Is bubble/foil insulation any good?

[jmc]

Hi

I'm disappointed with the heat loss I'm getting from my cool-box mash tun:
Its an Igloo 52USqt (47L) cooler.


I thought I'd improve things by adding some of the popular bubble/foil wrap insulation available at B&Q & Screwfix.
eg

However when I looked at the reviews on B&Q I was concerned by one review for item code 76477
at http://www.screwfix.com/search.do;jsess ... arch=76477. See Review title:Insulation Performance WRONG
23 Apr 2010

By InsulationExpert
(read all my reviews)(read all my reviews)
, Whiltshire
"Performance Warning. The Screwfix product description states the product has an insulation value the same as 55mm of polystyrene, it does not. The Screwfix description fails to tell you that this level of performance is only possible if used in conjunction with a large air gap and that most of the performance, (nearly all performance) comes from the large air gap. This is not mentioned at all in the Screwfix product description, the product its self has little insulation performance or R value. The product description as provided by Screwfix does not fully inform the buyer about the claims made. You will not achieve anywhere near this level of performance unless you use this product to create a large sealed airgap. This is the same for all bubble foil insulations. This item is very high priced for the kind of product it is and buyers should check the real ££££ value by comparing real performance."

Its just one review, but it made me think twice.

I know lots of people here have used this or similar products in recent builds.

Is it any good?
ATB
John

[Capped]

I dunno about that bubble foil stuff,but you could do far worse than that red lagging used for insulating hot water tanks. I've used it for years and it works brilliantly - even on a 'naked' FV used as a mashtun I never saw more than a 2C drop over 2 hours.. And it's dirt cheap and even comes with some plastic straps to secure it with!

[EoinMag]

I can't give exact values, but I've used it on my boiler, firstly to save money on heating it up. Practically it brought my time to get to boil down by half an hour, and on a 75l boiler that's considerable. I use it double layered.
I also use my boiler as a BIAB mashtun and it's pretty good on that too, although I also cover the whole setup with a quilt when mashing, I've not tried yet without as I don't really want to risk a large mash on too much temp loss and also I didn't intend it to be a mashtun when I did the original modification.

[Aleman]

I think the review is pretty much spot on to what I've found . . . it's great for reducing radiated heat . . . but conducted heat it's more or less useless against. . . . . As a test, wrap a kettle in the insulation, then boil the kettle . . . if you can measure a rise in temperature on the outside of the insulation it isn't doing its job. . . . Having said that, I've use it on my 50L keg mash tun , and my 100L fermenter . . one layer inside, then a couple of layers of camping mats, and then a layer of the bubble wrap on the outside. . . . negligible heat loss from the tun and I can take my FV down to 2C using my product chiller, when it is 27C outside.

Camping mat insulation is much more effective . . . but the cheap ones tear easily . . . the bubble wrap is much tougher, and easier to wipe clean . . . hence the reason for using it as an outer cover.

[Kev888]

I've used the shiny bubble wrap extensively - in fact possibly too extensively if thats possible e.g. here and here. To be honest its insulation value is pretty poor in our type of applications - its really designed as a radiant heat reflector more than a conductive insulation. I use it mostly to create a pleasant looking wipe-clean cover, and used closed cell foam to probide the real insulation.

Quality sleeping mats or armaflex are good examples of closed cell foam. This can be costly, but is equivalent to several times the thickness in rockwool or fiberglass. Some of the hot water cylinder jackets I've seen are only filled with fiberglass, but maybe there are better ones. Celotex or kingspan can be good too, if rigid sheets are suitable for the application.

For a quick solution though, sit the MT on some polystyrene and wrap old duvets or sleeping bags around it.

Cheers
kev

EDIT: - Gah, pipped to the post! Good to have confirmation, though.

[EoinMag]

Well my boiler is too hot to touch the outside of when the bubble wrap is not on it, it's only warm with two layers of wrap on. The bubbles themselves provide quite a respectable airgap for insulation has been my experience.

[Kev888]

Oh yes, it does something. When there's a high heat flow from a boiler with no insulation the losses are so massive that even a little bit makes quite a difference. But not so much from a cooler MT thats already insulated though, there the difference would be much, much less noticable.

Cheers
kev

[dave-o]

I've used that stuff on my MT and it makes a big difference. However, my MT is a thick plastic FV-style bucket, e.g.


I can;t see how it would make a big difference to a coolbox MT as its insulation is already very thick. I might be looking for air gaps.

[mysterio]

I use the bubble/foil stuff and it's fine for a mash tun, although as mentioned, camping mats do a better job.

[Blackaddler]

Hi

I'm disappointed with the heat loss I'm getting from my cool-box mash tun:
Its an Igloo 52USqt (47L) cooler.

A couple of things you could try...

Put something heavy on the lid, to keep it tightly closed.

Put a strap around the whole thing. I found that with a large volume mash in my 66L coolbox, the front side started to bow out very slightly, leaving a small gap to the lid. I used a pallet strap and a small piece of wood along the side at the top to tighten everything up.

I had a 4C drop in temp on my previous mash [even with a duvet wrapped around], but suffered no drop at all last time, with the strap in place. The ambient temperature that day was lower, too.

[fullclaret]

Have you added extra insulation to the lid? Coolboxes tend to have none in the lid as they're designed for keeping things cold, and conversely to heat rising, cold sinks. For my MT I squirted foam gap filler into the lid (I think the same stuff used in the walls of a coolbox) and then lined with tin foil (let foam dry and trim with Stanley knife). I tested heat loss over one hour to make sure it made a difference:

Before: 68-66.5
After: 68-61.5

[EoinMag]

Have you added extra insulation to the lid? Coolboxes tend to have none in the lid as they're designed for keeping things cold, and conversely to heat rising, cold sinks. For my MT I squirted foam gap filler into the lid (I think the same stuff used in the walls of a coolbox) and then lined with tin foil (let foam dry and trim with Stanley knife). I tested heat loss over one hour to make sure it made a difference:

Before: 68-66.5
After: 68-61.5

I think yer before and after values are backwards.

[fullclaret]

D'oh, must post before sampling last brew efforts next time. :-p

[Alan30]

Tropical fish shops use large polystyrene containers with lids to transport fish and live rock around. I place my MT (H&G coolbox) in the upside down lid and place the container over the whole thing - you need to experiment to get the right size but once you have it right there is hardly any temp drop over 90 mins.

This is the sort of thing I mean http://cgi.ebay.co.uk/Polystyrene-Shipp ... _500wt_928

My wife keeps tropical marine fish and the shop is usually happy to give the boxes away.

Alan

[JayM72]

Hi

I'm disappointed with the heat loss I'm getting from my cool-box mash tun:
Its an Igloo 52USqt (47L) cooler.

John

I'm really surprised you're getting big heat losses from this top of the range cooler. Do you prehaeat it?