Memory foam pillows come in two fundamentally different constructions, and they behave so differently that liking one tells you very little about whether you will like the other.
Solid Foam
A single moulded block, frequently contoured with a raised edge for the neck. It holds one shape and provides consistent, predictable support.
The height is fixed. If it suits your build and sleeping position it is excellent, and if it does not there is nothing to be done about it.
Solid foam also traps heat more than shredded, because there is no air movement through a continuous block.
The Practical Differences
- Adjustable height, on shredded fill with an accessible zip
- Cooler sleeping, since air moves between the pieces
- Washable, on many shredded pillows; solid foam generally is not
- Mouldable around a shoulder or under a neck
- Needs plumping, where solid foam holds its shape
Ranges built around adjustable shredded fill, of the kind at xtreme-comforts.com, are solving the fixed-height problem, which is the most common reason a memory foam pillow is returned.
Shredded Foam
The same material broken into small pieces and loose inside a cover. It behaves more like a conventional pillow: it can be plumped, moulded and reshaped.
Air moves between the pieces, so it sleeps cooler. And because the fill is loose, it can be added to or removed.
The trade is consistency. Shredded fill migrates during the night and needs occasional redistribution, which solid foam never does.
Why Adjustability Matters So Much
Correct pillow height is not a preference. It is determined by the gap between your head and the mattress in your sleeping position, which varies with shoulder width, position and mattress firmness.
A fixed-height pillow either matches that gap or does not. An adjustable one can be brought to it, which is why the same product suits side, back and front sleepers.
The Bulk Fill Option
Some manufacturers sell shredded foam separately, which allows a pillow to be topped up as the fill compresses over years.
That extends useful life considerably and is worth knowing about before replacing a pillow that has simply gone flat.
Not for Infants
Worth stating plainly. Memory foam pillows of either construction are not for babies.
Safe sleep guidance is consistent that infants should sleep on a firm flat surface with nothing soft in the cot, and pillows are generally not recommended under twelve months at all.
Which to Buy
If you know your correct pillow height and a contoured shape suits you, solid foam is excellent. If you are not sure, or sleep in more than one position, adjustable shredded fill removes the guesswork.