15 tog is the warmest standard duvet weight made — for genuinely cold bedrooms, unheated homes and the depths of a British winter. If you've searched for an 18, 20 or 30 tog duvet: togs above 15 aren't a standard rating, and 15 is the practical maximum. Here's why — and how to go warmer still.
Unheated or single-glazed bedrooms, cold sleepers, older properties, and anyone for whom 13.5 isn't enough in January.
Honest answer: the tog scale for standard duvets effectively tops out around 15 — a handful of brands market 16.5–18 tog, but beyond that, claimed togs aren't meaningful and extra weight harms sleep comfort. Warmer than 15? Layer: a 4.5 over a 10.5 (≈15 combined) traps more air than one heavy duvet, or add a fleece blanket over the duvet, and a mattress topper underneath you makes a bigger difference than any tog increase.
A 15 tog costs nothing per night to run — for cold homes managing energy bills, upgrading the duvet and adding a topper is the cheapest warm night available.
What is the warmest tog duvet?
15 tog is the warmest standard weight — the practical maximum for a single duvet.
Do 20 or 30 tog duvets exist?
Not as a meaningful standard. Beyond ~15–18, ratings aren't comparable; layering two duvets is warmer and more comfortable.
Is 15 tog too hot for a heated bedroom?
Usually yes — heated rooms suit 10.5–13.5. Choose 15 for genuinely cold rooms.
How do I get warmer than 15 tog?
Layer a 4.5 over a 10.5, add a blanket on top, and a mattress topper beneath — insulation under you matters as much as over you.
Not sure about tog? Read our duvet tog guide · Check our duvet size guide · Standard winter: 13.5 Tog Winter Duvet · Add warmth beneath: Thick Mattress Topper
Posh Tag is a family-run bedding business on Fieldhouse Industrial Estate in Rochdale, with more than fifteen years in textiles. Orders are picked, checked and packed by our own team rather than passed to a third party, so if something is not right we deal with it ourselves. Email support@poshtag.co.uk or call +44 7414 441213, Monday to Friday 9am to 5pm.
For the warmest possible bed, put a thick mattress topper underneath you, an extra deep 40cm fitted sheet over it, and a pair of hotel pillows on top. Orders over £50 ship free, so bundling saves on delivery.
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