HVAC Maintenance
Keeping your heating, ventilation, and air conditioning systems running efficiently.
Understanding Your System
Common System Types
| System | How It Works |
|---|---|
| Central forced air | Furnace/AC with ductwork |
| Heat pump | Moves heat (heating and cooling) |
| Boiler/Radiant | Hot water through radiators or floor |
| Mini-split | Ductless, individual room units |
| Window/Portable | Single-room units |
Key Components
| Component | Function |
|---|---|
| Thermostat | Controls system |
| Furnace | Heats air |
| AC condenser | Outside unit, releases heat |
| Evaporator coil | Inside unit, absorbs heat |
| Air handler | Moves air through ducts |
| Ductwork | Distributes air |
| Filter | Cleans air |
DIY Maintenance Tasks
Change Air Filters
Why it matters:
- Dirty filter restricts airflow
- System works harder
- Higher energy bills
- Shorter equipment life
- Poor air quality
Frequency:
| Filter Type | Change Frequency |
|---|---|
| Basic fiberglass | Monthly |
| Pleated | Every 2-3 months |
| High-efficiency | Every 3-6 months |
Steps:
- Turn off system
- Remove old filter (note size and direction)
- Insert new filter (arrow points toward system)
- Record change date
Clean Condenser Unit (AC)
When: Early spring, before cooling season
Steps:
- Turn off power (at unit and breaker)
- Remove debris from around unit
- Gently clean fins with hose (inside out)
- Straighten bent fins with fin comb
- Clear 2 feet around unit
- Restore power
Inspect Ductwork
Look for:
- Disconnected sections
- Holes or tears
- Crushed ducts
- Insufficient insulation
Fix minor issues with:
- Foil tape (not duct tape)
- Mastic sealant for major gaps
Check Thermostat
Verify:
- Proper programming
- Battery condition (if applicable)
- Correct temperature reading
- System response
Consider upgrading to smart thermostat:
- Programmable schedules
- Remote control
- Learning capabilities
- 10-15% energy savings
Seasonal Maintenance
Before Cooling Season
| Task | Purpose |
|---|---|
| Replace filter | Airflow, efficiency |
| Clean condenser | Heat transfer |
| Check refrigerant lines | Insulation intact |
| Clear drain line | Prevent backups |
| Test system | Catch problems early |
Before Heating Season
| Task | Purpose |
|---|---|
| Replace filter | Airflow, efficiency |
| Check furnace burner | Clean operation |
| Test carbon monoxide detector | Safety |
| Check pilot light/ignitor | Operation |
| Inspect heat exchanger | Safety (professional) |
Monthly Tasks
| Task | Notes |
|---|---|
| Check filter | Replace if dirty |
| Clear vents/registers | Don't block airflow |
| Listen for unusual sounds | Early problem detection |
| Check thermostat operation | Proper response |
Common Problems
AC Not Cooling
| Check | Solution |
|---|---|
| Thermostat set correctly | Set to cool, lower than room temp |
| Filter | Replace if dirty |
| Condenser clear | Remove obstructions |
| Condenser running | Check power, breaker |
| Ice on coils | Turn off, let thaw, check filter |
If these don't help: Low refrigerant or another issue. Call a professional.
Furnace Not Heating
| Check | Solution |
|---|---|
| Thermostat set correctly | Set to heat, higher than room temp |
| Power | Check switch, breaker |
| Gas | Is it on? |
| Pilot light/ignitor | Relight or replace |
| Filter | Replace if dirty |
No heat after these: Call professional.
Uneven Heating/Cooling
| Cause | Solution |
|---|---|
| Closed vents | Open all vents |
| Blocked ducts | Clear obstructions |
| Duct leaks | Seal with foil tape/mastic |
| Wrong size system | Consult professional |
| Poor insulation | Improve insulation |
Strange Noises
| Sound | Possible Cause |
|---|---|
| Banging | Ignition issue, duct expansion |
| Squealing | Belt or motor bearing |
| Rattling | Loose parts |
| Clicking | Relay or control issues |
| Humming | Motor problem |
Energy Efficiency
Reduce Energy Use
| Action | Impact |
|---|---|
| Raise/lower thermostat when away | Significant savings |
| Programmable/smart thermostat | 10-15% savings |
| Seal duct leaks | 20-30% of air lost in many homes |
| Proper insulation | Reduced heating/cooling load |
| Ceiling fans | Feel cooler with higher thermostat |
| Close blinds in summer | Reduce solar heat gain |
Ideal Temperature Settings
| Situation | Heating | Cooling |
|---|---|---|
| Home, awake | 68°F | 78°F |
| Sleeping | 65°F | 78°F |
| Away | 60°F | 85°F |
Each degree saves about 3% on energy costs.
When to Call a Professional
Annual Professional Service
Should include:
- Inspect heat exchanger
- Check refrigerant levels
- Clean and adjust burners
- Test safety controls
- Lubricate motors
- Check electrical connections
Schedule: Once a year, before heavy-use season
Call Immediately If
| Sign | Why |
|---|---|
| No heat in freezing weather | Pipes could freeze |
| Gas smell | Safety hazard |
| Carbon monoxide alarm | Evacuate, call 911 |
| Water leaking | Damage prevention |
| Burning smell | Fire hazard |
System Lifespan and Replacement
Typical Lifespan
| Equipment | Years |
|---|---|
| Central AC | 15-20 |
| Furnace | 15-20 |
| Heat pump | 15 |
| Boiler | 20-30 |
| Ductless mini-split | 20 |
Signs of Needed Replacement
- Frequent repairs
- Rising energy bills
- Uneven temperatures
- Excessive noise
- Age beyond expected life
- R-22 refrigerant (banned in new systems since 2020; R-410A also being phased down in favor of R-32 and R-454B)
When Replacing
- Size correctly (get Manual J calculation)
- Consider efficiency ratings (SEER for AC, AFUE for furnace)
- Higher efficiency = higher upfront cost, lower operating cost
- Get multiple quotes
Key Takeaways
- Change filters regularly - Most important maintenance task
- Keep condenser clear - 2 feet clearance around
- Seasonal checkups - Before heavy-use seasons
- Professional annual service - Worth the investment
- Seal ducts - Major efficiency improvement
- Smart thermostat - Easy upgrade with real savings
- Don't ignore warning signs - Small problems become big ones