Northern Virginia winters bring freezing rain, single-digit nights, and rapid temperature swings that stress every heating system. At All Year Appliance & HVAC Services, these are the seven winter problems we fix most often in Woodbridge, Dumfries, Lake Ridge, Montclair, and Dale City homes.
1. No Heat – Igniter or Flame Sensor Failure (Most Common Call)
Gas furnaces: The hot-surface igniter glows but no flame appears after 60–90 seconds, or the burner lights for a few seconds then shuts off. Quick check: Look through the sight glass—if you see repeated orange glow with no flame, the flame sensor is dirty or the igniter is weak. Technicians clean the flame sensor with fine sandpaper or replace the igniter on the spot.
2. Heat Pump Runs but Blows Cold Air
On mild days (above 35 °F), heat pumps should deliver warm air. If it feels cold or lukewarm:
- Check auxiliary heat strips (emergency heat) are activating.
- Look outside—ice on the outdoor coil is normal, but a solid block means the defrost cycle has failed.
- Common causes: bad defrost board, stuck reversing valve, or low refrigerant.
3. Short Cycling (Furnace Turns On and Off Every Few Minutes)
The system never fully warms the house and runs almost constantly. Main culprits in our area:
- Dirty flame sensor
- Clogged filter
- Over-sized furnace installed years ago
- Failing pressure switch from dust and spider webs (very common in attics and crawl spaces)
4. Banging, Popping, or Booming Noises When the Furnace Starts
Oil-canning ductwork and delayed ignition are typical in older Prince William County homes.
- Delayed ignition = gas builds up before lighting (dangerous—needs immediate attention).
- Duct noise = oil-canning metal from rapid temperature changes.
5. Frozen Outdoor Heat Pump or AC Unit
Ice is normal; a complete solid block is not.
- Turn thermostat to EMERGENCY HEAT and call.
- Never chip ice with a hammer—it damages coils. Most frequent cause: failed defrost sensor or timer.
6. Higher-Than-Normal Heating Bills
A 20–40 % increase from last year with the same usage usually means:
- Dirty blower wheel (common after summer construction dust)
- Closed or blocked supply/return vents
- Leaking ductwork in attic or crawl space
- Heat exchanger beginning to crack (carbon monoxide risk)
7. Strange Smells When Heat First Turns On
- Burning dust smell the first few cold days = normal
- Rotten eggs = possible gas leak (evacuate and call immediately)
- Burning plastic or electrical smell = wiring or motor overheating
Quick Winter Checklist You Can Do Today
- Replace furnace filter (use pleated MERV-11 or higher)
- Clear 2-foot radius around outdoor unit (leaves, snow, toys)
- Make sure all supply and return vents are fully open
- Set thermostat fan to AUTO, not ON
- Check that emergency heat (or auxiliary heat) strip indicator comes on when outdoor temp drops below 30 °F
If any of the top seven problems sound familiar, professional diagnosis and repair is the safest and fastest solution.
Contact All Year Appliance & HVAC Services at 703-955-4135 anytime—24 hours a day, 7 days a week, even on the coldest nights. We serve Woodbridge, Dumfries, Montclair, Lake Ridge, Dale City, Quantico, and all Northern Virginia.
All Year Appliance & HVAC Services Keeping Northern Virginia warm all winter long.