DIY Furnace Maintenance Guide for Bay Area Homeowners

Simple monthly and seasonal tasks keep your furnace running efficiently for 15-20 years instead of failing at 8-10 years. Most tasks take 5-15 minutes and require no special tools.

Monthly Tasks (5 minutes)

1. Check Air Filter

Frequency: Monthly check, replace when dirty (typically 60-90 days)

How to check:

1. Turn off furnace at thermostat
2. Locate filter (usually in return air vent or air handler)
3. Remove and hold up to light
4. If you can't see light through it, replace

Filter recommendations:

• MERV 11 for most Bay Area homes
• Buy 6-12 filters in bulk
• Mark date on filter frame when installed

Cost: $10-$15 per filter
Impact: Prevents 70% of furnace problems

2. Listen for Unusual Sounds

Normal: Quiet hum, gentle whoosh of air
Call for service: Banging, screeching, grinding, rattling

3. Check Vents & Registers

Do:

• ✅ Vacuum dust from supply and return vents
• ✅ Ensure furniture not blocking airflow
• ✅ Keep all vents open (even in unused rooms)

Don't:

• ❌ Close more than 20% of vents (strains system)
• ❌ Block returns with furniture/curtains

Fall Tasks (Before Heating Season - 30 minutes)

1. Test Heating Mode

1. Set thermostat to HEAT
2. Set temp 5°F above current temperature
3. Wait 5 minutes for furnace to start
4. Verify warm air from vents
5. Check all rooms for heat

2. Replace Thermostat Batteries

• Do this annually even if still working
• Prevents mid-winter failure
• Cost: $3-$5

3. Inspect Furnace Visually

Look for:

• Rust or corrosion on furnace cabinet
• Water stains (indicates condensate drain issues)
• Soot around burner area (indicates combustion problems)
• Disconnected or damaged wiring

Call for service if you see any of these.

4. Clear Combustibles

• Maintain 3-foot clearance around furnace
• Remove storage boxes, paint cans, cleaning supplies
• Fire safety requirement in California

5. Check Flue Pipe (Gas Furnaces)

Visual inspection:

• Look for rust, holes, or disconnections
• Verify pipe slopes upward toward vent
• Check connections are secure

Safety: Damaged flue pipes can leak carbon monoxide. Call for service if damaged.

What Homeowners Should NOT Do

❌ Don't Attempt These (Call Professional)

• Opening furnace cabinet to inspect interior
• Adjusting gas pressure or burner flame
• Cleaning burners or heat exchanger
• Testing safety controls
• Working with electrical connections
• Touching refrigerant lines (heat pumps)

Why: Risk of carbon monoxide exposure, electrical shock, gas leaks, or equipment damage.

❌ Never Do This

• Spray water on furnace interior
• Use furnace room for storage
• Block furnace intake/exhaust vents
• Ignore strange smells (especially gas or burning)
• Skip annual professional maintenance

Annual Professional Maintenance (Required)

When: September-October (before heating season)
Cost: $89-$159
Time: 60-90 minutes

What technicians do:

1. Inspect heat exchanger for cracks (CO safety)
2. Test gas pressure and burner flame
3. Lubricate blower motor bearings
4. Test all safety controls
5. Clean burners and flame sensor
6. Check electrical connections
7. Measure temperature rise
8. Inspect ductwork for leaks
9. Test thermostat calibration
10. Provide written report

Value: Prevents 80% of mid-winter breakdowns

Bay Area Specific Maintenance

Coastal Homes

Challenge: Salt air corrodes faster
Extra task: Inspect outdoor components quarterly, request protective coating during annual service
Frequency: Professional maintenance annually + visual checks quarterly

Older Homes (Pre-1990)

Challenge: Heat exchanger cracks (CO risk)
Extra task: Request camera inspection of heat exchanger annually
Critical: If cracks found, replace immediately (safety hazard)

During Wildfire Season

Challenge: Ash and smoke clog filters rapidly
Extra task: Replace filters monthly during active fires, schedule coil cleaning after major smoke events
Cost: $150-$250 for professional coil cleaning

Warning Signs Requiring Immediate Service

🚨 Call Same-Day

• Yellow or orange flame (should be blue)
• Smell of gas near furnace
• Carbon monoxide detector alarming
• Water pooling around furnace
• Burning smell or smoke from vents
• System won't turn on at all

⚠️ Schedule Within 1 Week

• Energy bills suddenly 20%+ higher
• Uneven heating room-to-room
• System short-cycling (on/off every 2-5 minutes)
• Loud grinding or banging sounds
• Reduced airflow from vents

Maintenance Cost vs Emergency Repair

With regular maintenance:

• Annual cost: $149-$249
• Unexpected repairs: 0-1 every 2-3 years
• 10-year total: ~$2,500

Without maintenance:

• Annual cost: $0
• Unexpected repairs: 1-2 per year @ $350-$800 each
• Premature replacement: 8-10 years vs 15-20 years
• 10-year total: ~$13,000

Savings with maintenance: $10,500 over 10 years

Simple Monthly Checklist

Print this and keep near furnace:

Monthly (5 min):

• Check air filter, replace if dirty
• Listen for unusual sounds
• Verify all vents clear and open

Quarterly (15 min):

• Vacuum all supply and return vents
• Test heating mode (even in summer)
• Visual inspection for leaks/rust

Annually (30 min + pro service):

• Replace thermostat batteries
• Clear 3-foot area around furnace
• Schedule professional tune-up

The Bottom Line

Minimum effort for maximum lifespan:

1. Change filters every 60-90 days
2. Annual professional maintenance ($89-$159)
3. Keep vents clear and open

These three tasks prevent 80% of furnace problems and extend lifespan to 15-20 years.

For Bay Area homes: Our mild climate means furnaces work less hard than extreme climates. Consistent maintenance ensures your system lasts decades, not years.

Galaxy Heating & Air offers maintenance agreements: 2 annual tune-ups, priority service, 20% off repairs, no overtime charges. Call (925) 578-3293 to schedule your fall maintenance.