Furnace Installation
New gas furnace installs sized by load calculation, with gas piping, venting, ducts and the city permit handled by our crew.
Learn moreHeating in Pasadena, CA
Furnace replacement in Pasadena when the old unit costs more than it is worth
An old furnace swapped for a right-sized new one in the same attic, closet or garage, with venting, ducts and permit handled.
- Answering 24/7
- Price quoted before work
- Pasadena and nearby cities
Quick answer
Replace a Pasadena furnace when the heat exchanger is cracked, when it is past about twenty years and needs a major part, or when repairs keep stacking up. Marco's removes the old unit, sets a correctly sized new furnace in the same spot or a better one, updates venting and gas connections, tests the ducts where state rules require it and handles the permit.
Furnace Replacement
What furnace replacement covers at your home
Furnace replacement usually starts with a repair visit that went badly. A technician finds a cracked heat exchanger, or an inducer motor fails on a furnace that has heated the house since the late 1990s, or the second big repair in two winters lands on the same unit. At that point the question is not whether the old furnace can be kept running, it is whether it should be. We give you an honest read, because a twelve-year-old furnace with a bad igniter does not need replacing.
When replacement is the right call, most of the job happens in the space the old furnace already uses. That keeps the cost reasonable, but it does not mean a blind swap. The old furnace may have been oversized, the vent may not suit a modern unit, and attic ducts may leak badly enough to fail the test California can require when a furnace is changed. We check all of it before we quote, so the new furnace works with the house as it is today.
Warning signs
Signs it is time to replace the furnace
Cracked heat exchanger found
A confirmed crack means combustion gases can reach the air in your home. Replacement exchangers exist for some models, but on older furnaces a new unit is usually the sensible fix.
Past twenty heating seasons
Furnaces from the early 2000s and before are reaching the end of their parts supply. A failed board or inducer may be costly, slow to source or simply unavailable.
Repairs every winter
When the same furnace needs a visit each season, those bills add up to a real share of a new unit, without fixing the age of everything else inside the cabinet.
Yellow, lazy burner flame
Healthy flames are crisp and blue. Yellow, wavering flames point to combustion trouble that can create carbon monoxide and soot, and on an old unit it often signals deeper wear.
Gas bills creeping up
Older standing pilot and early induced draft furnaces waste more gas than modern units. If winter bills keep rising without a change in habits, efficiency loss is a likely reason.
Rooms never feel even
An old furnace with a single-speed blower and a worn wheel can no longer push enough air to the far rooms. A new variable-speed blower often fixes what the old one could not.
Repair versus replacement, the honest math
We look at three things: the age of the furnace, the cost of the repair in front of you, and the condition of the parts that have not failed yet. A newer furnace with a single bad part should be repaired. An older furnace with a cracked heat exchanger, or one needing a control board and an inducer in the same visit, usually should not. We also check whether the model is still supported, because a furnace with no available parts can leave you cold for a week.
You make the call. We write both prices down side by side and explain what the repair does not fix. Many homeowners keep a repaired furnace another season or two while they plan, and that is a fair choice when the unit is safe.
Fitting the new furnace into the old space
Most replacements stay in the same closet, attic or garage, but the new furnace rarely matches the old one inch for inch. Modern cabinets can be taller or shorter, and the supply and return connections may need new transitions. If you have central air, the evaporator coil sits on the furnace, so we check whether the coil can be reused or should be replaced at the same time to keep the system matched. A horizontal attic furnace needs a sound platform, a drain pan and safe walkway access.
- Size confirmed by load calculation, since many older furnaces were oversized
- Vent pipe inspected and replaced if it is rusted, undersized or shared incorrectly
- Gas connector, shutoff valve and sediment trap renewed with the new unit
- Filter rack moved to a spot you can actually reach
Duct testing and the Title 24 question
California energy rules can require a duct leakage test when a furnace or air handler is replaced, and many replacement permits in Pasadena and nearby cities include one. Older attic ducts often leak at joints and boots, so a failed first test is common. If your ducts fail, we seal the leaking connections and test again. That work also lowers your bills and pulls less dusty attic air into the house, so the money comes back over time.
Gas furnace or heat pump this time
Replacement is the natural moment to ask whether a heat pump fits better. A heat pump heats and cools with one outdoor unit and an indoor air handler, and in a mild climate like Pasadena it heats efficiently through nearly every winter night. If your AC is also near the end, the comparison gets more interesting. We price both options and explain any electrical panel needs. Ask about current PWP, SCE or SoCalGas rebates and state heat pump incentives when funding is open.
Step by step
Replacement day, step by step
- 1
Confirm the plan
Before removal, we review the furnace model, location, vent path and any coil or duct work agreed in the quote, and lay down floor protection along the path.
- 2
Shut off and remove
Gas and power are shut off, and the old furnace is disconnected and carried out. We check the space for damage, rodent activity and any old duct wrap that needs special handling.
- 3
Set the new furnace
The new unit is leveled, connected to the supply and return ducts with new transitions, and tied into gas, venting, power and the thermostat wiring.
- 4
Test and tune
We leak test gas fittings, check manifold pressure, temperature rise and blower speed, and measure carbon monoxide in the flue and at the supply registers.
- 5
Duct test and paperwork
Where required, the duct leakage test is run and recorded. We can register the equipment with the manufacturer for you and schedule the city inspection.
Typical prices
What furnace replacement costs in Pasadena
Furnace replacement prices depend on the furnace type, its location, the vent and whether the ducts pass testing. A like-for-like closet swap is the most predictable job. Attic and high-efficiency installs take more labor. These are typical 2026 ranges for Pasadena and the San Gabriel Valley, and the final price comes after the technician sees the system.
| Job | Typical range | What is included |
|---|---|---|
| Upflow 80 percent furnace in a closet or garage | $3,960 to $6,480 | Same location, sound vent reused, new gas and duct connections |
| Horizontal 80 percent furnace in an attic | $4,640 to $7,920 | Attic labor, platform repair and a new drain pan add to the cost |
| 96 percent condensing furnace with new venting | $6,170 to $10,380 | PVC venting, condensate drain and sometimes a small condensate pump |
| Duct sealing to pass the leakage test | $485 to $1,760 | Depends on how many joints and boots leak in the attic |
Brand, blower type, permit fees, whether the AC coil is replaced at the same time and attic height all move the price. Manufacturers offer equipment warranties, and registering the furnace after install keeps that coverage in place. Compare other jobs in our Pasadena HVAC price guide.
Furnace replacement across Pasadena neighborhoods
Pasadena's postwar ranch homes, especially around Hastings Ranch and Chapman Woods, usually have their furnace in the attic or a hall closet, often the third or fourth unit to sit in that same spot. These are mostly straightforward swaps. Craftsman and Spanish Revival homes vary more. Some have a furnace that was added in a converted closet decades ago, with a vent path that would not pass today, and those replacements take more planning to bring up to current rules.
Attic furnaces here take a beating from summer heat, and attic ducts in older homes often show gaps, crushed runs and rodent damage when we go up for a replacement. If your home sits near the Eaton Fire burn area, we look for ash and smoke residue in the ducts and the return plenum before connecting a new furnace, because a new blower will pull that residue straight into the house. Cleaning or replacing the ducts first protects the new equipment.
Related work
Often booked with furnace replacement
Full HVAC System Replacement
Furnace, coil and condenser or a heat pump replaced together as a matched system, with duct testing and the city permit handled.
Learn moreDuct Sealing & Leak Testing
We measure duct leakage with a calibrated fan, seal joints with mastic, and test again so you see the actual improvement.
Learn moreHeat Pump Installation
New ducted and inverter heat pumps sized to your Pasadena home, with permits, line sets, electrical and duct checks included in the quote.
Learn moreWhere we do furnace replacement
Our technicians handle this work all over Pasadena and the surrounding San Gabriel Valley. A few of the places we cover:
Questions
Furnace Replacement questions from Pasadena homeowners
A horizontal attic furnace replacement usually takes one full day, sometimes a day and a half if the platform, vent or ducts need repair. Closet and garage swaps often finish in five to seven hours. Attic heat can slow the work in warm months, so we start attic jobs early. In most cases you have heat again the same evening.
Not always. If the coil is in good condition and matches the refrigerant and size of your outdoor unit, we can reuse it. If the AC is old, runs on R-22 or the coil leaks, replacing both together avoids paying for a second install later. The coil sits on the furnace, so changing it during a furnace replacement saves labor. We check it and give you both prices.
Many older systems do on the first try. Attic ducts in homes from the 1950s and 1960s often have loose joints, dried tape and disconnected boots. A failed test is not a disaster. We find the leaks, seal them with mastic and proper fittings, and test again. The sealing also cuts wasted heat and keeps attic dust out of your living space.
For many homes, yes. Pasadena winter nights in the 30s and 40s are well within what a modern heat pump handles efficiently, and you gain cooling from the same system. The real questions are electrical panel capacity, the age of your current AC and gas versus electric rates. We price a furnace and a heat pump side by side so you can compare actual numbers before choosing.
We disconnect and remove it the same day and haul it away with the job. Metal parts go to recycling. If the AC coil is being replaced too, its refrigerant is recovered properly before removal. You do not need to arrange anything or leave the old furnace at the curb, and the space is swept before the new unit goes in.
Need heat or cooling back today?
Call our Pasadena line any hour. A person answers, asks a few questions about the system, and gives you an arrival window.
(626) 879-0711Answering 24 hours, 7 days