Where Does All The Heat Go

In a house which has no or poor insulation the biggest heat loss, around a third, will be through the walls – thats why wall insulation (whether you have solid or cavity walls) can make such a difference.

Cavity Wall Insulation

Cost

Cost (depends on house type): £430 – £720
Saving per year: £160 – £400 per year
Payback: Around 3 years.

Un-insulated cavities can add up to 25 per cent onto your heating bill. Installing cavity wall insulation is a relatively simple process that can take just a couple of hours for a typical three-bedroom house. The insulation is blown into the cavity from the outside and disruption to the householder is minimal.

Your home will usually be suitable for cavity wall insulation if:

• Its external walls are unfilled cavity walls.
• Your cavity is at least 50mm wide.
• The masonry or brickwork of your property is in good condition.
• It is more than 10 years old (most newer houses will have insulation already).
• The walls are not exposed to driving rain.

Solid Wall Insulation

Cost

Cost* (depends on house type): £3k – £14K (internal insulation) £5k – 18k (external insulation)
Saving per year: £260 – £660 per year

*Costs may vary significantly depending on level of work required. You might be able to reduce these costs by carrying out the work at the same time as other home improvements or by not tackling all the house at once.

Unlike cavity walls solid walls do not have a gap which can be filled with insulation. Solid walls let through twice as much heat as cavity walls do! That is why solid walls insulation can help you reduce significantly your energy bills. Solid walls can insulated from the inside or from the outside of your house, and often its best (to keep the cost down) to do this when you are getting other work done.

Internal Walls Insulation

Can be a rigid insulation board fitted to the wall or a stud wall

filled with mineral wool fibre.

Advantages:
cheaper to install

Disadvantages:
Reduces the floor area of the rooms in which it is applied (the thickness of the insulation is around 100mm, is disruptive to the household, makes it hard to fix heavy things to the walls.

External Wall Insulation:

Can be a rigid insulation board fitted to the wall or a stud wall filled in with mineral wool fibre.

Advantages:
Isn’t disruptive, doesn’t reduce the floor area of the rooms, fills gaps in the brickwork and renew the appearance of the walls, improves sound resistance and waterproofing, reduces condensation on inside walls

Disadvantages:
Expensive, may require planning permission, requires good access to the external walls

Roof & Loft Insulation

Heat rises, and in an uninsulated home, 25% of heat is lost through the roof. Insulating your loft, attic or flat roof is a simple and effective way to reduce heat loss and reduce your heating bills.

Cost

Cost (depends on house type): £300 – £400
Saving per year: £200 – £350 per year
Payback: Around 1-2 years.

Loft insulation is easy to install – you can even do it yourself. Even if you already have loft insulation, check its thickness. Adding another layer to bring it up to the recommended 270 mm will save energy and money.

Floor Insulation

Floor insulation works through filling the gaps between the skirting board and the floor. It can reduce the heat loss by 10%-15%.

Cost

Cost (depends on house type): £950 – £2,200 (Solid Floor)* £300 – £750 (Suspended Floor)*
Saving per year: £40 – £130 per year
Payback: Around 3-6 years

* Costs can be significantly reduced by doing the work yourself. Gaps and draughts around skirting boards and floors are simple to fix yourself with a tube of sealant bought from any DIY store. Typical costs range from around £80 to £100 if you choose to insulate them yourselves

Older homes are more likely to have suspended timber floors. Timber floors can be insulated by lifting the floorboards and laying mineral wool insulation supported by netting between the joists.

Many homes – especially newer ones – will have a ground floor made of solid concrete. This can be insulated when it needs to be replaced, or can have rigid insulation laid on top.

You don’t need to insulate the floors of upstairs rooms in your house if they’re above heated spaces (like the living room). But you should think about insulating any floors that are above unheated spaces such as garages, as you could be losing a lot of heat through those

Other Areas To Save

Draught proofing

Draught-proofing is one of the cheapest and most efficient ways to save energy – and money.

The main places to draught-proof are your floors, windows, doors and chimney and all can be done for a relatively low price. Doing the entire home can cost around £120 to £150, but can save you up to £65 a year on energy. To draught-proof your home you should block up unwanted gaps that let cold air in and warm air out.

Check out the Energy Saving Trust video for advice on how to draught-proof your home: https://www.youtube.com/watch?v=XOuCzuL2qeU

Lagging

Lagging water tanks and pipes and insulating behind radiators reduces the amount of heat lost, so you spend less money heating water up, and hot water stays hotter for longer.

Insulating your hot water cylinder (to 75mm) is an easy way to save money. This could save you around £25-£35 a year, so with the cost of a jacket round £15 it pays for itself in less than a year.

Radiator reflector panels are a low-cost option. Fixed behind your radiators, they reflect heat from the radiator back into the room, instead of letting the heat out through an external wall.

Double glazing

All homes lose heat through their windows. But energy-efficient glazing keeps your home warmer and quieter as well as reducing your energy bills. The disadvantage is the cost of replacing all the widows in your home. The costs and savings will be different for each home and each window but could save you around £200 per year. Double glazing should last for 20 years or more.

Update your boiler

Old boilers are poor for energy efficiency, oid oil boilers can sometimes be only 60% efficient. Modern boilers are required to be energy efficient, so therefore putting in a new boiler could be a wise investment.

Use the Power to Switch comparison to see how much you could save by moving from an old oil boiler to a new oil boiler or as part of switching from oil to gas.