Insulation is often denounced as an overly expensive and complicated solution. However, it does address a significant problem. The UK housing stock is notoriously leaky and old, with a significant portion of it being uninsulated because it was built before the 1920s. The issue of cost is not the only myth swirling around insulation. In this blog, we will look at busting insulation myths, particularly those regarding overheating, damp, and cost.

Insulation Myth 1 – Insulation is expensive

Insulation being expensive is not necessarily untrue; however, this statement holds several caveats. Much of the cost depends on the property size and the extent of the measures required. A large, detached home with single-leaf walls will require significantly more insulation than a smaller semi-detached home. As a general guideline, we detail the costs of external wall insulation as follows:

Type of home	Size (sqm)	Bedrooms	Cost	Savings	Payback
Detached	147	4	£15,000 – £20,000	£1,000	20 years
Semi-detached	96	3	£8,000 – £10,000	£700	15 years
Mid-terraced	64-100	2-3	£6,000 – £8,000	£500 – £700	12-15 years
Bungalow	77	1-2	£6,000 – £8,000	£700	12-15 years

Some homes will only require loft insulation due to preexisting insulated cavities. Loft insulation can be relatively cheap and suitable for DIY whilst still making an impact on energy bills. A loft insulation kit can cost as little as £1,000 and save approximately £200 a year on bills. Whilst the above costs for external wall insulation seem sizeable, they can be offset with government grant funding. Any homes with an EPC below a C are eligible for some form of grant. The most popular for ability-to-pay customers is the Great British Insulation Scheme. In some cases, the GBIS can cover the entire cost of materials. Myth Busted.

Insulation Myth 2 – Insulation will make my home overheat

Insulation is often incorrectly blamed for issues with overheating. However, research into the topic pinpoints overheating issues on other features of building design.

Architect Tim Ross said architects overwhelmingly supported upgraded standards, and design flaws such as over-glazing, under-shading of windows and poor ventilation were to blame for overheating.

https://www.odt.co.nz/business/insulations-role-overheating-myth-building-experts

Architecture and Design Professor Robyn Phipps of Victoria University likened installing huge areas of unshaded glass to sitting in direct sun in summer and expecting to stay cool.

She said insulation helped keep homes cool in summer, and warm in winter.

“Just like if you put your picnic in a chilly bin it will stay cooler when you go to the cricket, the insulation will keep your house cooler, but it’s the windows – too much glass, wrong orientation – which are letting the heat in,” she said.

https://www.odt.co.nz/business/insulations-role-overheating-myth-building-experts

All of these design features feed into the Passive Solar and Passivhaus design principles. Correct orientation and shading are crucial in the summer to promote cooler internal temperatures. The same shading and orientation have to work conversely in the winter, where your home has to capture the limited sunshine available. Myth Busted.

Insulation Myth 3 – Insulation causes damp in my home

The insulation causes damp myth is one that has persistently scared off homeowners. In fact, it’s quite the opposite, wherein insulation can help prevent condensation and damp. Insulation reduces the heat transfer rate between the inside and outside of your home. Maintaining a more consistent indoor temperature helps to reduce energy consumption and create a more comfortable living space.

The most common cause of dampness related to insulation is improper installation. Gaps, overlaps, and compressions can create cold spots and thermal bridges where condensation can form. Ensuring that insulation is installed by professionals following best practices can eliminate these issues. Insulation should not be blamed for pre-existing problems in a building. Issues like leaking roofs, faulty plumbing, or poor drainage can cause dampness independently of insulation.

How does insulation help in preventing damp?

Properly installed insulation maintains warmer internal wall surfaces, reducing the likelihood of condensation, which forms when warm, moist air contacts cooler surfaces. Effective ventilation plays a crucial role in well-insulated homes, with modern systems like mechanical ventilation with heat recovery (MVHR) expelling moisture-laden air and circulating fresh air to prevent damp and mould growth. Advanced insulation materials used in External Wall Insulation (EWI) systems are breathable, allowing moisture to escape while blocking water ingress. This maintains a dry and healthy building envelope, with products like mineral wool particularly effectively managing moisture. A well-managed internal environment promotes improved air quality, which is beneficial to the health of the occupants

Myth Busted.

Insulation Myth 4 – Insulation is dangerous because it’s flammable

This topic has come to the forefront of many people’s minds due to disasters like Grenfell. The industry has responded by changing fire resistance regulations. However, not all insulation is a fire risk, with fire resistance a significant concern for many manufacturers. The gold standard for fire resistance is mineral wool, with a Euroclass rating of A1. Composed of non-combustible materials such as stone or slag, mineral wool can withstand extremely high temperatures without igniting or spreading flames. This fire-resistant property helps to contain fires and prevent them from spreading through the building, providing valuable time for occupants to evacuate and for emergency services to respond.

Other insulation materials may be more flammable, but manufacturers make conscious efforts to improve the rating. Wood fibre is often mixed with any flammable additives, and the compacted nature of the boards aids in maintaining overall fire resistance. Myth Busted.