What is “tog”?
Tog stands for “thermal overall grade”. More precisely, the tog rating of a duvet is a unit that indicates a fabric’s heat retention capacity. In this case, the feathers and down that make up a duvet. Simply put: the higher the tog rating, the warmer you will be at night.
The insulating power of a duvet is determined by several factors, including the amount of down, its quality, and the way in which the duvet is manufactured. Using the tog rating, we can sort duvets into seasonal variants based on the amount of warmth they provide. Continue reading to see how this helps you find the right duvet and to learn about the science behind tog testing.
At Downduvet.co.uk, all of our duvets have a verified tog rating that lets you know how warm they are. No one wants to sweat or shiver through the night, so getting a duvet with just the right amount of warmth is essential. Luckily, the tog rating system is scientific and precise, making it easy to choose the right duvet.
How tog is measured
Tog is measured by applying heat to one side of a fabric and measuring the heat flow to the other side. The tog value of a down duvet is equal to ten times the temperature difference between its two sides (in degrees Celsius) when the flow of heat across it is equal to one watt per m².
Testing the tog ratings of duvets requires highly precise measurements to be taken. This is typically done by spreading the duvet over a large rectangular hotplate in a room with an ambient temperature of 19.5-20.5 °C, setting the hotplate to a temperature of 32.5-33.5 °C, and then measuring the temperature of at least five points to discern the average thermal resistance of the material.
4.5 Tog: The Summer Duvet
Our summer duvets are light and airy, almost unbelievably so. Box stitching and high quality down ensures these duvets will keep you cool while providing a comfortable, breathable covering throughout the summer. With a tog rating of 4.5, they are suitable for most bedrooms.
The summer duvets manufactured by Dickenbergh, Falkenreck, Dickenbergh Manufaktur and Kauffmann 1st Class are particularly light and cool. Those from Kauffmann, Otto Keller and Bielefelder Verse are slightly warmer because of differing manufacturing techniques.
6.0 Tog: The SummerPlus Duvet
SummerPlus duvets are also box stitched and light, though less so than summer duvets. This means they are suitable for a greater part of the year, possibly from spring through to mid-autumn, depending on your local climate. If your home is well-heated, then a SummerPlus duvet can be used year-round.
The SummerPlus duvets from Otto Keller and Dickenbergh tend to be a little bit cooler. Those from Kauffmann and Falkenreck are warmer.
9.0 Tog: The Spring/Autumn Duvet
For many people, a Spring/Autumn duvet is ideal because it can be used comfortably almost the entire year in most homes. Spring/Autumn duvets have a tog rating of 9.0. Some are box-stitched, others are of a baffle box construction. These duvets will not only keep you warm during the cooler nights, but are also light enough to not necessitate a change every time there is a hot spell.
The coolest Spring/Autumn duvets are those from Otto Keller, Bielefelder Verse and Kauffmann 1st Class. Dickenbergh, Falkenreck and Dickenbergh Manufaktur duvets are a bit warmer. The warmest Spring/Autumn duvets are made by Kauffmann.
12.0 Tog: The Winter Duvet
Satisfyingly warm, decadently thick, and luxuriously soft, winter duvets are perfect for those who need to wrap themselves up in the winter, whether that be for comfort or to fight off the chills. With a tog rating of 12.0, winter duvets will keep you warm and cozy, except for the more extreme climates. They are constructed using the baffle box technique to provide optimal insulation.
As with other classes, the winter duvets from Dickenbergh and Kauffmann 1st Class are slightly less warm. The warmest winter duvets are made by Kauffmann, Otto Keller, Falkenreck, Bielefelder Verse and Dickenbergh Manufaktur.
15.0 Tog: The WinterPlus Duvet
The warmest of the warm, WinterPlus duvets offer unparalleled warmth and comfort. A tog value of 15.0 means WinterPlus duvets can bring luxurious and comfortable sleep in the most extreme climates. Their insulating power is so great that we generally do not recommend their use in houses with effective central heating, except for those individuals who require extreme amounts of insulation.
The lightest WinterPlus duvets are those from Dickenbergh and Kauffmann 1st Class. Warmer and heavier WinterPlus duvets are made by Kauffmann, Otto Keller, Falkenreck, Bielefelder Verse and Dickenbergh Manufaktur.
An exotic species, these are truly duvets for all seasons. Called the duo-duvet in Germany, All Seasons duvets consist of two duvets with different tog ratings that can be used separately or in tandem.
The lighter of the two duvets is perfect for keeping you cool, fresh, and dry on hot summer nights. When things start to cool down come autumn, you can switch to the warmer duvet. Once winter arrives, the two are easily combined to create a seamless winter duvet.
Is a Higher Tog Rating Better?
Tog doesn’t measure the quality of a duvet, nor does it say anything about how comfortable the fabric will feel against your skin. It does not reflect the weight of the duvet either. Tog tells us how efficiently a product will trap warmth. This is known as thermal resistance. The higher the tog rating, the warmer the duvet will feel. Even though tog ratings are a good indicator of how warm you’ll be under a duvet, it’s important to understand that tog is measured under laboratory conditions. Making sure that the duvet covers your bed sufficiently is another important consideration in determining how warm a given duvet will feel.
Another factor that can affect how warm a duvet actually feels is the overall quality of its manufacturing. A poorly constructed duvet made from cheap materials might have a certain tog rating when brand new and measured in a laboratory, but after a few uses this low-quality duvet may lose some of its insulating capacity. The duvets available on this website all come from reliable manufacturers and should remain close to their tested tog rating for many years.