Question 1

What is the most efficient Lennox furnace?

Accepted Answer

The Lennox SLP99V reaches 99% AFUE — the highest efficiency rating of any gas furnace on the market. It converts virtually every dollar of gas into usable heat.

Question 2

Are Lennox furnaces reliable?

Accepted Answer

Very much so. Lennox has manufactured HVAC equipment since 1895 and is recognized for premium build quality. With annual professional maintenance, a Lennox furnace commonly lasts 20+ years.

Question 3

How quiet is a Lennox furnace?

Accepted Answer

The SLP99V runs as low as 41 decibels — below whisper level. Even Lennox mid-range furnaces are substantially quieter than most competitors, thanks to insulated cabinets and variable-speed blower technology.

Question 4

What do Lennox furnace error codes mean?

Accepted Answer

Lennox furnaces display error codes via LED blink patterns on the control board. Common codes include E228 (ignition failure), E250 (rollout switch open), E270 (blower calibration fault), and E301 (high-limit switch open). On Lennox iComfort systems, error codes display as alphanumeric codes on the thermostat. Our technicians have access to the full Lennox diagnostic code library for all models.

Question 5

Why are Lennox parts so expensive and hard to find?

Accepted Answer

Lennox uses many proprietary components that are not interchangeable with other brands, including specific control boards, blower motors, and evaporator coils. Lennox restricts parts sales to authorized dealers, making it difficult for independent companies to source them. This exclusivity drives up costs, and repair parts can take days to arrive if not locally stocked. We maintain a stock of high-failure Lennox parts to minimize wait times for our Asheville customers.

Question 6

What is the difference between Lennox SL, EL, and ML series?

Accepted Answer

The Lennox SL (Signature) series is the premium tier with variable-speed operation, the highest SEER/AFUE ratings, and iComfort compatibility. The EL (Elite) series is mid-range with two-stage operation and strong efficiency. The ML (Merit) series is the builder-grade economy line with single-stage operation. For Asheville homes, we typically recommend the EL series as the best balance of performance and value for the mountain climate.

Question 7

Why won't my Lennox furnace blower turn off?

Accepted Answer

A Lennox furnace blower that runs continuously is often caused by a failed control board relay stuck in the closed position, a thermostat set to fan-on mode, or a shorted wire in the thermostat cable. On Lennox SLP98 and EL296 models, a control board firmware glitch can also cause continuous fan operation. Turning off power at the breaker will stop the fan, but the underlying cause needs professional diagnosis.

Question 8

How do I reset my Lennox iComfort thermostat?

Accepted Answer

To reset a Lennox iComfort S30 or E30 thermostat, press and hold the menu button for 10 seconds to access the reset options. A soft reset clears temporary faults while a factory reset erases all programming and Wi-Fi settings. If the thermostat is unresponsive, you can also reset by pulling the common (C) wire at the furnace for 60 seconds. Note that an iComfort reset will not fix underlying equipment faults.

Question 9

What does Lennox error code E228 mean?

Accepted Answer

Lennox error E228 indicates an ignition failure where the furnace tried to light but could not detect a flame. This is commonly caused by a dirty or failing flame sensor, a cracked hot surface ignitor, or a gas supply issue. Clean the flame sensor with fine emery cloth as a first step; if the error persists, the ignitor or gas valve may need replacement. This is one of the most common service calls we handle for Lennox systems in Asheville.

Question 10

Can I use a Nest thermostat with my Lennox system?

Accepted Answer

A Nest thermostat is compatible with standard Lennox ML and EL series equipment that uses conventional 24V wiring. However, Lennox iComfort-enabled systems (SL series) require the proprietary iComfort thermostat to access variable-speed and communicating features. Installing a Nest on an iComfort system will force the equipment to run in basic single-stage mode, dramatically reducing efficiency. We can evaluate your specific Lennox model for compatibility.

Question 11

Is Lennox a good brand or should I switch to something else?

Accepted Answer

Lennox makes high-quality, efficient equipment, but their proprietary parts strategy means higher repair costs and longer parts wait times compared to brands like Carrier or Trane. If you value top-tier efficiency and quiet operation and are prepared for higher maintenance costs, Lennox is excellent. If repair cost and parts availability are priorities, Trane or Carrier offer similar quality with better aftermarket support. We service and install all major brands in the Asheville area.

Question 12

Why does my Lennox furnace smell like burning?

Accepted Answer

A burning smell from a Lennox furnace at the start of heating season is usually dust burning off the heat exchanger and is typically harmless, clearing within 30 minutes. However, a persistent burning plastic smell may indicate an overheating blower motor, melting wire insulation, or a cracked heat exchanger allowing combustion gases into the airstream. If the smell does not clear quickly or smells like plastic or electrical burning, shut the system off and call for emergency service.

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