The Concept2 Model D is the ultra-popular air rower that you’ll see at most gyms. It is one of the best home indoor rowers you can buy period. Expertly constructed and ergonomically unequaled, this rowing machine looks great and rows smoothly without so much as a jarring catch. As an air rower, the Concept2 employs air baffles to create the resistance. A nickel-plated chain pulls the flywheel and you get your workout by pulling against the increasingly higher air pressure that the fan is creating.
The water flywheel is comprised of two paddles encased in an enclosed tank of water. As you pull the cable, the paddles move through the water creating resistance. The beauty of this machine is it uses the mass/density of water. The paddles create the drag, so the harder you pull, the more resistance increases. Think about moving your hands through water. The faster you go, the more dense water feels. The slower you go, the less you feel the resistance. And this type of resistance is excellent for your joints. Click here to read the full review.

The Challenge AR has the capability to allow the rower to control and adjust the resistance from “Feather light” to “Olympic sprint” delivering a silky smooth resistance to the user’s effort and instantaneous response to input with no “flat sport”.  With water resistance being the most accurate manner in which to simulate actual outdoor rowing, the Challenge AR provides a smooth and consistent sensation throughout the range of motion of the exercise experience.  

On theme with C2’s interchangeability, models D or E are essentially the same machine. When we talk about one we’re talking about both. The Concept 2 E is just 8 pounds heavier but is made out of stronger stuff all around — what’s plastic on the model D is aluminium on the model E, and what’s aluminum on the model D is welded steel on the model E. The only noticeable variations are seat height and display position.
Most people who are new to the sport of rowing have difficulty achieving low strokes rates while trying to obtain their desired intensity – there are many comments such as “it does not feel hard enough?” or “how can I make it harder?” Rowing is about ratio and rhythm and you need to focus on a long stroke length and a powerful drive phase (push with the legs and pull with the arms). Give yourself time to learn this, it can take a few weeks before you start to feel the intensity at low stroke rates.
The overall rowing experience encompasses pulley, seat, and — of course — resistance. Air and water have very distinct qualities, making them impossible to compare but interesting to contrast. Air stores inertia, which feeds into intense, constant effort during a goal-oriented workout. Water’s more sluggish drag makes for demanding exercise, but one that’s less consistent.

Being able to easily store your rower is a huge plus. Make sure you investigate how well the machine stores, if it folds up or comes apart easily to be able to put it in your closet, or in other storage areas. As an example, the Concept2 Model D rowing machine folds up nicely by a simple pull pin located in the middle of the rower. Wheels on the bottom allow for easy moving.
The WaterRower Classic is hand crafted in solid American Black Walnut. Like all woods, Black Walnut may vary in color from a rich brown to purple-black. Each machine has been hand finished with three coats of Danish Oil giving a deep lustre an warmth to the wood. Wood has been chosen due to its marvellous engineering properties, primary amongst these is its ability to absorb sound and vibration enhancing the WaterRower's quietness and smoothness of use. Black Walnut, like all woods used in WaterRower construction, is a premium hardwood with incredible longevity and dimensional stability. For reasons of ecology, all our woods are harvested from replenishable forests.

From a fitness perspective, the WaterRower Classic works 84 percent of your muscle mass, helping tone and strengthen your muscles while burning far more calories than most other aerobic machines. The exercise is also low impact, as it removes all the body weight from the ankles, knees, and hips, but still moves the limbs and joints through a full range of motion--from completely extended to completely contracted.
No matter the resistance we set or the power we applied, the machine remains sturdy, centered, and even. We amped up the intensity for 2000m sprints and found that the C2 supports consistent effort in a way water resistance can’t. The machine assists in keeping your intensity uniform, because it stores up remaining energy in the spinning flywheel. Comments about the ride feel of both Concept 2s were noticeably brief. As one tester put it, “It’s unremarkable because it’s good,” and leaves you free to focus on the effort you’re putting into your workout.
Other details include dual rails with four corner wheels that increase seat stability and reduce the amount of sweat buildup; a frame that flips upright for handy storage; and a weight capacity of up to 1,000 pounds. The WaterRower Classic measures 84 by 21 by 22 inches (W x H x D), weighs 117 pounds (with water), and carries a one-year warranty on the frame and components (WaterRower will upgrade the warranty to five years on the frame and three years on the components with the completion of a registration form).
Essentially, the water rower uses water as it's resistance and the air rower (click here to read our air rowing machine reviews) uses air resistance. Additionally, the resistance of the water gives a very similar feeling to actually rowing in the water. The rowing machines listed above all have fantastic rowing mechanisms that mimic the exact feeling of a rowing a boat.

Both the air rower and water rower machines are very popular choices of rowing equipment, particularly the former type. They have been around in the 80s, and many consumers and those that have tried them in gyms consider the equipment to be the best type ever. These air resistance equipment, often regarded as Ergometers, is the standard base model for indoor rowing sport.
There is much to love about the WaterRower--and I do love it--but I would echo others' comments that although the seat rolls solidly and smoothly on the wood rails, the seat itself is very hard (I use a gel seat pad I bought for my hard fiberglass kayak seat), and the footpads are in need up rethinking and upgrading--the cheap plastic doesn't let you row in socks or barefoot and is not really worthy of a machine that is otherwise a stunning piece of engineering and a beautiful one as well. As one other person noted about his machine, my machine made a clicking noise on the return stroke, so I had to adjust the wheel underneath the top rail that connects to the footpad and pull it away gently from where it was rubbing against another component. Also, be warned: the instruction booklet is in the DVD case. I did not see the little sticker on the case telling me that, thinking I'd wait to watch the DVD until after I'd assembled it. But WaterRower has a copy of the assembly instructions on their website, along with a video (I found the written ones better and easier to follow), so I was able to assemble it with no difficulty.
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