Home>Discussions>INSULATION & HVAC>Desperate for help- odor in the home when heating system is on
7 posts / 0 new
Last post
Desperate for help- odor in the home when heating system is on

Hello All,
I am so desperate for help in solving an odor issue in our home. The house was built around 1910 and a gut renovation was done around 10 years ago.
The chimney is a "cheater"- it looks like a brick chimney from the outside, but inside the house it is just a framed in area with metal venting pipes- one each for the fireplace and furnace.
The issue is that when the chimney is drafting- meaning when our Buderus oil furnace is firing or we have a fire going in our fireplace- a strong smell becomes present in our second floor laundry closet- which is right next to the chimney. It is a musty/moldy very unpleasant smell. It does NOT smell like soot/smoke. Here are some relevant details:

  • We had an inspection from our fuel company. They said that the venting of the furnace looked a bit "jerry rigged" and recommended a chimney company.
  • We had the chimney company come- they cleaned the chimney, resealed the top, and said that it indeed looks jerry rigged. They are recommending a solid piece of stainless pipe rather than the type that is in there now (it is SS, but it connects every 3 feet). They didn't have any real explanation for the smell. The replacement liner was more of a "should do at some point", but they didn't seem to think it was critical, didn't find any immediate safety concerns. Quote for the new liner is coming- expecting it to be in the $1000s.
  • Ever since the chimney guys came the smell has been worse. It is now present in a less concentrated form, in other areas of the house. I can smell it when I walk in the door. I want to cry. :(
  • Last year we had an issue whenever we lit the fire where the negative pressure was causing air to come out of a light switch in the wall that stunk badly of carrion. We had been hearing critters in the wall, so we had a fairly good idea of what the problem was. We had a pest control guy out. He cut open the wall and removed a dead mouse. Based on the sounds we were hearing we thought for sure there was a squirrel problem, but he only found evidence of mice. We do need to do more trapping as I suspect we still have some mice living in the walls.

I feel like the costs keep mounting with this but we aren't getting any resolution. I would be willing to pay quite a bit if somebody could say to me: this is your problem, and this is what it will cost to fix it. Instead, we just keep paying a few hundred over and over and not getting anywhere. I just don't know who I should call next to help figure this out?
If it is something in the walls, I still don't understand why the smell comes out only when the chimney is drawing??

Any advice would be GREATLY appreciated.

Thank you!!

Re: Desperate for help- odor in the home when heating system is on

Pretty hard to diagnose over the 'net.

Your "musty/moldy" description makes me wonder if the chimney chase is wet from a leak and the warmth from the chimney while the boiler is firing causes the smell. I'd look closely for water leaks on the framing.

I haven't ever seen a SS chimney that didn't come in sections. If they are talking about a SS "liner" then I would be careful that all clearances are met for the liner.

Re: Desperate for help- odor in the home when heating system is on

check to see if either the FP or home heater have adequate air supply to the fire box. If the FP is using inside air for combustion for example, you are creating negative air pressure in your home and it shows up in the laundry.

I'd start by checking for a leak in the laundry plumbing. Start by capping the waste pipe to the washer then run the furnace. If there is no trap in the waste pipe, the smell can be sewer gasses coming in backwards to balance the negative air pressure.

Re: Desperate for help- odor in the home when heating system is on

You have more dead rodents in there. You need to get them out.

Re: Desperate for help- odor in the home when heating system is on

and what DJ said

(I missed the rodent part)

Re: Desperate for help- odor in the home when heating system is on

Thank you so much for the responses.

Houstonremodeler...My dad did hypothosize at one point that it could be related to sewer gases. It isn't a strong unmistakable rotten egg kind of smell, but if it will be easy enough to test by just capping that waste pipe, then we can definitley do that ourselves. But yes, to both you and dj, I think the dead rodents are the most likely scenario. Not sure why we don't smell them in the summer though?

Anyway, we are going to try and agressively trap to eliminate the mouse problem (the pest guy last year recommended multi-mouse traps...we ordered them and will be setting them up this week).
If there are a lot of dead mice in the chimney case, how can we get them out?
Who can I call to help with this (firm diagnosis and then remediation)?? That is one of our biggest problems, we can't seem to locate the right kind of professional to assist with this problem.

Last year, when we went to all the trouble of cutting the wall open to remove the dead mouse, many laughed at us since here in New England I guess you are suppsed to just "Wait it out" and the smell goes away in a couple of weeks. But it seems we must have some endless cycle of them dying in our walls??? Maybe there is a booby trap somewhere in the chimney case? :eek: It is really so frustrating.

Thanks for you help!! :)

Re: Desperate for help- odor in the home when heating system is on

WHen the boiler (probably oversized) is running, it's making the house slightly negative pressure. It's very possible that in the top notch renovation (flippers paradise I'm sure) that some thing wasn;t vented correctly or a trap is incorrect on the plumging. I have 1 ro 2 traps that can suck themselves dry in my home from improper venting. ONe I plan to correct eventually. The other happens when we use the soaking tube.

Pour some water down all your traps, and.or crack a window ever so slightly, then run the boiler and see if the problem is still there.

Sponsored Stories

TV Listings

Find TV listings for This Old House and Ask This Old House in your area.