erv condo, odor transfer to the corridors

[Canadaq]

Hi,

I live in a new condo building in Toronto which uses the ERV system with individual fresh and exhaust vents for each unit and separate ones for the corridor and the front doors are weatherstripped to lower air transfer between the units and the corridors. There was never any cooking odors in the corridors until suddenly since about two months ago at about the same time a few nights a week there is strong cooking odors in the corridors, so strong that it seeps into my condo from around the front door and if you open the door it is quite warm and smelly, like you opened the door into somebody's kitchen. New neighbors have also moved into a unit on our floor at that time. I know that they don't keep their front door open when cooking, so what could be causing this?
Thanks

[stvc]

Can the tenants shut their Erv's off?

Just a guess but thinking the new tenants might not have realized what it was and shut it off.

[Canadaq]

Yes! I think people might confuse it with the bathroom fan and just turn it on when using the bathroom. Would the ERV being off cause this much air to come into the corridor though?

[tinknocker service tech]

it is also possible the evr in the hallway needs to be serviced
or isnt working

[Canadaq]

They say they checked the corridor erv and it works fine. Does cold weather affect how well these things work? Also, can they increase the pressure in the corridors so it wouldn't allow the air from the condos to come into the corridor?

[stvc]

Yes! I think people might confuse it with the bathroom fan and just turn it on when using the bathroom. Would the ERV being off cause this much air to come into the corridor though?

I would suggest a letter to everyone from the condo ass. reminding everyone on the proper use and advantages of the ERV's first.

As far as it being off causing air to move into the hallway is hard to say without being there. It is possible with it off for there to be pressure difference, it is also possible they have a window open.

To your question on increasing hallway pressure I wouldn't, that would also force that air into your apartment.

Try a little experiment. With your door slightly cracked open do you feel air moving either way? Try a little smoke from something to see.
Try it with your ERV on and off.

[Canadaq]

Hi,
I did the experiment. Air flow is from the corridor to my apartment both with erv on and off. It's stronger at floor level, but even up at the top of the door there is a slight flow inward. Comparatively when I open the balcony door the flow is from outside in up to 4 feet and inside to outside above that. I had to actually really seal around my front door for this cooking odor to not come inside.

so with this info, does it mean they would have to have their window open for the odor to come inside the corridor? Could there be some problem with that unit's insulation/weatherproofing?

Also, when you have the erv on, other than the vacuum produced by the bathroom fan, does it actively suck in air from the outside? because the vents are near the top of the ceiling, so based on the balcony door experiment, air wouldn't naturally flow in from that height right?

Thanks

[stvc]

Hi,
I did the experiment. Air flow is from the corridor to my apartment both with erv on and off. It's stronger at floor level, but even up at the top of the door there is a slight flow inward. Comparatively when I open the balcony door the flow is from outside in up to 4 feet and inside to outside above that. I had to actually really seal around my front door for this cooking odor to not come inside.
What I gather from this is your unit is under negative pressure with respect to the hallway [WRT] Try the same experiment at your balcony door to determine your unit pressure WRT outside.
so with this info, does it mean they would have to have their window open for the odor to come inside the corridor?
No, I only used that as an example of something else that could change the pressure in the building
Could there be some problem with that unit's insulation/weatherproofing?
Yes, but there may also be something elsewhere. Multi family buildings can be a challenge for many reasons. Amongst them users with different habits and knowledge, and of course the building itself. I'll try to keep this simple but it won't end up that way. The outside walls are the pressure and thermal boundary, all the walls inside are just rooms in the building. Think single family house, your bedroom is your unit, your brothers bedroom is his unit. It's hard to separate them.
Also, when you have the erv on, other than the vacuum produced by the bathroom fan, does it actively suck in air from the outside? because the vents are near the top of the ceiling, so based on the balcony door experiment, air wouldn't naturally flow in from that height right?
Yes, The concept of the ERV is that it takes air from the outside and tempers it with the air being exhausted thus recovering the energy and providing fresh air. There are a couple other very knowledgeable folks on this site with expertise in this area, surprised they haven't chimed in. Will see if I can get their attention.

Thanks

Hope this helps, BTW, how many floors, units, and what floor are you on?

[Canadaq]

it's 24 floors I think 8 to 10 (less on upper floors) units per floor and I'm on 10th.

at the balcony, from about the door handle downward air comes from outside to inside, from the door handle upward air goes from inside to outside. Also we keep the place pretty warm, around 80 degrees and outside is around 40ish.

[stvc]

it's about 20 floors I think 10 or 12 units per floor and I'm on 10th.

at the balcony, from about the door handle downward air comes from outside to inside, from the door handle upward air goes from inside to outside. Also we keep the place pretty warm, around 80 degrees and outside is around 40ish.

I had no idea the scope of this "condo unit" but that is why I asked.
There are really complex things going on in a building that size, stack effect being the most relevant in your case. The primitive tests I had you do don't sound like things are too bad though. How is the comfort and energy use?

If you are adventurous and have the time to do some research google stack effect and we can go from there.

Your problem probably won't be solved on this forum but may generate some informative discussion.

[Canadaq]

so stack effect means, basically if you are on the lower floors in winter a lot of air is sucked in from outside, especially with the window open? the thing is the problem started also with the weather getting cold, so the new neighbors might be a coincidence.

how can I produce positive pressure in my unit so that at least the smelly corridor air doesn't come in?

[Canadaq]

and there is a big temp difference from floor to ceiling. like, you can't get the floor warm no matter how high you set the fan coil.

[stvc]

so stack effect means, basically if you are on the lower floors in winter a lot of air is sucked in from outside, especially with the window open? the thing is the problem started also with the weather getting cold, so the new neighbors might be a coincidence.

how can I produce positive pressure in my unit so that at least the smelly corridor air doesn't come in?

I think you have the basic idea, but there should be building controls to balance things out. Think of it this way, you live in a 24 floor chimney, probably around 240' high. The colder it is outside the better the chimney drafts, or wants to expel air out the top. Absent any control if you open a window on the 1st floor you would be blown down.Middle floor [or neutral pressure plane] nothing happens because it's the same pressure as outside. Top floor you get sucked out!

All kidding aside there is probably nothing "you" can do, it needs to be building management.

Do you know of others experiences on different floors?

[Canadaq]

No, I think they frown upon knocking on neighbor's doors.

yeah, I wanted to go to management with some knowledge so they wouldn't brush me off.

btw, here condo means highrise that you own your unit. I guess it could be lowrise, but most of them are this size. I'm sensing in the states it different?

[stvc]

No, I think they frown upon knocking on neighbor's doors.

yeah, I wanted to go to management with some knowledge so they wouldn't brush me off.

btw, here condo means highrise that you own your unit. I guess it could be lowrise, but most of them are this size. I'm sensing in the states it different?

It is always best to have as much info as you can when conveying any problem to those fixing it whether it be your HVAC, car, washing machine, or anything. It may not be a big deal at all so just tell them what you know. Part of that process is gathering information. Regarding the cold floor, is the floor below occupied? just thinking since it's new maybe not and unheated?

Here [NH], condo also means you own unit but you are correct, most are not high rise. Not that we live in the woods but most 20 story buildings here are office buildings. Biggest residential I can think of in Manchester is 10, maybe 12.

[thermojohn]

Also we keep the place pretty warm, around 80 degrees and outside is around 40ish.

and there is a big temp difference from floor to ceiling. like, you can't get the floor warm no matter how high you set the fan coil.

Been reading this, but refraining to post until I saw this. 80°F for heating? This is causing stack effect. You noticed it when the weather got cold.

General idea to solve your problem.... Your living area's envelope needs positive pressurization in relation to the adjoining common area. The common area needs to be negatively pressurized in relation to your living area. How much air for each will need to be defined by testing the 'tightness' of each space by qualified professional. If the 'intake' vent for your space's ERV is in the hall, or near the 'exhaust' of the common area, it will short circuit, and have negative influence on the quality of the air entering your living space.

There is a lot going on with this building that cannot be solved by my keyboard over the internet. ERV's / HRV's are balanced machines, and are not designed for positive or negative pressure applications. Manufacturer's data on most don't recommend any deviation beyond 10%. If any exhaust fans are run continuously, you may be adding to your odor problem without realizing it.

If you have the ability to 'crack' a window on a side of your space not adjacent to the hall, your entering air will naturally ventilate your unit with fresh air. The entering air has to be below the neutral column, as low as you can get to be effective. If you can allow a small amount of air to escape on the hall side of your unit, up high, you will effectively create a passive convective path that will positively ventilate your unit with fresh air using stack effect.

You may also need to monitor your indoor RH, as it may make it very dry with colder northern temperatures.

[Shophound]

Bottom line is that the condo where the cooking odors originate is positively pressurized to the corridor, and the corridor in some aspect is positive to your condo. You stated that improvising some form of seal around the entry door checks the odors. This would indicate the door is the point of entry into your condo, not some other path such as cavities or voids in walls or ceilings.

Are there exhaust hoods over the cooking appliances in the condos?

ERVs can be adjusted for keeping a structure pressurized. But it could be something as simple as encouraging the owners of the the unit where the cooking odors originate to have their entry door seals checked.

[Canadaq]

Thank you all.

yes, there are exhaust hoods over the stoves. They assured me all the exhaust goes out of the balcony, although, sometimes it feels like theirs opens to the hallway. (they are on the other side of the building so their exhaust vent is nowhere near my input vent which is on my balcony as well.)

The entry door seals on these units aren't very good. I had to add several more layers, at the bottom there was almost a pinky finger thick gap. still there is a small breeze at the bottom.

if the erv is on even minimum, the bathroom fan turns on as well. There doesn't seem to be a way to have it on and not have the fan on at the same time. I never put it on high because you get the nextdoor neighbor's exhaust pulled in but it's still much better than the corridor odor!

yes, when I open the balcony door the airflow at the front door goes the other way. But in winter we would freeze to death also within minutes but I'll try it with the smaller window and see what happens.

Yes, there are people right bellow me. Should I try to decrease this internal stack by lowering the temperature? is it contributing to the problem? I tried at 75 degrees and the flow from the corridor to my home is
slightly less.

[thermojohn]

yes, there are exhaust hoods over the stoves. They assured me all the exhaust goes out of the balcony, although, sometimes it feels like theirs opens to the hallway. (they are on the other side of the building so their exhaust vent is nowhere near my input vent which is on my balcony as well.)

The entry door seals on these units aren't very good. I had to add several more layers, at the bottom there was almost a pinky finger thick gap. still there is a small breeze at the bottom.

if the erv is on even minimum, the bathroom fan turns on as well. There doesn't seem to be a way to have it on and not have the fan on at the same time. I never put it on high because you get the nextdoor neighbor's exhaust pulled in but it's still much better than the corridor odor!

yes, when I open the balcony door the airflow at the front door goes the other way. But in winter we would freeze to death also within minutes but I'll try it with the smaller window and see what happens.

Should I try to decrease this internal stack by lowering the temperature? is it contributing to the problem? I tried at 75 degrees and the flow from the corridor to my home is
slightly less.

Everything in bold indicates to me your unit has the ability to achieve a negative state created by a combination of mechanical operating exhaust devices. ERV, bathroom fan, kitchen exhaust, and I suspect your air handling unit are all factors.

I tried at 75 degrees and the flow from the corridor to my home is
slightly less.

So when you turn the unit down from 80° to 75°, you notice the air from outside to in less, meaning less negative pressure when the heating system turns off?

How many square feet is the heated space?

You indicated earlier that it is cold at your feet and warm up high. Are your return (intake for unit) grille, and supply grilles all in the ceiling?

My real gut feeling of your problem, though, points to the prevailing wind as the culprit, IMHO. I'm getting the impression that the wind is blowing through your neighbors unit, carrying the aroma through the corridor, and continuing right through your unit, and out through the rear on the balcony. This is not related to stack effect, but another force that affects the conditions of the living space in a major way.

I would recommend sealing around exterior cracks and crevices around your unit as best as you can to stop the 'flood' of air. Anything beyond that will require a professional with qualifications in building envelope analysis. House maintenance most likely would be in the dark for a real solution. It would be interesting to see the results, as there is a lot going on here.

[Canadaq]

Thank you.

the wind theory seems interesting (not very good for me though! ). I should follow wind patterns and how bad the smell gets.

also I thought maybe the exhaust ducts in the corridor have a leak.

yes, everything is in the ceiling and it's a small apartment. seven hundred or so. At 75 degrees there isn't much temp difference, but at 80 degrees it's too cold at the floor and a sauna at head level.

I'll do some more experimentation later.

the management was very accommodating and said they are checking things out. I hope it's something simple that can be resolved without bothering the neighbors. meanwhile, off to get more weatherstripping! the choices seem to be either so thick I have to wrestle with the door to get it closed, or so thin there still is a draft