Browse our heating and cooling services.
Short answer
Most furnace complaints that look like heating faults are airflow faults. A restricted filter, blocked returns or a crushed duct makes the unit overheat and shut down on a safety control. Heat that starts then stops. Check the filter first; it costs nothing and resolves a meaningful share of calls.
The reason this matters commercially is that the symptom looks identical to a failing component, and a quote written against the symptom, not the cause can replace a part that was never at fault. If the filter is clean and returns are clear, note how long the unit runs before it stops and whether it restarts on its own. That pattern is the most useful thing you can hand a technician, and it is the thing a good quote will refer back to.
Jobs this covers
- Gas, propane and oil furnace repair
- Ignition and burner diagnosis
- Blower and motor service
- Limit and control problems
- Airflow and filter issues
- Duct-related comfort problems
Common problems and warning signs
- The furnace starts then stops
- Air is cool or weak
- Some rooms stay cold
- The blower is noisy
- The thermostat calls but nothing happens
- The unit displays a fault code
What service may include
A clogged filter can trip the high limit. A technician may check controls, ignition, fuel, safeties, blower components, temperature rise, filter, return and supply airflow and accessible ductwork.
What affects the recommendation and price
Igniters and flame sensors are common, cheap fixes. Fuel, furnace type, failed part, airflow, duct access, equipment age, venting and compatible parts affect repair cost and whether replacement should be discussed.
What is different around Burlington
Where a fault code is displayed, it narrows the diagnosis considerably before anyone arrives, so photographing it is genuinely useful.
What a written quote should tell you
- The fault code displayed, and what the technician determined it meant
- Whether airflow was checked before a component was replaced
- Heat exchanger condition, which is a safety matter rather than a performance one
- Whether the repair addresses the cause or the symptom, said explicitly
- The unit's age against the repair cost, with replacement priced if it is marginal
| Check | Cost |
|---|---|
| The filter | Free, resolves a meaningful share of no-heat calls |
| A crushed duct or blocked return | Cheap to find, easy to mistake for a failing component |
Safety comes first
For gas odor, a carbon-monoxide alarm, smoke, fire or heavy soot, leave the area when appropriate and contact emergency services or the utility.
Common questions
Why does my furnace start and stop every few minutes?
A control, limit, ignition, airflow, sizing or thermostat problem may cause short cycling.
Can a dirty filter stop the furnace?
Restricted airflow can trigger safety limits and reduce performance. Replace filters only with the correct approved size and type.
Why is one room colder?
Duct leakage, balancing, closed dampers, insulation, air leakage or room load may be involved.
Can an oil furnace be serviced through a service request?
Yes: identify the fuel so the request goes to a professional who works on oil equipment.
What does AFUE mean on a furnace?
Annual Fuel Utilization Efficiency is the share of the fuel's energy that ends up as usable heat over a heating season, so a 95% AFUE furnace turns 95% of the fuel into heat and sends 5% up the flue. It is a seasonal average rather than a peak figure, which makes it more honest than a single-point efficiency number. Two caveats worth holding: AFUE does not account for the electricity the blower uses, and it does not account for duct losses: a 95% furnace with leaky ducts running through an unconditioned Vermont attic or crawlspace delivers considerably less than 95% to the rooms.
How do I know if my heat exchanger is cracked?
You generally cannot confirm it yourself, which is exactly why it is dangerous, but there are signals worth acting on. A yellow, flickering or lifting burner flame instead of a steady blue one; soot around the furnace; a sharp or acrid smell when it runs; visible rust or scaling on the exchanger; and, most importantly, carbon monoxide alarms activating or household members reporting headaches, nausea or drowsiness that improve when they leave the house. Any of those means shut the furnace off and get it inspected, and any alarm means leave the building and call from outside.
What furnace repairs can a homeowner do?
Change the filter, clear blocked or closed registers and return grilles, replace thermostat batteries, confirm the service switch and breaker are on, and check that the condensate drain on a high-efficiency unit is not blocked: a plugged condensate trap shuts down a condensing furnace routinely and looks like a serious fault. Beyond that, the furnace's interior involves line voltage, a gas valve and a heat exchanger, and the failure you cannot see is the one that matters: a cracked heat exchanger is a carbon monoxide problem that produces no symptom in the furnace's behaviour.
What happens if I ignore a furnace that is short cycling?
You are running the equipment through its most stressful moment repeatedly, and you are usually ignoring a restriction that is also overheating the heat exchanger. Repeated overheating and cooling is a recognised contributor to heat exchanger cracking, which is the failure that ends the furnace's life and can release combustion products into the airstream. The most common underlying cause is the cheapest to fix, a filter nobody has changed, so the cost of ignoring it is disproportionate to the cost of addressing it.
How long does a furnace last and how often does it need service?
Fifteen to twenty years is typical, with well-maintained units exceeding it and neglected ones falling short. Annual service before the heating season is the standard, and the filter is on a much shorter cycle. A one-inch filter often needs changing every one to three months during the heating season, and in a Vermont house with pets or a woodstove, at the shorter end. The single highest-return habit in furnace ownership is putting filter changes on a calendar.
Should a landlord provide carbon monoxide detectors?
In Vermont, yes: the state requires carbon monoxide alarms in rental dwelling units, alongside smoke alarms, and it is the landlord's obligation to provide them. Tenants should confirm they are present and working, and test them rather than assuming. If you rent and there is no CO alarm in a unit with any fuel-burning appliance or an attached garage, raise it in writing immediately. This is one of the few maintenance items where the downside is measured in lives, not money, and the town health officer can be involved if a landlord will not act.
What does a furnace repair's warranty cover?
Furnace part warranties vary by component: an ignitor or a blower motor might carry a shorter warranty than the heat exchanger itself, which is often warrantied for a decade or more. A repair replacing one part does not extend the warranty on the rest of the unit.
What is the most common mistake before calling about a furnace fault?
Letting a dirty filter go unchanged and blaming the furnace when it starts short cycling. Restricted airflow is the single most common cause of nuisance shutdowns, and it is also the cheapest possible fix: checked last instead of first, it wastes a service call.