To say anything is the best insulation for homes is clearly a subjective statement and I’ve no doubt there are people out there who may disagree with my choices.
However these are my opinions (if you disagree please feel free to comment or suggest your best insulation for homes at the bottom of the page).
For a more in-depth information on each type of insulation please feel free to follow the links below to each of the individual insulation articles.
An uninsulated home loses approximately (these are very rough figures and will vary with different house types and construction methods):
The vast majority of that heat loss (around 58%) comes from two areas i.e. the roof and walls.
The ironic thing is these are areas which are fairly straight forward to insulate (unless you have an old house with solid walls or your house has a room built into the roof space).
So it’s not hard to see why adding insulation to your walls and roof can reduce your heating costs significantly and it’s pretty affordable and easy to do.
It's really important to understand how insulation works, if you want to have any chance of choosing the best insulation type for your situation.
When building a new home or extending your current home the amount of insulation will be dictated by building control. You could always increase on what they suggest if you’d like to try to reduce your heat loss even further.
However modern standards are pretty high and you do get to a point where it’s no longer cost effective to just keep adding insulation.
The most important thing to ensure with a new build project is that the insulation is well installed with no gaps.
As mentioned above the two main areas where people retrofit insulation are the loft and the walls, but you should also consider insulating any suspended timber ground floors you have. But even in these areas there are lots of different wall and roof construction types out there and these all have different requirements when it comes to retrofitting the best insulation for homes.
When retrofitting there will be certain insulation types that you simply can't use, such as solid insulation sheets like polystyrene sheets or foil backed PIR boards etc. when installing cavity insulation to an existing property, as you can't gain access to them.
And don’t forget that when you add or upgrade insulation you’ll need to add a vapour barrier or vapour control layer (VCL) on the warm side of the insulation and an airtightness layer on the cold side of the insulation. The vapour barrier or VCL prevent or restrict the amount of water vapour entering the insulation. Failure to do so, if using a manmade insulation such as mineral fibre or fibreglass, would allow interstitial condensation within the insulation, reduce its effectiveness and could potentially cause rot to timbers.
The airtightness layer will help reduce heat loss from wind wash (where air movement over the insulation draws heat out of it) and it will reduce draughts from uncontrolled ventilation, but more about that later.
Traditionally, in a new build cavity wall, there would be a layer of insulation board against the inner leaf of the wall and an air void next to the outer leaf of the wall. But if there are gaps between the sheets of insulation the thermal efficiency fo the wall falls off a cliff.
The principle of this was to have a gap next to the outer leaf in order to avoid any moisture that may penetrate the outer leaf from being transported across the insulation to the inner leaf which could cause penetrating damp.
In an existing property with cavity walls as you can't remove the outer leaf to install insulation boards and maintain a gap, the only options are to pump in insulation or insulate externally or internally. But the latter two usually aren't done due to the increased costs involved. Filling an existing cavity with insulation can raise its own issues which are explained in my article on cavity wall insulation problems below.
There are of course a few types of cavity fill insulation that are available but I'm not a fan of a few of them for reasons that I will go into in the articles below.
If your existing property has solid walls then your only option is to insulate internally or externally. You have a huge choice of materials but you should use a material that is breathable and install a vapour barrier or VCL and an airtightness layer if you want to do it right. Have a read through the articles below to see what the advantages and disadvantages of each are and why the majority of these types are installed incorrectly, without vapour barriers, VCLs and airtightness layers.
If your home has suspended timber floors on the ground floor theres a good chance that they're pretty draughty and uninsulated. Some people add rolls of fibreglass wool between the floor joists held in place with chicken wire but this isn't ideal and thermally isn't great. The good news it that once you've decided to do it the extra stages involved in insulating your suspended timber floor right aren't that difficult and will make a massive difference to how the floor insulation performs.
When upgrading the insulation in your loft area it will depend on whether you have an open loft are or a room in roof type loft. Both can be done but the latter will be more difficult unless you're about to carry out a total refurbishment anyway.
Have a read through each of the articles above and you should be able to see which of my choices for the 'best insulation for homes' is going to be right for your situation.
Provided your chosen option is installed correctly the best insulation for your home will be the one you go for after getting all the relevant information and making your own informed decision based on your unique circumstances.