Continuing from our last blog post, we’ll be looking at some of the larger changes we can make to insulate our homes.
1. Floor insulation. Rugs and carpets are the most elementary form of floor insulation, though the term is usually applied to material (such as mineral wool) laid beneath the floorboards, held in place between the joists with the aid of netting. Solid concrete floors can be insulated either with rigid insulation panels laid on top of the concrete or, if the floor is replaced, rigid insulation foam put in at the time of building.
Floor insulation can generally be carried out entirely or partially by yourself, without professional help, making it quite cost effective. Typical DIY costs for floor insulation are from £100, with resultant annual savings of £40-50. In general, only downstairs floors need be insulated, since upstairs floors are above heated spaces, though it’s worth considering insulating any upstairs floors where this isn’t the case (for example, floors above garages or archways).
2. Loft installation. Given that heat rises, a great deal of it can be lost through the loft space of a house. It’s possible to insulate the loft yourself in a similar way to how you might insulate a regular floor, using mineral wool between joists. The job is more complicated when joists are irregular (inhibiting the use of standard-width mineral wool rolls) or the loft is difficult to access. In these cases, loose-fill insulation (for example, cork granules or cellulose fibre) can be poured between joists or otherwise introduced into the loft by a professional.
The Energy Saving Trust states that ‘the recommended depth for mineral wool insulation is 270mm but other materials need different depths.’ It may be that your loft is already insulated but could benefit from being supplemented to make it up to the recommended depth. In this case, the payback period could be in the region of 5-10 years, though if you’re increasing your loft insulation to 270mm from nothing then this decreases to just a couple of years.
3. Wall insulation. Just as heat rises, so it also travels from warmer areas to colder ones. In the case of houses, this translates to losing heat through the walls – this accounts for approximately a third of the total heat lost in houses without any insulation. Wall insulation is generally performed by professionals, and what exactly the job consists of will depend on the kind of walls your house has.
In the UK, most houses built from the 1930s onwards have cavity walls, consisting of two layers of bricks with a gap in between. These can be insulated (if they’re not already) by drilling holes in the outer layer and blowing insulating material into the cavity, refilling the holes afterwards.
Houses built before the 1930s generally have solid walls and can be insulated from inside or outside by laying insulating material over the inner or outer walls respectfully. This can be considerably more costly and labour-intensive than insulating cavity walls and best left to the professionals. However, you may decide to go the DIY route and do the job piecemeal – perhaps when carrying out some other home-improvement work on a section of wall – rather than insulating the whole house and needing to restore the whole interior or exterior in one go.
4. Windows, double glazing, etc. As mentioned in the last blog post, windows are a significant source of heat loss in a house. This is especially the case when windows are only single-glazed, i.e. have only a single sheet of glass. Double-glazed windows contain two sheets of glass (triple-glazed windows have three), providing an insulating layer between sheets which keeps in the heat. They also keep noise out, which serves as an agreeable secondary benefit.
Different materials are available for both windows and frames, with varying advantages and disadvantages in terms of heat conservation, durability and environmental impact. Replacing the windows in a house is expensive, with a payback period of up to 20 years, whereas a cheaper – and potentially DIY – option for insulation is secondary glazing, usually consisting of a second pane of glass fitted over the existing pane. While not providing the same heat-conserving seal of double glazing, secondary glazing still saves energy and is a considerably easier job to accomplish.
(Photos by Jesus Rodriguez and Sam D)
