How to identify a Herman Miller Aeron's size and generation

Finding the size dots

Aerons come in three sizes and each is marked on the chair itself. Look at the back of the backrest, along the rear edge of the frame near the bottom, and you will find small raised or printed dots: one dot is size A, two dots is size B, three dots is size C.

A is the smallest, B is the standard size and by far the most common in UK offices, and C is the largest. If your batch came from one fit-out, expect mostly Bs with a scattering of As and Cs. Counting them is worth doing, because the mix affects how a batch is valued.

The underside label

Tip the chair forward and look at the underside of the seat pan. There is a manufacturer's label carrying the model information and build details for that specific chair. Where the size dots have worn away — common on older stock that has been cleaned repeatedly — this is the reliable fallback.

A clear photo of that label is one of the most useful things you can send with an enquiry. It answers questions about specification that a photo of the whole chair simply cannot.

Classic or Remastered?

The quickest tell is the frame profile. The Remastered has a slimmer, cleaner outline than the Classic, particularly around the back frame and the arm supports, and the overall look is less chunky.

Next, look at the tilt mechanism under the seat: the Remastered uses a redesigned mechanism with a different housing shape and control layout to the Classic. Then check the lumbar area. A Classic typically has a separate lumbar pad or PostureFit unit bolted onto the back of the frame, adjustable by hand from behind. The Remastered integrates PostureFit SL into the chair, adjusted from the back but forming part of the structure rather than sitting on it as an add-on.

Side by side the difference is obvious. On its own, the back of the chair — frame profile plus how the lumbar support is attached — will tell you within seconds.

Why size and generation matter when selling

Both feed directly into what a batch is worth. Size B is the volume seller and the easiest to place; A and C sell too, but into narrower markets. Generation matters because Classic and Remastered are valued as different products, and specification differences between them affect what a refurbished chair can be sold as.

Providing this detail up front also shortens the whole process. A list that says "84 × Remastered size B, 20 × Classic size B, 16 × Classic size C, fully adjustable arms" can be valued far more confidently than a headcount of chairs, which usually means a cautious figure until someone visits.

Our Herman Miller Aeron buying page sets out what we look for and how the valuation works for this range specifically.