I have an orange flame in all my gas appliances (gas furnace, gas water heater, and gas stove) and cannot seem to determine the cause.


So far, I have had the gas company come out. I had an appliance tech look at our stove, and tomorrow, I am having a guy check it out on the furnace.

When the gas company (XCel energy) checked it out yesterday, they measured the pressure on with appliances running and without. In both situations things measured fine. Our meter was making some noise, so the gas company put in a new one. They also measured Carbon Monoxide (CO) levels and found nothing wrong throughout the house.

Today, I had an appliance tech come check it out. He checked our stove and he said everything checks out fine. He also checked CO levels throughout the house. In any case, his tests revealed no cause for the issue.

Tomorrow, I am having a furnace guy come in, this is the big one, because the orange flame seems to be causing the furnace to short cycle.

My hypothesis

My hunch is that something must be entering the line elsewhere. No gas inside the house makes me think the natural gas lines coming into the house have the problem. However, the gas company says everything is fine.

What I am looking for

Anyway, I am seeking direction on the course of action to take here. From my perspective, I cannot see how all three appliances would have issues that cause an orange flame at the same time. This seems very clear that something is going on with the gas lines, but I am at a loss of who to call to actually fix the core issue.

  • How long has this been going on? Was the house recently changed over from a different fuel source? Have you recently made any changes that would seal your house better than before? Can you think of any other changes that you've made recently? Has there been any utility service done in the area lately? Is there a drip leg installed at each appliance?
    – Tester101
    Commented Jan 16, 2014 at 17:20
  • This was going on for the last few months, I noticed stove first but it was late summer and heat was not running. I originally assumed impure lines because of utility work (I have not observed any work on our street, but do not know about other neighborhoods that might be connected). However, I did not worry about it because the CO detector did not see a problem. I honestly don't know about the drip legs. I will check tonight when I get home.
    – Terry
    Commented Jan 16, 2014 at 18:31

2 Answers 2


It is (very) surprising that the gas company (Xcel) says "everything's fine." This document from a different gas company certainly calls out non-blue flames as an issue that needs to be resolved. As does this site. And Xcel themselves.

Happening on all appliances does seem a bit less likely to be "and suddenly the air adjustments on all three went whacky" than a contamination issue - possibly water in the gas line?

I wonder how your furnace tech visit went, and what your neighbor's flames look like.

Editing post-comments: Ultrasonic humidifiers make small water droplets (without evaporating the water first) and then those small droplets evaporate while floating around - if the water contains salts or minerals, any salts or minerals in the water will end up floating around the house as tiny specks when the water evaporates from the tiny droplets. Those, evidently, are what is contaminating your gas flames as they are sucked in along with the air required to burn the gas. Old-style "sponge" dehumdifiers (should) only result in water vapor in the air, as they actually evaporate the water (and this eventually leads to a build-up of scale and salts in the humidifier and its sponge element, as those do not evaporate.)

  • Our furnace tech could not explain the flame either. We did find that the eliminating humidifiers in the house worked. It is strange because our air is very dry whenever the humidifiers are not running. As far as neighbor flames go, I do not have any further information on that front. Something about it being freezing cold here in MN means that people pull into their garage and never venture outside :-)
    – Terry
    Commented Jan 21, 2014 at 21:10
  • Hmm - so that would imply that the "contamination" was from the water in the air - ultrasonics and hard water, perhaps? The old-style evaporative (foam/sponge) humidifiers (should) only put water vapor into the air - the ultrasonics make small water droplets without evaporation, and those water droplets evaporate, leaving whatever dissolved minerals/salts they had floating around as specks - which might then be flame contaminants. Or such is my best guess. If you have evaporative humidifiers, then I don't know how that's enough to cause the problem...but if it is, it is.
    – Ecnerwal
    Commented Jan 21, 2014 at 21:21
  • Ecnerwal. I have an ultrasonic humidifier. I think that you are correct in your assessment. Testing back and forth, I was able to determine that it only happens when we run the humidifier(s). Both are ultrasonic. I never knew the water droplet vs evaporation thing. That is interesting. Can you edit your answer and include the comment about minerals in ultrasonic humidifiers? Then I will accept your answer. Thanks!
    – Terry
    Commented Jan 22, 2014 at 16:36
  • 2
    I had the same problem after buying and activating an ultrasonic humidifier. The range flame was very orange. I read the answers here, unplugged the humidifier and an hour later gas flame was back to pure blue. I confirmed this weird problem by turning humidifier on. Ten minutes later flame was basically orange, shut off, waited five minutes and flame was almost back to normal blue. Maybe using distilled water would be fine?
    – user19497
    Commented Jan 26, 2014 at 19:20
  • Most sources state that an orange flame as dangerous because it produces more carbon monoxide. Is that true if an ultrasonic humidifier is causing the orange flame from hard water / minerals?
    – ashes999
    Commented Feb 7, 2016 at 15:45

The quick answer is that the humidifier/vaporizer causes the orange flame. This happened to us a couple of weeks ago. The gas company said they would send over a technician. He called us first to confirm our orange flame. He asked if we recently turned on a humidifier/vaporizer. We had. We shut it off and things went back to normal in an hour or so.
I am surprised other gas companies did not know this and I'm surprised my company did not include this in their monthly mailings.

Not the answer you're looking for? Browse other questions tagged or ask your own question.