TL;DR
A vacuum that has lost suction on carpet is almost always restricted, not broken -- in most cases it is a full bin, a loaded filter, a clogged hose, or a blocked floor head. Walk the airflow path in order from the carpet to the exhaust and you will find the restriction in a few minutes. Motor failure is rare and usually announces itself with noise or smell.
Think of It as One Air Path
Air enters at the floor head, travels through the neck or hose, drops into the bin or bag, passes through one or more filters, goes past the motor, and exits at the exhaust.
Anything narrowing that path anywhere reduces suction everywhere. It does not matter whether the restriction is at the beginning or the end -- the whole system slows down.
So the fix is not guesswork. Start at the carpet and work toward the exhaust, checking each stage. The first thing you find that is blocked, loaded, or leaking is almost certainly the answer.
Why Does My Vacuum Have No Suction on Carpet?
Because something is restricting the airflow. The usual culprits, in order of frequency, are a full bin or bag, a loaded filter, a clog in the hose or neck, debris jammed in the floor head opening, hair wrapped around the brush roll, or an air leak at a seal. Motor failure is uncommon.
Step 1: The Bin or Bag
A bagless bin should be emptied at roughly two-thirds full. Past that, debris packs against the pre-filter and chokes airflow while the bin still looks like it has room. Hair is worse than dust because it mats.
A bag should be changed when it feels firm or the indicator trips, not when it is bursting. Bags restrict progressively as the media loads, so a bag at capacity is costing real performance.
Step 2: The Filters
The most common cause of a gradual decline that people mistake for age.
Fine dust loads filter media over weeks, and airflow drops a little at a time. Washable foam and mesh filters usually rinse clean; pleated and most HEPA elements are tapped or replaced. Getting this wrong ruins the filter, so check the type first -- the full routine is in how to clean a vacuum filter.
Do not skip the pre-filter. On bagless machines it sits between the bin and the rest of the machine and is often the dirtiest part of the vacuum.
Step 3: The Hose and Neck
If bin and filters are clean, look for a blockage.
The quick test: pull the hose off both ends and drop a coin through it. If the coin falls straight out, the hose is clear. If it stops, you have found your clog and its rough location.
Clogs collect at bends, at the base of the neck on an upright, and at the wand joint. Socks, tissue, string, and clumps of matted hair are the usual finds. The safe removal methods are in how to clear a clogged vacuum hose.
Source: IICRC S100 carpet cleaning standard, equipment maintenance guidance
Step 4: The Floor Head
Turn the machine over and look into the intake opening.
Debris wedged across the throat of the head is common and easy to miss, because you have to look at the right angle. Coins, bottle caps, pen lids, and compacted lint all lodge there.
While you are there, check the brush roll. Hair and thread wrapped tightly around it slow the roll and raise its effective diameter, so the head sits differently on the carpet. Cut it free with scissors, and clear the end caps, which collect packed hair that binds the bearings.
Step 5: Brush Height
This one surprises people because it does not feel like a restriction.
A brush roll set too low buries itself in the pile and seals the head against the carpet. With no gap for air to enter, the machine strains and pickup falls -- exactly the symptom of a clog, from a completely different cause.
The tell is a machine that is very hard to push and whose motor pitch rises on carpet but sounds normal on hard flooring. Set it correctly with the paper test in how to set vacuum brush height.
Step 6: Leaks
Air is lazy and takes the easiest route. If there is a gap in the housing, the motor draws air through it instead of through the carpet.
Run the machine and move an open hand slowly around the bin door, the hose cuffs, the neck joint, and any seams. A noticeable stream anywhere other than the exhaust is a leak. Cracked housings, hardened gaskets, and loose hose cuffs are the usual sources, and the testing method is covered in what a sealed system means.
When Suction Is Fine and Pickup Is Not
These are two different faults, and confusing them wastes time.
If the machine sounds strong, the hose has good pull, and carpet still looks poorly cleaned, the problem is agitation rather than airflow. That points at a slipping or broken belt, a brush roll that is not turning, or worn bristles. Start with how to replace a vacuum belt.
Worn bristles are the quiet version. A roll whose bristles have gone soft or short still spins and still looks fine, but it no longer flexes the fibers enough to release grit.
When It Really Is the Motor
Rare, but it happens, and it usually signals itself with a change in sound -- grinding, screeching, or a rattle -- often alongside a hot electrical smell. Motors wear their carbon brushes out over years, and bearings fail. A machine run repeatedly with a blocked airflow path has been running hot, which shortens its life.
At that point, weigh the repair against the machine. On a serviceable vacuum with available parts, a motor replacement can be worthwhile. On a machine with no parts support, it is the end.
FAQ
Why did my vacuum suddenly lose suction?
A sudden loss almost always means a blockage. Check the floor head opening, then the hose using the coin test, then the bin. A gradual loss over weeks is more likely a loading filter.
How do I find a clog in my vacuum?
Separate the machine into sections and test each one. Drop a coin through the detached hose -- if it falls out, that section is clear. Look into the floor head intake at an angle, and check the neck where the head meets the body.
Can a dirty filter cause loss of suction?
Yes, and it is the most common cause of gradual decline. Fine dust loads the media over weeks and restricts airflow steadily. Clean washable filters and replace non-washable ones on schedule to restore most of the original performance.
Why does my vacuum have suction but not pick up carpet?
That is an agitation problem, not an airflow one. The brush roll is likely not turning because of a stretched or broken belt, or its bristles are worn down and no longer flex the fibers enough to release grit.
Does a full bag really reduce suction?
Yes. Bags restrict progressively as the media loads, so performance falls long before the bag is physically full. Change it when it feels firm or the indicator trips rather than waiting for it to be packed.
Should I fix or replace a vacuum with no suction?
Fix it first -- most cases are a bin, filter, hose, or head restriction and cost nothing. Replacement only makes sense when the motor has failed or the housing is cracked on a machine with no available parts.
When the whole floor needs it rather than one spot, professional carpet cleaning is the wider option.
Restoring airflow gets your vacuum removing soil again, but nothing dry lifts the film bonded into traffic lanes. Otesse is local, prices upfront with no hidden fees, books online, and sends background-checked crews. Get a quote when the carpet needs a reset.