Best passive insulation solution??

[Alaniho]

I have been trawling through the many intersting threads on this forum to find out peoples experiences for the best value for money heating solutions.

I am now of the opinion that the passive insulation installed in new builds has a vastly greater bearing on the cost of running a house than all of the heat pumps, solar, geothermal type solutions.

I am building a new 2600sqft Bradstone/blockwork house and am planning to use a combination of oil/solid fuel (i live on a farm so loads of wood) and maybe a tube type solar panel system combined with the best possible wall insulation.

So the only question not really answered here so far is what is the best specification to insulate a cavity wall? What insulation products are most efficient???

Also are any makes of oil burners significantly more efficient than others???

i'd be really interested to hear your opinions on this.

 

[VByrne]

Hi Alaniho,
There is a system new to Ireland for insulating between the leafs in a cavity, it has a long history in the US and Canada, the problem with cavity wall insulation is it fills the cavity, which is there for a reason, to control vapour drive, you can insulate with any number of foam board products on the market, but these to have limitations, if not installed correctly they can fall down through the cavity and cause cold bridging.

You can spray the inner leaf with a closed cell foam to a dept of 50mm, it is the same material as foam boards used for this purpose, but it forms an air-tight barrier, and is monolithic which means it's one piece, so it will never move or fall down in to the cavity, it can eliminate cold bridging and draughts, closed cell is also a vapour-retarder.

But remember it must be CLOSED CELL foam, I hope this helps

 

[durafoam]

I agree with V, Byrne. Closed cell foam is by far the best insulation. But not foam boards-- the sprayed foam creates a seamless monolithic barrier.

Closed cell foam is actually what manufacturers have been using for many years in refrigerators, to make them insulated & energy efficient.

No doubt, using the same type of material in your home will have the same effect.

 

[sydthebeat]

i hope v byrne and durafoam can come clean on their relationship with thes efoam companies...

also, please link to an IAB or BBA certificate for this material and the particular use you suggest.....

 

[galwaytt]

I agree with V, Byrne. Closed cell foam is by far the best insulation. But not foam boards-- the sprayed foam creates a seamless monolithic barrier.

Closed cell foam is actually what manufacturers have been using for many years in refrigerators, to make them insulated & energy efficient.

No doubt, using the same type of material in your home will have the same effect.

Closed cell foam, yes, but not sprayed foam. Dow RTM is the most common closed cell foam used in Fridges, and it is in board form - this I know because our sister company makes them : www.quinnrv.com

We use the building version of that product for our SIP panels, for houses/roofs, etc., which is why it's so good, and airtightness so high, and no membrane required.

Sprayed foam - it depends on the exact chemical formulation. PU foam, for example, if you cut/sand it afterwards, becomes a veritable sieve for airtightness (e.g. where it might bulge through opes ), as the skin is key. So, not all foams, not even all sprayed foams........are created equal.