The Myth of U-Values...

Posted 17/04/17

I'm often asked...what is the U-Value of Icynene? 

Fair question...for years now consumers have been led to believe that the use of U-values is the only measure of insulation performance...And there then usually follows a lengthy explanation...

U-value by itself is almost a worthless number, as it is impossible to define insulation effectiveness by this number alone.

What would the U-value of insulation be after it has been submersed in water or had a 20 mile per hour wind blowing through it? Would the "Effective" U-value of fibre insulation go to zero? U-values are meaningless unless we know the other important factors...

Insulation systems which quote low U-values when not properly sealed will allow the wind to travel through it as if there were no insulation at all.

U-values are a result testing the loss of heat through material in a sealed test fixture under controlled laboratory conditions, but these conditions are not even remotely associated with the real world (ie Scotland..!) of installed performance of insulation. 

Dense fibre insulation is generally assigned low U-values, yet it can only achieve these values when tested in an absolute zero air-movement and zero moisture environments. In addition, water vapour from the atmosphere, showers, cooking, breathing, etc. constantly moves back and forth through the walls and ceilings of our homes.

If a building is not properly ventilated on a fibre insulated home, the water vapour generated inside a house will very quickly semi-saturate the insulation above the ceiling and in the walls. Even small amounts of moisture will cause a dramatic drop, as much as 50 percent or more, in fibre insulation's performance.

For the record, Icynene LD-C-50 has a thermal conductivity of 0.039 W/mK...

ICYNENE® open cell and closed cell spray foam insulation products. Ideal for homes and commercial buildings - insulate and air seal in one step. Our spray foam insulation is guaranteed to perform as specified for the life of your home or commercial building. 


ICYNENE® open cell and closed cell spray foam insulation products both insulate and air seal homes and commercial buildings in one step.


ICYNENE® spray foam insulation provides an air barrier and helps protect against the introduction of pollutants, dust, mould, carbon monoxide, and pollen.


ICYNENE® has a global warming index of 1 – the lowest in its class. Making a healthy environment for the buildings occupants.


The ICYNENE® insulation system is the most accredited insulation available with worldwide acknowledgement of its exceptional performance.

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