the outside wall and then the insulation material is simply pumped in through these holes, filling the space. With prices starting at around £500 or so, the investment can be recouped in around five years, less as fuel prices rise, but it’s only suitable if you have a cavity wall in the first place. Houses built within the past 10 years or so tend to have this type of insulation fitted as standard. To find out if it’s suitable for your home, contact the EST or NIA for advice.

If you do opt for it, choose a BUFCA member or an NIA installer, who can offer guarantees on the work. There are three main types of filler – mineral wool, EPS beads, or urea formaldehyde foam. The foam option can cost £1,500-£2,000 but gives better insulation and airtightness and can withstand flooding, unlike mineral wool, which would have to be removed.

Foam insulation

Another approach to loft insulation is spray-applied rigid foam at roof level

Another approach to loft insulation is spray-applied rigid foam at roof level, especially suitable if you plan to use the loft. This can be sprayed directly onto the roof underside to form an insulating layer; it can also strengthen the roof by bonding the materials to help prevent storm damage and weathering. The British Urethane Foam Contractors Association has a list of members who offer this service. Warmroof customers report 30 per cent savings on heating bills. According to Sprayseal, at approximately £2,300 per application, it’s less than half the cost of a new roof. It’s half that if you spray direct onto a felted roof, says Renotherm. Meanwhile, just launched in the UK is US product Icynene – a spray-on liquid foam internal insulation and air barrier that expands to 100 times its volume to create a highly efficient building envelope. Prices vary with supplier; check the website for one near you.

External insulation

Installing external insulation gets impressive results, creating a warm building envelope.Installing external insulation gets impressive results, creating a warm building envelope. According to INCA, it could reduce heating bills on a three-bedroom semi by £500 per year. It’s not cheap, though, costing between £5,000 and £10,000, and can change a house’s appearance. External insulation makes financial sense on properties that need re-rendering or re-pointing, which are expensive procedures that could cost up to £4,000. External cladding will replace this job and provide a far better thermal performance as well. On new-builds, it’s an effective way of reducing heating bills from the outset as part of the building design.

Systems consist of insulant (generally expanded polystyrene or mineral wool fibre), fixing and weather-protective decorative render or cladding, and take around three days to apply. INCA has a register of approved installers that offer certified systems with a 25-30 year lifespan. These include Sto, which has the StoTherm system in up to 800 colour finishes, and CarbonEco, which claims its insulation is 33 per cent more efficient than cavity wall insulation. Both cost around £70 per sqm. ‘The solid wall becomes the thermal mass with a more constant temperature. You don’t have to re-point. It’s like a tea cosy on a teapot,’ explains CarbonEco director Ann Barradine.


There are three main sources of funding for cavity wall and loft insulation
Government Up to £2,700 towards insulation for households receiving certain benefits under a scheme known as Warm Front in England (warmfront.co.uk); Warm Homes in Northern Ireland (eaga.com – go to the government contracts section); Warm Deal and the Central Heating Programme in Scotland (communitiesscotland.gov.uk – search for ‘warm deal’) and the Home Energy Efficiency Scheme in Wales (heeswales.co.uk). Some grants are also available to those aged over 70, regardless of income. A new £350 million Community Energy Saving Programme from the Government will also offer free and subsidised insulation in 100 fuel-poor areas.

Energy suppliers Under the Carbon Emission Reduction Target scheme, energy suppliers are obliged to achieve targets for improving home energy efficiency, and therefore offer grants. These can be taken up from any energy company (regardless of whether they supply your gas or electricity), although priority groups will benefit first.

Local authorities Most provide grants and offers for local residents to encourage energy efficiency. Contact your council for advice on local grants.

Further information To find our more about available grants, use the postcode search on the home page of nationalinsulationassociation.org.uk to find a list of local members. These companies will offer a free home visit to advise on which kind of insulation would benefit your home and the grants available for each option. It’s also worth looking at the website of the Energy Saving Trust (energysavingtrust.org.uk) for a list of grants available in your area. Simply go to the ‘What can I do today?’ section to find the link to ‘energy saving grants and offers’.

Words Pamela Buxton

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