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furnace: the air from the vents never gets warm
The one fault on this page that is not about money is the cracked heat exchanger: the source calls it a critical safety issue and a carbon monoxide hazard, and it decides the machine rather than the repair. Clogged air filter: 5 minutes, no part needed [S1] — the first of 3 causes on this page that need no part at all. On a furnace the complaint is the air from the vents never gets warm, and it arrives in these words: the furnace runs but the air from the vents is cold, the furnace will not fire up at all, the furnace starts and shuts off after a few minutes, the burner lights and goes straight back out or the house never gets warm no matter what the thermostat says. Until that check comes back clean, every price below is premature — the completed repairs behind this symptom run $180–$490 [S1].
high likelihoodmoderate$200–$350 installedabout 90 min
the furnace will not fire up at allthe burner lights and goes straight back out
S1 prices ignitor replacement at $200-350 and lists it first among the common service issues on the post-war forced-air stock that makes up most of this market - brick twins, split-levels and colonials of the 1940s to the 1970s, with equipment from the 1990s and 2000s now reaching the end of its life. An ignitor that has burned open gives a furnace that runs its draft inducer, clicks and never lights. The part is small and the diagnosis is the work, and the failure it is most often confused with is the gas valve further down this page, which is why the diagnosis is what decides the invoice rather than the symptom.
the source prices the fitted replacement at $200-350 and publishes no part-only figure, so the installed band is what stands here
medium likelihoodmoderate$175–$325 installedabout 60 min
the furnace starts and shuts off after a few minutesthe furnace runs but the air from the vents is cold
S1 prices capacitor replacement at $175-325 on the same table and names capacitor failures beside blower motor wear as one of the four common service issues in this housing stock. A capacitor on its way out is what makes a blower start slowly, hum, or drop out once the cabinet is warm, and it is the cheapest priced part on this page. The same component appears on the outdoor unit of a system that heats and cools with one blower, which is part of why it is one of the most-replaced parts in this market rather than an occasional one.
the source prices capacitor replacement at $175-325 and publishes no part-only figure, so the installed band is what stands here
the furnace runs but the air from the vents is coldthe house never gets warm no matter what the thermostat says
The source lists blower motor wear with capacitor failures as one of the four common service issues on this housing stock and attaches no number to it. It belongs on this page because it is the other half of that pair: a motor drawing high current takes the capacitor with it, so a furnace that has eaten two capacitors in two seasons is a motor question rather than a capacitor question. Because S1 puts no price on the motor, this record puts none either - the honest answer to what a blower motor costs is that the source behind this page does not publish one.
S1 names blower motor wear among the common service issues in this market and publishes no figure for the motor or for the labour on either of its pages; the only price it prints for this assembly is the capacitor that starts it, at $175-325, so no motor price is claimed here.
the furnace will not fire up at allthe burner lights and goes straight back out
S1's own list names gas valve replacement on older units, without a price, and it is the cause that makes the ignitor diagnosis matter: a furnace that will not light can be the ignitor at $200-350 or the valve behind it, and from the thermostat the two are identical. It is gas-side work behind the burner door, so it is not an owner job at any price. The page publishes no figure for it, and this record carries none rather than borrowing one from a different machine.
the source lists gas valve replacement on older units among the common service issues in this market and publishes no figure for it on either of its pages, so no price is claimed here.
medium likelihoodpro$150–$200 installedabout 150 min
the burner lights and goes straight back outthe house never gets warm no matter what the thermostat says
S1's own words are why this is the cause the page leads with: heat exchanger concerns on aging furnaces, which it calls a critical safety issue, and a cracked exchanger is a carbon monoxide hazard. Its table prices the inspection at $150-200, included in the annual tune-up, and the inspection is a camera or a visual check rather than a repair. What follows a crack is not a part: flue gas is being drawn into the air the house breathes, and on a furnace of that age the answer is a new machine rather than a new casting. S1 prices an annual tune-up at $160-275, which is the price of finding this in September rather than in January.
the source prices a heat exchanger inspection at $150-200, included in an annual tune-up, and publishes no figure for the exchanger itself: on a furnace old enough for the casting to be cracked there is no separate part price to quote, because the exchanger is most of the machine.
the house never gets warm no matter what the thermostat saysthe furnace starts and shuts off after a few minutes
This is the cause this record cannot price, and the reason is worth printing: the page behind it publishes repair bands, an inspection price and a tune-up price, and nothing at all for what a furnace costs to replace. What it does give is the age at which a machine reaches the point of the decision - equipment from the 1990s and 2000s is reaching the end of its life, in a market where the housing stock runs from 1890s Victorians to 1970s colonials and the heating plant was installed across five decades. So the replacement call on a furnace is made on age, on a cracked exchanger and on how many of the priced causes have already been paid for, rather than against a half-of-new-price line this page does not have. Time basis: no source publishes a duration for a furnace replacement, so the figure here is a book estimate.
no source behind this page publishes a furnace replacement price, so no replacement figure is claimed here. What the source does publish is a repair table and an age line, and this cause is decided on those.
Repair or replace?
Almost every answer on this machine is cheaper than the visit it arrives with, and the order to work in is the source's own: thermostat, breaker and the disconnect switch at the equipment, ignition, filter. Three of the nine causes here cost nothing - a filter, a thermostat setting and a switch - and none of the priced ones is large: an ignitor at $200-350, a capacitor at $175-325, a heat exchanger inspection at $150-200 inside a $160-275 tune-up. The two causes with no published price, the blower motor and the gas valve, are the ones where the diagnosis is worth more than the part, because a furnace that will not light can be the $200-350 ignitor or the valve behind it and the two are indistinguishable from the thermostat. One cause is not a price question at all: a cracked heat exchanger is a carbon monoxide hazard in the source's own words, and on a machine of that age the answer is a replacement. What this page cannot do is put that replacement against a repair, because no source behind it publishes a furnace replacement figure - so the decision is made on age and on the safety finding, and both are printed here rather than filled in. [S1]
The band above is one published row: 38 heating jobs completed in and around Glenside between January 2024 and February 2026, a $300 median, middle half $180-490, an average of $407, 10th percentile $160, 90th percentile $825, minimum $140 and maximum $1,800. Two things about it are worth stating plainly. It is a heating-repair row rather than a furnace-only row - S1's own table beside it prices steam traps, circulator pumps and boiler pressure relief valves next to the ignitors and capacitors - so the band covers the heating work this company did in one township, not furnace work alone. And the failure it is priced around is the ordinary one rather than the expensive one: S1's own reading of the market is that the work skews toward service calls and component repairs, which is what a $300 median against a $1,800 maximum looks like. One limit belongs in the same sentence, because it is the reason no per-cause count stands on this page: S1 publishes its repair table as price bands with no count beside an individual row, so the ignitor, capacitor, blower, gas valve and heat exchanger entries are the source's own rows without a denominator, and the record states that rather than attaching the 38 to any one of them. The 38 belongs to the heating-repair row as a whole and is named as such.
There is no half-of-new-price line on this page and the record says why: no source cited here publishes a furnace replacement band, so printing a break-even figure would mean inventing the other half of it. The honest version of the rule on this machine is the one the source does support - the repair band tops out at $1,800 and the median is $300, which means the fault in front of you is usually a component and occasionally a cabinet full of them, and the cause that changes the decision is the cracked heat exchanger rather than the number on the quote. Against a $200-350 ignitor or a $175-325 capacitor the repair is worth doing on any furnace with years left; against a heat exchanger on a machine whose own service history is a motor and a valve, the money is a down payment rather than a repair, and the age of the equipment is the figure that decides it.
No source behind this page publishes a service life for a furnace, and the record does not invent one. What S1 gives instead is the end-of-life signal it works to - equipment from the 1990s and 2000s is reaching the end of its life - together with the age of the housing stock it is working in, and that is a statement about when a fleet of machines is due rather than a measured service life for one of them. The calculator therefore has no planning-life figure to apply to a furnace from this record, and says so rather than using a number no source published.
the furnace starts and shuts off after a few minutesthe house never gets warm no matter what the thermostat says
S1 puts this fourth on its own no-heat list and gives the mechanism in one line: a clogged filter can cause the system to overheat and shut down on a safety limit. On a forced-air furnace that is the whole failure - low airflow across the heat exchanger opens the high-limit switch, the burner drops out, and the house cools down while the thermostat still calls. It is the one item on this page that costs nothing to rule out and the only one whose condition gets worse on a schedule, which is why S1's list is ordered thermostat, breaker, ignition, filter rather than by what fails most often.
thermostat set wrong, or its batteries are dead [S1]
high likelihoodeasyno part neededabout 10 min
the furnace will not fire up at allthe house never gets warm no matter what the thermostat says
S1's first check is written for the way this actually fails: is the thermostat set to HEAT, is the setpoint above the room temperature, and are the batteries dead if it is a battery-powered unit. On the pre-war and post-war housing S1 describes, a thermostat left on cooling in January, or one whose schedule was never switched over, reads from the vent exactly like a furnace that has died. Nothing here needs a tool and nothing here needs a part, which is why it comes before every priced cause on the page.
tripped breaker, or the local disconnect switch at the furnace is off [S1]
high likelihoodeasyno part neededabout 10 min
the furnace will not fire up at allthe furnace starts and shuts off after a few minutes
S1's second check names both ends of the circuit: the furnace or boiler circuit breaker in the panel, and the local disconnect switch near the equipment, which is the one an owner has usually never looked at and the one that gets left off after a service visit, a filter change or a power cut. It sits above the ignition on S1's list because the switch is free to check and the repair behind a breaker that trips again is not - a circuit that will not hold is telling you about the motor or the wiring, not about the switch.
What each fix costs
Cause
Cost
Time
DIY?
clogged air filter
no part needed
5 min
easy
thermostat set wrong, or its batteries are dead
no part needed
10 min
easy
tripped breaker, or the local disconnect switch at the furnace is off
no part needed
10 min
easy
worn blower motor
not priced
180 min
advanced
failed gas valve on an older furnace
not priced
150 min
advanced
the furnace is at the end of its life
not priced
480 min
pro
cracked heat exchanger
$150–$200 installed
150 min
pro
failed capacitor on the blower motor
$175–$325 installed
60 min
moderate
failed hot-surface ignitor
$200–$350 installed
90 min
moderate
A technician visit starts with a diagnostic fee of $150–$180 [S1]. Completed repairs run $180–$490 [S1].
Sources
[S1]McCorry Comfort (Huntingdon Valley, Pennsylvania; family-owned HVAC and water heating company serving Philadelphia, Bucks, Montgomery and Delaware counties since 2001; page published 24 April 2026) (2026-04-24). the 38-job row the headline band comes from, in the source's own byline - based on 38 jobs completed in Glenside and nearby communities between January 2024 and February 2026 - with its full published distribution (average $407, median $300, 10th percentile $160, 25th $180, 75th $490, 90th $825, minimum $140, maximum $1,800) and its own note that the work skews toward service calls and component repairs; the repair table the per-cause prices come from (heating service call or diagnostic $150-180, annual furnace tune-up $160-275, ignitor replacement $200-350, capacitor replacement $175-325, zone valve replacement $300-550, steam trap replacement $100-200 each, circulator pump replacement $375-650, pressure relief valve $200-400, thermostat installation $200-500, heat exchanger inspection $150-200 included in a tune-up); its own list of the common service issues on the post-war forced-air stock (ignitor replacement, heat exchanger concerns on aging furnaces which it calls a critical safety issue and a CO hazard, blower motor wear and capacitor failures, gas valve replacement on older units) with the note that equipment from the 1990s and 2000s is reaching the end of its life; the housing-stock and market picture it works from (pre-war Victorians and early colonials of 1890 to 1930 with steam or gravity hot-water heat, post-war brick twins, split-levels and colonials of the 1940s to 1970s with forced-air furnaces, gas and occasionally oil, steam traps failing every 10 to 15 years and causing banging pipes, uneven heat and efficiency losses, and its warning that it has seen too many steam systems repaired by technicians who did not understand them); the five no-heat checks it gives in order (thermostat set to heat with the setpoint above room temperature and working batteries, the furnace or boiler circuit breaker and the local disconnect switch at the equipment, an older pilot light or electronic ignition, a clogged filter causing the system to overheat and shut down on a safety limit, and the boiler water level where hot-water boilers fill automatically and steam boilers are monitored by hand); and its neighbouring-community row for Elkins Park (10 service call jobs at a $251 average)
Last verified: 2026-09-20. Prices are US market figures from the sources above; your quote may differ.
Built from a fact record, not from a template: every number above is tied to one of the sources and the record is re-checked against them. Editorial choices (which symptom leads, which cause is the single tell) are kept in a separate block so the facts stay auditable.
Quick answers
How much does it cost to fix a furnace with this problem?
Completed repairs run $180–$490 according to the sources cited on this page, after a diagnostic fee of $150–$180.
How long does a furnace last?
No source cited on this page publishes an expected life for the machine itself, so the page says so rather than guessing; the decision here turns on the fault and on how the unit is built and installed, not on an age line.
Repair or replace?
Almost every answer on this machine is cheaper than the visit it arrives with, and the order to work in is the source's own: thermostat, breaker and the disconnect switch at the equipment, ignition, filter. Three of the nine causes here cost nothing - a filter, a thermostat setting and a switch - and none of the priced ones is large: an ignitor at $200-350, a capacitor at $175-325, a heat exchanger inspection at $150-200 inside a $160-275 tune-up. The two causes with no published price, the blower motor and the gas valve, are the ones where the diagnosis is worth more than the part, because a furnace that will not light can be the $200-350 ignitor or the valve behind it and the two are indistinguishable from the thermostat. One cause is not a price question at all: a cracked heat exchanger is a carbon monoxide hazard in the source's own words, and on a machine of that age the answer is a replacement. What this page cannot do is put that replacement against a repair, because no source behind it publishes a furnace replacement figure - so the decision is made on age and on the safety finding, and both are printed here rather than filled in.