Draught proofing
Cold draughts are easy to detect and simple measures will deal with many. Door and window seals are cheap and effective – replace them if they are damaged. Suspended wooden floors are usually ventilated with air bricks beneath and gaps between boards or around walls may admit cold draughts. The airflow to joists is needed to prevent rot but draughtproofing or insulating boards may be possible.

Remember that any fuel burning appliances in the house need an adequate air supply so think carefully before making a house airtight. Dedicated air inlets from outside are one solution for stoves etc. Some airflow is also needed to remove the atmospheric moisture from cooking, washing and even breathing, so airtight buildings need proper re-cycling, de-humidifier and heat recovery systems.

Roof insulation
Traditional roof insulation consisted of a relatively thin layer of mineral wool laid across the loft floor. This is totally inadequate and a cheap and simple solution is to add

a thick layer of mineral wool insulation on top of the existing layer. An alternative or additional measure is to install rigid insulation boards beneath roof tiles, either from underneath or as part of a roof replacement. Kingspan and Celotex are major suppliers of insulation boards and the best for this purpose have aluminium foil bonded to each side. It is easily cut with a saw and can be fitted between rafters. A suitable combination is 10mm thickness between rafters and 5mm sheets nailed or screwed below rafters to hold it in place and cover gaps. With a semi-permeable tiling membrane or no tiling membrane above, the roof timbers are aired adequately to prevent rotting. The Energy Saving Trust has useful information on insulation and there is financial support available to some groups of homeowners.

There is some concern that production of insulation materials is a high carbon process and that they are environmentally unfriendly materials. This needs to be balanced against their effectiveness and durability.

Windows
Modern window systems are double glazed to comply with building regulations but a lot of older homes still have single glazed windows, sometimes huge areas in traditional sash windows, and these cause massive heat losses. Where window replacement is impractical, secondary glazing may be a suitable alternative. Ornamental windows and conservatory roofs may be single glazed or have poor performance standards.

All double glazing units are not the same. Look for units with the largest possible gap between panes and filling with inert gas. Manufacturers should mark each unit with the U-value. Triple glazing is common in cold climates and worth considering if cost and design considerations allow.

Many window systems are fitted with trickle air vents and these can be a source of draughts and heat loss, so consider when they need to be open or closed.

Underfloor insulation
Many new houses have solid concrete floors on the ground floor and, to comply with building regulations, these should have adequate insulation below the screed. A suitable insulation layer is 10mm of Kingspan or similar placed either between the damp proof membrane and the concrete floor pad or between the concrete and a screed. Underfloor heating pipes, if used, would be clip fastened to the insulation and the screed laid over.

If you own or are buying a modern house, do you know the specification of the floor insulation?

Many older houses have solid floors, consisting of ceramic tiles or stones laid in a mix of ash and lime, with no damp proofing. These floors are, not surprisingly, cold and damp and it may be possible to re-lay them with a DPM and insulating layer.

External wall insulation
The external walls of a house comprise a large area and potentially the second biggest source of heat loss after the roof. Building regulations specify the insulation requirements for external walls and, in traditionally built UK houses, these will typically consist of an external brick wall, a cavity filled with insulation sheets or mats and an interior wall of insulating blocks. Timber framed buildings are totally different structures and can perform better or worse, depending on design.

Our older housing stock is much more varied, from uninsulated cavity walls through solid brick and tile-clad walls to solid limestone or gritstone buildings with very thick walls. Secondary cavity wall insulation is commonly performed by injection techniques but has many pitfalls.

The worst performing walls are solid limestone, with very poor insulation characteristics. The “obvious” solution is to dry-line the building by applying an insulating layer to the inside – typically plasterboard backed by 5-10mm of Kingspan – either fastened to battens or stuck to the walls with special adhesive. This provides effective insulation, though the obvious snag is reducing the internal room size. However, the biggest potential problem is sealing the wall against movement of moisture. This can result in water condensing within the wall and causing invisible damage to the structure – these buildings generally had lime mortar and lime plaster, all allowing water vapour to move freely across the structure. There is conflict here between building regulations and advice from conservation specialists. Some new materials and systems are appearing to deal with the problem of insulating traditional stone buildings using wood fibre (e.g. https://www.lime-green.co.uk/warmshell/warmshell-interior) and may be worth considering.

One product recommended by a member as a simple solution is Wallrock Thermal Liner , an insulated wallpaper. However, the supplier cautions about fire resistance so it needs evaluation. The product is listed as breathable (depending on surface treatment too), so it should be suitable for traditional stone buildings.

Directly reducing energy consumption
Insulation of homes is a really efficient way of reducing energy needs and there are other ways to make significant reductions in energy consumption. Whilst compact fluorescent bulbs and tubes were “state of the art” in 2010, they were often disliked for slow switch-on and poor light quality. LED technology has been a dramatic advance in both light quality and energy conservation. Look at all the light fittings in your home or business and consider changing to LED wherever possible – typically this could halve the lighting energy input and improve the quality of light at quite low cost.

Reducing room thermostat settings and aiming for constant temperature throughout a house may improve comfort and energy efficiency. Even lowering the setting by 1DegC is useful. Wearing a jumper and not just a T-shirt in the house used to be the norm. A recent newspaper article listed the average UK room temperature in 1960s as 12DegC!

Smart energy meters, with in-house displays can be useful tools in prompting us to think about unnecessary energy consumption – what is the effect of turning off unneeded lights or turning off electronic equipment instead of leaving on stand-by? When used with micro-generation systems, they can suggest when surplus energy makes it sensible to use washing machines, etc.