Loft insulation is the most cost-effective energy efficiency measure that can be installed. It can reduce heating costs up to 20%. The purpose of them is to hold the heat below within the property, reducing heat loss to the roof void and outside but also reducing the amount of heating needed to maintain the property at an ideal temperature. With insulation, the property will be warmer, more comfortable and it will cost less to heat. How loft insulation reduces heat loss?
Heat will always flow from a warm area to a cold one. The colder it is outside, the faster heat from your home will escape into surrounding air. Glass fibre is laid across the loft to reduce heat transfer out of the roof. Glass fibre traps air and trapped air is a poor conductor therefore reduces heat transfer from the ceiling to the loft by convection and conduction. How the thicknesses of the loft insulation affect heat loss? As you increase the level of insulation in the loft, it will slow the rate of heat loss and maintain the comfortable temperature for longer. Installing 290mm thick insulation can save up to approximately 20%, compared to thin insulation which is only 14% The pay back time is long term Generally, loft insulation cuts loft’s u value rom around 2.3 (for an uninsulated loft) to 0.16 W/m2K, a reduction of around 95%. A more specific example is sheep wool. It shows for sheep wool over 140mm, it has a U value of 0.16 compared to over 250mm, it has a U value of 0.11 showing how thickness can affect heat loss greatly.