Epsom and Ewell Energy Group

Insulation in the home

Introduction

70% of the CO2 caused by housing in the UK results from heating space and water. The best way of reducing this is by an integrated package of insulation, heating and ventilation. With adequate insulation, comfortable temperatures can be achieved using less energy. Controlled ventilation is needed to minimise condensation, once air filtration has been reduced. If you can’t install heating and insulation packages at the same time, install the insulation first. This will reduce the required heat load, and enable you to install a smaller heating system later. As legislation now requires house sellers to provide Home Information Packs, it is worth improving the energy efficiency of your home to make it more attractive to buyers when the time comes to sell it.

The first thing to do to save energy is to stop heat from escaping from your home. This means having good insulation – in the loft, around doors and windows, and on your walls and floors. Increasing fuel bills means it’s even more important to insulate your home! Grants and discounts may be available to help with the cost, and some jobs can be done by the average DIY-er. If you rent your home, check with your landlord about improving insulation.

The picture below shows how heat can be lost from the average house. Some areas are cheaper to insulate than others, and can give a quicker payback (in other words, the savings you make from the insulation in reduced heating bills will cover the cost of the insulation more quickly).

Note: The costs and savings figures are based on a gas-heated 3-bedroom semi-detached house.

Loft Insulation

This will give the quickest payback as it doesn’t cost much to do but saves a lot of lost heat. You should have a minimum of 100mm (4”), but the recommended level is 270mm (10.5”). You can use loose fill, but insulating mats are better for the bigger depths and are easier to handle anyway. A fully insulated loft can save around £200 a year in heating costs and pay for itself in little more than a year. Grants are available for having loft insulation put in, or having existing insulation topped up

Once your loft is insulated it will be a good deal colder than before as it is no longer being heated by the rooms underneath! So it is important to make sure all pipes and tanks in the loft are insulated, but do not insulate underneath tanks as the heat from the rooms underneath will help stop them freezing.

Tank and pipe insulation

One of the most cost-effective ways of saving money is to fit an insulating jacket to your hot water tank; this will keep the water in the tank nice and hot for a long time (but it won’t be necessary to fit a jacket if your tank is a fairly modern one which comes already insulated). Where possible, you should also make sure your hot water pipes – that is, those pipes which deliver hot water to your taps – are also insulated; this will stop heat being lost on the way to your taps. But don’t insulate the pipes which deliver hot water to your radiators as these help to heat your house.

Draught-proofing

Here’s a simple test – hold the palm of your hand up against the windows in your home. If you feel cold air coming through, warm air is escaping. In fact, in a typical home 20% of all heat loss is through ventilation and draughts.

Draught-proofing is an easy, cost-effective way to reduce heating bills and does a lot to make your home more comfortable. You should draughtproof all external windows and doors – and the letterbox! Most materials are available from DIY stores. Check the quality of the products. It will affect their performance and durability. They should conform to the standard BS 7386. There are several types of materials available – from brushes, foams and sealants to strips and shaped rubber or plastic. The Draught Proofing Association can help you decide which is best for your home. There could even be grants and offers available to help you pay for draught-proofing. Full draught-proofing will cost around £90 if you install it yourself, and pay for itself in about 3 years.

Draughtproofing should not cause ventilation problems as most homes are fairly leaky anyway. It may, however, cause condensation in places like the bathroom or kitchen because of the amount of water vapour which is generated there, so you may need to make sure these rooms are properly ventilated.

Wall Insulation

Wall insulation can reduce heat loss by up to 40% through cavity walls and up to 60% through solid walls. It is therefore one of the most important energy-saving measures to consider.

Cavity Wall Insulation

Cavity walls are the cheapest and easiest walls to insulate. They will feature in the majority of homes built after 1930, including semi-detached and terraced houses, and low-rise and high-rise flats. Cavity walls are usually suitable for filling and a survey will confirm if this is so. The survey is important, as any defects in the walls, making them unsuitable for filling, can result in moisture from outside crossing the cavity through the insulation. Cavity wall insulation is quick, clean and relatively inexpensive. It will create an even temperature in your home, help prevent condensation on the walls and ceilings and can also reduce the amount of heat building up inside your home during summer hot spells.

Cavity wall insulation can only be installed professionally; it will cost around £250 and save about £160 a year, giving a payback of less than 2 years.

Cavity walls that are not suitable for filling can be insulated internally or externally.

Internal Wall Insulation

Internal insulation is usually applied to solid-walled properties, but could be applied to the internal party walls and external walls of any type of property, including those with cavity walls that are not suitable for filling. It is cheaper than external insulation, but has some potential drawbacks: it will slightly reduce the room size and make the fixing of heavy items more difficult depending on the type of insulation used. Additionally, if the property is occupied, it is very disruptive to install. You can use ready-made insulation/plaster board laminates or wooden battens in-filled with insulation or flexible linings. Insulation/plaster board laminates usually consist of plasterboard backed with insulating material typically to a total thickness of up to 90mm. Installing them involves the boards being fitted directly to the inside of the wall and the thicker the board the better the insulation. You can also attach wooden battens in-filled with insulation to a wall. This involves attaching battens to the wall, filling the spaces between the battens with insulation and then covering them with a plasterboard finish.

Costs for internal wall insulation start from £42 per square metre, and you could save around £470 a year on your energy bill..

External Wall Insulation

External insulation is usually applied to solid-walled properties, but could be applied to any type of property, including high-rise flats and buildings with cavity walls which are not suitable for filling. Restrictions may apply on buildings that are listed or in conservation areas. It involves adding a decorative weather-proof insulating treatment to the outside of your wall. The thickness of the insulation needs to be between 50 and 100mm and is usually installed where there are severe heating problems or the exterior of the building requires some form of other repair work, providing the opportunity of adding insulation. This is more expensive than cavity wall insulation and internal insulation but it could save you £500 a year on your energy bills. Financial help may be available. External wall insulation also has the following advantages:

1. It can be applied without occupants having to move out
2. Thermal bridging is generally avoided, except for projections such as balconies.
3. It can improve the appearance of a building.
4. It can be a cost-effective energy-efficiency measure if carried out alongside remedial work to the wall.
5. It can help to protect the structural integrity of the building and alleviate damp penetration.

Floor insulation

Rooms can sometimes feel cold due to strong draughts rising up from gaps between the floorboards or between the skirting board and the floor. These can be fixed by using a flexible sealant such as silicon to fill the gaps, as the greatest heat loss through the floor is around the perimeter. This will save you £25 a year in heating bills. Another way of reducing draughty floors is to insulate underneath the floorboards on the ground floor. As well as making the room feel warmer, it will save you £50 a year. And a good carpet and underlay can also reduce draughts from the floor.

Caution: Don’t block under-floor airbricks in your outside walls. Floorboards and joists will rot without adequate ventilation.

Windows

Double glazing can cut heat loss through windows by 50% and cut your heating bill by about £140 a year. It is, however, expensive to install and will take some years to recover its cost. The benefits include increased comfort, improved appearance and reduced maintenance of your windows. It may be worthwhile replacing your windows with double glazed ones if your existing frames are rotten or warped. There is a rating system for the thermal performance of different windows, and information on this is available from The British Fenestration Rating Council. Information on double glazing is also available from the trade association for manufacturers, suppliers and fitters of double glazing, The Glass and Glazing Federation.

An alternative to double glazing is secondary glazing, where a separate frame – often with sliding windows – is installed inside the room and next to the original windows. The glazing can often be removed in summer for ease of access to the original windows. This is cheaper than double glazing but may not look as neat.

Another way of reducing draughts is to put plastic film inside the windows, though this will not improve insulation, and the film will have to be renewed each year. It also makes it difficult to get access to the windows.

Good thick curtains – lined if possible – will also reduce draughts from windows; however, it is important to make sure that curtains do not cover the front of any radiators that may be in front of the window as this will reduce the amount of heat reaching the room.

November 11, 2008 at 16:26 Leave a comment