Insulating a chest freezer

[Tim+]

Well, I stuck a temperature probe in my old chest freezer and discovered that it?s not really performing to spec. It?s a 3/4 star rated freezer (I think he 4* rating only applies when the fast freeze mode is switched on) and the temperature seems to cycle between -15.5 and -12 C.

When I turned it off for the hours the temperature rose to -4 C which is clearly not good for longer term food storage. Fortunately it?s very much a ?spare? freezer that?s only been pushed into service to allow us to stockpile a few essentials should we have to self isolate.

Anyhow, I don?t think that the insulation has obviously failed (the case isn?t bulging anywhere) but I was wondering if I could just glue some kingspan/celotex etc to the outside? If I were to do this, should I glue the foil side to the cabinet or have the foil to the outside?

Tim

[Thomas Prufer]

Vapor barrier on the warm side, i.e. outside.

Thomas Prufer

[polygonum_on_google]

rated freezer (I

ice to allow us to

Have you cleaned the back? All the "radiator" fins, etc.

Are you sure it has not lost some gas?

Have you considered placing a very modest fan to encourage better airflow?

[Dave Liquorice]

What climate class is it and where is it located?

[Tim+]

No idea. We?ve had it for donkey?s years.

In our garage which stays relatively cool even in this weather.

Tim

[Tim+]

Not recently but the radiator at the back definitely isn?t choked with fluff/dust. A Light coating of dust at most. Still, won?t hurt to brush it down.

It may have, but given its age and ?non-critical? use, I doubt it?s worth regassing.

Don?t think it?s worth it really. It?s not in an enclosed position and air can circulate pretty freely.

Tim

[soup]

Not always a good thing . Outside air temperature comes into play as to when the compressor will run . If the outside air gets too low then the compressor may not run so often, so eventually the Freezer will only be as cold as the outside air .

Probably better put by these people.

See :- "Thawing" In fact that whole article seems to think keeping a freezer in an unheated uninsulated Garage is iffy. Maybe fine, on the south coast, to. nah, in the north of Scotland.

[Nick Cat]

rated freezer (I

ice to allow us to

Yes that can be done. Foil must be on the outside, and needs to cover /all/ outside surface and be well sealed. Leaving the edges unfoiled will not do . Don't apply it to modern machines that use the case to get rid of heat, b ut as long as it's got a black radiator on the back go for it. Keep it away form the compressor.

NT

[williamwright]

That's not going to happen in August.

Bill

[williamwright]

Well it's obviously f***ed then. Don't waste time and money on it. Get rid. Get a new one and the reduced power consumption will help pay for it over a period of time. Bill

[RJH]

I'd maybe question your source there.

The thing that determines whether the compressor kicks in or not is nothing to do with outside temperature.

Certain freezers don't cope well with low temperatures (< 4C), but that's to do with the refrigerant not being able to cope. So the compressor is still activated - it just won't work as well/at all.

[Andrew]

I have on offcut of 2 inch celotex sitting flush against one side of my fridge-freezer which struggles in hot weather and if I move it away and feel the side of the FF, it is clearly much colder than the other side, so it is beneficial. Every little helps ...

[Andrew]

Didn't snow stop a cricket match in August once in Buxton ?.

[Adrian]

In message , Andrew writes

The famous incident was June 2nd 1975 (Derbyshire v Lancs). Whether or not there have been others, I don't know.

Adrian

[Nick Cat]

Unfortunately this is close enough to true to rule. It might be that the ma chine is simply out of its environmental rating, but either way if it's dec ades old you're financially best off replacing it.

NT

[charles]

There was one in Essex.

[Brian Gaff (Sofa)]

I'd have thought that it would make little difference. To do some good you would need to get right up to the actual walls of the compartment. I had a freezer that went like yours, always running etc, and it was replaced. On looking at the stuff in the sandwich of insulation, it had somehow got wet and thus was about as useful as no insulation at all, in the end. Now there is only me, I only need my little freezer on the Fridge and they most certainly seem to have improved the insulation over the intervening years. Brian

[Martin Brown]

You need to look fairly carefully at the ratings plate. It will have a code on to tell you which refridgerant is in it. Some modern ones practically stop working at ambient temperatures around 4C but are fine inside a modern centrally heated garage but fail in a winter garage.

This time of year I would not expect this caveat to apply since ambient is pretty much what the unit expects in normal operation. Mid winter a modern freezer can go to hell in a handcart if used in a garage as my brother found out to his cost. Entire thing had thawed during a cold snap when the garage ambient was a steady 4C for days on end.

However the problem you describe sounds more like the "insulation" on the fridge is saturated with water and no longer an insulator. Any decent design of freezer even a couple of decades old should only lose a few degrees over a matter of hours (assuming that it is reasonably full).

Foil outwards if you do want to put additional insulation on the outside. How hot and often is the compressor running?

[Theo]

+1. A freezer that can't cool to -20C at room temperature (~20-25C) is knackered, and will be thrashing itself trying.

Fridges can often be picked up relatively affordably on ebay when someone is remodelling their kitchen and needs it gone ASAP. Not sure if the same applies to chest freezers, but there may also be commercial ones going spare. You might be able to pick up a late model for relatively little money.

(also when you account for what Kingspan costs)

Theo

[Andrew]

Yes Charles, but that wasn't snow, it was 'snow' (as in the white powdery stuff)