Insulating Your Home

By at home

Although some types of home insulation cost thousands, others will set you back just a few pounds and still help keep your home warm and your bills low.
No-one likes paying out more than necessary for anything, yet if your home is poorly insulated, you might as well throw your hard-earned money out of the window. As if this wasn’t bad enough, escaping energy damages the environment too adding to global warming, so effective insulation can help save the planet as well as your money. Insulation and draughtproofing can reduce hot water and heating bills by as much as sixty per cent, but installation costs vary hugely, so you need to consider all the options before deciding what’s best for your home.

Weigh up the outlay on insulation against the savings you’ll make on fuel, and also take into account how long you plan to stay in your home. Loft insulation and draughtproofing around doors and windows are inexpensive, easily fitted without expert help and will make a real difference to your fuel consumption. In fact they will probably pay for themselves over about two years. Cavity wall insulation is a job for an expert, involving considerable financial outlay, but will certainly reduce heat loss, making it worth considering if you are not planning to move for at least five years. Double glazing, on the other hand, saves a relatively small amount of energy, yet can cost a great deal, so could actually leave you out of pocket for many years.

Loft Living
Heat naturally rises, so a significant proportion is lost through your roof. Look outdoors on a freezing day in the city and you’ll soon notice the roof where the frost has melted and the pigeons are gathered – you can be sure that poor insulation is making it the warmest spot!

If the loft is used as a room, or for storing anything that could be affected by cold, it’s a good idea only to insulate the roof, so that warmth from the house will still rise into the space. It’s worth installing some draughtproofing between the rafters first – building paper is inexpensive and simple to use. Cut strips slightly wider than the gaps between the rafters, and line each gap with a small overlap either side tacked onto the rafters. To join two strips, tape them together with a generous 100mm overlap. You can then fill in the channels with lengths of glass-fibre blanket, to a depth of at least 100mm. If the blanket is paper-backed, face the paper into the loft and attach it to the rafters with drawing pins every 150mm or so. Otherwise, place tacks at intervals along the rafters and hold the blanket in place by winding string between them. As an alternative to glass-fibre blanket, polystyrene sheets, supported by tacks can also be inserted between the rafters. They are a little more expensive, but easier to handle.

In lofts used only for storage, floor insulation is the best route as it will prevent heat rising into the space, warming all your paraphernalia unnecessarily, and then disappearing. Lofts can be cramped, dark and awkward to work in, so equip yourself with sufficient lighting and at least two boards, large enough to span a couple of joists, that you can kneel on and move around. Never put your weight on the surface between the joists as you’re likely to fall through!

Unless you are using a foil or plastic-backed insulating material, first put down a vapour-proof barrier to prevent moisture penetration from warm air below. This can be foil-backed building paper or polythene sheeting, held in place with masking tape. Lay strips of glass fibre, or mineral fibre blanket at least 100mm deep between the joists, starting about 50mm from the eaves to allow air from outside to circulate, minimising condensation. Alternatively you can pour a loose-fill material such as vermiculite or polystyrene granules to a 100mm depth between the joists. Floor-level insulation keeps the roof-space cold by preventing heat from rising up from the house, so pipes and water-tanks in the loft will also need to be well-lagged to prevent freezing and bursts. Cut the blanket into strips to wrap neatly around pipes but do not insulate beneath a cold-water tank or it could freeze.

Handle With Care
Glass-fibre blanket is awkward stuff! The fibres can cause irritation. If you wish to wear gloves, make sure you tuck them into long sleeves. Any fibres that get into the gloves will be incredibly irritating and hard to remove. If you don’t suffer too badly it’s easier to work with bare hands and rinse them thoroughly in cold water afterwards. It’s also a good idea to shower at the end of the job. Wear a face-mask and avoid touching your eyes. Wear smooth clothing that will not pick up fibres – cotton or nylon overalls are ideal. Tuck trousers into socks. When possible, cut the roll with a panel saw into the pieces you need before you unwrap. Once unrolled, use sharp scissors.
Safely Sealed
If you added all the gaps around your doors and windows together they would probably equal a hole the size of a couple of housebricks through which freezing draughts can blow in and warmth can escape. Draughtproofing is one of the simplest and most cost-effective ways to keep your heating bills down, and is usually done with lengths of weatherstripping fitted around door and window frames. Don’t forget that letterboxes, keyholes and cat-flaps can also let in cold air.

Weatherstrip products are generally self-adhesive, with a peel-off backing and must be pressed onto a clean, dry surface. The cheapest type is foam strip, which comes in various widths and can be used on interior doors and casement windows. It will last anything from two to five years. Rubber strip is a little more expensive but more durable, while nylon brush strips should last at least five years. These are tough and particularly recommended for exterior doors and sash windows as well as casements. You can also buy sprung bronze strips that fold to form a flexible seal when the door or window is closed. These are long-lasting, are fixed to the frame with small pins and work well on sash windows. A handy alternative for a window or door with large or uneven gaps, is silicone frame sealant. A bead of sealant, applied to the fixed frame, is activated by contact with a soapy solution wiped over the closing edge of the window. The window is closed to compress and mould the sealant and then re-opened. The sealant sets firm in about two hours, creating a weather-proof seal when the window is closed. For a seldom-used window, try clear liquid draught seal. This will weather-proof the gap and can easily be peeled away if you want to open the window.

There’s no point in sealing all around your doors and forgetting about the gap at the bottom. As well as draughts, rain and dust can blow in under an exterior door so in most rooms a good threshold excluder makes sense. These fall into three categories; some are fitted onto the door, some to the floor below and some combine the two arrangements. Threshold excluders come in standard lengths and different styles are designed for external and internal doors so make sure you choose the correct size and type.

In Hot Water
Heating water can account for around a fifth of your fuel expenditure, so it makes sense to ensure that the water stays hot for as long as possible. Most new cylinders now come ready-fitted with an insulating foam casing, but cylinder jackets for older types are readily available in DIY stores and are simple to fit. Choose one at least 80mm thick. In a very tight or awkward space where a jacket will not fit, it may be possible to use loose-fill insulating material like polystyrene or vermiculite granules, contained in a solid hardboard box built around the cylinder. If you are having new central heating put in make sure the pipes under the floor boards are lagged, and if your boiler is situated in a garage or outbuilding make sure the pipes leading to the house are lagged.

Open The Airways
With good insulation it is vital to keep your home well-ventilated to prevent condensation from moisture in the warm air forming on cold surfaces like windows and bathroom walls. Minimise vapour in the air by shutting doors to keep steam inside the bathroom and kitchen drying laundry outdoors or in a tumble-dryer with an outside vent, whenever possible. Gas-fires and boilers can give out poisons if they have insufficient air to operate properly, so keep airbricks clear and open windows daily to keep the air fresh and allow damp to escape outdoors.

Find That Draught
If you can feel a draught but can’t locate where it’s getting in, or want to check that your insulation is working, hold a lighted candle close to the area. It will flicker if a draught hits it. You can also use a smoking wax taper. (Take great care with tapers and candles, especially near curtains or carpets).

We all like to feel cosy and safe from the cold, but no-one likes to throw money away or waste resources by letting heat escape. Keeping your home well-insulated will guarantee you stay warm and when the bills arrive at least you can feel confident that you’ve enjoyed as much comfort as possible from what you’re paying for.

Useful Contacts
Central Heating Information Council: 0845 600 2200 or
Energy Saving Trust: 020 7222 0101 Heating and Ventilation Contractors Association: 020.7313.4900

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