Earth Notes: On Spacetherm Aerogel Thermal Insulation

Spacetherm aerogel edge
The best robust wall insulation for where space is at a premium such as big cities.

Sam Proctor of Proctor Group contacted me 2008/05/15 having seen my mention of the Spacetherm product here on Earth Notes. He is in charge of Spacetherm development and offered to chat to me about existing and upcoming products.

(In fact, he told me about one new product that I'd very much like to try this winter as it would fit in with my general insulation-improvement plans, and as of 2010 I think that it is well known that they have an aerogel-based insulating 'wallpaper' in the works, hopefully due out this year.)

The Spacetherm product at core is a silica-gel-derived aerogel (such as is used by NASA in the Space Shuttle heat-resistant tiles) with an embedded polyester fabric matrix to reduce brittleness.

None of the manufacturing is environmentally unpleasant as he explained it, and in particular, by being able to avoid blowing agents used in other products, there are no harmful leaks/emissions of these agents possible, and thus no ensuing degradation in insulation performance over time. Spacetherm should be good for 50 years without loss of performance, I am told.

The embodied energy is less than most insulation alternatives other than wool.

I asked him about the insulation value of Spacetherm vs (say) blown foam, and Sam suggests that it is up to twice as good, ie a given thickness of Spacetherm will reduce heat loss by as much as twice that the same thickness of foam will, at a cost of maybe 2.5x for the same overall insulation performance. So there's a significant cost premium if you have space for alternatives, but where space is the premium then Spacetherm may well be valuable. (1m^2 of 9mm Spacetherm blanket might cost GBP25, vs 20mm drylining backed by plasterboard at maybe GBP10 for example.)

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Spacetherm-P Arrives

5 Spacetherm boards stacked on pallet

I am testing out Spacetherm-P (plasterboard faced). We speced out dry-lining our living room to get its exterior-wall U-value from somewhere between 1 and 2W/Km^2 where it is now down to something closer to modern building regs at 0.3W/K^m2, using conventional Kingspan Kooltherm K17 rigid phenolic insulation with thermal conductivity 0.020--0.022W/Km. Then we adjusted the spec to replace the K17 with Spacetherm-P (0.013W/Km core), and we'll see how easy the material is to use and how well it works in practice. Full write-up here...

Stats

Sam Proctor told me (as of 2013/03/26) that Proctor Group ships very roughly 30,000m^2 of aerogel per year.

Spacetherm-F

In April 2013 I took delivery of some Spacetherm-F Fermacell-faced 40mm aerogel, which should be stronger than the -P (plasterboard) version. The builders hated this even more than the Spacetherm-P and Magnaline, citing the following issues:

Some responses in an eBuild.co.uk thread.

Kitchen north wall construction now (assumed for east also) calculated to have a U-value of 0.24W/Km^2, and no obvious condensation risk with interior 18°C@70%RH and exterior -2°C@100%RH:

(The area behind the existing gas boiler has not been touched and the aerogel will be applied when the boiler is replaced.)

Ed Davey Energy Secretary with aerogel samples

Other Names

The product that Proctor brands in the UK as Spacetherm is originally Aspen Aerogel's Space Loft. Other firms use brands such as Spaceline and Magnaline.

Avoiding Snagging

According to "Saint" at GBF:

The reason that the aerogel sometimes grabs the drill bit is because the polyester reinforcing in the insulation melts at high temperature so once the drill bit gets hot it sticks to the bit. The secret is to drill the holes ... quickly avoiding the bit overheating too much. Use a new bit, set the drill on hammer if necessary and go at it with some gusto pulling the bit out as soon as possible.