Attached garage ventilation

[wanderer]

My house has a three car attached garage. Over the winter my wife accidentally left the car running overnight and ive been thinking about garage ventilation since. We do have a carbon monoxide sensor near the bedrooms on the upper level of our home as we are on a heat pump this was never much of a major concern. Clearly though there was a slight negative pressure on the house and it pulled air from the garage.

still not sure what caused it but that day I noticed a very “industrial” smell, sort of like a solvent but not quite. I was convinced one of my chemicals was leaking and all day looking for It. Finally the kids and I were talking about the smell at dinner and my wife told me what she had done.

so I’m looking for a few ideas here. Easy enough to put a bath fan or some type of duct fan in the attic, but what kind of switch can I use to turn it on and off to prevent something like this from happening again?

 

[tboy]

I had a chuckle about how this is written:

Over the winter my wife accidentally left the car running overnight ... what kind of switch can I use to turn it on and off to prevent something like this from happening again?

Let me know if you find that switch!

To try and be SOMEWHAT helpful, if you were to put in an attic fan, It would be cool to have some sort of smart wifi switch that you could run on a schedule, but really neat would be to run it for a certain time after a garage door was operated (would need a smart garage door as well). That wouldnt help for leaving a car on overnight, but would be nice to clear out the fumes when cars came and went.

 

[ez-duzit]

...Easy enough to put a bath fan...

Pretty sure you need to reassess your ventilation requirements.

BTW I have a 30" fan in my shop for ventilation. Plus I leave the overhead door half open whenever I'm working in there.

 

[allinon72]

Wow, I don't want to be overly dramatic but you and your wife are lucky to be alive if the car was idling for that length of time. Seems a CO detector just inside the garage entry door into the house would do the trick.

 

[wanderer]

Ha! Yeah I hear ya.

mainly I’m just looking for some kind of failsafe to prevent something like this from happening again. Can’t really put a carbon monoxide detector in the garage.

not worried about ventilation when I’m in there. I can easily open a window or the door.

 

[wanderer]

Wow, I don't want to be overly dramatic but you and your wife are lucky to be alive if the car was idling for that length of time. Seems a CO detector just inside the garage entry door into the house would do the trick.

Agreed. Whole family was at home. Five kids plus the two of us. Like I said, we do have carbon monoxide detectors near the bedroom. None downstairs near the garage though. I probably need to swap one of the fire detectors out for a combo unit.

still curious if there’s any kind of smart switch that would have detected this that could be tied to a fan.

 

[wssix99]

still curious if there’s any kind of smart switch that would have detected this that could be tied to a fan.

Yes. You can get these controls, but they are outrageously expensive and they need to be regularly replaced. Some commercial garages have them installed.

For a house, it's much more cost effective to install CO detectors where the people are and to teach the people to turn the cars off. The CO detectors will go off way in advance of things getting dangerous.

 

[Zaxxn]

I have CO/Smoke combination units on the ceilings of every bay in the shop since it's just a hobby shop and attached to the house as well. They are Z-Wave networked and alarm through sound as well as text message. They don't go off from just bringing cars in and out of the shop. The only time one of them went off was for good reason when I was stupid and figured I can run a car in the middle of the winter just long enough to check timing. Needless to say, I have an exhaust hose leading to the outside by now. One thing to maybe note is that the shop has 14' ceiling height.

There are all kinds of environmental sensor available to use with small microcontrollers like Arduinos and the like - something like that would probably lend itself to building a fan controller like you're looking for.

--Zax

 

[Adam Baker]

Maybe see if it's possible to install a CO detector that could trigger a relay attached to the fan?

 

[wssix99]

so I’m looking for a few ideas here. Easy enough to put a bath fan or some type of duct fan in the attic, but what kind of switch can I use to turn it on and off to prevent something like this from happening again?

There are codes for commercial garages to evacuate CO and my City requires that we have passive ventilation in all our garages. (Open vents all the time.)

However... I have an energy efficient house with an attached garage, so open vents aren't a good option. The City allowed me to install an active venting system, which I confirmed using ASHRAE's CO fan equations.

I use an HRV attached to the lighting controls of my garage door openers. The HRV retains heat in the winter. (I now take the heat exchanger module out in the winter, so it acts as a simple fan in the summer.) As the cars come and go from the garage, the light (and the HRV fan) remains on long enough to evacuate any CO that might have accumulated with the car coming and going. ... Keeping my garage fresh as a daisy.

Here is a thread on the HRV and some early complications I had with too much heat in the summer: https://www.garagejournal.com/forum/threads/ventillation-in-an-energy-efficient-garage.337783/

This thread, in post #39, shows the electronics that tie the garage lights (and their timing circuits) and my wall switches, to the fan: https://www.garagejournal.com/forum...d-lights-with-a-new-liftmaster-opener.288164/

 

[BillK]

Ha! Yeah I hear ya.

Can’t really put a carbon monoxide detector in the garage.

Why not ??? Maybe a standalone one that will alert on your phone ? I dont know how sensitive they are but I wouldnt think that pulling a car in and shutting it off would be a problem. The detectors are cheap enough that it would be worth a try.

 

[bbxlr8]

I use CO detectors in my garages period whether for the propane heater or working on old cars, tractors etc. Nothing beat common sense Also, use a wall-mounted commercial fan moving across diagonally facing outward. Nothing automatic though...

 

[wake74]

I've got one in the garage as well, 3 car attached with the master bedroom and bathroom directly above. I've never had it go off from routine in and out, but I have had it go off when I was messing around with one of the projects with the doors open I think us car guys can get too use to the exhaust smell, and don't even notice before it gets dangerous. I also had it go off during a power outage in the middle of the night. Generator was outside, with the garage door maybe open a foot. The wind had shifted just right to push the exhaust into the garage. Very cheap insurance.

 

[Stuart in MN]

How about something as simple as a baby monitor - one unit in the garage and one in the house, so you can hear if the car is running or not. I think they're really inexpensive, and you could probably even find some at yard sales in the neighborhood.

 

[Stuart in MN]

I also had it go off during a power outage in the middle of the night. Generator was outside, with the garage door maybe open a foot. The wind had shifted just right to push the exhaust into the garage. Very cheap insurance.

You were lucky...every year there are people who die doing just that. Keep the generator well away from the garage door.

 

[htmdude57]

I think a CO detector in the garage would prevent that from happening again. They usually sound a very loud horn if CO above a certain limit is reached, maybe 100 ppm?

 

[wanderer]

I never considered a carbon monoxide detector in the garage. Figured it would go off from just starting the vehicle. Seems like that probably makes the most sense. Thanks a lot guys.

 

[steaks&anvils]

If you can't trust the wife to shut off the car, can you trust her with actually driving? or with children? What about the kitchen stove?

Really, that sounds absurd doesn't it? The odds of this accident happening again is very slim. If we took a GJ poll, how many of us have left the car running in the garage?

I will confess, when I had just gotten a new car, it was so quiet that I couldn't hear it running and it had remote door locks. AND it was a show room model so the seat belt and open door buzzer had been deactivated. My old truck was loud and had manual door locks. I got distracted and got out of the car in a hurry, because of years of the same routine, I manually locked the door and closed it, just as I realized I had just locked the car and it was running. BUT I have never done that again...

So your my vote is to get a detector for the garage and stop worrying that it will happen again.

 

[Scubadriver]

If you want to take the garage CO detector, you can get a Z-Wave integrated CO detector that can be integrated with your Ring alarm or other Z-Wave home automation system.

 

[nadogail]

How about a sign in the garage reminding everyone to make sure all engines are turned off before you leave the garage?

 

[ambenz]

I have a baby monitor in my detached garage to hear the fire alarm. I can hear if the compressor was left on and yes, if the car is running. I can even hear someone is trying to break in...those monitors are inexpensive and sensitive!
As far as addressing the positive pressure compared to the home, you can buy an inexpensive pressure switch and whenever the pressure is greater in the garage than the house, you can either pump fresh air into the house or discharge air from the garage using the pressure switch to control a fan. Below is a crude illustration of a fan run on pressure with a min run timer on the circuit. Comparing pressures between the 2 "vessels" you could dial in when high pressure in the garage runs a fan.

 

[tool_scrounge]

There are nice industrial CO sensors with relay outputs. Work great but you will find the price high. I like Scott Safety for my work applications. For garage ventilation, I have a used furnace fan mounted to one of the garage vents. Really high flow rate and quite cheap. Open the garage door to the house and it will **** all the air out of your house. Poor mans whole house ventilation. I have my fan hooked to a thermostat and a firestat to keep the garage cool. With manual override of course.

 

[klassenl]

Kidde has you covered.

Carbon Monoxide Relay Module CO120X | Kidde

CO120X is used to activate auxiliary warning devices such as external bells and sirens, hallway or stairway lighting. This relay will only activate when it receives a CO signal from an interconnect Carbon Monoxide Alarm.

www.kidde.com

 

[kbs2244]

Maybe see if it's possible to install a CO detector that could trigger a relay attached to the fan?

I like this idea

From some other posts it seems Z wave may be the buy instead of build solution.

 

[CraigStu]

I'd just buy a standard CO detector. As I remember CO sinks so experiment w/ mounting it higher on the wall than you normally would. You can experiment on height location but taping it in position and then let the car idle for 15-20 minutes.

 

[P0234]

A zwave compatible CO detector and a zwave home controller of your choice will do what you want and more. The home controller will get the alarm and you can have it turn on a fan, flash lights on and off in the house and even email/call you when you are away.

 

[wanderer]

Kidde has you covered.

Carbon Monoxide Relay Module CO120X | Kidde

CO120X is used to activate auxiliary warning devices such as external bells and sirens, hallway or stairway lighting. This relay will only activate when it receives a CO signal from an interconnect Carbon Monoxide Alarm.

www.kidde.com

that’s exactly what I was looking for right there. I mean add a relay to a ventilation fan of some sort and it’s something you don’t have to worry about again. given that there are other sources of carbon monoxide present in the garage it seems like a relatively minimal cost.

 

[ripperd]

Why not ??? Maybe a standalone one that will alert on your phone ? I dont know how sensitive they are but I wouldnt think that pulling a car in and shutting it off would be a problem. The detectors are cheap enough that it would be worth a try.

Agreed.

I have one in our garage. In 3 years it has only ever gone off once. That was in the winter when my wife let the car run for a minute or two while it was still in the garage (door open). And that was just a slow infrequent chirp, not the imminent danger wail.

 

[manwithtools]

A zwave compatible CO detector and a zwave home controller of your choice will do what you want and more. The home controller will get the alarm and you can have it turn on a fan, flash lights on and off in the house and even email/call you when you are away.

This is on the right track. Get a Hubitat controller ~ $140, a Zwave CO detector ~ $40 and then a Shelley 1 WiFi relay ~$18 and you would have all you want and more. The Shelley relay also has a input - so you could tell if a door is left open with the addition of a switch to the door track. It's a great way to get started in home automation at the same time. You could even set it up to call or text your wife's phone if she does this again

 

[tool_scrounge]

The Kidde CO relay module is rated for 10A NON-INDUCTIVE load. Fans motors are inductive loads. So you can use this CO sensor, but consider having it drive an external relay module and have that relay turn on the fan.