Your Duvet TOG Guide: Choose Warmth, Not a Bigger Number

TOG describes a duvet's thermal resistance. A higher number means more insulation under the test conditions, not a better-quality duvet. Choose the amount of warmth you need, then the filling and feel you enjoy.

The number is useful because a photograph cannot show insulation. It is less useful when turned into a rigid rule about which month or room temperature every person should use it in.

Use the rating as a starting point

IDFL's TOG explanation notes that a laboratory result does not capture every effect of drape around a sleeper. The practical lesson is to compare ratings while keeping the rest of your bed in mind.

A cover, sleepwear, extra blankets and your usual room conditions all influence the experience. If you change several at once, it becomes difficult to tell whether the duvet itself is the part that helped.

One range, four different warmth choices

Notice that Royal Lightweight is a lower warmth option within Royal, but still has a higher rating than Air. Names such as Lightweight and All Season need the context of the particular range.

Choose for your ordinary nights

If you regularly kick the duvet away, consider a lower warmth option after removing unnecessary throws. If you stay covered and still feel cold, consider more insulation and check whether poor side or foot coverage is part of the problem.

A heated Canadian apartment, a cool British bedroom and an Australian room in winter can each need a different choice. Country and season help describe the situation, but your indoor conditions and preference complete the decision.

When one duvet is not the simplest answer

If your bedroom changes sharply through the year, two warmth options may be more useful than forcing one duvet to cover every night. A lighter summer layer and a warmer winter layer can make the adjustment straightforward if you have room to store the spare.

For two sleepers with different preferences, an extra removable layer on one side may work better than choosing the warmest shared duvet. Separate sleeping layers are another possibility if the compromise never feels comfortable.

Do not ask TOG to describe softness

Cloud and Royal can have different fill materials and a different feel even when their warmth choices are relatively close. Air's lower rating does not mean its construction is lower quality. TOG is one dimension of the purchase.

Read fill amount, shell, cover and size separately. A duvet with an appropriate warmth rating can still be too narrow for your mattress or awkward to wash in your home machine.

Make one useful adjustment at a time

Keep your usual cover and room setup when comparing a new warmth level. Notice the whole night rather than the first moment you touch the fabric. You are looking for a layer you can comfortably keep around you.

See YumeFeel's warmth and feel comparison for the complete range, or use the bedroom notebook to turn that number into a practical choice.

YumeRest is YumeFeel’s bedding journal. Product examples use published specifications; this guide does not claim independent hands-on testing or a universal ranking.