Is External Wall Insulation more effective than Internal?

manan.shah.82

Hello,

We live in a 3 Bed semi detached solid wall house and our house is really cold (never gets really warm and if we turn off heating it loose warmth very quickly).

We read about the external wall insulation but were put off because of the cost and potential return period (mainly because we were not sure how long we will be in this house) but now we are thinking about it again because of the recent government green /cashback deal.

I have read the differences between internal and external wall insulation on government websites, which and other places but one thing I'm still not clear, is either of them better than other in terms of the energy saving and results you can expect?

I mean with internal wall insulation its bit of inconvenience and loss of space but to me I'm thinking (might be completely wrong) it should make house warm more quickly because heat loss stops within the house while in external insulation it gets up to the outer level and stops it.

Can some please advice me if one is better than other from energy point of view and helping to get most value out of it?

Thank you.

A.Penny.Saved

I was looking into this myself a few years back because my home has solid walls but due to the cost I was interested mainly in internal insulation. Until I looked into it and found that internal insulation can cause structural problems due to damp rotting timbers. That would be a problem with the upstairs mainly due to the way in which my home is built where the roof section is supported on the front & back walls of my property and therefore any insulation could cause damp penetrating the joists supporting the upstairs ceiling. The ground floor does not have that problem because the upstairs is supported on internal walls and the two party walls either side in my mid terrace house.

External insulation is the preferred method of insulation because it does not cause the same problems as internal insulation. Fortunately for me, ECO came to the rescue and I got external insulation fitted. However it comes down to your area whether this might become available.

I was reading that there is £2000 cashback towards external insulation.

If your outer walls are kept warmer then your internal temperature will tend to move less towards the cold without the problems posed by internal insulation.

External insulation helps with heat as well helping to maintain the internal temperature.

captainhindsight_2

There a pros and cons for either internal or external. And you shuold be able to get an ECO grant to cover most of the cost of the installation.

External Insulation:
-bricks/fabric of the house stay warm and water tight no/little risk of frost damage to bricks.
-the heating has to heat up the bricks before the insulation actually does anything
-the bricks can act as a thermal mass and release heat into the house after the heating has been turned off.


Internal Insulation:
-the central heating has to do less work to heat the house up because the walls of the house are not absorbing heat.
-since you house was built, the external walls have been leaking heat and have been 'warm', internal wall insulation mean they will be cold 24/7 and will be more at risk of frost damage
-waterproofed the whole house so less risk of damp

There are more pro-s and cons but thats all I can remember of the top of my head.

I would recommend external as it tends to have less problems.

I wouldnt worry about damp issues, this is only really a problem if the insulation hasnt been fitted properly.

savemoney

I am thinking of getting my solid walls insulated I believe under Green deal cashback from June 2014 you can get up to 6K back up to maximum of 75% of the cost

https://www.gov.uk/government/news/7600-to-make-your-home-more-energy-efficient

captainhindsight_2

savemoney wrote: »

I am thinking of getting my solid walls insulated I believe under Green deal cashback from June 2014 you can get up to 6K back up to maximum of 75% of the cost

https://www.gov.uk/government/news/7600-to-make-your-home-more-energy-efficient

Definitely worth taking advantage of, but.make sure you get the installer to give you an option with ECO funding as well because it could be completely free depending on the size of the house. Ironically the bigger your house, the more likely it is to be free through eco

savemoney

Thanks just noticed my supplier Scottish power have closed there ECO funding for time being

captainhindsight_2

You don't have to get the ECO funding from your energy supplier, the installer arranges this through the ECO brokerage.

lackingwedge

captainhindsight wrote: »

You don't have to get the ECO funding from your energy supplier, the installer arranges this through the ECO brokerage.

Really? I have a large house. I should get an amended GDAR at the beginning of next week. Interesting times ahead.

stebiz

Just had mine done. I had my scaffold up anyway so it saved me scaffold fees. Approx £3000 materials and £2,500 labour. So 5.5k in all. No grant and no green deal attached to my house.

As for it being warmer. Hard to tell right now. Might be Autumn before I know.

captainhindsight_2

stebiz wrote: »

Just had mine done. I had my scaffold up anyway so it saved me scaffold fees. Approx £3000 materials and £2,500 labour. So 5.5k in all. No grant and no green deal attached to my house.

As for it being warmer. Hard to tell right now. Might be Autumn before I know.

Why didn't you get the grant or cashback? You would have saved your self thousands? It seems a bit silly...

You could have got:

Green Deal cash back = £2750

Or

Home improvement fund = £4125

Or

ECO may have covered the full cost of the job

Expensive mistake??

A.Penny.Saved

stebiz wrote: »

Just had mine done. I had my scaffold up anyway so it saved me scaffold fees. Approx £3000 materials and £2,500 labour. So 5.5k in all. No grant and no green deal attached to my house.

As for it being warmer. Hard to tell right now. Might be Autumn before I know.

It is not just about staying warmer, it should help regulate the temperature all year round. During very hot weather your home should not heat up as much which can be a problem with solid walled homes, it certainly was with mine until I had mine done just before last summer.

It certainly helped last winter but it still takes heat to keep a house warm even with insulation. Unfortunately it does not solve that. If only!