Green homes guide: Insulation

Article, Energy & Housing

Thermal Image House

Insulation: the best place to start

Heat Loss Diagram

Insulation is possibly the easiest and most cost-effective way of reducing your home’s energy consumption. It can help in reducing your bills, save CO2 and will give you and your family a warm comfortable glow knowing that that you’re doing your bit for the environment.

Since the 1970’s government and industry have produced various iterations of pictograms showing how heat escapes through a poorly insulated and draughty home.  So, if you’re serious about reducing your carbon footprint, insulation should be your starting point as its probably the cheapest and easiest thing to do.


Think of insulation before Heat Pumps or Solar

Another reason to get the insulation done early is that you’ll need to demonstrate your house is not too leaky before you can apply for several government incentive schemes.

If you’re thinking of installing Solar PV, for example, then you’ll need to have an Energy Performance Certificate (EPC) confirming your house is a band D or better before you can claim for Smart Export Guarantee payments.

And if you’re considering a renewable heating system such as Air Source or Ground Source Heat Pump and wish to claim the Renewable Heat Incentive (RHI) then you need to have the following in place when you apply:

  • An EPC that has been produced within 2 years of the installation date.
  • The EPC must not include any recommendations for cavity wall or loft insulation. If it does then these issues need addressing and another EPC obtained to show it’s been done.

If you’re thinking of getting an Air or Ground Source Heat Pump NOW is the time to be planning your insulation, not when your current boiler packs up.

The reality is that quite a lot of boiler replacements turn out to be a distress purchase in the middle of the winter when it’s really cold and the old boiler packs up.  Because it would take too long to sort out better insulation and an EPC, many miss out on the opportunity to go green and end up putting in another gas or oil boiler because it’s the quickest thing to do.   So, in the words of Baden Powell, get insulated early and “be prepared”.


Loft Insulation

Loft Insulation2Since the 1960’s the recommended thickness of loft insulation has risen over the years from the original 65mm, to the current building regulations requirement of 270mm for new builds and is also recommended for retrofitting purposes. However, depending on the circumstances of your own particular property you may wish to exceed the current requirements, as there’s a good chance the regulations will be raised again in the not too distant future. You can find out more on loft insulation from the Energy Savings Trust website.

The most common and cheapest type of loft insulation is Rockwool. This is laid between the joists up to the top level, then at a 45-degree angle for the remainder, up to a minimum of 270mm. This is an easy DIY job not requiring any special tools except perhaps gloves, a boiler suit or that old pair of dungarees you’ve been meaning to take to the charity shop, and a face mask.

CosywoolAlternatives are sheep’s wool and sheep’s wool blended with polyester.  These are more “natural” but more expensive.

Cellulose insulation is another option usually made from recycled newspaper and cardboard and treated with a fire retardant and blown into the attic. This type of insulation is more common in Europe and North America than the UK.

However, these types of insulation can’t be compacted down to work effectively so it’s as waste of time and money doing this and then chucking a load of suitcases and other stuff on top of it. Be ruthless and get rid of all that tat you’ll never going to use by donating it to a local charity shop, Steyning Freecycle  or one of our “Give Your Stuff Away Days”.

If your kids have flown the nest and left you holding on to their stuff give them a deadline to get it out.  Tell them that Greta is on their case!

If you’re not able to get rid of all of it, you can still store stuff in the loft by building a raised platform using loft stilts and boards.  It’s a relatively easy DIY project for the average homeowner if you have basic DIY skills.   The LoftZone website will give you some ideas.

Img 0769If you insulate between the joists, you’ll have what’s known as a cold roof. If you’re thinking of using the loft as a full or part time living area, or workspace then don’t insulate the floor as it’ll be a bit chilly up there. For this scenario the best option is to insulate between the rafters using sized pre-cut rolls of Rockwool or insulation boards.

Insulation boards such as Celotex or Kingspan can be cut to size and “friction fitted” between the rafters. This is easier and less itchy than using rockwool.  The photo shows a double layer of insulation – which makes for a extra cosy loft.


Spray on Loft Insulation …….. maybe!

A lot money goes into marketing spray on insulation between the rafters. This works well for insulation purposes if you have a seamless roof such as fibreglass, rubber or zinc. However, it’s not recommended for tile or slate roofs as the downside is, you’ll have a “bonded” roof making it very difficult to replace damaged/broken tiles or slates. It also makes the installation of solar panels very difficult should you decide to install these at a later date to a tile or slate roof that’s been foam sprayed.


In summary

  • Loft Insulation is easy!
  • Loft Insulation is cheap!
  • Loft Insulation will de-clutter your life!
  • Loft insulation will make you a new person!
  • Loft Insulation can be done this weekend!

So, get on it with a trip to Wickes, B&Q or their websites and place your order.  They even deliver so no excuses!


Cavity Wall Insulation

More info coming soon ….

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