Duvet TOG value

[Dave Baker]

Is there actually any consistency about how warm a given TOG value keeps you?

The first (and only) duvet I ever bought was from Tesco and I just picked the highest TOG one because the price was the same for all. I think it was a

12 or maybe even higher. It was ok but not exactly roasting. A bit too hot in summer and a bit too cold in winter.

When I moved into my new house last year some friends very kindly donated a single bed, duvets and all the linen because my removal company had screwed everything up and most of my stuff was still in storage. One duvet is a 4.5 and the other a 6. The 4.5 one is really light and feels a bit like you're only sleeping under a sheet. It's better if I put a big towel on top which gives it enough weight to feel comfy but it's no way near warm enough in winter. In the summer it's fine.

The 6 TOG one despite the supposed minimal increase in TOG value one is boiling. Much heavier so it snuggles down round you nicely and so warm that I have to turn the radiator off and keep the temp down to 15c in winter or I wake up sweating. I've never been cold under that duvet even when it's 7c below zero outside.

So I don't see much consistency in thermal performance here even though the TOG value is supposed to be a scientific measurement. A 12 TOG duvet that behaved in proportion to my 6 TOG one would parboil me alive even though the Tesco one was less warm than my current 6.

So what gives?

[John Rumm]

The weight of the filling does seem to make some difference. Heavy floppy fillings like down tend to wrap round you closely and hence you feel warmer (once they have warmed up - which takes a bit longer). Lighter fillings like synthetic hollow fibre don't tend to get so closely wrapped - they warm up fast - but you are in a bigger pocket of hot air.

[Jethro_uk]

[polygonum]

Togs are defined: A tog is 0.1 m2K/W.

I find that a down duvet usually seems to work better over a wider range of temperatures than other fillings. Both very light and, if the fabric components are appropriate, superbly draping. Many others, especially cheap polyester, seem not to drape very well and leave large air channels ideally suited to the passage of cold air through the bed.

But age and how it has been treated will affect any duvet. For down. well fluffed up regularly, and hung on the line in the sun during the summer.

Some duvets do generally seem to be warmer than anticipated from the tog rating.

[Michael Chare]

What is the K for in that formula?

[Michael Chare]

I've found it. It's Kelvin