Do you smell it when outside? Sounds like it is just something smelly outside that is coming in when you open the windows. Nothing to do with the house itself...more to do with the location or surroundings outside.

Are there still other fields/farmlands nearby? Have you ever been near farmland after they have spread fertilizer on them? It is a horrid smell that lingers for quite a while.

Is there a creek or bog nearby?

Is there a waste treatment plant nearby?

Is there a horse/hog farm nearby?

Is there a trash landfill nearby?

Do you have septic or sewers? Any pumping stations?

These are all things that will produce more smell as the weather warms up. When I say nearby, it could be several miles away and you would still be affected by the smells.

We live about a mile from a farm and we sometimes smell the cows....the manure or whatever. Also we recently bought a home with a small ornamental tree....probably some ornamental pear. The spring blossoms were beautiful but smelled terrible.

It’s not a manure or fertilizer smell. There are fields close by but no one else in the neighborhood has responded saying they know what I am talking about on our neighborhood Facebook group. There is a lady who owns a few horses and some kids outside the neighborhood that have a few pigs but it’s not an industrial farm. All sewers are underground and no waste treatment nearby. It’s not a sewer smell. I don’t smell the smell directly outside our home at all and no other homeowners in the area have this smell issue. I can only smell it outside a few streets over where they are building our friends house. When I walk by their lot, I smell it. It’s kind of limestone-ish maybe? I can smell it walking my dog back there which if they are digging, sure, maybe some gases are being disturbed but this has been happening in our house for over a year.

Foundation type - guessing basement?

Radon test done? Radon doesn't smell but maybe helpful to determine if ground based gases are entering the house.

I am reaching - I don't have specific ideas.

Have you done a IAQ test - getting VOC readings etc. HVAC guys like to do them so they can sell you are purifiers and ionizers.

and do invite a third party with a sensitive nose over that will give you direct feedback to describe the smell, along with David'd suggestion above.

We have Cleveland pears on Every tree lawn. But the smell happened before them and continues all summer after the blooms happen.

I was able to put my finger on the smell. When I was younger I would spent a lot of time at sprint car racing trucks, and this smell, smells like the trailer... like an oil product.

Our acreage is full of trees. When we dig anything, the bacteria in the soil smells terrible. All those dying plants release smells. Could be that.

First, check how far above the roof the plumbing vents go. Too low, and air currents can carry the sewer gasses back through the open windows. That’s easily correctable.

Second a “oil” type smell could be associated with your HVAC system. I’m assuming a forced air system. Maybe the air handler, if you’re getting it when both heat and AC have been enabled. But that’s most commonly associated with the burners of a gas or oil fired furnace. Or, perhaps it could be a gas fired water heater. Any combustion appliance should be checked over.

For something environmental, look at an aero at a google map to see if there are any refineries or fertilizer factories close by. What type of production plants or agricultural structures are near?

It's not a sewer smell.

The smell doesn't happen if the windows are closed (with AC/Heat on).

The land used to be a crop field (corn or soybeans).

Poltergeists?

They're here ...

Seriously, we have all given lots of guesses and that is all we can do, without getting to see your house, lot, neighborhood, etc. in person.

Maybe call one of the services that does restorations after floods/fires and eliminates damage and smells from those events. You need a real person to inspect and investigate.

It has to be something in the air or soil that wafts in only comes in when I open the windows. I don't really know what to do about that other than NOT open the windows, I guess?

Hmmm... What about planting some fragrant evergreen herbs and perennials? Or installing window boxes (or freestanding raised beds, up to window height) with sweet-smelling annuals?

Any bodies of water nearby? Ponds, creeks, drainage ditches? And you haven’t said if you’re near any industrial concerns.

Fo your direct neighbors not smell anything?

Could the smell be coming from your garage and when you open the window you create some sort of draft that pulls the smell into the house from the garage.

Otherwise go and smell the earth around the house and see if it smells like what you're smelling in the house.

The only place I can smell it, otherwise is a street back where they are doing new construction/new homes. Otherwise, I don't smell it in the air at all until it collects in the mudroom and our entryway - the two areas that don't really have air movement (entry way because we don't have a front door screen and keep most of the upstairs doors closed because we have cats).

We do have a retention basin, but I never smell it having a bad smell.

No industrial concerns.

Direct neighbors on Facebook Group don't have this issue, I haven't spoken to anyone in person yet that just moved in.

hi Jamie

did you solved the mistery with the odor? i am having a similar situation.

No, we never figured it out. I don't know if it was the limestone used in the basement or something they dug up outside when they were still building other houses.

3 years in, most of the digging and construction is done the smell isn't nearly as bad when we have the windows open.

Could it be oak wood. I think it's only one variety of oak. When I used to split wood I'd get a very off smell. I only had Red Oak and White oak trees on the property. Are the windows where you smell the odor different than the rest? It would shock me if anyone still makes windows out of wood; let alone oak. Maybe the wood wasn't ever stained or painted.

A woman comes into an architects office and says, "It smells when I open the window"; the architect replies, "Don't open your windows'.

(get it? kind of like the doctor joke, It hurts when I do this . . . .)