Quick Answer
Uneven heating in SE Melbourne homes is usually caused by closed dampers, blocked vents, or a clogged filter. Fix closed vents first (free, 5 minutes), then check your filter. If one room stays cold despite open vents, you may have a damper issue requiring a licensed HVAC technician ($150-300).
Why Ducted Heating Heats Some Rooms But Not Others
Ducted heating systems distribute warm air through a network of ducts and vents. When one room stays cold, the problem is almost always one of five things: a closed vent, a stuck damper, a clogged filter restricting airflow, an unbalanced system, or a duct leak. Most causes are fixable without a technician.
In SE Melbourne, homes in Berwick, Pakenham, and Officer often have older ducted systems installed during the housing estate booms of the 1990s-2000s. These systems can develop damper issues as they age, especially during the cold snaps that hit in June and July.
Step 1: Check Your Vents First (Free Fix)
Walk through every room and check the floor or ceiling vents. Each vent has a lever or dial that opens and closes the louvres. Make sure every vent you want heated is fully open. This is the most common cause of uneven heating and takes under 5 minutes to fix.
Step 2: Clean or Replace the Filter
A clogged return-air filter reduces total airflow, which means some rooms (usually those furthest from the unit) don’t get enough warm air. Clean the filter using a vacuum and compressed air. If it’s torn or extremely dirty, replace it ($20-40 from Reece). See our guide on cleaning ducted heating filters.
Step 3: Check and Adjust Dampers
Dampers are valves inside your ductwork that control airflow to different zones. On older systems, they’re manual—often a lever or dial accessible at the duct junction. On newer systems, they’re motorised and controlled by the thermostat.
Manual dampers: locate the duct access panel (usually in ceiling cavity or utility cupboard) and check if any dampers are partially closed. A damper that’s stuck closed will starve a room of heat.
Step 4: Check for Duct Leaks
Ducts that have come loose or developed holes leak warm air into the ceiling or under-floor space instead of into rooms. Signs: one area of ceiling feels warm, you can hear air escaping near the unit, or one branch of rooms is always colder. Duct repairs require a licensed HVAC technician.
Step 5: Balance the System Professionally
If your system heats some rooms well but consistently underserves others despite open vents and a clean filter, the system may be unbalanced. An HVAC technician can adjust damper positions across the whole duct network to equalise airflow—this costs $200-400 and is a one-time fix that lasts years.
Troubleshooting
| Symptom | Likely Cause | Fix |
|---|---|---|
| One room always cold | Closed vent or stuck damper | Check vent is open; call technician for damper |
| All rooms cold but system running | Clogged filter or thermostat issue | Clean filter; check thermostat settings |
| Rooms near unit warm, far rooms cold | System pressure imbalance or duct leak | Balance system professionally; check ducts |
| Heating works then stops | Thermostat or overheating cut-out | Check thermostat battery; call technician |
| Warm air from vents but room stays cold | Poor insulation or draughts | Draught-proof windows and doors; check ceiling insulation |
When to Call a Professional
Call a licensed HVAC technician if: you can’t locate or adjust dampers, you suspect duct leaks (requires specialist sealing), the system is more than 15 years old and uneven heating has worsened, or the thermostat is unresponsive. In SE Melbourne, service calls cost $150-300; duct rebalancing $200-400.
Tips & Gotchas
- Check all vents before calling a technician—it’s the most common fix and costs nothing.
- Don’t close vents in unused rooms. It raises system pressure and reduces efficiency.
- Clean the filter every 4-8 weeks during heating season. A clean filter improves flow to all rooms.
- Rooms on the south side of the house are always harder to heat in Melbourne winters. Check insulation in those rooms.
- Older homes in Dandenong and Berwick often have flex duct that sags and reduces flow. Ask technician to check.
- Thermostat placement matters. If the thermostat is in a warm room, the system may cut off before cold rooms reach temperature.
Frequently Asked Questions
Why is one room in my house always colder than the rest?
Usually a closed or blocked vent, a stuck damper, or the room is on the end of a long duct run with lower pressure. Check the vent first, then call a technician to inspect the damper.
Can I fix uneven heating myself?
You can fix closed vents and clean the filter yourself. Damper adjustments and duct repairs require a licensed technician. Don’t attempt gas or electrical components.
How much does it cost to balance a ducted heating system?
$200-400 for a professional system balance in Melbourne. It’s a one-time fix that lasts years and improves energy efficiency.
Why does my ducted heating work in some rooms but not others after cleaning the filter?
If cleaning the filter didn’t fix it, the problem is likely a stuck damper, duct leak, or system imbalance. Call an HVAC technician to diagnose.
Local Resources (SE Melbourne)
- Reece Plumbing & Heating – Filters, parts, technician referrals
- Bunnings – Draught-proofing supplies, ceiling insulation
- Victorian Building Authority – Check HVAC technician licensing
