The office chair market is built on features that are easy to photograph: mesh panels, headrests, armrests that move in four directions. Almost none of them are the reason a chair does or does not help a painful back.
The one feature that matters
If you read nothing else
Lumbar support that adjusts vertically. Not lumbar support that exists. Not lumbar support with a tension dial. Support that slides up and down so it lands in the curve of your lower back, which sits at a different height from the next person's.
Steelcase publishes exactly this on the Series 1: height-adjustable lumbar support that slides up and down to sit in the curve of your lower back. That is the feature you are buying, and it is why the Series 1 is on this page rather than a cheaper chair with a fixed bulge in roughly the right area.
A fixed lumbar curve is designed for a person of average torso length. If your torso is longer or shorter than that average, a fixed curve pushes on the wrong vertebrae all day — which is worse than no lumbar support, because it actively deforms your spine into the shape the chair expects.
Why adjustable lumbar, specifically
The lumbar spine has a natural inward curve. Sitting, especially sitting while concentrating, flattens it — you slide forward, the pelvis rotates back, and the curve reverses. Sustained for hours, that is one of the most common mechanical contributors to low back pain in desk workers.
Lumbar support props that curve back up. For it to work it has to be in the right place, which is the entire argument for vertical adjustment.
The Series 1's other published adjustments matter for the same reason:
- Seat depth adjustment. So the seat front does not press into the back of your knees, which restricts circulation and pushes you forward off the backrest.
- Weight-activated recline with an upright lock. The chair responds to your weight rather than to a tension dial you will set once and get wrong.
- 400 lb capacity. Not a specialty model, and headroom in a chair matters the same way it does in a desk.
The sit-stand problem nobody mentions
Here is the complication specific to this site's readers. A task chair is designed for a desk at a fixed seated height. Once you own a sit-stand desk, there is a third position neither a chair nor standing covers well: perching at a desk raised to something between seated and standing height.
A conventional chair cannot go high enough for that. Vari publishes the Active Seat at 23" to 32.5", on a fully articulating pedestal, rated to 250 lb, with a 17" x 13.75" seat. The 32.5" top end is what makes perching possible, and the articulating base keeps the pelvis tilted forward instead of folded — which is the whole point of perching rather than sitting.
It is also honest to state the trade: the Active Seat has no back support at all, and Vari's warranty on it is one year against Steelcase's twelve. It is a third position, not a chair. The full comparison.
Read the warranty for labor
Chair warranties are usually quoted as a number of years and usually cover parts. Steelcase publishes a limited 12-year warranty on parts and labor in the US and Canada. That distinction is worth real money: a gas cylinder is cheap and replacing it is not, and gas cylinders are the single most common chair failure.