My husband and I moved into a rental house. The AC isn't working properly, and a professional told us that a pipe needs a small cut so the water flows easily for the AC to work. We cannot of course make any changes to a pipe without permission.

Every time the AC stops working (almost daily now) I or my husband have to go to the attic to flip a little cup (attached to pipes for the AC) to pour the water out and flip it back. AC starts working right away.

Now I went to the attic and noticed this orange glowing thing, first I thought it was a pipe but it has a rectangle form or maybe not all pipes are in a cylinder form?

I also thought it might be sticking out of the roof and got hot by the sun however I went to the attic in the morning (darkish outside) and it was still glowing, less bright but still glowing (see picture).

I don't know if the AC has anything to do with it and maybe this is completely normal. Orange glow looks same glow when a iron gets hot.

Any answer appreciated. Thank you.

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  • 5
    Sun shining into a pipe? What time of day was this taken? Shine a flash light on it, what color is the pipe, white?
    – matt.
    Commented Aug 31, 2023 at 13:25
  • 2
    Did it got lit by some light in your house? That must be the consequences of something illuminating the tube. I cannot immagine an scenario, except an chimney fire, that would make it glow by heat.. In that case the house would have burnt down long ago..
    – Martin
    Commented Aug 31, 2023 at 13:51
  • 1
    Observe it while someone switches off the main breaker. If it turns off, it's somehow connected to electric power
    – Martin
    Commented Aug 31, 2023 at 14:06
  • 1
    And if the main breaker cuts it off, then do a binary search to find out which breaker controls it. Turn off half the breakers - if still on, turn those back on and turn the other half off, if off then turn 1/2 of those on and check again. Lather, rinse, repeat. Once you have figured out which breaker controls it, see what else is on the same circuit so that (a) you know if it is OK to leave it off and (b) that may provide a clue. Commented Aug 31, 2023 at 14:52
  • 1
    That makes completely sense. Hopefully, it is connected to something in my house. I have to figure out which breaker it is (after the main breaker test) so I can leave it off until someone fixed the problem. Hopefully, this will do the trick. I'm happy I posted on this site. Thanks again! ^^
    – Patricia
    Commented Aug 31, 2023 at 15:54

4 Answers 4


It's a PVC white pipe. I've got two in my attic. The 4" pipe goes through the roof and has no cover on it, probably a vent and could be used for running a snake down to unclog it. All it needs is a little daylight, or a street light/flood light to start glowing and direct sunlight really brightens it up.

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Just for the heck of it, I took another picture, with the same settings, at 1:00 PM ET with the sun overhead. The first picture was at 8 AM and just daylight.

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  • Looking at the OP's picture again, I can just see a line on the pipe that looks like the standard printing I've seen on the PVC I've been installing lately. I'd venture to say you're correct except that the OP states the pic was taken before the sun came up and that the thing is rectangular instead of round. +1 anyway.
    – FreeMan
    Commented Sep 6, 2023 at 21:02
  • @FreeMan Some of that bothered me too but I thought the standard printing could be mistaken for a corner and in the comments the OP mentions it could be a pipe. My neighbor's flood lights cause a slight glow...
    – JACK
    Commented Sep 6, 2023 at 21:36
  • @FreeMan How can you tell its rectangular and not a round pipe? I'm curious.
    – matt.
    Commented Sep 7, 2023 at 2:18
  • @matt. by reading the OPs description of the "thing".
    – FreeMan
    Commented Sep 7, 2023 at 14:51


It looks like you have a thin-walled, light color pipe coming up. The sun is shining into it, and so it looks like it's glowing. Probably a thin-wall PVC pipe, like you would usually see in drainage.

I'm guessing you have a bathroom right about there? If so, that's likely your bathroom fan vent.

  • It is indeed close by the bathroom (above), so it might be a PVC pipe? It was shining bright through the night without any sunlight outside and without any reflection coming from the house ( I turned off the main breaker to be sure of it). I wonder what makes it glow like that. It is cooling down outside, so is that PVC pipe? It has a rectangular form and has a whitish - beige color. I will try to make another picture when it cools down completely. Thank you for sharing this information.
    – Patricia
    Commented Sep 4, 2023 at 16:36

No idea about the orange thing. But I'll give you some help with the air conditioner.

An air conditioner effectively operates as a dehumidifier. The humidity removed from the air is called condensate. It needs to go somewhere. The good news is that with the air conditioner in the attic you should be able to rely on gravity instead of needing a pump - so one less thing to fail.

A properly designed/installed air conditioner will typically collect condensate in a pan and either have a drain pipe connected to it or a condensate pump. But just in case the pipe clogs or the pump breaks, there should be a switch that turns off the air conditioner if the pan fills up. Your switch works! That is a really, really good thing, because too many times the switch doesn't work (or doesn't even exist, or there is a leak just outside the pan so the pan never actually fills up to trip the switch) and you end up with a flood - which in this case would be flood the attic and eventually drip down into the rest of the house. So the air conditioner stopping a couple of times a day is actually not a bad thing in the grand scheme of things.

What to do about it? Putting a hole in a pipe sounds strange, but might be what is needed. More typically, if the air conditioner used to work, is that the pipe is clogged. The key though is that what you need is an HVAC technician and not a plumber. There are many people who are both, but you don't want a plumber who knows nothing about HVAC.

If you are comfortable with it, do it yourself cleaning may be reasonable. Google clean condensate drain and you can find all sorts of ways to clean condensate drains, and if this is a typical clog then one of those methods should do the trick. The catch is that it might turn out to be something truly broken or, if the air conditioner never really worked correctly (e.g., new installation and not tested for more than a few minutes, or previous tenant didn't bother to complain) then it might need some change to the condensate piping.

  • 1
    Remember, though, @Patricia, that this is a rental and that maintenance work should fall to the landlord. If you have her permission, though (get it in writing!) hop right to it! Cleaning a condensate drain shouldn't be a difficult task at all.
    – FreeMan
    Commented Aug 31, 2023 at 15:30
  • 1
    "a hole in a pipe" sounds like a hacked solution that will probably work but isn't the trap and vent that is actually required.
    – Tiger Guy
    Commented Aug 31, 2023 at 16:50

this orange glowing thing, first I thought it was a pipe but it has a rectangle form or maybe not all pipes are in a cylinder form?

Yes, pipes will be cylindrical, not rectangular.

To me, that looks like a piece of wood that is oddly colored & lit from the outside, not from any "glow" coming from the inside.

It would really help if you could

  1. Get a picture that is more in focus and not so fuzzy, and
  2. Get closer to the item. It's highly unlikely to be a rod of uranium glowing in your attic, so getting closer shouldn't cause you any harm. If you feel it, you should be able to determine if it's plastic or metal indicating it might be a pipe of some sort, or if it feels like wood, well, it's going to be wood.

It does look like your attic is quite well insulated, which is a nice bonus in a rental! Be sure to push the insulation aside to ensure you're stepping on rafters and not through the drywall attached to them, then fluff the insulation back up after you've had a closer inspection.

  • The only way to make a clearer picture is to get close to it. This is a bit risky to me because the house has a lot of reparations done in a very poor cheap way. I will try to make close-up picture tonight. However, if that fails, I definitely like the idea of turning the main breaker as soon as possible off to see if it will help.
    – Patricia
    Commented Aug 31, 2023 at 23:17
  • I smelled two times a fire smell in the house around 3-4 weeks ago but couldn't find anything. Now that we just discovered this issue, I just hope it doesn't link to each other. Next week, someone will come over to check things out. That way, we are sure what's going on. Thank you for your time and feedback ^^
    – Patricia
    Commented Aug 31, 2023 at 23:21
  • A) that is not the glow of embers of wood on fire. B) If something in your house were on fire 3-4 weeks ago, you would definitely have known by now.
    – FreeMan
    Commented Sep 1, 2023 at 12:01

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