Top 10 Most Common Ventilation Problems (and How to Fix Them)
🔧 Top 10 Most Common Ventilation Problems (and How to Fix Them)
Published by: Ventilation Superstore
Updated: October 2025
Even the best ventilation system can run into issues if it’s not correctly installed or maintained.
From noisy fans to damp rooms, these problems affect both air quality and energy efficiency — and often signal that your system needs a simple adjustment rather than a full replacement.
Let’s look at the 10 most common ventilation problems and how to fix them like a pro.
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Poor Airflow
The problem: Some rooms feel stuffy while others are well-ventilated.
The cause: Blocked ducts, dirty filters, or undersized fans.
How to fix:
- Clean or replace filters regularly.
- Check ducting for kinks or crushed sections.
- Upgrade to a higher-capacity fan if airflow remains weak.
Tip: Always balance air supply and extract rates to ensure even distribution.
Condensation on Windows and Walls
The problem: Moisture builds up on glass and cold surfaces.
The cause: Inadequate extraction in kitchens or bathrooms, or insufficient airflow in winter.
How to fix:
- Run extractor fans longer after cooking or bathing.
- Install humidity-sensing fans or MEV/PIV systems.
- Increase background ventilation through trickle vents or grilles.
Mould and Mildew Growth
The problem: Black spots on walls or ceilings.
The cause: Excess humidity and stagnant air.
How to fix:
- Ensure continuous ventilation in affected areas.
- Treat existing mould with a safe biocide.
- Consider an MVHR system for whole-home moisture control.
Noisy Ventilation Units
The problem: Fans or ducts create rattling or humming noises.
The cause: Loose fixings, worn bearings, or vibration through walls.
How to fix:
- Tighten screws and brackets.
- Fit anti-vibration mounts or acoustic ducting.
- Replace worn fans or motor components.
Pro tip: Mount fans on solid surfaces, not plasterboard, to reduce vibration noise.
High Energy Bills
The problem: Your ventilation system seems to use too much electricity.
The cause: Old fans, blocked filters, or systems running continuously at full speed.
How to fix:
- Install energy-efficient EC motors.
- Add timer or humidity controls.
- Clean filters and ducting for smoother airflow.
Upgrade option: An MVHR system can recover up to 90% of heat and cut energy waste.
Bad Odours That Won’t Go Away
The problem: Persistent smells in kitchens, bathrooms, or offices.
The cause: Ineffective extraction or recirculated stale air.
How to fix:
- Deep-clean ducts and fan blades.
- Replace carbon or grease filters.
- Ensure air inlets and outlets are unblocked and correctly positioned.
Uneven Room Temperatures
The problem: Some rooms are too warm, others too cold.
The cause: Poor air balance or duct layout.
How to fix:
- Adjust dampers or diffusers to balance flow.
- Re-seal leaky ducts.
- For MVHR systems, ensure the heat exchanger and sensors are functioning correctly.
Dust Build-Up and Poor Air Quality
The problem: Visible dust even with regular cleaning.
The cause: Dirty filters or outdoor air entering unfiltered.
How to fix:
- Replace filters every 3–6 months.
- Use high-quality ePM1 or HEPA filters in MVHR systems.
- Keep vents clear and inspect for leaks in duct joints.
Draughts or Cold Air Coming from Vents
The problem: Uncomfortable cold air entering rooms.
The cause: Poor insulation or missing backdraft dampers.
How to fix:
- Check for missing or faulty dampers.
- Insulate ducts passing through cold spaces.
- Fit insulated diffusers or adjust fan speed.
Fan or System Not Working at All
The problem: No power, no noise, no airflow.
The cause: Electrical fault, blown fuse, or blocked motor.
How to fix:
- Check power supply and fuses.
- Inspect motor connections and switches.
- If wiring looks damaged, call a qualified electrician or HVAC engineer.
🧰 Preventative Maintenance Tips
- Clean or replace filters regularly.
- Check ducts and vents for blockages twice a year.
- Listen for unusual noises and fix them early.
- Schedule professional servicing annually for larger MVHR or MEV systems.
Consistent maintenance keeps your system efficient, quiet, and long-lasting.
Final Thoughts
Ventilation problems are common — but with regular care and the right equipment, they’re easy to fix.
Whether you’re tackling condensation, noisy fans, or poor air quality, a modern ventilation system from Ventilation Superstore can make all the difference.
👉 Browse our range of fans, ducting, and MVHR systems today to restore fresh, healthy air throughout your property.
