When it comes to heat, around 25% is lost through the roof.




When it comes to heat, around 25% is lost through the roof. This can be easily reduced by installing 25cm of insulation throughout your loft. It is also worth seeing what is going on in the walls, as around a third of the heat in an uninsulated home is lost this way. Although it is not as cheap to install as loft insulation, cavity wall insulation could save up heating bills in a year. The solution to make sure the house keep warm all day is to install the cavity wall insulation.


Why get cavity wall insulation?

A home can lose as much as 35% of its heat through uninsulated external walls. By investing in cavity wall insulation, it can significantly reduce the heat loss from home. The concept of insulating a cavity wall is really very simple where it involves filling the cavity between the two skins of masonry bricks with an insulating material, which the movement of heat through the wall will be slower. Maintaining the heat inside the home will keeps you warm and cozy when you need to be. It also works in reverse by keeping the house cooler in the summer months.

          Installing cavity wall insulation in the house will not only help to decrease the heating bills by saving energy lost through the walls, it will also help to reduce the carbon footprint by limiting the amount of carbon dioxide (CO²) and other greenhouse gases emitted from the property.

          Many houses since the late 1930s were built with a cavity between the inner and outer walls. Because of this cavity, many of Britain’s homes have thermal performances which are well below the standards required by current building regulations. These properties suffer from unacceptably high levels of heat and energy loss through the walls. A system was introduced in the 1970s to inject insulation into these cavity walls.

          A cavity wall is made up of two masonry brick walls running parallel to one another with a space (cavity) between them of at least 50mm. Masonry bricks are very absorbent, so moisture absorbed by the outer wall typically drains through the cavity, rather than coming into the home, helping to prevent damp issues. This type of wall construction became the norm in the 1930s superseding solid walls and as time has gone on, the size of the cavity between the two skins of brick has continued to grow a typical cavity wall now is between 280-300mm thick. In addition cavity walls tend to be over 250mm in width, with more recent cavity walls closer to 300mm. If you can see lots of half bricks in your wall, you have a solid wall with no cavity, so unfortunately cavity wall insulation is a no-go. In this case, you could look into external wall insulation as an alternative.


How does cavity wall insulation work?

If a hot room is partitioned from the cold by a wall, heat will move through the wall, eventually cooling the room until an equilibrium is reached, where the outside temperature is equal to the inside temperature. In reality this very rarely happens, because rooms tend to be heated. This means that as some heat escapes through the wall, more hot air is supplied, keeping it at a comfortable ambient temperature. If the thermal gradient is larger, movement of thermal energy across the wall will be accelerated. Insulating a cavity wall helps to provide a thermal barrier, which slows the flow of heat out of a room considerably. By slowing down the rate at which heat escapes from the home, less heating is needed to keep the house at the required temperature. In the summer, the reverse happens; hot air outside the home cannot get in as easily, which means it do not need to use energy to keep the home cool. Therefore, in both summer and winter, cavity wall insulation can make an enormous difference to the energy bills. The process is relatively quick and inexpensive, so it is certainly worth considering.

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