At a glance
Before the first cold spell, inspect the filter, test the thermostat, keep the furnace and vents clear, check exterior terminations, and test carbon-monoxide alarms. Arrange professional service if the system short-cycles, produces unusual odors or sounds, shows soot, or does not heat consistently.
Since 1973, The Metalsmiths has helped local homeowners prepare heating systems for damp Pacific Northwest winters. Seasonal maintenance cannot prevent every failure, but it can identify airflow, safety, and performance concerns before colder weather places greater demand on the system.
Before You Start: Safety First
Important safety guidance
If you smell gas, leave the area immediately. Do not operate electrical switches or try to find the source. From a safe location, call 911 and your gas utility. If a carbon-monoxide alarm sounds, move everyone outside, call 911, and do not re-enter until emergency personnel say it is safe.
DIY Maintenance You Can Do Today
1. Replace Your Filter
A clean, correctly sized filter supports airflow and helps protect the equipment. Check your system's filter location and replacement instructions before making changes.
When your filter is clogged:
- Your furnace works harder, driving up energy bills
- Reduced airflow can cause overheating and system shutdowns
- Your heat exchanger is under stress, which can lead to cracks
- Your home gets dusty and air quality suffers
Filter replacement schedule
Inspect the filter monthly during periods of frequent heating or cooling. Replace a disposable filter when it is visibly dirty, or follow the equipment and filter manufacturer's stated interval. Homes with pets, renovations, smoke, or heavy dust may need more frequent changes.
2. Check Your Thermostat
Before the cold hits, make sure your thermostat is working properly:
- Switch it to "heat" mode and set it a few degrees above room temperature
- Listen for the furnace to kick on within a minute or two
- Feel the vents to confirm warm air is flowing
- If you have a programmable thermostat, update the schedule for fall/winter
If your thermostat uses replaceable batteries, confirm their condition and follow the manufacturer's replacement guidance.
3. Clear the Area Around Your Furnace
Keep storage, laundry, paper, paint, fuel, and other combustible materials away from the furnace. Maintain the clearances stated by the equipment manufacturer and keep service panels accessible.
4. Check Your Vents and Registers
Walk through your home and check each vent:
- Make sure furniture, rugs, or curtains are not blocking them
- Open any closed registers—closing too many can create pressure problems
- Vacuum out any dust or debris
5. Test Your Carbon Monoxide Detectors
Every home with a gas furnace should have CO detectors. Test them now and replace batteries. If you don't have CO detectors on every level of your home, install them before heating season begins.
Fall Furnace Checklist
- Replace furnace filter
- Test thermostat in heat mode
- Replace thermostat batteries
- Clear stored and combustible materials from the furnace area
- Check all vents are unblocked
- Test CO detectors
- Check exterior vents for debris
- Listen for unusual noises during startup
- Schedule professional tune-up
When to Call a Professional
While the above tasks are safe for homeowners, some maintenance requires a professional. We recommend annual tune-ups that include:
- Heat exchanger inspection — Cracks can leak carbon monoxide
- Burner cleaning and adjustment — Ensures efficient combustion
- Electrical connection check — Loose connections cause failures
- Gas pressure testing — Improper pressure reduces efficiency
- Safety control testing — Verifies shut-off systems work
- Carbon monoxide testing — Checks for dangerous leaks
Service cost and appointment length vary by equipment, accessibility, and the work required. Ask what the visit includes and request a written estimate before authorizing additional repairs.
Warning Signs to Watch For
During the first few days of running your furnace, pay attention to how it sounds and performs. Call a professional if you notice:
- Unusual noises — Banging, squealing, or rattling
- Soot, scorch marks, or visible combustion changes — These require professional evaluation
- Short cycling — Furnace turns on and off frequently
- Cold spots — Uneven heating throughout the house
- Persistent or unusual odors — Especially electrical, chemical, smoky, or gas-like odors
- Higher bills — Sudden increase without usage change
How Old Is Your Furnace?
System age is only one factor in a repair-or-replacement decision. Consider the equipment's condition, safety, maintenance history, comfort performance, repair frequency, available parts, and the cost of the proposed work.
A qualified technician should explain the diagnosis, the immediate repair, any safety concerns, and reasonable alternatives. Efficiency improvements depend on the existing equipment, the replacement system, ductwork, controls, weatherization, fuel prices, and how the home is used.
The Bottom Line
Seasonal preparation can reduce avoidable surprises and give you time to address concerns before colder weather. Check the filter, test the system, confirm alarms are working, and arrange service when performance or safety concerns appear.
