How To Look At A House

McGarry and Madsen's home inspection blog for buyers of  

site-built, mobile/manfuactured and modular homes

What does an orange or yellow flame at gas furnace mean?

Friday, December 3, 2021

A natural gas flame should be blue, with maybe just a small streak of orange at the tip, which indicates proper combustion. Any other color means incomplete gas combustion; which can be due to insufficient air supply, dirt buildup, or even a cracked heat exhangler. An orange or yellow flame also increases the amount of carbon monoxide (CO) produced. 

    We recommend you take a peek at your gas burners, while they are operating, at the beginning of the each heating season. If you don’t like the color of the flame, or the flame pattern is irregular or wavering, like in the photo below, call a service tech for further evaluation. An even better idea is to have a service contract with a heating and air conditioning company that checks your complete system annually.

• • • • • • • • • • • • • • • • • • • • • • • • • • • • • • •

  To learn more about gas furnace systems, see these other blog posts:

• Is the energy efficiency of the furnace part of the SEER rating of a central air conditioning system?

Why is the base of the gas flue at the roof red? 

• Where is the air filter for my central furnace? I can’t find it?

• What is the required clearance for access and working space in front of a furnace or air handler?

• What is the minimum slope of a flue connector for a gas furnace or water heater? 

• When is it acceptable to use indoor air as combustion air for a furnace? 

• Is a furnace allowed in a bedroom, bathroom, or an adjoining closet? 

• Can the return air be in the same room as the gas furnace?

• What color should the flame be in a natural gas furnace?

     Visit our HEATING AND AIR CONDITIONING page for other related blog posts on this subject, or go to the INDEX for a complete listing of all our articles.



Water Heaters

Water Heater Age

Wells

Septic Tank Systems

Structure and Rooms

Plumbing Pipes

Termites, Wood Rot

& Pests

Sinkholes

Stairs

When It First

Became Code

"Should I Buy A..."

Park Model Homes

Site

Shingle Roofs

Safety

Stucco

Remodeling

Wind Mitigation

Roof and Attic

"Does A Home

Inspector...?"

Pool and Spa

"What Is The Difference Between..."

Radon

Brick

Plumbing

Concrete and

Concrete Block

Metal Roofs

Foundations

Modular Homes

Rain Gutters

Mold, Lead & Other Contaminants

Condominiums

Older and

Historic Houses

Crawl Spaces

Mobile-Manufactured Homes

Building Permits

Life Expectancy

Clay Soil

Insurance

Floors

Insulation

Toilets

Exterior Walls

& Structures

Generators

Common Problems

HUD-Code for

Mobile Homes

Garages and Carports

Flat (Low Slope) Roofs

Electrical Panels

Sprinkler Systems

Electrical Receptacle Outlets

4-Point Inspections

Hurricane Resistance

Frequently Asked Questions (FAQ)

Home Inspection

Heating and Air Conditioning

Building Codes

Fireplaces and Chimneys

Inspector Licensing

& Standards

Energy Efficiency

Washers and Dryers

Electrical

Kitchens

Doors and Windows

(placeholder)

Cracks

Electrical Wiring

Click Below  

for Links

to Collections

of Blog Posts

by Subject

Plumbing Drains

and Traps

Appliances

Smoke & CO Alarms

Aging in Place

Top 5 results given instantly.

Click on magnifying glass

for all search results.

Bathrooms

Lighting

AFCI, CAFCI,

DFCI, & GFCI

Sinks

Air Conditioner & Furnace Age/Size

Attics

Electrical Switches

Siding

Search

This

Site

Water Intrusion

Electrical - Old

and Obsolete

(placeholder)

Foundation Certifications

Tiny Houses

About Us

(placeholder)