The best filler for your cushions is the one that meets your needs and that you prefer. You may have allergies that prevent the use of some materials or you may want low or no-maintenance cushions. You may want softness most of all or you may prefer firm, long-lasting cushions. There are four main types of cushion fillers, each with its own advantages and disadvantages. Understanding these four types will help you choose the filler that is best for you.
Sheet foam, a product of the petroleum industry, is the most common furniture cushion filler. Density and compression indicate the softness and longevity of foam. Density is the weight per cubic foot, with 1.13kg. judged to be a good quality for sofa cushions. Compression is the amount of pressure needed to compress the foam by 1/4. A compression factor of 35 is considered mid-range for sofa seat cushions; 15.9kg. of pressure is required to compress 30 cm (12 inches) foam to 20 cm (eight inches). Generally, "hard" foam has high density and high compression, while "soft" foam has low density and low compression. Higher density foam will remain responsive longer. Foam cushions are usually wrapped with terylene, a polyester similar to quilt-batting material, to soften the edges and add loft to the cushion.
Loose fiberfill, a polyester fibre, resembles down when used in cushions. It is soft to sit on but flattens quite quickly and requires frequent turning and plumping. It must be encased in a fabric shell before being inserted into the cushion and is not recommended for use alone in seat cushions; however, it works well in separate back cushions. Fiberfill is not graded and the quality varies from manufacturer to manufacturer. A product of the petroleum industry, polyester is mildew-resistant and is much less expensive than foam.
A foam inner core surrounded by loose fiberfill and encased in a fabric shell makes a popular seat cushion. It looks like down but will be much firmer and will require less fluffing. The foam will hold the cushion shape much better than down and the cushion will last years longer. If the fiberfill flattens, that portion of the cushion may be replaced or supplemented.
The most expensive cushion filler is down. It is comfortable to sit on, conforms to the body well and stays cool in warm weather. Filled with down only, cushions must be fluffed and turned regularly and will eventually become soiled, flatten permanently and become difficult to fluff up. Cleaning may restore some fluffiness but the expense of the cleaning is often more than the cost of replacing the cushions. Foam-core down cushions are a less expensive substitute for all-down cushions. Down is a natural material and is considered a renewable resource. However, it should be noted that down is not hypoallergenic.