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Is insulating your house actually worth it?


Insulation is a clever little idea that keeps your house warmer in the winter and cooler in the summer.

By having pockets of air between the interior and exterior of your home, heat can’t travel through your walls/roof very easily. Air is a poor conductor of heat, so during the winter your heat can’t get out, and during the summer the heat can’t get in. But is it really economical?


It may come as a surprise to discover that double-glazing is not the most efficient way to save energy/money in your house. While 35% of heat is lost through walls and 25% through your roof, only 10% is lost through windows. Considering the cost of double-glazing windows, you should be sure to check your house is better insulated in the aforementioned walls and roof first. There are cheap alternatives for those looking to get window insulation, however, albeit less glamorous. Since pockets of air work so well for insulation, bubble wrap can be placed over your windows to stop the transference of heat. Just spray some water on the window and place some appropriately cut bubble wrap (bubble side against glass) over the window. It might not have the look of double-glazing but it gets the job done!

Alternatively there are sheets of film you can buy to place over your windows for another cheap option. This video can give you some pointers on how to do it.


As we mentioned, your walls will be the biggest culprits for losing/gaining heat. Because there are exterior and interior walls that you need to get the insulation in between, it can be tricky to get it done. Unless it’s done during the build, or you happen to be having major renovations done in your home, you’ll most likely need to use cavity insulation. This involves blowing the insulation in through holes in the wall between the wall studs. It’s advised you do this from the exterior because: while it may be more expensive, the interior damages can’t be properly fixed and could have an effect on your property value.

If you are able to insulate during renovation or the build, you should soon be able to use the eco-friendly method of old curtains and rugs for insulation. Sadly it’s not just a case of shoving your old rags into the wall and brushing your hands. The materials have to be treated, not least of all to make sure the insulation is fire proof. This is a process that hopes to remove the waste from the textile industry while also saving on energy.

It is strongly recommended that you do not attempt to insulate your walls yourself, though. You’ll need to find a registered installer who can be sure the job is done thoroughly and safely.


Loft insulation is something you could potentially do yourself, although if you’re not confident you may wish to have someone install it for you. Try getting up to the loft and checking how easy your access is, and then check that the joists – the wooden beams making up your loft’s version of a ‘floor’ – are regular. If so, you can probably insulate it yourself, saving you a few bucks on the installation!

Roll your insulation out between the joists, and then layer it up so that the joists are also covered. Go in prepared though. The recommended thickness for your insulation is 270mm, so check the depth of the space between joists to see if you need an extra layer. Also, sort out some boards to walk on up there, as the joists don’t offer superb balance for would-be handy-people. And don’t forget your gloves and face mask!

But is it worth it?

That’s the question many are asking about insulation: does it actually save you money? There are several costs involved in adding insulation to your house, and it won’t immediately pay for itself. Add to this that the government has stopped funding the Green Deal Finance program and it’s starting to sound less encouraging (although some providers finance the scheme themselves).

But look at the bigger picture. Insulating your loft in a semi-detached house is estimated to cost around £300, but offers an annual saving of £140. In two years the installation has all but paid for itself, with carbon dioxide savings of 590kg every year. Cavity insulation takes about four years to pay for itself and from there you’re saving energy and money.

Perhaps most encouraging, however, is the increase in property value a properly insulated house can have. With better insulation comes a better Energy Performance Certificate (EPC) rating, and those lower energy bills are enticing to house hunters. Opinions vary, but most agree that it can significantly increase the value in your home from 14% to as much as 38%.

So, provided that you are staying in your home for over four years from installation, it’s safe to say that insulation is worth the investment. Plus there’s the added warmth you’ll feel this Christmas!

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Andrew Montlake

Written by Andrew Montlake

Andrew Montlake, better known as Monty, began his journey with an Hons degree in Economics & Politics before starting in the mortgage industry in February 1994. As a main founder of Coreco in 2009, he successfully grew the brand, marketing, and communications, and was made MD in 2019 focussing on the overall vision, strategy, and culture of the company. As Coreco’s media spokesperson, Andrew can often be seen or heard on TV and radio as well as regularly commenting in the national, local, and trade press. He is the author of this acclaimed Mortgage Blog and is well-known for his social media, podcasts, and public speaking. Andrew is now proud to serve as Chairman of the Association of Mortgage Intermediaries, (AMI) as a cheerleader for the Mortgage Industry as a whole and continues to work at the coal face, writing mortgage business and advising clients.

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