Direct answer: Most HRV condensation drips come from a blocked condensate drain, a sagging or disconnected drain hose, dirty HRV filters that slow airflow, or cold surfaces sweating because the unit is moving the wrong amount of air. First figure out whether the water is dripping from the HRV cabinet itself or from nearby ducting.
Most likely: The most common fix is clearing the HRV condensate drain path and cleaning or replacing clogged HRV filters so water can leave the unit instead of pooling and spilling.
If you catch this early, it is usually a wet-service call, not a major rebuild. Reality check: a little moisture inside an HRV during cold weather is normal, but drips outside the cabinet are not. Common wrong move: wrapping random tape or insulation around the wet spot before you confirm where the water is actually starting.
Don’t start with: Do not start by replacing motors or controls. On this symptom, water usually points to drainage, airflow, insulation, or setup before it points to an electrical part.
A puddle forms under the unit, or water hangs from the cabinet seam or service door edge.
Start here: Start with the condensate drain pan and drain hose. A clog, sag, or loose connection is more likely than a failed component.
The cabinet looks mostly dry, but beads of water form on the outside of metal duct close to the HRV.
Start here: Start by separating duct sweating from an internal leak. Check insulation, room humidity, and whether airflow seems weak or unbalanced.
The problem gets worse during freezing outdoor temperatures and may improve on milder days.
Start here: Look for partial drain blockage, ice buildup inside the unit, or restricted airflow from dirty HRV filters.
Fans run and the HRV exchanges air, but water still escapes the unit.
Start here: That usually points to water not leaving fast enough, not to a dead motor. Inspect the drain path, pan slope, and filter condition before anything else.
Condensation is supposed to collect and leave through the drain. When the hose or trap plugs with slime, dust, or debris, water backs up and spills out of the cabinet.
Quick check: With power off, inspect the drain outlet, hose, and trap for standing water, kinks, sludge, or a low spot that stays full.
Restricted airflow can make the core run colder, increase moisture buildup, and let water collect faster than the drain can handle.
Quick check: Pull the HRV filters and look for heavy dust, pet hair, or a gray felted surface that blocks light and air.
If warm indoor air meets a cold, uninsulated, or poorly sealed duct surface, water can bead on the outside and look like the HRV is leaking.
Quick check: Wipe the cabinet dry, then watch where fresh droplets appear first. If they start on the duct jacket or bare metal, the problem is outside the unit.
When airflow is off, defrost is not working right, or the unit is installed out of level, moisture can collect in the wrong place and overflow.
Quick check: Look for frost, ice, or water trails inside the cabinet, and check whether the unit appears level and the fans sound even.
You do not want to chase a cabinet leak when the real problem is sweating duct, and you do not want to insulate duct when the drain is overflowing inside the HRV.
Next move: Once you know the starting point, the rest of the checks get much faster and you avoid replacing the wrong thing. If everything is already soaked and you cannot tell where it begins, shut the unit back off and move to the drain and filter checks anyway. Those are still the most common causes.
What to conclude: Cabinet-origin water usually means drain, pan, ice, or internal airflow trouble. Duct-surface water points more toward insulation, room humidity, or balance issues.
A restricted drain is the most common reason an HRV drips. It is also the safest, least destructive thing to check first.
Next move: If the dripping stops and water now leaves through the hose, the problem was a blocked or poorly routed drain path. If the pan still fills, the hose is clear, and water still escapes the cabinet, move to the filter and airflow checks.
What to conclude: A clear hose with continued overflow usually means the unit is making too much condensate for current airflow or the water is not reaching the pan correctly because of ice, tilt, or internal blockage.
Dirty HRV filters are a common reason for excess moisture, icing, and poor drainage. This is often the second half of the fix after clearing the drain.
Next move: If airflow improves and the dripping stops, restricted filters were likely causing the moisture buildup. If clean filters do not change the symptom, inspect for ice, level, and duct sweating next.
These two problems look similar from the floor, but the fix is different. Ice inside the HRV points to airflow or defrost trouble. Water on the outside of duct points to insulation, sealing, or humidity.
Next move: If you confirm the water is only on the outside of duct, you have narrowed it to a duct condensation problem instead of an HRV cabinet leak. If the cabinet still leaks after thawing, draining, and cleaning filters, the unit likely needs airflow balancing or internal service.
By this point you should know whether this was a simple maintenance problem, a duct condensation issue, or a service-level airflow problem.
A good result: No new water under the unit and no fresh droplets on nearby duct after several run cycles means you found the right fix.
If not: If dripping returns quickly after these checks, stop guessing on parts and have the unit tested and balanced.
What to conclude: A repeat leak after the basic fixes usually means the problem is not a homeowner-cleaning issue anymore.
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Yes. In cold weather, some moisture inside the HRV is normal. What is not normal is water dripping outside the cabinet, pooling under the unit, or forming repeatedly on nearby finished surfaces.
Cold outdoor air makes the heat-recovery process produce more condensate. If the drain is partly blocked or airflow is restricted by dirty HRV filters, winter conditions make the problem show up fast.
Yes. Dirty HRV filters can choke airflow enough to increase moisture buildup and sometimes contribute to icing. That extra water can overwhelm the drain path or end up where it should not.
Dry everything first, then watch where fresh droplets appear. If the cabinet and drain area stay dry but the outside of nearby metal duct gets wet, that is usually duct sweating rather than an internal HRV leak.
Not based on dripping alone. A blocked drain, dirty HRV filters, duct sweating, or airflow imbalance is much more common. The core is not a first-guess purchase on this symptom.
Call if the drain is clear, the HRV filters are clean, and the unit still leaks, ices up, or seems out of balance. Also call right away if water is reaching wiring or causing ceiling, wall, or insulation damage.