What MFD capacitor do I need for my Lennox AC?

The correct replacement for Lennox model OEM Lennox Dual Run Capacitor — 81W20 is this exact part. It is the factory-specified replacement with exact OEM specifications. Using a part with different specifications can cause equipment damage or void your warranty. You can verify this by checking the data plate on your Lennox equipment which lists the model number OEM Lennox Dual Run Capacitor — 81W20.

My AC hums but will not start. What part do I need?

An AC that hums but will not start is the classic symptom of a failed capacitor. The capacitor provides the electrical boost needed to start the compressor and fan motors. When it fails, you hear the hum of the motor trying to start but it cannot overcome inertia. Other symptoms include the fan spinning slowly, the AC cycling on and off rapidly, or a visibly swollen or leaking capacitor. Replacement cost: $15 to $80 for the part, DIY in 30 minutes.

Lennox

OEM Lennox Dual Run Capacitor — 81W20

Name: OEM Lennox Dual Run Capacitor — 81W20
Brand: Lennox
SKU: LNX-81W20
Price: 18.95 USD
Availability: InStock

SKU: LNX-81W20 Brand: Lennox

$18.95 $24.95

OEM Guaranteed

Same-Day Ship

30-Day Returns

Secure Checkout

Texas CMBL #19328542014

SAM.gov Registered

Govt POs Accepted

The genuine OEM Lennox 81W20 dual run capacitor delivers the electrical charge that starts and runs both the compressor and the condenser fan motor in your Lennox outdoor unit. This single component provides two capacitance values, giving each motor the phase shift and torque needed to spin up smoothly and run efficiently under load.

Common failure symptoms: The outdoor fan won't start (or only starts when spun by hand), the compressor hums but won't turn on, warm air from the vents, frequent breaker trips, or a bulging/leaking capacitor top. A weak capacitor forces motors to draw excess current, leading to overheating and premature motor failure.

Why OEM matters: Capacitance rating, voltage, and tolerance must match your motors exactly — an incorrect value strains the compressor and shortens its life. The OEM Lennox 81W20 is spec-matched to your unit's motors, protecting your most expensive components and restoring reliable cooling.

Shipping Information

Orders placed before 3PM CST ship same business day
Standard delivery: 2-5 business days
Express shipping available at checkout
Free shipping on orders over $75
Tracking number emailed upon shipment

Return Policy

30-day returns on unused parts in original packaging
Electrical parts (capacitors, contactors, control boards) are final sale once installed
Email info@nationalhvacparts.com to initiate a return
Refunds processed within 5-7 business days

OEM Lennox Dual Run Capacitor — ...

$18.95

Frequently Asked Questions

Does this Capacitor fit my Lennox OEM Lennox Dual Run Capacitor — 81W20?

Yes. This is the factory-specified OEM capacitor for the Lennox OEM Lennox Dual Run Capacitor — 81W20. It is a direct drop-in replacement that fits without modification. Always verify the model number on your equipment nameplate before ordering.

How do I replace the capacitor on my Lennox OEM Lennox Dual Run Capacitor — 81W20?

Difficulty: Easy (20–30 min)
Step 1: Turn off power at breaker. Step 2: Open condensing unit panel. Step 3: Photograph the old capacitor wiring (Common/Herm/Fan). Step 4: Discharge old capacitor with insulated screwdriver. Step 5: Disconnect and remove old capacitor. Step 6: Mount new capacitor, reconnect wires to matching terminals. Step 7: Close panel, restore power, test. Tools: screwdriver, needle-nose pliers.

My AC hums but won’t start. What part do I need?

An AC that hums but won’t start is the classic symptom of a failed capacitor. The capacitor provides the electrical boost to start the compressor. When it fails, you hear humming but the motor can’t overcome inertia. Other symptoms: fan spinning slowly, AC cycling on/off rapidly, or a visibly swollen capacitor. Fix: replace capacitor ($15–$80 DIY, 30 min).

Is this capacitor compatible with Bryant or Payne too?

Many Lennox parts are cross-compatible with Bryant and Payne since all three brands are manufactured by Carrier Global Corporation. The same physical part is often used across brand labels with different model numbers. To verify: check your Bryant or Payne equipment service manual for cross-compatible part numbers, or email info@nationalhvacparts.com with your model number.

Should I use OEM or aftermarket for my Lennox capacitor?

OEM strongly recommended. OEM capacitors have ±6% MFD tolerance vs aftermarket ±10%. The looser tolerance causes motor winding stress, higher temps, and shorter compressor life. Price difference is only $10–$20 — OEM is the clear value choice.

How fast does National HVAC Parts ship?

Orders placed before 3:00 PM CST ship the same business day. Standard delivery is 2–5 business days anywhere in the continental United States. Express shipping available at checkout. We ship from Houston, TX to all 50 states. 30-day return policy on all parts.

Menu

OEM Lennox Dual Run Capacitor — 81W20

Shipping Information

Return Policy

Frequently Asked Questions