Hello, I am looking for some advice. In our house, we experience a very strong burning smell (like burning wires). Now, this smell mainly occurs on hot, humid days from mid May through September. The smell only happens between 8:30 pm to 10 pm. We first notice this smell on the 2nd floor, then in the two areas of the house where the ceiling is open to the 2nd floor. The smell will stay pretty much confined to just the hallway area, and not go into the 2nd floor rooms. The smell will last about 15 to 20 minutes, then leave. The smell tends to happen a couple of days in a row, then we will not notice it for about a week or two. This is going on the third summer of noticing this smell.

We have had two different HVAC companies out to look at this. The first company replaced the motor in the upstairs unit (we have two units, one in the basement and one in the attic). Although, the motor did not look that bad, plus the smell came right back in about a week. The second company inspected both units and again found nothing wrong with either units (no smell inside or any sign of burn marks) nor wiring to the units. We had the recessed lights checked on the second floor and nothing was found wrong. We do change the filters regularly and will still notice this smell after one is changed.

Unfortunately, none of the companies were here to experience the smell. Since the smell only lasts about 15 to 20 minutes, it would almost be pointless to call someone to come check it out.

So, any advice or pointers. We would love to hear them since we are going nuts thinking what could be a possibility

Thanks for the help

Turn the heating system off before the time you smell the whatever, see if it still there, if it was coming from the heating equipment it would seem it would be in all the rooms that have heat vents

Pylepdc, You should get a medium or Psychic to your house. Trust Me.

Did you check all the wires in the house by sniffing them?

Yeah... this was asked on May 27 of 2010... I'm guessing they either solved it or the house burned down by now.

Hopefully you found out what it was. For anyone else who googled "burned smell in house":
Could be metal thieves burning copper wire. If you have wooded or abandoned areas near you metal thieves may be using them to burn the insulation off wires and cables.
We have a real problem in our area. There are established burn sites where they burn all the time. They burn small amounts for many hours (little smoke), usually at night. People don't report it because it is so constant and because it doesn't smell like you would expect, like only plastic. Until I started using air purifiers, I only smelled it when I came back in my house after being gone for a few hours. Took me more than a year to figure out what it was. In the daytime, the smell wasn’t outside, only in my house.

What you describe, the few minutes of smell in the late evening, could be the surge of smoke when they first start up. It is part wood smoke, part something toxic smelling.

They steal different kinds of cable and wire so the smell can change. Sometimes, it smells like a really dirty oven on self-clean, or like a barbecue grill being burned off after it sat all winter with rancid grease and mold. Other times it is a toxic chemical kind of smell.
Think about it. The news is full of reports about the massive amounts of metal theft, particularly wire. Where are they burning all that wire?

In my community, it is in the woods behind a rental trailer, surrounded by subdivisions full of children and families. Because this is their “business”, they have gotten really clever about disguising the burn location (like two older burn barrels as decoys) so even when enforcement is called, they don’t find anything. If you are in a rural area, you are even more likely to have a wire burning site nearby.

If the odd burning smell is outdoors, please report it, even if you aren't sure what it is or where it is coming from!! 
There isn't a "they" out there automatically dealing with this. They only investigate when people complain about it.