The great man-made global warming debate is entering an interesting phase, as early snow blankets much of Britain. If this winter is anything like as cold and long as last year’s, my postbag will soon be bulging with cries for help. I expect the top topics will be:
Condensing boilers not firing
Last winter, thousands of readers found that the external condensate drain pipes from their new boilers froze, triggering the sensor that shuts the boiler down.
Prevention is better than cure for this one, so make sure the condensate pipe runs vertically to the drain, and is well lagged. If it still freezes up, and your service engineer can’t get around to fix it, the condensate pipe can simply be unscrewed and pulled clear from the bottom of the boiler and a bucket or bowl positioned underneath it to collect the drips.
The best way to keep your home warm
The British habit of running the central heating full blast for two hours in the morning and six in the evening is a recipe for condensation problems. When the heating switches off, all the moisture collected in the warm air simply condenses back out onto the nearest cold surface. It is far better to run the heating constantly, but at a lower temperature. Put the timer on “24 hours”, turn the boiler thermostat down to “Min” or “1”, open all the thermostatic radiator valves fully, and set the room thermostat(s) to 20C. This not only helps prevent condensation, but will actually save you money on your heating bills, whatever the government propaganda says.
Frozen water pipes
Again, prevention is better than cure. Pipes that run outside, or under suspended ground floors, or along unheated external walls or roofs should be insulated with foam sleeving and have water run through them regularly. If the pipes that froze last year freeze again, it’s time to re-route them or install trace-heating cables along their length. (I’m supposed to tell you that this operation must be delegated to a qualified electrician, but there’s no rule that prevents a DIYer from fitting a three-pin plug to the end of the cable and plugging it into a 13-amp socket.)
The single most cost-effective thing you can do to keep warm and cut fuel bills this winter is to draught-proof your windows and external doors. Ten quid’s worth of self-adhesive draught stripping will pay for itself in a couple of weeks. Feel for draughts with the back of your hand, and if you’ve got a particularly wide gap, (e.g. at the corner of a warped window) stick one piece of draught strip on top of another until you’ve filled it.
Q We have recently purchased a timber-framed dormer bungalow. We have been told we cannot have the normal foam or mineral wool cavity wall insulation. Is there any type of wall insulation we can have installed, and would you recommend it? BB, by email
A Your timber-framed home will have been constructed with full thermal insulation when it was first built. This will be between the studs of the timber frame itself, sandwiched between the internal plasterboard and the ply sheathing. It is essential to maintain a clear cavity between this and the external brick outer leaf of the external walls. Were this cavity to be filled, it might trap moisture that could rot the load-bearing timber frame itself. If you are determined to install extra insulation, then this should only be on the inside of the home. My recommendation would be to leave well alone.
Don’t cover air bricks
Q We live in a centrally heated three-bedroom Sixties bungalow with a suspended wooden floor that is fully carpeted over a good quality rubber underlay. In winter, the carpets feel cold, even in stockinged feet, and the building needs quite a lot of heating. The underfloor cavity is surrounded by air bricks and is dry and well ventilated.
Would it be a good idea to cover up the air bricks in winter only, perhaps, so as to stop cold winds from accessing the cavity? MC, by email
A Certainly not. The air bricks are there to ventilate away the moisture coming up from the ground beneath the building. If you block them up, you could soon find yourself having to deal with wood rot in the floor structure and perhaps even condensation inside the home.
If your timber floor is cold, then do the right thing and insulate it between the joists. If there is a sufficient “crawl space” below the floor, you might be able to do this from below, using rigid PIR board insulation (Kingspan, Celotex, or builders merchants’ own brands). Otherwise it might be possible to lift a few floorboards and slide in semi-rigid mineral-wool cavity batts from above, supporting them on battens fixed to the sides of the joists.
WHAT’S THE DIFFERENCE BETWEEN … Double glazing and secondary glazing?
In a double-glazed window, the two panes of glass have a narrow gap (usually 6mm) and are sealed at the edges. The narrow gap lessens the circulation of air by convection within the cavity, which is important for thermal insulation. Secondary glazing is a free-standing window frame inside the original window, and is better for sound insulation. The bigger the gap, the greater the amount of noise reduction, which is improved still further if the glass in the two panes is of different thickness.