Yes, and the low usage is the reason rather than an argument against it. Sitting idle in humidity for most of the year causes corrosion on flame sensors and relay contacts, dust settling on burners, and electrical degradation — none of which is visible while the system is off. A furnace that ran daily would at least tell you when something changed. One that sits silent tells you nothing until you need it.

Before the cold season, ideally autumn. Two reasons: any fault found can be repaired calmly rather than urgently, and you avoid the week when every furnace in East Central Florida is asked to start at once and every contractor's diary fills. A tune-up in November is a routine appointment; the same fault discovered in January is an emergency call.

Because a furnace burns fuel inside your building, and the heat exchanger is what keeps combustion gases separate from the air you breathe. Corrosion or cracking compromises that separation. Carbon monoxide testing, heat exchanger evaluation, and venting inspection together confirm the system is safe, and they are the parts of the visit you could not carry out or verify yourself.

It is the difference between the air entering the furnace and the air leaving it, and manufacturers specify an acceptable range. Measuring it reveals whether the furnace is firing correctly and whether airflow matches the heat being produced — too little airflow and it overheats, too much and it underperforms. It is a measurement rather than an opinion, which is the point.

You can and should change filters and keep the area around the furnace clear of stored items. Beyond that, this equipment involves gas pressure, combustion, and venting, and the meaningful checks require instruments and licensing. Burner cleaning, gas pressure adjustment, and heat exchanger evaluation are not DIY territory on a fuel-burning appliance.

Yes, though the checklist differs — no burners, gas pressure, or combustion testing. Electric systems need heating elements, sequencers, relays, blower motor, and airflow inspected, and because they draw heavily the electrical connections matter. Idle-season corrosion affects them just as much, so annual service is still worthwhile.