Air Conditioner & Heat Pump Repair vs Replace FAQs

Repair vs replace the air handler unit

Indoor Air Handler Repair vs Replace FAQs

Because Q&A on this topic often involves decisions about replacing components in either or both the indoor and outdoor A/C or heat pump equipment you may want to see both the Q&A just below and also

COMPRESSOR / CONDENSER UNIT REPAIR vs REPLACE FAQs - repair vs replace?

New Condenser Unit, humming sound, squealing noise - Tech now says replace Air Handler?

I had new condenser installed about a month ago, due to it tripping and a/c stops working.

A couple days later after install, there was a humming sound, with a high pitch squealing noise that's not so loud.

I could hear condenser from inside the house start up loud.

This noise lasts for 5-10 minutes and it regulates to the normal sound. Air coming out of house's vents is not cold.

So no A/C inside the house.

With the next start up of the A/C, the cool air blows again.

Tech keeps saying it's not the condenser and I need to replace everything up in the attic.

I have warranty with the new unit but tech is saying the unit is fine. Can you please help? Thanks. 2017-08-04 by MP

Reply: humming suggests failing motor or bad bearing

I'm a bit worried, too, that there is a motor or bearing or pulley failing in the air handler in your attic.

The humming is often a motor having trouble starting. We can't do more arm-waving here: you need the tech to take a careful look in the air handler to track down the noise and report to you its source.

Watch out: diagnose the problem more accurately before even considering replaing "everything in the attic" - it would be shameful to sell you a multi-thousand new attic air handler when all that was really needed was a fan motor or pulley or belt.

New cooling coil doesn't fit my existing indoor air handler

I need to replace my A/C on the outside of my house and the indoor air handler's evaporator coil.

My problem is that my existing furnace has a 13in wide evaporator coil and I can't find that size anywhere. The smallest I can find are 14 and 14.5 inch.

Can I use a bigger evaporator coil on my furnace? What would be need to do so? Thank you! On 2023-05-30 by Ben - N

Reply by InspectApedia Publisher (mod) - Upflow furnace installation of an add-on cooling coil or evaporator coil

@Ben,

Yes you can use a larger evaporator coil, but be sure to discuss with the installer just how the air plenum should be shaped for best air flow across the coil.

Watch out: if your new coil is too large for the system's design it may cool the building without adequate dehumidification (because it cools everything down too fast to complete moisture removal).

The transition plenum that you install will be shaped to direct air flow across the coil without creating dead air spaces.

Don't just slap on a larger coil atop the air handler, sticking out at the sides.

Here is an often-quoted excerpt from Trane's IO manual

FURNACE UPFLOW INSTALLATION

Standoffs and screws (See Figure 1, page 6) are included with the cased coils for attachment to the furnace. NOTE: The top flanges on the furnace must be bent 90 degrees upward to allow the coil attachment.

There are clearance alignment holes near the bottom of the coil wrapper. Drill screws are used to engage the furnace top flanges. The standoff is inserted into the cabinet alignment hole.

The drill screws are inserted through the standoffs then screwed into the furnace flange. The coil is always placed downstream of the furnace airflow. The above instructions apply only if the coil is on top of an upflow furnace.

COIL

a. Apply gasket material (duct seal field supplied) to ALL mating surfaces between the furnace and the coil case.

b. Set the coil case on top of the furnace. Connect the ductwork to the coil case using the field supplied screws.

c. Secure the coil case to the furnace and seal for air leaks as required.

Is it better to replace the cooling coil or to buy a whole new air handler?

Is is worth replacing coils on a/c or better to buy new unit? - On 2012-09-13 by debbie

Reply by Mod

Debbie:

The choice to repair versus replace air conditioning or heat pump equipment depends on answers to a few questions to put to your repair technician:

How old is the system?

What refrigerant is it using? (If it's an older unit that uses a discontinued refrigerant such as R22 it's often better to replace the equipment).

What is the problem with the cooling coil on your system: dirty versus leaky?

Typical cost to replace the cooling or evaporator coil is in the $1400 - $2000 range (USD) depending on coil size and accessibility.

Typical cost to replace the entire indoor air handler (including the blower unit, furnace, cooling coil, etc.) is about $1500 for the equipment and another $1500 or more (depending on where you live) for installation labor.

Comparing those prices, most technicians will recommend installing a new unit (air handler) if your system is an older one.

On a newer A/C system in good condition but with a damaged coil that needed replacement, I'd consider that move.

What does your heating tech say?

Cost to replace the box coil and plenum in an air handler

How much should it cost to replace the Box Coil and Plenum in Texas? On 2011-07-13 by M. Cooper

by (mod) -

M. Cooper: typical central air system replacement costs (compressor/condenser unit and indoor air handler) if you are NOT replacing ductwork is $2,000 to $10,000.

The variation is more than by geographic area - it's unit size and special installation requirements.