That musty smell that always comes back, even after a big cleaning, is annoying. We immediately think of the range hood, and that's a valid lead, but it's only one possible cause among others. In a house or bungalow that is 25 years old or more, kitchen humidity can come from cooking, limited ventilation, condensation, or a hidden water source. Before replacing anything, the best approach is to check methodically. At Solutions Rénovation Québec (SRQ), we carry out renovation work that corrects the cause, not as a specialized air quality diagnostician: this nuance matters for what follows.
Why does a kitchen retain a smell of humidity?
A kitchen is the most humid room in the house after the bathroom. We boil, simmer, heat water, and run the dishwasher there. All of this releases steam.
When this steam is not properly evacuated, it condenses on cold surfaces and accumulates in materials. Over time, it ends up smelling. The smell is not the problem; it is the symptom of excess humidity looking for a way out.
In other words: humidity accumulation, then risk of deterioration or mold, then persistent odor. Tracing this chain back to the source is the whole challenge.
Cooking and the dishwasher produce steam
Boiling a pot releases liters of water into the air as steam. Add the hot water from the dishes and the dishwasher's drying cycle, which releases humid heat every time the door is opened too early.
In a well-ventilated kitchen, this humidity goes outside. In a poorly ventilated kitchen, it stays, settles on cabinets, walls, and windows, and feeds a stubborn odor. The ordinary daily action becomes a cumulative problem.
Leaks and condensation can be hidden
Not all humidity odors come from steam. Sometimes it is a discreet leak. Take a look under the sink, around water pipes, behind the dishwasher, near windows, and behind low furniture where air circulates poorly.
In the Quebec context, freeze-thaw cycles stress the building envelope and can promote infiltration. Be careful, however: this is not the automatic cause of a kitchen odor. It is a regional risk factor, an element to check, not a conclusion.
Does the kitchen range hood really evacuate humidity?
Here is the heart of the misunderstanding. Many people believe that their range hood evacuates humid air outside, when in fact it only recirculates it in the room.
This difference changes everything when talking about humidity. A range hood can very well filter cooking odors while leaving the water vapor exactly where it was.
Recirculating range hood or range hood connected to the outside?
A recirculating range hood draws in air, passes it through a filter (often charcoal), then sends it back into the kitchen. It captures some of the grease and odors, but it does not remove water vapor from the room. The humidity stays inside.
A range hood connected to the outside, on the other hand, evacuates humid air out of the house through a duct. It is this type of system that truly helps manage cooking steam. If your kitchen retains humidity, the first question to ask is simple: does your range hood evacuate outside, or does it recirculate the air on site?
What signs reveal insufficient extraction?
Even a range hood connected to the outside can malfunction. The usual culprits: filters clogged with grease, too low a flow rate, an improperly sized or too long duct, and an exterior damper blocked by frost, dirt, or a nest.
Some maintenance is within your reach: cleaning or replacing filters, clearing the accessible damper. But when the duct is difficult to access, poorly connected, or absent, a professional check becomes relevant. You don't guess at a duct hidden in a ceiling.
Flow rate, duct, and compliance
The extraction flow rate and connection rules matter as much as the range hood itself. The Quebec Construction Code contains requirements relating to range hoods and evacuation, but the edition and applicable provisions depend on the building and the type of work. Rather than citing an isolated figure as a universal rule, it is better to have verified what actually applies to your project before choosing or installing an appliance.
How to find the source: a step-by-step check
Before spending money on a new range hood, take an hour to investigate. An orderly approach saves you from replacing the wrong element.
Measure relative humidity
A hygrometer costs a few dollars and can be found at a hardware store. It gives you a concrete number. As a general reference, Health Canada recommends maintaining indoor relative humidity between 30 and 50%, to be adapted according to outdoor conditions and the building. In winter, if condensation runs down the windows, it is often a sign that you should aim for the lower end of this range. A reading is better than an impression.
Inspect possible sources
Review, one by one, the possible sources. The range hood: does it evacuate outside, are the filters clean? Traces of water: under the sink, around pipes, at joints? Windows: condensation, mold in the corners? The basement and the dryer vent, which can load the whole house with humidity.
Distinguish what you can see and clean yourself from what requires a specialist. Observing a stain under the sink is within your reach. Diagnosing a hidden duct, measuring humidity in a wall, or evaluating extensive mold is another matter.
When should an evaluation be requested?
If the smell persists despite your checks, if materials feel damp to the touch, or if the source remains elusive, it is time to have the situation assessed rather than replacing the range hood at random. A new range hood will not fix anything if the real problem lies elsewhere.
Are you planning work to correct a humidity problem in your kitchen? Contact SRQ to discuss the relevant renovation work.
Why can Lévis's climate complicate the problem?
Lévis has its particularities: harsh winters, a wide temperature range, and a housing stock where many buildings are several decades old. All of this weighs on humidity management.
Older homes, Quebec winters, and airtightness
Bungalows and older homes often have limited ventilation, designed for another era. Colder windows promote condensation, and humid kitchen air has fewer ways to escape.
Paradoxically, recent renovations can accentuate the phenomenon. By making the house more airtight (new windows, insulation, weatherstripping) without adjusting ventilation, moisture that once escaped through air leaks becomes trapped. A more efficient home can therefore become more humid if ventilation does not keep up.
Is the St. Lawrence River responsible?
Proximity to the river is part of the regional landscape, and outdoor humidity varies with the seasons. But living near the river is not proof that it is the culprit behind your kitchen smell. It is context, not a diagnosis. The cause is almost always found inside the house itself: ventilation, condensation, or a leak.
Before undertaking work, identify the probable cause and the interventions actually needed.
Which solutions to choose depending on the cause?
Once the source is identified, the solution becomes logical. It is not the same depending on whether it is an outdated range hood, insufficient overall ventilation, or damage to be repaired.
When maintaining or replacing the range hood is enough
If the problem is limited to cooking, sometimes it is enough to clean the filters, clear the duct, properly connect the range hood to the outside, or install a better-sized unit. In these cases, the problem is fixed at the source without major work.
When to assess the home's overall ventilation
If humidity is high throughout the house, not just in the kitchen, the problem goes beyond the range hood. A heat recovery ventilator (HRV) can then renew the air in the entire dwelling. This is a possible solution when overall ventilation is deficient, not an automatic replacement of the range hood: the two have distinct roles.
When renovation work is necessary
When humidity has left traces (damaged materials, finishes to redo), repair or restoration work becomes relevant once the source has been corrected. You repair after stopping the water, never before. And be careful: significant mold or the possible presence of asbestos in an older building require an adapted approach and qualified professionals, not a simple renovation.
For a residential renovation project in Lévis, request a no-obligation estimate from SRQ.
Why entrust the work to Solutions Rénovation Québec?
Our role is clear: once the cause of the humidity is identified, we take charge of the renovation work that corrects it, properly and in the right order. We don't present ourselves as ventilation or decontamination experts if that isn't the mandate: when a situation requires that type of specialist, we tell you.
SRQ holds RBQ license 5811-7821-01, has more than 10 years of combined experience and more than 500 completed projects. The five-year warranty on labour applies according to its terms, the on-site estimate is free, and each step (planning, execution, clean delivery) is explained to you without jargon or surprises on the invoice.
Call 418-476-1747 to discuss your renovation project.
FAQ: humidity and ventilation in the kitchen
Does a recirculating range hood eliminate humidity?
No. A recirculating range hood filters some of the grease and odours, but it returns the air to the room without removing water vapour. Only a range hood connected to the outside actually evacuates cooking humidity.
What humidity level should you aim for in a home in Quebec?
As a general reference, Health Canada recommends a relative humidity between 30 and 50%. In winter, aim for the lower end of this range: condensation on windows often indicates a level that is too high.
Why does my kitchen smell mouldy even after cleaning?
Because cleaning treats the surface, not the cause. If humidity remains trapped (poor ventilation, hidden leak, condensation), the smell returns. You need to find and correct the source, not just clean.
Can an air exchanger fix excessive humidity?
It can help when the ventilation of the whole house is insufficient, because it renews the air. But it does not replace a range hood that exhausts outside, and it does not correct a leak. It is one piece of the puzzle, not the only solution.
How can you tell if a leak is hiding under the sink?
Open the cabinet under the sink and look for traces of water, water rings, swelling of the back panel or a concentrated odour. Touch the connections: if they are damp, there is a leak to have checked.
When should a kitchen range hood be checked?
When the flow seems low, when steam stagnates despite the range hood, when the filters get dirty quickly or when you doubt the outside connection. If the duct is hidden or difficult to access, a professional check is required.
Does a persistent odour mean there is mould?
Not necessarily. The odour indicates excess humidity, but only an on-site check confirms the presence of mould. An odour that persists is still worth taking seriously.
When should you request an estimate from a renovation contractor in Lévis?
When the source is identified and correction or restoration work is necessary. A contractor like SRQ can then evaluate the relevant work and provide you with a detailed quote.
In the end, the winning reflex is always the same: correct the cause before replacing equipment or redoing surfaces. A new range hood or a nice paint job is useless if the humidity continues to accumulate. Find the source first, the rest will follow.