Insulating your home or improving the insulation will yield a number of benefits:
A large proportion of your energy costs will be for heating specially in the colder winter months. Much of the heat used to heat your home will escape through windows, walls, doors and the roof. You even lose heat through the floors in your home.
Improving the insulation in your home can make a big reduction in the amount of heat you lose. This saves you money on your monthly heating bills although there is obviously the outlay to have insulation installed.
In many areas of the UK you may be able to get insulation discounted or even free if your property has only a little or no insulation installed.
Good insulation in your home can reduce your energy bills by around £100 per year. This obviously depends on the level of insulation you already have in your home but it illustrates that there are savings to be had by better insulations
There are other benefits too of better insulation in that it will make your home more comfortable as the heat will be better dispersed around your home reducing cold patches which make it more comfortable and in the hot weather it will keep your home cooler as well.
There are some that argue that a well-insulated house will be worth more than a home that is not insulated well.
Saving the environment
More than a quarter of the carbon emissions in the UK is caused by lost energy from the home. Improving the insulation in your home will help reduce this and if everyone did the same would help reduce climate change.