Cavity wall insulation? Worhwhile?

TUVOK

I had a door step visit this week from a 'Smart Energy' rep.
Their  product is Thermalite 'B' carbon bead cavity insulation.
Any one had experience of this product and firm, also is cavity wall insulation safe long term.

My property is a semi detached house , built in 1995 with internal wall thermal block and conventional outside brick, no flat roofs.
My house has double glazed windows and insulated loft.

In order to save money on heating bills is this the way to go using cavity wall insulation or what other ways?

All opinions, views would be appreciated. 

stuart45

Are you sure the cavity isn't part filled with insulation boards already?

TUVOK

stuart45 said:

Are you sure the cavity isn't part filled with insulation boards already?

Not sure, I just thought that the house was of conventional build, but as I wrote, buily with thermal blocks for the internal wall.

stuart45

Conventional build at that time was often brick outer skin/4 inch cavity with 2 inch insulation board fixed to inner skin/4 inch Thermalite block inner skin.

FreeBear

TUVOK said: My house has double glazed windows and insulated loft.

In order to save money on heating bills is this the way to go using cavity wall insulation or what other ways?

Had cavity wall insulation done here a long time ago. Just the lower half got done, as the upper half is solid brick wall. The insulation in the cavity made no discernible difference to the warmth of the rooms, nor did it reduce the heating bills. The money would have been better spent on increasing loft insulation to 300mm+ (which I have now done).

TUVOK

FreeBear said:

TUVOK said: My house has double glazed windows and insulated loft.

In order to save money on heating bills is this the way to go using cavity wall insulation or what other ways?

Had cavity wall insulation done here a long time ago. Just the lower half got done, as the upper half is solid brick wall. The insulation in the cavity made no discernible difference to the warmth of the rooms, nor did it reduce the heating bills. The money would have been better spent on increasing loft insulation to 300mm+ (which I have now done).

Thanks, more research required I think.
ps. just googled loft insulation 300mm maximum advised.

stuart45

The majority of heat loss is through the roof. There is a certain amount lost through the external walls, although in theory the walls in a 1995 house should have a relatively low U value.
There's loads of different opinions on CWI. Some people I've spoken to are delighted with it. Others say it's caused damp issues.

poolboy

I have considered extra insulation on a north facing wall, detached bungalow.  It gets v damp though, unless builder or architect can guarantee damp won't persist I won't do it.  I was thinking more stud wall inside than cavity insulation.

Any door step visit it's a straight no from me though.

I m concentrating on roof and new windows.

TUVOK

Yes, entirely agrre, you cannot be too careful with damp and houses!

diveunderthebonnet

We had our loft insulation done by a firm who were carrying work under a gov scheme ,they also were doing wall insulation BUT they drilled a hole in the brickwork cement and inspected with a camera and said it was already done ,saved us some money ,even if the same firm came round several months later offering to do it for free as the local council were now paying for it.

Emmia

I would avoid any company which does door step visits like this.

It's fine for you to consider their "suggestion" but if you did proceed you should do your research carefully and get several quotes.