Blog>Planning Guides>Adding insulation to your home: your complete planning guide
Last updated: 19 July 2024
Adding insulation to your home: your complete planning guide
Unless your home was deliberately constructed to be energy efficient, you can probably lower your energy bills by adding more insulation. Here’s the lowdown.
Adding insulation to your property can help you improve your home’s energy efficiency, reduce your energy bills, and keep you warm during winter.
But where should you start when it comes to planning this project?
Here, we’ll walk you through everything step-by-step so you can get your home toasty without a hitch.
Why add insulation to your home?
Insulation is key to keeping your home warm in winter and cool in summer.
Without it, the heat generated by your heating system in cold weather will simply be lost – as will any cool air generated by your cooling system in summer.
Not only will this lead to higher energy bills (after all, your heating and cooling systems will be continually working to replace what’s lost), but it’s also bad for the environment.
Plus, it’ll make it hard for you to control your home’s temperature and make your home less comfortable for you to live in.
All in all, insulation is vital for efficient, modern-day living.
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Do I need to upgrade my home’s insulation?
The chances are your home has some level of insulation already. So, how do you know if you need to add more?
Well, unless your home was specially built to be energy efficient, the chances are you can lower your energy bills by making improvements to your insulation.
To check what improvements could be worth making, you’ll need to work out how much insulation your home currently has and where it’s located.
There are two ways you can do this.
1. Energy Performance Certificate
An Energy Performance Certificate (EPC) is a report that looks at the energy efficiency of your home and makes recommendations for how to improve it.
Unless you’re a landlord, you don’t legally have to get an EPC unless you plan to sell your property.
But it can be a great way to get a better understanding of how well your home is insulated and where you could look to make improvements. It will even give you an estimated figure for how much each improvement could save you on your energy bills!
Usually, an EPC costsbetween £65–£120. But this will be a small price to pay if it helps you to reduce your energy usage!
Find an EPC assessor near you to get started.
2. Assess your property yourself
If you’re not keen to pay for an EPC, you’ll need to inspect your insulation yourself.
The goal here is to work out where your home is properly insulated, and where it isn’t. So, you’ll need to check your loft, walls, and floors to see what type of insulation you have and measure its depth and thickness.
Just be sure that you don’t look at thickness alone when it comes to loose-fill insulation, especially in the attic. Instead, you’ll need to determine your insulation’s thermal resistance or R-value.
Basically, the higher the R-value of your insulation, the more effective it is as an insulator.
You can determine the R-value of your insulation by dividing its thickness by the lambda of the material (the materials unique insulating properties).
In the UK, a decent R-value is typically around 4.15m²K/W, but the higher the better – we’d aim for at least 4.54m²K/W.
Don’t worry if this all seems a bit mathematical for your liking. You can also get recommendations for home improvements that could make your property cheaper to heat and keep warm using the government’s online tool.
Types of insulation you could add to your home
When it comes to upgrading your insulation, there’ll be four main areas to focus on:
Loft
Walls
Floor
Pipes
1. Loft insulation
Of the heat that’s lost from your home, 20-25% is typically lost through the roof. That’s why insulating your loft space is so important.
When it comes to insulating your loft, you’ll have lots of different methods to choose from. Here are the most common.
Blanket insulation
Blanket loft insulation is sold by the roll, making it possible to install on a DIY basis – check out our guide on how to insulate a loft if you want to give it a try.
It comes in lots of different materials, including fibreglass, mineral fibre, and sheep’s wool.
The only downside is that it’s pretty bulky, which means it doesn’t always fit neatly into small spaces or around obstacles.
Loose-fill insulation
Loose-fill loft insulation is often made from materials like cork granules, mineral wool, and cellulose fibre.
It’s a popular choice due to the availability of greener alternatives. It’s also great for making sure an entire area is covered.
Just bear in mind that it has to be installed with safety equipment to avoid skin irritation or breathing in harmful fibres. It can also come loose in more draughty lofts.
Sheet insulation
Sheet loft insulation is another greener option. It’s used on the sloping sides of roofs, making it perfect for loft conversions and covering plasterboard.
It’s a great insulator and often even comes with its own attachment system.
However, these benefits come with a higher price tag.
Spray foam insulation
Spray foam insulation is a controversial option but one that still deserves a mention.
This loft insulation is quick to install and light to handle and cut, making it ideal for hard-to-reach areas – although it does need to be installed by a professional tradesperson.
The controversy comes from the fact that it can restrict the air circulation in your loft. This has led to condensation and rotting roof supports in the past.
With that in mind, some mortgage lenders won’t lend for a house with spray foam insulation. So, be sure to think carefully before having it installed.
2. Wall insulation
Surprisingly, even more heat gets lost through the walls of your home than through the roof. A whopping 30-35% of the heat lost from a house typically escapes through uninsulated walls!
So, don’t delay when it comes to wall insulation.
To determine what kind of insulation to go for, you’ll need to figure out what type of walls you have.
Cavity walls are most common in houses that were built post-1920, whereas most houses built pre-1920 have solid walls.
Cavity walls
If your home has cavity walls, you’re in luck. These are typically quick and easy to insulate.
A cavity wall is essentially two walls that are held together by wall ties with a gap between them – known as the cavity.
Cavity wall insulation involves injecting an insulating material into this cavity from the outside of your home.
The most common materials used are blown mineral fibre, polystyrene beads and granules, and foam.
Solid walls
If you have solid walls, we have bad news for you. These let twice as much heat escape as cavity walls!
This shows how important it is to get these walls insulated – although sadly, solid wall insulation is much more expensive than cavity wall insulation.
Solid walls can be insulated in two different ways:
The first is to insulate your walls internally. This involves fitting rigid insulation boards to the internal side of your wall, or building a stud wall and filling it with insulation material.
The main downside is that it will reduce the size of your room by around four inches. Plus, you’ll need to redecorate.
The second option is to insulate your walls externally. This involves fixing a layer of insulation to the outside of your wall using mechanical fixings and adhesive, before covering it with render or cladding.
It’s more expensive than insulating internally, but it’s also less disruptive and won’t reduce the size of your living space. However, it will change the look of your house – which may be a good or bad thing, depending on the character of your property!
3. Floor insulation
When we think about insulation, the loft and walls are often the first things that spring to mind.
But you might be surprised to hear that around 10% of heat lost from your home will typically escape through the floor.
With that in mind, making sure your floor insulation is up to scratch is a must.
How you choose to insulate your floors retrospectively will depend on whether you have solid or suspended floors.
Suspended floor insulation
If you have suspended floors, you might find that cold air often rises up between your floorboards.
Luckily, suspended floors are usually fairly quick and easy to insulate.
There are two main ways of doing this:
Remove the floorboards and re-lay with insulating materials
Insulate under the floor using the crawl space beneath
Just a few insulating materials that are commonly used include blanket insulation, rock mineral wool, foam board, and foam spray insulation.
Solid floor insulation
If you live in a newer home, it’s likely that it’s been built with a solid floor base made from concrete or screed.
But you can still add insulation to make your floor feel warmer underfoot.
Retrofitting solid floor insulation involves carefully removing your existing flooring to try to avoid damaging it.
Then, your tradesperson will place a layer of rigid insulation on top of the concrete or screed, followed by chipboard.
Your existing flooring can then be laid back over the top.
Just be aware that you’ll likely need to remove and replace your skirting boards as part of the job, as well as make adjustments to doorways and thresholds. After all, adding solid floor insulation in this way will increase your total floor depth.
4. Insulating pipes
It’s easy to overlook your water tank, pipes, and radiators. But insulating these small things can help you save money on your energy bills quickly, easily, and affordably. A few ideas include:
Hot water cylinder jackets
Pipe insulation
Radiator reflector panels
These steps can help you to reduce your energy consumption on a budget.
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How much does it cost to add insulation to your home?
So, how much will all these insulation upgrades set you back? Well, that will depend on a number of factors, including:
The size of your home
Your existing insulation
The insulation methods and materials you choose
The accessibility of the space
Any removal of old insulation required
Remedial works such as painting and decorating
You may also be able to get free or cheaper insulation from the government’s Great British Insulation Scheme – check on their website to see if you’re eligible for support.
That said, here are some ballpark costs for retrofitting insulation.
Loft insulation cost
The average cost to insulate the loft of a detached house with blanket insulation is£1,206. This includes both supply and installation.
Just bear in mind that the cost of insulating your loft can vary widely depending on which method you choose.
Head over to our loft insulation cost guide for more details.
Wall insulation cost
The cost to insulate your external walls will depend on whether you have cavity or solid walls.
The typical cavity wall insulation costfor a detached house is £4,600.
This is in contrast to around £25,000 for solid wall insulation.
Our external wall insulation cost guide has more information.
Floor insulation cost
If you have suspended timber floors, you’re looking at roughly £105 per m² to add insulation.
Alternatively, the typical solid floor insulation cost is around £80 per m².
Check out our floor insulation cost guide for the full lowdown.
Find a professional to upgrade your home’s insulation
Hiring a professional is the best way to add insulation to your home.
They'll get the job done efficiently and to a high standard. They’ll also have the knowledge, skills, and experience to recommend the best types of insulation for your property.
That way, you can be sure that any home improvements you invest in will pull their weight in helping you to improve your home’s energy efficiency and reduce your bills.
Luckily, finding the right professional for the job is easy with Checkatrade!
All our tradespeople have to pass up to 12 checks and adhere to our high standards to be listed in our directory. In fact, we’re so confident in the quality of the trades on Checkatrade that if you book through us, we guarantee their work up to £1,000. Guaranteed for 12 months – Eligibility and T&Cs apply.
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