What is insulation?
Insulation protects your home against cold in winter and excess heat in summer, and can even reduce noise pollution (like the sound from a road or passing aircraft). Different measures work for different homes - some only need small additions like better draught-proofing, while some require more significant measures like cavity wall insulation. Whatever is installed, it should improve your Energy Performance Certificate rating and/or have a realistic timeline for starting to pay for itself through reducing your energy bills.
What types of insulation are there?
As mentioned above, there are different types of insulation that properties could install, but some involve more work and materials and some involve less.
- Cavity wall insulation - filling the gap between an external and internal wall with insulation material to reduce heat loss through the two layers
- Solid wall insulation - this essentially involves making a solid wall thicker by adding insulation material to either the external or internal side
- Loft and roof insulation - similarly to wall insulation, loft and roof insulation involves filling in the spaces between joists with insulation material
- Floor insulation - this again involves insulating the spaces between joists and is particularly effective in floors made of timber
- Draught-proofing - this is one of the simplest insulation measures, which usually just requires the gaps around window and door frames to be filled in
- Glass in windows and doors - those who only have single glazing in their windows and doors may want to consider upgrading to double glazing, which helps ensure better insulation
- Tanks, pipes and radiators - making sure that these are well-insulated can mean that water spends less time heating up and more time staying hot.
How does heat escape from a property?
Unfortunately, no matter how well-insulated your home might be, heat loss is inevitable.
The main ways that heat can escape are:
- Conduction - this is when heat moves through solid materials like metal or brick. Insulation works here by denying heat a path outside the home by using non-conductive materials to pack cavity walls and other spaces
- Convection - this is the natural tendency of warm air or water or other gases and liquids to rise, while cold air or water falls. Warm air has a propensity to escape through the loft or attic spaces if they are left uninsulated.
How much heat is being lost from different parts of my home?
This depends on the type of house you live in, whether it's detached or semi-detached, or if it's a terrace property, and if so, if it is mid or end terrace. If you live in a flat, the losses will be different again, and will depend on whether your flat is in the middle, at the top or at ground floor level.
For a typical house, the walls will lose most heat, around 30% and up to 40%. The roof will be next at around 25%, probably followed by windows and doors at around 20%, and the floor (of your lowest storey) at around 10%.
How much does insulation cost?
Insulation can cost anywhere from a few pounds to a few thousand pounds depending on the measure that’s being installed and the property it’s being installed in. For example, buying a hot water cylinder jacket (about £20) will cost much less than insulating cavity walls (up to £1,800).
Being able to afford the installation and material costs is obviously important, but you should also consider the effect the insulation will have on your energy costs, because ultimately that’s where cost-effectiveness is determined. It could be years before a big measure like cavity wall or roof insulation starts paying for itself, so consider whether you’re going to be living in the property long enough to reap that benefit.
How much can I save if I get insulation?
Again, the amount you can save depends on the type of home you have and the insulation measure you’re installing.
According to the Energy Saving Trust, cavity wall insulation can save between £125 and £455 a year on your energy bills (depending on your home), and loft insulation can save between £225 and £415 a year.
Can I get any insulation grants?
There are some energy efficiency grants and financial help available to customers from different sources, but not all customers will be eligible for them.
The Energy Company Obligation (ECO) scheme has been running in various forms for a few years. The core ECO scheme is only available to those who receive certain benefits, but there is also a new Great British Insulation Scheme which will run alongside the core scheme and allow a wider group of people (those in properties with a low-rated EPC and in certain council tax bands) to apply.
Do I need planning permission for insulation work?
In most cases, insulation work does not require planning permission from your local council because it probably won’t involve making extensive structural changes to your building. The exceptions may include external wall insulation and, in areas where there are conservation schemes, glazing.
Even if you don't need planning permission, certain building regulations could still apply, so check with your local council's building control department.
