Both impeller and agitator washers load from the top, but they clean clothes in almost opposite ways. Here’s how to tell which one you own, how each fails, and which fits your household best.
What an agitator washer does
An agitator is the tall center post you probably picture when you think “washing machine.” It has fins or vanes running up its length, and it twists back and forth during the wash cycle, physically shoving clothes against each other and against the sides of the tub. That mechanical rubbing action is aggressive and effective at loosening heavy, ground-in soil, which is why agitator washers have historically been the choice for work clothes, cloth diapers, and heavily soiled loads.
The tradeoff is capacity and fabric wear. The post takes up a meaningful chunk of the tub’s usable space, and the physical agitation is harder on delicate fabrics over time than a gentler wash action would be. Agitator washers also tend to use more water per cycle, since clothes need to be fully submerged for the agitator to work them properly.
What an impeller washer does
An impeller is a low-profile cone or disc, sometimes with small fins, mounted flat at the bottom of the tub with no center post. Instead of physically shoving clothes, it spins to create currents and friction in the water, and clothes rub against each other as they’re pulled through that current. There’s more usable tub space with the post gone, and impeller washers generally use less water since they don’t need clothes fully submerged to work.
The tradeoff runs the other direction. Impeller washing is gentler, which is good for fabric care but can leave heavily soiled items needing a pretreatment or a longer cycle to get fully clean. Impeller machines can also be more prone to unbalanced loads twisting into a lopsided pile rather than tumbling loose the way an agitator load does, which shows up as longer cycles or extra rebalancing spins.
How to tell which one you have
Open the lid and look at the bottom of the tub. A tall center post running most of the height of the tub is an agitator. A short, low disc or cone sitting flush with the tub floor, sometimes barely a few inches tall, is an impeller. If there’s nothing at all, no post and no low disc, you likely have a front-load washer instead, which uses a completely different tumbling action and doesn’t fall into either category. Front-load washers spin the entire drum on a horizontal axis, lifting and dropping clothes through the water rather than agitating or spinning a plate beneath them; we cover that comparison separately in our top-load versus front-load guide.
How each one tends to fail
Agitator washers most often fail at the drive block, sometimes called the agitator dogs, a set of small plastic or nylon pieces that let the agitator engage with the transmission during the wash stroke but disengage during spin. When these wear out, the agitator spins freely without actually moving, or doesn’t move at all. A technician confirms that with the model procedure; it is not a frequency ranking for this brand. Beyond that, agitator machines share wear parts with other top-load washers: water inlet valves, lid switches, and drive belts.
Impeller washers don’t have a drive block to wear out, since there’s no agitator to engage and disengage. Instead, owners often report unbalanced loads that trigger extra rebalancing, and clothes tangling into a twisted mass, especially bulky towels or sheets washed alone. Mechanically, impeller machines still rely on water inlet valves, drain pumps, and bearings. A technician confirms which of those, if any, has failed.
Which one makes sense for your household
If you regularly wash heavily soiled loads, work clothes, sports uniforms, or cloth diapers, an agitator’s mechanical scrubbing action tends to get them cleaner in a single cycle. If you’re washing mostly everyday laundry and want lower water use, more usable capacity, and gentler handling of delicate fabrics, an impeller machine may fit better. Which design is on the showroom floor still depends on the brand and the year you shop. Ask for the wash action you want rather than assuming the lineup has already moved.
For repair on either type, see our washing machine repair service page.
Frequently asked questions
How do I know if my washer is impeller or agitator without a manual?
Open the lid and check the tub floor. A tall center post means agitator. A short, flat disc or cone means impeller. No post or disc at all usually means it’s a front-load washer instead.
Do impeller washers clean as well as agitator washers?
For everyday laundry, yes, though it may take a slightly longer cycle. For heavily soiled items, an agitator’s physical scrubbing action generally gets them cleaner faster, since it’s a more aggressive mechanical process.
Why does my impeller washer sound like it’s rebalancing constantly?
Impeller machines are more sensitive to unbalanced loads than agitator washers, since there’s no center post helping distribute clothes evenly. Try washing bulky items like comforters or single large towels separately, and distribute mixed loads more evenly around the tub before starting.
Can I convert an agitator washer to an impeller washer?
No. The tub, transmission, and drive components are built specifically for one style or the other. Switching mechanisms means replacing the washer, not modifying the existing machine.
When to call us
Call us if your agitator isn’t engaging, your impeller washer keeps failing to balance loads that seem evenly distributed, or either type is leaking, not filling, or not draining properly. Call (858) 988-7787 and we’ll match you with a technician.