Air Handler Services in Kirkwood and West St. Louis County

The air handler is the unsung infrastructure of forced-air HVAC — the blower motor that moves conditioned air, the evaporator coil that delivers cooling, the supply plenum that distributes air to the duct system, the return plenum that brings air back from the home, and (on furnace-based systems) the heat exchanger housing through which combustion heat transfers to circulating air. When the air handler underperforms, the symptoms show up elsewhere: reduced airflow at supply registers, equipment cycling on limit switches, supply temperature differential outside design range, persistent humidity issues despite functioning AC, and noise complaints from velocity-related duct sounds. Air handler services cover the component-level work that addresses these issues short of full equipment replacement — blower motor replacement, ECM upgrades, evaporator coil replacement, plenum modifications, and full air handler replacement when component-level service isn’t sufficient.

Service Categories

Blower Motor Replacement

Blower motors fail in predictable patterns over 8–15 years of service. Symptoms: equipment runs but no air movement, intermittent operation, audible bearing noise, motor running hot enough to trip thermal protection, capacitor-related failure on PSC motors. Replacement scope:

• PSC (permanent split capacitor) motors: standard fixed-speed motors on most pre-2010 equipment. Direct replacement with matching specifications.
• ECM (electronically commutated motor): variable-speed motors on premium equipment since the late 2000s, standard on most current equipment. Replacement requires matching motor module compatibility.
• Direct-drive versus belt-drive: most residential equipment is direct-drive; older or larger equipment may be belt-drive requiring belt and pulley assessment.

PSC-to-ECM Blower Motor Upgrade

Retrofit upgrade of existing equipment from PSC fixed-speed blower to ECM variable-speed blower. Benefits:

• Energy consumption reduction: ECM motors use 30–50% less electricity than PSC equivalents at typical operation, particularly during low-stage cooling and continuous fan operation
• Improved comfort: variable-speed operation modulates airflow based on system demand, reducing temperature swings and improving dehumidification
• Quieter operation: lower fan speeds during low-demand operation reduce noise
• Better IAQ filtration: continuous low-speed fan operation circulates air through filtration without high-cost fan power penalty
• Smart thermostat integration: ECM blowers work better with smart thermostats that benefit from variable airflow control

Best candidates for ECM upgrade: equipment 5–12 years old in good condition (not approaching whole-system replacement); equipment with combined AC + furnace setup where the upgrade benefits both heating and cooling operation; households running continuous fan circulation for IAQ purposes.

Evaporator Coil Replacement (Distinct from Refrigerant Service)

Evaporator coil replacement when the coil itself has failed (corrosion, formicary corrosion pinhole leaks, biofilm damage, freeze damage) but the rest of the air handler and outdoor unit are functional. Different from refrigerant leak repair (covered under evaporator coil repair service) when the coil is replaceable rather than the refrigerant leak is repairable.

Coil replacement considerations:

• Cased coils: pre-built cabinet with coil inside, slides into place on top of furnace or in air handler. Easier installation, standardized fittings.
• Uncased coils: coil only, installed inside existing air handler or plenum. Requires modification of plenum opening; lower cost but more installation labor.
• R-454B versus R-410A compatibility: replacement coil must match the refrigerant of the outdoor unit. AHRI-listed combinations only.
• TXV (thermal expansion valve) replacement: most coil replacements include matching TXV for the refrigerant and capacity
• Refrigerant recovery and recharge: existing refrigerant recovered before coil removal; new refrigerant charged after installation per AHRI specifications

Supply and Return Plenum Modifications

Plenum modifications address airflow restrictions, undersized capacity, leakage issues, or accommodate new equipment:

• Plenum upsizing: increasing supply or return plenum cross-section for higher-CFM equipment
• Return air path additions: adding return air grilles and ducts to homes with single central return causing pressure imbalance
• Take-off modifications: adjusting individual branch take-offs from the supply plenum for improved airflow distribution
• Plenum leak sealing: mastic sealing of plenum joints, seam repair, gasket replacement
• Filter box modifications: relocating or upsizing return filter housing for improved filter access and reduced static pressure

Air Handler Replacement (Full)

Complete air handler unit replacement when component-level service isn’t sufficient — multiple failed components, cabinet corrosion, electrical issues affecting multiple sub-systems, or upgrade scope requiring different cabinet specifications. Common scenarios:

• AC-only homes converting to heat pump: existing air handler may not have heat pump-compatible control board, larger blower for heating mode airflow, or auxiliary heat capacity
• Major component failure in older air handlers: 15+ year old air handlers where multiple components are reaching end of life
• Capacity changes: home additions or modifications requiring different air handler capacity than original

The ECM Upgrade Economics

Typical ECM upgrade pays back through reduced electricity consumption:

• PSC blower at low cooling stage: 400–500 watts continuous
• ECM blower at low cooling stage: 80–150 watts continuous
• Continuous fan circulation (24/7 IAQ operation): PSC at 350–450 watts continuous = 8.4–10.8 kWh/day; ECM at 35–75 watts continuous = 0.84–1.8 kWh/day
• Annual electricity savings: $120–$280 for households running continuous fan; $60–$140 for households on heating/cooling-only operation
• Upgrade cost: $540–$980 typical
• Simple payback: 4–8 years for continuous fan households; 6–12 years for heating/cooling-only operation

The economics favor ECM upgrade for households planning to keep the existing equipment 6+ years; households planning equipment replacement within 5 years often defer the ECM upgrade and include ECM blower in the replacement equipment specifications instead.

Pricing

• PSC blower motor replacement: $480–$780 installed including motor, capacitor (if needed), and labor
• ECM blower motor replacement: $680–$1,180 installed including motor module, control board interface (if needed), and labor
• PSC-to-ECM upgrade: $540–$980 installed including ECM module, mounting modifications, control wiring
• Blower wheel replacement (separate from motor): $280–$480 installed
• Cased evaporator coil replacement: $1,180–$1,940 installed including coil, TXV, refrigerant recovery and recharge, brazing, leak testing
• Uncased evaporator coil replacement: $1,380–$2,180 installed (higher labor for plenum modifications)
• Supply plenum modification: $340–$880 typical depending on scope
• Return air path addition: $540–$1,380 depending on ductwork routing
• Plenum leak sealing: $240–$540 typical scope
• Filter box modification or relocation: $280–$680 depending on access changes
• Full air handler replacement: $2,800–$4,800 installed including new air handler, electrical connection, plenum interface modifications, post-installation verification

All pricing includes diagnostic, parts, labor, manufacturer warranty registration, and Purisync 2-year labor warranty on installation work. Refrigerant work performed under EPA Section 608 certification.

Frequently Asked Questions

How much does air handler service cost in Kirkwood?

Component-level service: PSC blower motor replacement runs $480-$780. ECM blower motor replacement runs $680-$1,180. PSC-to-ECM upgrade runs $540-$980. Blower wheel replacement (separate from motor) runs $280-$480. Cased evaporator coil replacement runs $1,180-$1,940. Uncased evaporator coil replacement runs $1,380-$2,180 (higher labor for plenum modifications). Plenum work: supply plenum modification runs $340-$880, return air path addition runs $540-$1,380, plenum leak sealing runs $240-$540, filter box modification runs $280-$680. Full air handler replacement runs $2,800-$4,800. All pricing includes diagnostic, parts, labor, manufacturer warranty registration, and Purisync 2-year labor warranty. Refrigerant work performed under EPA Section 608 certification.

Should I upgrade my PSC blower to ECM?

Depends on equipment age and operating pattern. ECM motors use 30-50% less electricity than PSC equivalents at typical operation, particularly during low-stage cooling and continuous fan operation. Typical annual savings: $120-$280 for households running continuous fan circulation for IAQ purposes, $60-$140 for households on heating/cooling-only operation. Upgrade cost: $540-$980. Simple payback: 4-8 years for continuous fan households, 6-12 years for heating/cooling-only operation. Best candidates: equipment 5-12 years old in good condition (not approaching whole-system replacement); equipment with combined AC + furnace setup where the upgrade benefits both heating and cooling operation. Households planning equipment replacement within 5 years often defer the ECM upgrade and include ECM blower in the replacement equipment specifications instead. We provide payback analysis specific to your operating pattern during quote consultation.

What’s the difference between cased and uncased evaporator coils?

Cased coils come in a pre-built sheet metal cabinet with the coil inside, sliding into place on top of the furnace or in the air handler with standardized fittings — easier installation, less labor. Uncased coils are just the coil itself, installed inside the existing air handler or plenum, requiring modification of the plenum opening to fit the coil. Uncased coils have lower equipment cost but higher installation labor due to the plenum modifications. Pricing: cased coil replacement runs $1,180-$1,940 installed, uncased runs $1,380-$2,180. Choice typically follows the original installation — if the home has a cased coil, replacement with cased coil is standard; if the original was uncased, replacement with uncased is typical to match existing plenum configuration. R-454B refrigerant compatibility, AHRI-listed combinations, and TXV (thermal expansion valve) matching to refrigerant and capacity are technical requirements regardless of cased versus uncased choice.

I have airflow problems — should I add more return ducts?

Often yes, particularly in older Kirkwood homes built before 1980 when single central return was the common design. Symptoms of inadequate return: hot rooms despite cooling running, pressure imbalance causing door swings or whistling at door undercuts, equipment cycling on limit switch from inadequate airflow, dust accumulation patterns suggesting air infiltration from outside. Diagnosis: static pressure measurement with Testo 510i manometer at the air handler — total external static pressure above 0.8 inches WC indicates restricted airflow, with return-side measurement isolating whether the restriction is supply-side or return-side. Return air path additions typically run $540-$1,380 depending on ductwork routing complexity. Adding return registers in bedrooms (which have closing doors that isolate them from central return air paths) is a common scope. We evaluate the specific airflow situation during site walk-through rather than recommending standard solutions without measurement.

When should I replace the whole air handler versus repair individual components?

Component-level repair makes sense when: a single component has failed on otherwise-functional equipment (blower motor replacement on 10-year-old air handler with sound cabinet and working coil); the failure is in a wear component with expected replacement during equipment service life (capacitors, blower wheels, control boards); the equipment is under 12 years old with substantial remaining service life; and the failure is straightforwardly diagnosable to a specific component. Full air handler replacement makes sense when: multiple components are failing or approaching failure on aging equipment (15+ years old); cabinet corrosion compromises structural integrity or refrigerant connections; electrical issues affect multiple sub-systems; capacity change is needed (home addition, equipment upgrade); or component-level repair cost approaches or exceeds replacement cost. We provide explicit repair-versus-replace cost comparison with the specific findings rather than defaulting to one approach.

---

Contact Purisync Heating and Air

For air handler diagnostic, blower motor or ECM upgrade quote, evaporator coil replacement, plenum modification, or full air handler replacement, contact our 325 N Kirkwood Road office at (314) 338-5111. We provide diagnostic visits with specific findings and repair-versus-replace cost comparison so customers can choose the approach that fits their equipment age and budget.

• Emergency Line (24/7): (314) 338-5111
• Address: 325 N Kirkwood Rd #245, Kirkwood, MO 63122
• Email: info@purisyncheatingairconditioning.xyz
• St. Louis County Mechanical Contractor License: #MC-2014-08439-STL
• Kirkwood Business Registration: #BL-2014-1187
• EPA Section 608 Universal: #608U-2014-385721

Contact Us →

Office Hours

• Emergency Service: 24 hours a day, 7 days a week
• Office Staff: Monday – Saturday, 9:00 AM – 5:00 PM
• Closed: Sundays and State/Federal Holidays (emergency line always active)