Winter duvet: down, wool or synthetic — which is really the warmest?

2026 08 03

The autumn is ending, the cold is drawing in and suddenly you realise that the duvet you slept under all summer is no longer enough. Time for a winter duvet. And then the flood of questions begins: down or synthetic? Wool or microfibre? Which is the warmest? Which is best for allergy sufferers? Which lasts the longest?

In this article we will try to answer these questions simply and honestly — without any sales talk.

First of all — what does "warmest" mean

Before comparing duvet types, it is worth understanding one important thing: a duvet does not warm you by itself. It only retains your body heat. This means that the warmest duvet is the one that best retains air between its fibres — because air is the best natural insulator.

In this sense all three duvet categories — down, wool and synthetic — work according to the same principle, but with different levels of effectiveness.

Down duvet

How it works

A down duvet is filled with goose or duck down — those small, airy fibres that naturally create air pockets. These air pockets retain heat very effectively. This explains why a down duvet can be both extraordinarily warm and very light at the same time — it does not press on the body but warms superbly.

Down quality and fill power

The quality of down duvets is measured by fill power — an indicator that shows how much space one ounce of down occupies. The higher the fill power (500, 600, 700+), the better the thermal insulation and the lighter the duvet.

Advantages

The down duvet is the lightest of the three types — and that is its greatest advantage. It regulates temperature excellently: warms in winter but does not cause excessive heat. It is long-lasting — a quality down duvet lasts 10–15 years with proper care.

Disadvantages

The down duvet is the most expensive option. It is also not suitable for people with allergies to materials of animal origin. Moisture is its enemy — when wet it loses its thermal insulation properties and is slow to dry. Care requires attention — professional dry cleaning or washing in a special programme is usually recommended.

Wool duvet

How it works

Wool is a natural material with a special property — it regulates temperature in both directions. This means that a wool duvet warms when it is cold and cools when it is warm. This is possible because wool fibres absorb moisture (up to 30% of their weight) without losing their thermal insulation properties.

Advantages

The wool duvet is the best choice for those who sweat at night — it absorbs moisture, prevents it from accumulating against the skin and maintains a dry, warm environment. It is naturally antibacterial and antifungal. It is suitable for almost all seasons — it regulates temperature itself according to the body's needs.

Merino wool is particularly soft and suitable even for the most sensitive skin — it does not cause the itching that ordinary wool can produce.

Disadvantages

The wool duvet is heavier than the down duvet. It can trigger allergies in those who react to wool — although merino wool significantly reduces this risk. The price is also higher than synthetic duvets, though usually lower than down duvets.

Synthetic duvet

How it works

Synthetic duvets are filled with artificial fibres — polyester, microfibre, hollofibrefill and so on. These fibres imitate the structure of natural fibres and create air pockets that retain heat.

Advantages

The synthetic duvet is the cheapest option — and that is its greatest advantage for many buyers. It is easy to care for — washed in the washing machine without any special precautions. It is suitable for allergy sufferers who react to materials of animal origin. Modern synthetic duvets can be very warm and even imitate the feeling of down.

Disadvantages

Synthetic fibres breathe less well than natural ones. This means that a synthetic duvet can cause overheating — particularly for those who sweat during sleep. It is less long-lasting than natural duvets — the fibres compress over time and the duvet loses its thermal insulation properties. On average a synthetic duvet lasts 3–5 years.

Comparison table

Property	Down	Wool	Synthetic
Warmth	⭐⭐⭐⭐⭐	⭐⭐⭐⭐	⭐⭐⭐
Lightness	⭐⭐⭐⭐⭐	⭐⭐⭐	⭐⭐⭐⭐
Breathability	⭐⭐⭐⭐	⭐⭐⭐⭐⭐	⭐⭐
For allergy sufferers	❌	⭐⭐⭐	⭐⭐⭐⭐⭐
Longevity	⭐⭐⭐⭐⭐	⭐⭐⭐⭐	⭐⭐
Care	Demanding	Medium	Simple
Price	High	Medium	Low

Which duvet suits whom

Choose a down duvet if: you like light duvets that warm without pressing, you have no allergy to down and are prepared to invest in a long-lasting product.

Choose a wool duvet if: you sweat at night, want a duvet that would suit you all year round, or are looking for a natural, ecological choice. Particularly recommended for those who do not maintain a stable temperature during sleep.

Choose synthetic if: you have an allergy to materials of animal origin, are looking for an easy-care option with a smaller budget, or are buying a duvet for children that will need to be washed frequently.

How many TOG do you need for winter

TOG is the unit of measurement for thermal insulation in duvets. The higher the TOG, the warmer the duvet.

For the UK climate in winter, 10–13.5 TOG is recommended — this provides sufficient warmth even on the coldest nights if the bedroom is kept at around 16–19 °C.

If the bedroom is colder or you are someone who is always cold — choose 13.5 TOG and above. If you tend to run warm — 10 TOG may be enough even in winter.

In summary

There is no single correct answer to the question of which duvet is the warmest — it depends on your sleep habits, your body's temperature regulation, allergies and budget. But a simple guide is this: if you want lightness and maximum thermal efficiency — down. If you sweat or want an all-seasons option — wool. If you are looking for a practical, easy-care and affordable choice — synthetic.

A wide range of winter duvets — from light microfibre to warm down duvets — can be found in the Savashome duvet category, where everyone will find their perfect winter night.