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How does Low-E Insulation compare?

Foil insulation is a very simple idea; use pure aluminium to reflect heat back to the heat source.

So why do so many companies get it wrong?

Read our blog if you want to know more about how Low-E works?

How Does Low-E Reflective Insulation Work?

This blog has been put together to answer some of the most basic questions about Low-E Reflective insulation and foil insulation in general 

– What is the difference between Low-E and Multi-Foil Insulation? 

– What is the difference between Aluminium and Mylar? 

– What is the difference between Low-E and traditional insulation? 

 

It is possible to reflect heat with a single layer of aluminium, that bit is easy! The problem is, when you do that, it creates an increased risk of condensation forming on the surface or the product. So, the obvious answer is to add an additional separating layer to reduce the risk condensation and create a thermal break. Different companies have tried to do this several ways, using various materials and methods. The problem is that these separating materials and methods of production tend to create additional problem which then need to be dealt with. 

Product types;

– Bubble wraps or single layered products 

– Glued or laminated  

– Fibrous cores

All of these product (in my opinion) end up creating more problems than they solve.

Bubble Wraps and Single layered products have an increased the risk of condensation forming on or in the product

Glued and laminate products contribute to fire spread and the glues break down over time and the products de-laminate, especially when subjected to heat and cold the way insulation is.

The obvious problem with a fibrous material is that it can absorb moisture. However, products with fibrous cores usually have multiple layers and are usually referred to as Multi-Foil Insulations and these can have a whole host of problems.

LOW-E – vs – MULTI FOIL

Fire Rating
Multi Foil Insulation is a multi-layered product that can often have lots (and lots, and lots, and lots) of layers. This tends to make them thick and heavy which (in my opinion) defeats the purpose of a thin reflective insulation. It also makes them hard to work with, but the problems don’t end there.  Multi Foil Insulation is a multi-layered product that can often have lots (and lots, and lots, and lots) of layers. This tends to make them thick and heavy which (in my opinion) defeats the purpose of a thin reflective insulation. It also makes them hard to work with, but the problems don’t end there.

– Poor Fire Ratings 

– Fibrous Cores 

– Hard to install

– Drag on screws 

– Thick and Bulky 

– Require large batten  

– Does not meet stated U-value 

– Made from Mylar 

Multi-foil insulations are not used or found in countries where regulations and foil insulation is widely understood. In the USA for example, foil insulation has been used for over 30 years but multi-foil insulation is not sold there and cannot be used due to its lack of compliance and failure to meet basic Fire Safety Standards. 

Fibrous Cores
Any product with a fibrous core risks moisture absorption. When that product has a layer of aluminium (or mylar) as an outer layer, you risk the moisture travelling through the core of the product, the product sweeting, and over the course of time, corroding and delaminating.

Fire Rating
Most of the Multi Foil Insulations on the market tend to have poor fire ratings or no fire testing at all, which means they are unsuitable for use in a wide range of applications. These products need to be installed behind plasterboard to comply with fire regulations. But that is little help if a fire starts in the wall cavity.

Hard to Install
Their multiple layers make them difficult to cut and hard to work with. This makes them very labour intensive and time consuming to install.

Drag on Screws
Anyone who has installed a multi foil product will know that their multiple layers and fibrous cores tend to catch on screws, and this causes them to “bag up”.

Require larger batten
A lot of Multi Foil Insulation companies recommend their products can be installed 20mm or 25mm battens. The problem is, Multi Foil products can be anything from 35mm – 75mm thick. They fail to explain that to create a 20mm airspace beside a product this thick you would need a minimum 47mm – 97mm batten (as long as you also have an airspace above the insulation).

 

Does NOT Meet Stated U-Value
If a foil insulation is installed with a smaller counter batten than required and does not have an airspace beside the foil surface, it will not achieve the claimed (or required) U-value.

Thick and Bulky
These thick and bulky multi foil products require thicker battens, longer screws and fixings.

If you have read How does Low-E Insulation work? you will understand how foil insulation works you will understand that surface material is the most important part of a reflective insulation. The core is supplementary. So, if the work is done by the surface, why would you the product thicker than it needs to be? You would be better using a thinner foil insulation more a thicker secondary insulation. It would be quicker and cheaper to install…. and more thermally efficient. If you have read How does Low-E Insulation work? you will understand how foil insulation works you will understand that surface material is the most important part of a reflective insulation. The core is supplementary. So, if the work is done by the surface, why would you the product thicker than it needs to be? You would be better using a thinner foil insulation more a thicker secondary insulation. It would be quicker and cheaper to install…. and more thermally efficient. 

The only reason we make different versions of our insulation is that some application require a thinner or thicker material for reasons other than thermal efficiency 

– Micro-E Insulation (3mm thick) – No as robust as Low-E Insulation. Generally used in off-site construction and very lightweight applications where extreme flexibility is required (sewn with fabric in tents and roman blinds etc)

– Low-E Insulation (5.5mm) – Has a crush resistance of 72 PSI. Used it nearly all applications.

– Ultra-E Insulation (11mm thick) – Very robust. Used in applications where extra sound deadening or crush resistance is required

 

‘Low-E Insulation is different. Low-E is not a multi-foil insulation and it does not have any of these multi-foil drawbacks!! We pride ourselves of having one of the best fire ratings on the market. We achieve a Class 1 (BS 476) and we have performed fire tests all over the world to the strictest standards.
If you want to know How is Low-E Insulation made? You can read more here… 

HOW DOES LOW-E COMPARE TO OTHER INSUALTION MATERIALS?

ALUMINIUM – vs – MYLAR

A lot of ‘foil’ insulation products are made from a product called mylar instead of aluminium. Only aluminium has a natural low emissivity value. Mylar is much cheaper to produce. It is a plastic laminated or painted with an aluminium coating. Companies that use Mylar claim it to be a low emissivity product. But Mylar, while it looks ‘shiny’ and is good at reflecting light, it does not reflect heat in the same way as aluminium.

You tend to see mylar used in a lot of single use applications. (Emergency foil blankets, packets of crisps and Kit-Kats wrappers). It might be good at keeping food fresh but it is not something you want used in an insulation material.

These coated plastics crack, chip and peel and de-laminate within a very short space of time (especially when it is exposed to heat and cold as often as insulation is), you end up with the emissivity value of plastic rather than aluminium.

Here you can see a comparison between Low-E Insulation a number of other foil insulation on sale today.

 

LOW-E – vs – TRADITIONAL INSULATIONS

Reflective insulation is not a new idea and it is not supposed to replace all other insulation materials. It is designed to compliant an insulation system and to address issues which are not addressed by traditional insulation (Radiant heat, Air-tightness, Moisture control)

For years people have people have thought that to insulate better, they should simply add more material, believing that the thicker the insulation, the better it works. However, that doesn’t really solve the problem. But very high R-values don’t stop heat transfer, they only slow it down. You cannot ignore the need for good U-values but by addressing the U-values alone, a large percentage of heat transfer is being ignored.

All insulation materials have drawbacks, so using more and more of the same material may only compound a problem.

Fibrous Insulation

Just like a foil insulation with a fibrous core, all ‘traditional’ fibre insulations risk moisture absorption and can cause them to become compressed. You can read more in our blog here Moisture Control – Why is it important?

 

Rigid Foam Insulation

Bulky
Rigid boards are extremely popular and there is no question that they are good insulators. However due to their rigid design they are extremely bulky which means there is a huge amount of space required to transport and store them.

Hard to Handle and install
Rigid boards are also very cumbersome to handle and install. They can be difficult to cut and produce a lot of waste material.

Environmental Impact
There has been worldwide criticism in recent years of the environmental impact of these types of insulation. Although designed to last 20+ years, once they come to the end of their life cycle, a lot of rigid foams cannot be recycled, incinerated, or put into landfill. The waste needs to be kept dry stored above ground. This is going to become a massive environmental issue over the next 20+ years. There are increasing reports of these products being cleaned out of our oceans and off our beaches.

 

A MODERN SOLUTION

Occupied Space
Low-E Insulation is arguably one of the best performing insulations on the market. It has huge environmental benefits over other insulation materials with the added advantage of occupying less space. Low-E is only 5.5mm thick. Occupying less space results in more internal floor space but Low-E does not just benefit the finished building.

“People don’t understand, it doesn’t just save space in the building. We can design thinner wall and roof profiles, this means we can use smaller timbers, shorter nails and screws. The knock-on effect of utilising Low-E Insulation in buildings is huge”

Anthony Brown – Director, Dwell Design Architects

Transport and Storage
Using Low-E Insulation means there is much less material to transport on the roads, there is less material for the builder’s merchants to handle and deliver to site. There is less material on site to handle. It reduces install time; it reduces labour cost. The impact it massive. Just look at the difference between Low-E Insulation and the same amount of Fibrous insulation!

Air Quality
‘Traditional’ insulations can have a negative effect on indoor air quality, due to airborne fibres that can stick to your skin or get in your eyes, some are even classed as carcinogens and are produced using toxic blowing agents.

Where using such traditional materials, it is always a good idea to combine a barrier material such as Low-E which can prolong the life expectancy of an insulation system and stop airborne fibre and gases from entering internal spaces. It will also work to stop the penetration of dust, pollen and other such allergens, making it ideally suited for uses in homes, offices, schools and other health sensitive applications. 

SUMMARY

Using Low-E Insulation as part of a combination system alongside a fibrous insulation protect from absorption, prolonging the life of the insulation system.
Modern design and modern buildings require modern thinking. Using a combination of materials designed to address specific issues should be best practice and the goal of all holistic designers and thinkers.

I’ve used low e for the past 15 months. I’ve found it to work fantastic is all conditions. I’ve probably got 20 vans with it fitted and I’ve had no complaints from any of my customers about being cold. Some of the vans are used for skiing holidays in places that are -20C and more.

Johnny Cochran

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