A damp British winter requires more than guesswork — understanding TOG helps you sleep consistently rather than uncomfortably.
Why "Just Buy a Thick One" Doesn't Work
In a draughty Victorian terrace with intermittent central heating, a 13.5 TOG duvet is the right choice. In a modern flat that stays at 21°C through the night, the same duvet will have you kicking it off by 1 a.m. Thickness is visible. TOG is measurable. One tells you how the duvet looks; the other tells you how it performs.
TOG (Thermal Overall Grade) is the UK-standard measure of a duvet's thermal resistance — its ability to retain the heat your body generates during sleep. Higher TOG = greater warmth retention. It is assessed in laboratory conditions and is consistent across fill types and brands.
Three Variables That Determine Your TOG
Bedroom temperature — the most important factor. British homes vary significantly: a well-insulated new build with underfloor heating is a different sleeping environment from a period property with single glazing. If your room stays above 18°C overnight, you can comfortably go one TOG level lower than you might expect.
Your body temperature — people who run warm (often men, younger adults, higher metabolism) typically benefit from going down a level. People who feel the cold (often women, older adults, lower body weight) should go up a level.
How you sleep — side sleepers lose more heat and often need a higher TOG. Back sleepers retain warmth more efficiently. Partners who disagree on temperature are often better served by two separate single duvets rather than a shared double at a compromise TOG.
From a light summer layer to a full winter duvet — the five TOG levels cover the full range of British sleeping conditions.
The Five TOG Levels
| TOG | Room Temp | Season | Suited To |
|---|---|---|---|
| 1.5 | 24°C+ | Peak summer | Hot sleepers, or as a light layer in very warm rooms |
| 7.5 | 18–24°C | Late summer / early autumn | Mild evenings when a sheet alone isn't enough |
| 10.5 | 12–18°C | Spring and autumn | The most versatile choice — suits most UK bedrooms for most of the year |
| 13.5 | 8–12°C | Autumn and winter | Standard winter duvet for average-temperature sleepers |
| 15+ | Below 8°C | Deep winter / unheated rooms | Very cold sleepers, older properties with poor insulation |
The 10.5 TOG is the anchor of a practical duvet wardrobe for most people in the UK. Combined with the right sleepwear and a well-regulated room, it covers roughly eight months of the year.
The two-duvet approach is worth considering: a 4.5 TOG and a 9 TOG used separately or combined (13.5 TOG equivalent) gives you three configurations from two duvets — far more adaptable than a single fixed-weight option.
Our Warmth Series
Five TOG levels — 1.5, 7.5, 10.5, 13.5, and 15+ — each clearly labelled with recommended room temperature range. Choose one for the season, or combine two for year-round flexibility.
