Humanscale Diffrient Smart Task Chair 2021 Review + Pricing

The Diffrient Smart chair had some high standards to live up to after following other notable Humanscale chairs, like the Freedom and Liberty. We wanted to find out if it could live up to the hype. While it is not going to be an ideal option for everyone, we were not disappointed with what we found. In this review, I will go over all the different aspects of the Diffrient Smart chair. I will share the things that I like and what I don’t like. This should help to make it easier for you to decide if the Diffrient Smart is the best choice for your new task chair.

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Diffrient Smart Review Snapshot


Ergonomic Adjustments


  • Made in USA with high end build quality
  • Good seat comfort
  • Good back support
  • Strong warranty
  • Ships almost fully assembled
  • Environmentally friendly


  • Very little adjustability
  • Recline may not be comfortable
  • Not good option for people over 6’2”



Humanscale was founded in 1983 by Robert King, CEO. It has always had a focus on creating healthy ways to work. It has been a leader in ergonomic products for decades and continues to produce high-end products like keyboard trays, monitor arms, standing desks and ergonomic chairs. The Diffrient Smart was designed by Neils Diffrient. Neils Diffrient is also the designer of the popular Freedom, Liberty and Diffrient World chairs.

Humanscale Diffrient Smart Review Links

Specs / Features / Pricing
Return Policy and Warranty
Shipping and Assembly
Build Quality
Scope of Users
Seat Comfort
Back Support
Armrest Comfort
Ergonomics Adjustments
Upholstery Options
Mechanism Options
Wheel/Caster Options
What I Like
What I Don’t Like
Bottom Line

Humanscale Diffrient Smart Video Review

Country of Origin

Made in USA

Overall Dimensions: 26.5”W x 26.5”D x 40-44.5”H
Seat Height: 16” – 20.5”
Weight Capacity: 300 lbs.
Seat Dimensions: 19.25”W x 16.25”-18.75”D
Back Dimensions: 18.5”W x 24”H
Distance Between Arms: 17- 20.5”
Arm Height from Seat: 2.75-7.25”
Base Dimensions: 26” Diameter
Chair Weight: 34 lbs.
Shipping Box Dimensions: 24.5” x 27.5” x 29.5”
Shipping Box Weight: 45 lbs. 


Weight sensitive, self-locking recline mechanism
Automatically pivoting backrest
Tri-Panel Mesh Technology back and lumbar support
Contoured seat cushion
Pneumatic seat height adjustment
Seat depth adjustment

2021 Starting Price – $1,322.99

There is some customization available on the Diffrient Smart. If you go with the most basic version of the chair, it will cost $1,222.99. This version is armless with a black frame and trim, Lotus seat upholstery and a standard height cylinder. The available upgrades are below. For more details on the upholstery options see the “Upholstery Options” section.

The model we ordered has the following configuration: 4D Adjustable Duron Arms, Black Frame with Black Trim, Silver Check Mesh Pattern, Alloy Mesh Color, Lotus Textile, Navy Textile Color, No Stitching, Standard Seat Pan, Standard Cylinder 5″, Standard Hard Casters, No Fireproofing = $1,364.99.

Option Upcharge
400 lbs. Weight Capacity (SmartPlus) $400.00
Fixed Duron Arms $0.00
Adjustable Duron Arms $0.00
4D Adjustable Duron Arms $42.00
Polished Aluminum Frame $84.00
5” Return to Height Cylinder $42.00
High 8” with 18” Foot Ring $138.00
High 8” with 21” Foot Ring $164.00
CAL 133 Fireproofing $45.00

Humanscale sells their products directly on their website and through a network of authorized dealers and retailers. Whether or not you can return your Diffrient Smart chair will be completely dependent on who you buy the chair from. Humanscale does not offer returns when you purchase from their website. Humanscale also does not allow authorized dealers and retailers to return the chair to them.

For this reason, many dealers and retailers have chosen not to allow returns on the Diffrient Smart. Other dealers have decided to take returns back to their own location. If you are concerned about being able to return the chair if you do not like it, then make sure to check the return policy for the dealer you would like to make your purchase from.


Humanscale covers the Diffrient Smart chair for 15 years. The warranty covers the chair for 24/7 usage and for people up to 300 lbs. The upholstery, foam and arm pads are an exception to this coverage. They have a coverage period of five years and are covered for usage periods of eight hours a day and 40 hours a week.

One aspect about Humanscale’s warranty, that separates them from a lot of other brands, is they will make on-site repairs for you, if you are located near a Humanscale authorized dealer. Humanscale’s warranty isn’t quite as good as companies like Herman Miller or Steelcase, but it is better than almost every other company out there.

See The Best Office Chairs For 2021

After months of testing 40+ ergonomic chairs, the results are in!

The Diffrient Smart chair ships via FedEx/UPS ground in a pretty large box and it weighs about 45 lbs. It has some handles cut into the sides of the box that make it easier to carry or drag but it would be helpful to have someone available to move the box with you.

The box has some cardboard inserts to help keep the parts in place to prevent damage. It also has a large plastic bag that covers the backrest and seat of the chair to help protect it. Overall, the Diffrient Smart is well packaged. Our box arrived a bit beat up, but the chair was still in perfect condition.


Humanscale ships the Diffrient Smart almost fully assembled. It comes in 2 main sections. The lower section consists of the base, wheels and cylinder pre-installed. The upper section consists of the seat, back and arms pre-installed. You just need to connect the upper and lower sections by placing the seat on top of the cylinder.

Assembly time should only take a few seconds. The upper section isn’t too heavy, but it helps to have another person on hand because lining up the hole on the bottom of the seat with the cylinder can be a bit tricky on your own.

There was a lot of thought that went into the design and build quality on the Diffrient Smart. The Smart chair was designed to be a sleek option for high-design environments. Neils Diffrient envisioned this chair as a great task chair for modern, active workspaces. The chair has clean lines and quite a few options to customize its look. This makes it a nice option for people that want something other than the standard generic colors offered on a lot of competing mesh models, like the Aeron.

High-quality base

The Diffrient Smart was designed to look attractive, but it is also made with good components. Often times plastic is associated with something being “cheap”. That is not the case with the Diffrient Smart. There is a lot of plastic on the chair, but it is high-end injection molded plastic. This plastic is strong where it needs to be, but also flexible in areas where it should be. The plastic helps to keep the weight of the chair down, which is noticeable when compared to other chairs. Humanscale also incorporates texture into their plastics which helps to prevent it from scratching.

Along with the injection molded plastics, there is also die-cast aluminum parts with powder coat. This helps to add to the quality, high-design look and also the low weight. The mesh is also nice quality compared to other chairs we have tested. It looks nice, is soft to the touch and has good flexibility.

Underside of seat showing mechanism

Overall, Humanscale makes high quality chairs. The Diffrient Smart is currently ranked #13 on our best office chair list for build quality.

Backrest and armrests

The Diffrient Smart did not receive a high scope of users score. For scope of users, we are focusing on how many people can sit in the chair comfortably. The Diffrient Smart does well in accommodating users that are short to average in  height. A couple downsides, that knocked the Diffrient Smart’s scope of users score down, were the lack of back height adjustment and a short maximum armrest height.

If you are tall, these will both hinder your ability to get comfortable in the chair. The backrest may not be as big of an issue depending on where you prefer to have the curve line up on your back. The arms will most likely be a problem if you are over 6’2” though. They have the shortest maximum height out of all the chairs we have tested so far.

The seat on the Diffrient Smart is fairly large and does not have any bolsters or a pronounced frame. This makes the seat feel very spacious. The outside edges of the seat are rounded so it is comfortable to use the entire seat.

Front view of the seat to show seat pan shape
Side view of the seat

The seat pan is made from a flexible plastic. This gives the seat a bit of flexibility to move with you while you work. The seat is padded with 2” of foam and you can choose from a variety of upholstery options. The seat is more of a firm style of sit but it was well received in our office, scoring an 72/100 for seat comfort.

Similar to the seat comfort score, the Diffrient Smart also received an 75/100 for back support. This is currently the 3rd ranked chair for back support. The really interesting thing about the Diffrient Smart doing so well in the back support category is that it does not have an adjustable height back or adjustable lumbar support system. The backrest just has a built-in curve for your lumbar area.

Front view of the backrest

The curve in the back is very pronounced and the mesh is really flexible. It is designed in what Humanscale calls a “tri-panel” mesh backrest. This creates three different zones in the backrest, which helps it to conform to the specific person that is sitting in the chair. The mesh allows you to sink into the back and then the pressure of the mesh flexing will provide the support you need. Along with providing good support, the mesh is also breathable, which helps to keep you cool while you work.

Side view of backrest showing natural lumbar curve
Backrest while seated in chair

Another factor that helps with the back support is that the backrest has a pivot function that is independent from the recline. This gives the backrest a bit of “wiggle” so it will adjust to your back position, without you having to recline at all. 

Back view of backrest while seated in chair

The Diffrient Smart chair can come armless or with your choice of three different arm styles. The first choice is fixed arms. These will offer no adjustability. The second choice is height adjustable arms. The final option is what Humanscale calls their “4D adjustable” arms. While they are called 4D, they are actually only 3-dimensional. They have height adjustment, arm pad depth adjustment and arm pad width adjustment. These are the arms we opted for on the model we tested.

Side view of arm pads
Top view of arm pad

The armrests have a wide height adjustment range, but the range is on the low end. The arms can go almost as low as the seat, which is nice because it gives you the option to have them out of the way if needed. The downside was discussed earlier in the Scope of Users section. The armrests do not go as high as other models, so they are not a great option for tall people.

Lowest (left) and highest position (right) of armrests
Making height adjustments to armrests

The arm caps have depth a width adjustment. The range is generous on both adjustments and they are easy to do. The arm caps feature a separate foam insert, which makes them more resistant to breaking down. They have nice rounded edges and are soft, which make them more comfortable than a lot of arm pads we tested. 

Armrest depth adjustment
Armrest width adjustment

The Diffrient Smart chair was purposely designed with only a few functions. The idea behind the chair is to have a minimalist design that requires only a couple adjustments for you to be comfortable. Humanscale wants you to be able to get in the chair and be comfortable and ready to work right away. While the thought process is good, it leaves very little room for you to customize the chair.

The Diffrient Smart chair comes standard with two adjustments: seat height and seat depth. You can add adjustable arms, but there are no other adjustments available. The most notable adjustments missing are back height, adjustable lumbar, tilt lock and tilt tension.

Height adjustment function
Seat depth adjustment

The recline function also acts differently than most office chairs. Most chairs have a rocking function. Whether it is a swivel tilt mechanism, knee-tilt, synchro-tilt, etc., most office chairs give you the ability to rock back and forth in the chair. That is not the case with the Diffrient Smart. When you recline the backrest, the seat moves but it does not keep you in the same position to simply rock back. Instead, it pushes the back of the seat up. If you recline the back far enough the top of the seat will actually contact the bottom of the backrest.

Tilt adjustment function

This is a much different feeling than most office chairs and takes a bit of time to get used to. The idea is to open your hips as you recline, which is thought to be an improved posture to the standard rocking motion. If you are looking for a chair that has a normal rocking function, then the Diffrient Smart is not a good option for you.

The Diffrient Smart has good quality casters. They look nice and stand out more so than competing chair models. They are large, at 2.75” in diameter. They are dual wheel and work smoothly. The inside of the wheels are black and the outside of the wheels are grey.

Diffrient Smart wheels

There are two different options to choose from. There are standard carpet casters, which will be good for medium to low pile carpets. There are also soft casters, which are ideal for hard surfaces. 

There is only one mechanism option available on the Diffrient Smart chair. It is a weight sensitive mechanism that automatically adjusts to the person that is sitting in the chair.

Upholstery Options

You have quite a few options for the backrest mesh. Each option will be the same tri-panel construction, but you have five different pattern designs to choose from. Each pattern has a few different color options. In total, you have 23 different mesh back options. Each choice is the same price.

Pushing hand into mesh material

You will have even more customization for the seat upholstery. There are seven different textile types to choose from ranging from standard fabrics to vinyls to real leather options. Each textile type has different color options. In total, you will have 57 different seat upholstery options to choose from. The prices will vary depending on which textile you choose. The upcharges range from $30 all the way up to $900+.

Close up of seat upholstery

The seat textiles are all commercial grade and have been tested to exceed 150,000 doubles rubs so they are built to last. Humanscale does not use adhesives to attach the upholstery to the seat cushion. This helps to prevent wrinkling.

Finish Options

Humanscale offers three different finish options on the Diffrient Smart chair. The first is a black frame with black trim. The finish is matte so there will be no shine.

The second option is a black frame with a polished aluminum trim. This will change the u-shaped back frame to a polished aluminum and the top of each base leg will have a white accent. The main chair finish is a matte black. This option comes with an $84 upcharge.

The final option is a dark grey frame with polished aluminum trim. This will be similar to the previous option, with the u-shaped back frame being polished aluminum. But, the main finish of the chair will be a matte dark grey. The top of each base legs has a white accent strip. This options also comes with an $84 upcharge.

Cylinder Options

There are several different cylinder options on the Smart chair. The standard cylinder is called a Standard 5” but it actually has 4.25” of adjustment range. It goes from 16.5”-20.75”. This is the most commonly used cylinder and will fit the 5th to 95th percentile of people.

The next cylinder option is for shorter people. There is a Low 3.75” cylinder but the actual adjustment range is 3”. It moves from 14.875”-17.875”. This will be a nice option for people that are around 5’4” and under. This cylinder is a $25 upcharge.

The next cylinder option is designed for taller people. It is called the Tall cylinder and has a 5” adjustment range from 17.625”-22.625”. This will be a nice option for people that are around 6’2” or over. This cylinder is a $35 upcharge.

There are also a couple specialty cylinder options. The first is called a 3” Return to Height cylinder. This cylinder will have an adjustment range of 2.625” going from 17.125”-19.75”. The unique thing about this cylinder is that it returns to its tallest height after you get up from the chair. The Return to Height cylinder costs an extra $42.

The final cylinder option is called the High 8” cylinder, which also comes with a footring. This cylinder will have an adjustment range of 7.5” going from 20.75”-28.25”. The upcharge will range from $95-$165, depending on the size of the footring you choose. 

Designing products with the environment in mind is something that Humanscale focuses on. Each chair has a modular design, which allows you to easily replace parts instead of the whole chair. The Diffrient Smart is made from recyclable components. The packaging is almost entirely recyclable as well. The Diffrient Smart chair has received a few certifications for its materials and indoor air quality. Those certifications are: GREENGUARD Indoor Air Quality, GREENGUARD Gold and level® 2 certified.

The Smart chair also comes in a Smart Ocean version for those of you that have the environment as a top priority. Humanscale has partnered with Bureo to create a version of the Diffrient Smart chair that is made from discarded fishing nets that are polluting the oceans. The nets are recycled and turned into plastic to be used to make the Diffrient Smart Ocean. 

What Do I Like? 

Made in USA with high-end build

The Diffrient Smart has good quality parts and it is made in the USA. It has a high price point, but you know where the money is going. The chair is high-end and built for the long haul.

Good seat comfort

I think the seat will be comfortable for most people. It has a subtle contour and provides good support. It is not plush but not so firm that it becomes uncomfortable after short periods.

Good back support

The lack of any of back adjustments didn’t hold the Smart chair back from nabbing a top three score for back support. The tri-panel mesh and pronounced lumbar curve make the backrest comfortable and supportive.

Strong warranty

Having a high-end chair doesn’t mean much if it breaks and you have no coverage. That won’t be a problem with the Diffrient Smart. It comes with one of the best warranties in the industry so you can be confident that you will have a working chair for many years to come. 

Ships almost fully assembled

The Diffrient Smart chair arrives basically fully assembled. This was fantastic to see when the chair arrived. High-end chairs are often complicated pieces of furniture, so not having to deal with any installation was really nice.

Environmentally friendly

The Diffrient Smart chair is one if the more environmentally friendly chairs on the market. You can also take environmentally friendly to the next level by going with the Diffrient Smart Ocean. 

What Don’t I Like? 

Very little adjustability

I think the biggest downside to the Diffrient Smart chair is its lack of adjustments. The chair can come with as few as two adjustments. A chair that is self-adjusting is great if it fits you comfortably, but it is tough to make a chair that is going to be comfortable for everyone’s taste without the ability to tweak and change it.

Recline may not be comfortable

I am not a fan of the way that the seat moves when you recline the backrest. I prefer a chair that has a rocking motion. I am not always typing or tasking, so there are times that I want to just sit back and relax. I think the Diffrient Smart is best suited as a task chair and not the best option for relaxing or kicking back.

Not a good option for people over 6’2”

The Diffrient Smart chair is not a good option for people over 6’2” because of the arm height issues discussed earlier. They simply do not go high enough for tall people. The chair will still work if you do not plan on using arms, but if you do want good armrest support, then I would look for an alternative option. 

Bottom Line

The Diffrient Smart chair placed high on our list of the best office chairs for 2021 but it was not perfect. The chair costs around $1,000 and you get very little adjustability. You cannot adjust the backrest, lumbar, tilt tension and there are no lockable positions. This chair is not the best option for people that like to rock back and forth and the arms are not going to work for people over 6’2”.

Even with these downsides, I think the Diffrient Smart chair is a great task chair. It is Made in the USA and has high quality components. They are backed by a solid warranty and the chair is environmentally friendly. It has good back support, a comfortable seat and armrests that feature good adjustability and soft arm pads. It also has numerous upholstery and color options.

The Diffrient Smart chair is a nice alternative, to chairs like the Aeron, for people that don’t like mesh seats or would like a broader color selection. If you are looking for a high-end task chair, with a design oriented focus, then I would definitely recommend adding the Diffrient Smart chair to your list of potential candidates.

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