The real benefits of cavity wall insulation are preventing heat loss in winter and lower heating bills, but along with these, reducing your energy consumption means reducing global warming and climate change, and less wear and tear on your boiler and finally, keeping you cooler in the summer.How does it work?The insulation material is pumped into the cavity between the inner and outer skins of brickwork that make up the external wall of your property. With homes already built this is done by the installation company from the outside of your property. There are several types of insulating materials, but they all work by combining with the still captive air to act as a barrier to heat loss.A specialist contractor can install cavity wall insulation and with most homes it?s a very straight-forward and clean job. Currently, you may be eligible for a Government grant towards the cost, and in certain circu get in shape mstances, qualify for free insulation.The installation technician will normally inject the insulation from the outside through small holes drilled in the wall. The material is then pumped in to completely fill the cavity. When the work is finished the holes are filled in to make as perfect a match as possible with the existing wall. The materials used are mineral wool, u.f. foam and expanded polystyrene bead. These materials are all resistant to water penetration and will not transmit water across the cavity or from below d.p.c. level by capillary action. However, they are not a water vapour barrier and any moisture that collects within the fabric of the building is allowed to disperse harmlessly into the outside atmosphere (provided normal ‘breathable’ constructional materials have been used). Materials do not affect the fire resistance of the walls; and they are resistant to rot, fungi and vermin.