What Does Fill Power Mean?

Different Types Of White Goose Down

If you have ever shopped for bedding, outerwear and sleeping bags you may have come accross the term ‘fill power’ – but what exactly does it mean? Fill power can be simplified as ‘how fluffy something is’. Techcnically speaking, it is measured using a specially calibrated measurement system – but for most consumers, ‘high fill power = fluffy’. Buy why does down fill power matter and where does it make sense to spend extra on a high fill power item?

Fill power is only used to describe the loftiness of down and not feathers. Fill power also only applies to Down and not down alternatives, although some times it is used as a reference like ‘like 550 fill power down’ (DOWNLITE sometimes will use this as a reference for our Down Alternatives, like PrimaLoft).

The actual measurement of fill power involves placing 1 ounce of treated down into a specially designed filling tube. Then a calibrated weight is added on top and allowed to push against the down for a set period of time (24 hours as a baseline). Things like temperature and humidity can alter the results, so the down is tested in an environment free from those variances.

For bedding like comforters, blankets and throws – having a high fill power means that the article of bedding can keep you warmer, but with less weight. For other items like pillows, it is not as important to have a high fill power number – because your resting your head weight against the item. A high fill power does give you a nice ‘bounce’ in terms of how a pillow springs back against your weigh,t which some sleepers really like. Other sleepers, like more of the ‘cradle’ effect and a basic fill power of say 550, feels great and fits their budget.

Generally, the higher the fill power, the higher the cost of the material – in fact the price curve is less linear in shape and tends to be more ‘exponential’. So if your buying new comforter, and you want that cloud like feeling on top of you – opt for a high fill power in the 700-800 range.

Other things to consider for fill power is the material it is placed or stored in. When a high fill power is sought, it is prefered to compliment the filling with a very light weight fabric weave like a ‘batiste’ (batiste refers to the yarns being of 80′s or better quality – resulting in a paper thin fabric that is extremely light weight, yet down proof). One of the best down comforters made by DOWNLITE is the 800 Fill Power German Batiste Down Comforter.

It can be a little confusing for consumers to understand how fill power and weight can impact the warmth of an item, as well as comparing ‘like’ items at a store. All else being equal – if  two comforters have the same fill power – then the only difference that can impact warmth between the two is the physical weight used for it’s filling. A ypical heavy weinter comforter might be in the 60 oz range using a 600 fill power white goose down. However, the same fill power – but at a lighter weight – say 48 oz, can make the item offer less ‘warmth’.

They way down works is by providing a barrier to store your own body’s warmth. So the high fill power down basically holds that warmer ambient air in place, thus letting you stay snuggly.

A common mistake made by consumers is to overbuy the fill power or warmth of a comforter, which results in an unpleasant ’too warm’ sleep environment. For first time buyers we always suggest going down a warmth level to make sure you don’t get too warm. Consumers with previous down experience can then opt for higher fill power comforters knowing full well how the items work and provide comfort.