Silver foil behind radiators worth it?

pm1961

So why ARE space blankets silver?

To reduce heatloss by evaporation (the windproof bit) and reflect the radiation from the body .(The silver bit).

how does a thermos flask work?... and why do they make them "silver" on the inside?

Vacuum bit stops convection loss. Silver bit reduces loss through radiation.

Now, if only we could create a vacuum in the cavity....... and line the walls with foil..........

patty65

For the cost of a roll of tinfoil and a bit of cardboard try it and see, then report back whether it works or not.

Patrick

Cardew

pm1961 wrote: »

Of little use at all I'm afraid........ Intuitively it sounds like a good idea but doesn't really stand much close inspection and is never backed up with facts.

If you've done absolutely everthing else then maybe, but I still think the effect is more placebo than anything else.

Only partly true I'm afraid...... every hot object "radiates." What we call a radiator relies mostly on convection and less so on radiation. It's probably the most inappropriate name for a device ever......

Stick your hand 1m in front of a rad....... how much heat can you feel?..... a little maybe?

Stick your hand 1m above a rad........ feels much hotter.... Warm air by convection... the main mode of room heating.

Not true I'm afraid.....there will always be a temperature gradient across the brick unless the outside temp is the same as the inside temp.

Stick a metal spoon and a brick in a pan and boil the water....... they all get to 100C eventually..... it just takes the brick longer because of the rate at which they conduct heat...... take 'em out and stick them on your worktop..... the spoon will cool down PDQ, the brick will be warm for ages.......

Besides, that is just a theoretical case..... we are mainly talking about cavity walls with or without insulation in them. The only saving would be, as a previous poster said, the miniscule amount of insulation that it adds to that tiny portion of wall. Plus, a tiny amount of radiated heat which is reflected back to the radiator.

because they are windproof and reduce heatloss by evaporation. The human body is also quite an effective radiator, so in this case it is more appropriate. Just sitting in a chair a body pushes out around 100W. Fill a room with people and the temp soon goes up...

They (the people trying to sell you something) mess with the science and your head. Their claims might have a grain of science "fact" in them, but that doesn't make them cost effective or worthwhile.

Ask British Gas for the science paper on which the £19 saving is based.... I bet they don't reply with one!

Spot on!! Especially the placebo effect