What is the best TOG rating for winter?

Many UK households use about 13.5 TOG or higher for cold bedrooms. 10.5 TOG is a common all-season middle. 4.5 TOG suits warmer rooms. Room temperature and personal preference matter more than one fixed winter number.

Is fill power the same as TOG?

No. Fill power measures how lofted a mass of down is. TOG measures the finished duvet's warmth. A high fill-power down duvet can reach high TOG with less fill weight.

Down versus hollowfibre — what differs?

Down clusters trap air well and squash small. Hollowfibre and microfibre use synthetic fibre shapes for loft and are often easier to wash. Allergy and care needs drive many choices.

bedding

Duvets, Fill Power and TOG Ratings

Entity: duvet fill and TOG

Layered duvet and pillows on a king bed with a tall fabric headboard — Sheets, duvet and pillows work together with the bed — not just the mattress alone.

In short

TOG measures how warm a duvet is: higher TOG means more insulation. Fill power describes how much loft down gives per weight — a quality score for natural fills, not a TOG substitute. Natural fills use down and feather. Synthetics use hollowfibre or microfibre. Pick TOG for room climate and fill type for loft, weight and allergy needs.

Educational diagram linking TOG insulation bands with down loft versus synthetic hollowfibre fill structures — TOG rates warmth. Fill power rates down loft efficiency. Synthetic fills use fibre shape instead of cluster loft.

TOG bands commonly used in UK shops

Approx. TOG	Typical seasonal use
~1–4.5	Warm rooms / summer
~7–10.5	Mid-season / many year-round uses
~13.5+	Cold rooms / winter

See the scientific unit in TOG rating.

Natural vs synthetic fills

Fill class	Structure idea	Plain notes
Down	Soft clusters under feathers	Loft efficiency via fill power
Feather	Quills with vane	Heavier; often blended with down
Hollowfibre	Tubular synthetic fibres	Washable loft; no fill power rating
Microfibre	Fine synthetic fibres	Soft feel; denser packs possible

Comforter vs duvet (terminology)

In UK usage a duvet sits inside a cover. “Comforter” is more common in US shops for a finished quilted top layer — always check whether a cover is needed.

Frequently asked questions

What is the best TOG rating for winter?: Many UK households use about 13.5 TOG or higher for cold bedrooms. 10.5 TOG is a common all-season middle. 4.5 TOG suits warmer rooms. Room temperature and personal preference matter more than one fixed winter number.
Is fill power the same as TOG?: No. Fill power measures how lofted a mass of down is. TOG measures the finished duvet's warmth. A high fill-power down duvet can reach high TOG with less fill weight.
Down versus hollowfibre — what differs?: Down clusters trap air well and squash small. Hollowfibre and microfibre use synthetic fibre shapes for loft and are often easier to wash. Allergy and care needs drive many choices.