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Honeywell · MO08CESWK 8,000 BTU Compact Portable Air Conditioner

Honeywell MO08CESWK 8,000 BTU Compact Portable Air Conditioner E1 Error Fix: Room Temperature Sensor Fault

The room (ambient) temperature sensor has malfunctioned or is disconnected — the unit cannot accurately measure room temperature and will not operate in auto mode; try unplugging the unit for 5 minutes and plugging it back in; if E1 persists, the thermistor sensor has failed and requires professional replacement or warranty service

Medium severity2 fixes available✨ Free fix available

Quick Answer

Error E1 on the Honeywell MO08CESWK 8,000 BTU Compact Portable Air Conditioner means: Room Temperature Sensor Fault. The top-ranked community fix is “Test and Replace Room Temperature Sensor Thermistor” (hard difficulty, ~60 min, DIY cost: $10-$30). 2 community-ranked fixes available below.

Published February 2026 · 2 fixes · air conditioner

Content is based on manufacturer service documentation, community repair experience, and OEM technical bulletins. Always verify with your owner's manual.Learn about our editorial standards.

When to Call a Professional

While many air conditioner repairs can be done safely at home, consider hiring a qualified technician if:

The repair involves electrical wiring, gas lines, or refrigerant
You've tried the top-ranked fix and the error persists
You smell gas, see sparking, or notice water leaking
The repair requires specialized tools you don't have
Your appliance is still under manufacturer warranty

Average professional repair cost for this issue: $150-$250.

Other Honeywell Models with Error E1

MN14CCSBB 14,000 BTU Portable Air Conditioner with Dehumidifier and Remote Control

air_conditioner · 2 fixes

Other Honeywell MO08CESWK 8,000 BTU Compact Portable Air Conditioner Error Codes

Clean Filter Reminder

2 fixes

Evaporator Temperature Sensor Fault

2 fixes

Condenser Temperature Sensor Fault

2 fixes

Water Tank Full — Unit Stopped

2 fixes

System Defect — Contact Service

2 fixes

MECH-EXHAUST

Exhaust Hose Installation Problem

2 fixes

MECH-ICING

Ice Buildup on Evaporator Coils

2 fixes

MECH-LEAK

Water Leaking from Unit

2 fixes

People Also Ask About Honeywell MO08CESWK 8,000 BTU Compact Portable Air Conditioner Error E1

What does error code E1 mean on a Honeywell MO08CESWK 8,000 BTU Compact Portable Air Conditioner?

Error code E1 on the Honeywell MO08CESWK 8,000 BTU Compact Portable Air Conditioner means: Room Temperature Sensor Fault. The room (ambient) temperature sensor has malfunctioned or is disconnected — the unit cannot accurately measure room temperature and will not operate in auto mode; try unplugging the unit for 5 minutes and plugging it back in; if E1 persists, the thermistor sensor has failed and requires professional replacement or warranty service

How do I fix error code E1 on my Honeywell MO08CESWK 8,000 BTU Compact Portable Air Conditioner?

The most successful fix is "Test and Replace Room Temperature Sensor Thermistor" (hard difficulty, ~60 minutes). Estimated DIY cost: $10-$30. HomeMD has 2 community-ranked fixes for this error.

Is error code E1 on a Honeywell MO08CESWK 8,000 BTU Compact Portable Air Conditioner serious?

This error is rated medium severity. It should be addressed soon, but your appliance may still function in a limited capacity.

Can I fix Honeywell MO08CESWK 8,000 BTU Compact Portable Air Conditioner error E1 myself?

Yes — the top-ranked community fix ("Test and Replace Room Temperature Sensor Thermistor") is rated hard difficulty and takes about 60 minutes. Tools needed: T20 Torx screwdriver, Multimeter.

How much does it cost to repair Honeywell MO08CESWK 8,000 BTU Compact Portable Air Conditioner error E1?

DIY cost: $10-$30. Professional repair typically costs $150-$250. Many homeowners save money by trying the top-ranked community fix first.

What other error codes does the Honeywell MO08CESWK 8,000 BTU Compact Portable Air Conditioner have?

The Honeywell MO08CESWK 8,000 BTU Compact Portable Air Conditioner has 8 other known error codes, including: CF (Clean Filter Reminder), E2 (Evaporator Temperature Sensor Fault), E3 (Condenser Temperature Sensor Fault), E4 (Water Tank Full — Unit Stopped), E5 (System Defect — Contact Service), and 3 more.

Which other Honeywell models have the E1 error?

Error code E1 also appears on 1 other Honeywell model: MN14CCSBB 14,000 BTU Portable Air Conditioner with Dehumidifier and Remote Control. The fix may vary by model, so check each model's specific page for tailored repair steps.

What other error codes does the Honeywell MO08CESWK 8,000 BTU Compact Portable Air Conditioner have?

The Honeywell MO08CESWK 8,000 BTU Compact Portable Air Conditioner has 8 other known error codes:

CF — Clean Filter Reminder (2 fixes)
E2 — Evaporator Temperature Sensor Fault (2 fixes)
E3 — Condenser Temperature Sensor Fault (2 fixes)
E4 — Water Tank Full — Unit Stopped (2 fixes)
E5 — System Defect — Contact Service (2 fixes)
MECH-EXHAUST — Exhaust Hose Installation Problem (2 fixes)
MECH-ICING — Ice Buildup on Evaporator Coils (2 fixes)
MECH-LEAK — Water Leaking from Unit (2 fixes)

Which other Honeywell models have the E1 error?

Error code E1 also appears on 1 other Honeywell model:

MN14CCSBB 14,000 BTU Portable Air Conditioner with Dehumidifier and Remote Control (air conditioner) · 2 fixes

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