Best loft insulation 2023: An easy way to cut your heating bills
Want your home to be warm and toasty? Prevent heat from escaping through the roof by installing our pick of the best loft insulation
With electricity and gas costs spiralling, we’re all looking for ways to cut our energy use – and ensuring your loft space is properly insulated is one of the easiest and most effective methods to do so. The best loft insulation helps to prevent rising heat from escaping through your ceilings, into the loft and out through the roof. To experience this in practice, open your loft hatch on a cold day, and you’ll immediately feel the warmer air in your house rushing upwards.
There are three types of insulation available to the keen DIYer. Blanket insulation comes in slabs or rolls, and you simply place it between the loft joists – having emptied your loft first. Loose-fill loft insulation is arguably even easier to fit; you pour it between your loft joists. There’s no cutting required, and it can be used on its own, to fill gaps in blanket insulation, or to insulate hard-to-reach areas.
Loft insulation boards are the trickiest option, but are the preferred choice if you want to make your roof space warmer – particularly if you’re using it as a games room or a home office. You can mount the board beneath the rafters, which is easier, but this will eat into your available headroom. If you mount them between the rafters, you’ll need to take care to ensure there’s sufficient space between the boards and the roof membrane to avoid condensation.
So, to make it easy for you to decide which type works for you, below you’ll find our pick of the best loft installation, considering price, coverage, ease of installation, plus online reviews from real customers. First, though, we reveal how you go about picking the best loft insulation for your space.
Best loft insulation: At a glance
- Best blanket loft insulation: Knauf Insulation Super Top Up 200mm Loft Roll | £25
- Best loose-fill loft insulation: Dupré Micafil Vermiculite Loose-Fill Loft Insulation | £30
- Best loft insulation board: Recticel Instafit Polyurethane Insulation board | £9.65
How to choose the best loft insulation for you
How much could insulating my loft save me?
According to the Energy Saving Trust, adding 270mm-thick loft insulation to an uninsulated loft could cut £590 from the annual energy cost of heating a detached house, and more than £300 off the cost of heating a semi-detached or mid-terrace house. Boosting the thickness of 120mm insulation to the recommended 270mm could save homeowners around £50 a year. It’s clear that despite an initial outlay, loft insulation could quickly pay for itself.
Do I need special equipment to fit loft insulation?
Not really. If you’re fitting blanket insulation, you’ll need scissors or a knife to cut it to size (don’t tear it), while protective clothing such as gloves and a face mask are highly recommended because some types of insulation can cause irritation. Loose-fill loft insulation requires even less kit, since you simply pour it where it’s required. Insulation boards can be cut with a saw.
Whichever type you go for, use some strong wooden planks as crawler boards to reduce the chances of you putting a foot through the ceiling.
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Do I need to clear my loft before fitting loft insulation?
If you’ve lived in your home for a long time, clearing the loft may be the most time-consuming part of the entire insulation process. But it’s worth doing because it will make the job easier, and will reduce the risk of you causing damage by tripping over something.
Does loft insulation cure dampness?
Houses need to breathe in order to avoid damp buildup. That means if you have a damp loft, you should sort that issue before trying to insulate it, which could mean paying for a comprehensive damp survey to identify the cause. Typically, damp in lofts can be remedied by fitting vents to improve airflow. If you do have a damp loft, sheep’s wool insulation can help draw out moisture. It’s worth noting that if you’re installing insulation boards between the rafters, you need to leave a gap of at least 50mm to allow air to flow and to prevent condensation forming.
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The best loft insulation you can buy in 2023
1. Knauf Insulation Super Top Up 200mm Loft Roll: Best blanket loft insulation
Price: £25 | Buy now from B&Q
German firm Knauf is one of the biggest and more well-known producers of insulation materials, so it’s perhaps little surprise that its 200mm blanket roll proves popular across a range of retailers. The roll measures 4,925mm and 1,140mm wide, for a total coverage of 5.61m2. It’s 200mm thick and is Euroclass A1-certified, meaning it’s non-combustible.
Helpfully, the roll comes combi-cut, which means it’s perforated to make it easier to cut for fitting between joists, or laid uncut as a full-width top-up layer. It’s constructed from glass mineral wool, which is up to 80% recycled, and uses Knauf’s ECOSE technology, a bio-based binder that reduces dust and ensures the insulation is soft and easy to handle.
While the plastic-wrapped roll is tightly compressed to make it easier to pass through a loft hatch, it’s weighty at 10.55kg, so it may well be a two-person job to manoeuvre it up a loft ladder.
Key specs – Material: glass mineral wool; Coverage: 5.61m2; Fire retardant: Yes (Euroclass A1)
2. Dupré Micafil Vermiculite Loose Fill Loft Insulation: Best loose-fill loft insulation
Price: £30 | Buy now from Buildingmaterials.co.uk
First things first: while loose-fill insulation is brilliantly easy to lay, it’s also very expensive to cover large areas. That’s true of Dupré’s Micafil, because one bag will cover only 1m2 at a depth of 100m, meaning it’s better suited to fill in gaps around blanket insulation or in hard-to-reach areas.
Nevertheless, it’s a naturally occuring mineral that’s exposed to heat by Dupré to ensure each chipping is around 90% air – vital for its insulating properties. It’s a versatile material, and can also be used in cavity walls, around pipework, and can even be mixed with cement for screeding. And unlike some vermiculite, it contains no asbestos.
The bags are light, making carrying into loft spaces and pouring easy – and, when the non-toxic material is laid, it’s fireproof to 1,300ºC and offers good acoustic insulation properties.
Key specs – Material: Vermiculite; Coverage: 1m2 at 100mm deep; Fire retardant: Yes (up to 1,300ºC)
3. Recticel Instafit Polyurethane Insulation board: Best loft insulation board
Price: £9.65 | Buy now from B&Q
Recticel Instafit is a superb option if you’re insulating between rafters. The 50mm-thick panels measure 1,200mm long and 450mm wide, making them easy to transport in your car and lift into your loft. The panels can be cut with a saw or jigsaw, and can either be mechanically fitted by squeezing a precisely cut panel between the rafters, or held in place using a suitable adhesive, or screws and washers. However, it will require the correct membrane to help prevent damp.
The panels are covered with a metallic film with guidelines to aid accurate cutting, and they’re resistant to moisture, ensuring they won’t degrade in the presence of condensation. Recticel recommends the board is covered with plasterboard of at least 12.5mm thick, if you’re insulating your loft to use as a living space.
Key specs – Material: Polyurethane; Coverage: 0.54m2; Fire retardant: Yes (Euroclass F1)