All Seasons Foil™ vs Traditional Loft Insulation: Which Saves You More?

If you're looking into loft insulation for your home, you've probably seen two main options: traditional fibreglass (the yellow fluffy rolls you'll recognise from any DIY store) and multifoil systems like All Seasons Foil. Both claim to reduce heat loss and cut energy bills — but they work in very different ways, and one significantly outperforms the other in a typical UK home.

Here's an honest, straightforward comparison.

How Traditional Fibreglass Works

Traditional fibreglass insulation works by trapping air within its fibres, creating a layer of warmth that slows the conduction of heat through your loft floor. It's been the standard UK insulation solution for decades and is widely available, relatively cheap, and quick to install.

However, it has real limitations. Fibreglass absorbs moisture over time, which reduces its thermal performance significantly. It's also susceptible to compression — once it's squashed down, it loses much of its insulating value. And it does nothing to address radiant heat loss, which accounts for a large proportion of the heat your home loses through the roof.

How All Seasons Foil Works

All Seasons Foil is a multifoil insulation system — a multi-layered blanket of reflective foil and insulating wadding that is fitted directly to your roof rafters or loft floor. Instead of trapping air, it works by reflecting radiant heat back into your home — stopping it from escaping through the roof in the first place.

It also creates an air gap and vapour barrier, which prevents condensation and moisture from building up in your roof space. This protects your roof timbers and keeps the insulation performing at full capacity throughout its lifetime.

The Key Differences At a Glance

Thermal performance: All Seasons Foil addresses both conductive and radiant heat loss. Traditional fibreglass only addresses conductive.

Moisture resistance: All Seasons Foil is fully moisture-resistant. Fibreglass absorbs moisture and loses performance.

Lifespan: All Seasons Foil carries a 25-year manufacturer guarantee. Traditional fibreglass typically needs replacing after 15–20 years.

Installation: All Seasons Foil is clean, hygienic, and non-irritant to install. Fibreglass is itchy, dusty, and unpleasant to handle.

Year-round performance: All Seasons Foil keeps homes warm in winter AND cool in summer. Traditional fibreglass primarily addresses winter heat loss.

Mortgage safety: All Seasons Foil is accepted by all UK mortgage lenders. Spray foam (a different product often confused with multifoil) is not.

Which Saves You More?

Based on Ofgem UK energy data, a typical UK semi-detached home with poor loft insulation can lose up to 25% of its heat through the roof. All Seasons Foil — by addressing both radiant and conductive heat loss — consistently outperforms traditional fibreglass in independent thermal performance tests.

Kirsty and the team at KMS can provide specific savings estimates based on your property type, size, and current insulation during your free survey.

The Verdict

If you're comparing the two purely on performance, lifespan, and long-term value, All Seasons Foil wins. It costs more to install than a basic fibreglass top-up, but with a 25-year guarantee and significantly better thermal performance, it's the smarter long-term investment for any UK homeowner.

If you're based in Wolverhampton, the West Midlands, or anywhere across the UK and want to find out which option is right for your home, book a free survey with KMS today. We'll give you an honest assessment — no pressure, no obligation.

Call 01902 288 209 or visit kmsinsulationsltd.co.uk.