On or off indication for Attic exhaust fan

No just a dome on the roof with a screen mesh and a fan mounted parallel to the roof and the dome, so no place that opens when the fan is on and closed when off.

You can probably attach a battery operated vibration sensor nearby and use that, the way some people do to alert when their dryer stops running. Not something that monitors the power draw, which is more accurate but needs to be wired or plugged in. Just something that senses the shaking and notifies you. Look for forum topics on laundry monitoring.

I am going to try a SmartThings Multi sensor that detects vibration and see if that works. I will post my results.

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attic ventilation goal is usually temperature control to maximize roof lifetime, with a nice side effect of reducing cooling load. So a high temperature monitor would be useful, and the smartsense multi can do that also.

It would be amusing to put the magnet on a blade and the sensor on a brace, and watch the open/close pulses fly by. It would work on those old passive ventilators too. Pretty useless traffic but fun. you can balance with counterweights. Mount magnet as close to shaft or even on the shaft/axle if possible, for the least impact on the fan/vent. I wonder if this is an awful load on the cloud.

You can’t really control humidity in attic but it is nice to know remotely, so I stuck a temp+humidity sensor Up there.

Actually this house is very well sealed and the humidity sensor turns on the fan in the winter to prevent moisture buildup and condensation which is very damaging. And I have used my Smart Sense temp/hum sensor to see if it actually reduces the humidity and the fan does the job. I have neighbors that have moisture dripping from the fixtures on the cathedral ceiling. They installed the same fan and no more dripping. I will just mount the sensor to the motor mount not the motor as I think the heat of the motor might melt the plastic housing.

Nice project, @joelw135!

It will be nice as long as it works. I will post the results.

I purchased the Smart Sense Multi sensor and just attached it to the frame of the fan motor and I now have the temp in the attic and the indication of the fan being on by the vibration sensor. It works great. I don’t use the open close so that is just wasted. I ty-wrapped the magnet to the sensor so it shows closed all the time, but this way I don’t loose the magnet. I just wish they didn’t leave the Hydrometer out of the sensor like they have in the temp/Humidity sensor, as the humidity in the attic during the winter would be helpful.

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Let me ask a stupid question but seriously. If I place a battery operated Sensor in the attic… Can the battery explode due to the heat up there?

More likely to leak than to explode, but just check the operating specs.

135 - 140 degrees is pretty typical for summer heat in an attic, although obviously there’s s lot of variation.

Also, right near a vent is often 10 - 15 degrees cooler than in a more enclosed section.


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I was just curious…:slight_smile:

Well I hope they don’t explode, but I can tell you the temp on the day I had my house inspected was 133 near the attic door, much hotter in the middle away from the door. With the attic fan running the temp near the fan today is 105 degrees, The temp outside in the shade is now 96 degrees so 105 at the fan isn’t bad. I also like that I can see if the fan fails as it is very quiet and the ceilings are very high like 20 feet.


Are there any smart attic fans? I had new roofing installed thru Power home remodeling group which set me back 22K (replaced beam, ply etc.) with top of the line stuff (as they claimed) but they got rid of all attic fans saying that they were no longer required. I am not too sold on the idea though… Made too many mistakes in the first year of home ownership. :frowning:

There is no true smart attic fan but you can come close. My fan has an adjustable thermostat and an adjustable humidistat that lets the fan go on during the winter which removes high humidity from the attic which causes mold and damage to roof and insulation. My home is to well sealed so I have to keep my humidifier off or I get humidity on the windows. I thought it was a cheap humidistat so I replaced it with one that is computerized and reads outside temp. But I wasted my money as the humidity was still to high. So now I keep it off and the inside humidity is around 40+ or-%.

My inside humidity is pretty much between 45 - 58 degrees range now after new roofing and the temp above in the second floor (split level house) for the rooms below attic is significantly higher than the lower floors.in my case it may be the ducts too as in my master bedroom, the cold air velocity is much lower than other rooms on the same floor. Man, I was so much happier living in an apartment. :slight_smile:

I lived in a split level for 30 odd years and found a few solutions that help your problem.

  1. the return air duct on the upper floor was moved up near the ceiling and the down stairs return air I installed a damper so in the summer the falling cold air was drawn to the lower return and in the winter to the upper. The hot air rises so in the winter the upper returns were open to draw the hot air from the ceiling upstairs to the lower floor and the summer the cold air to the upper floors. I hope that wasn’t confusing. I also installed 6" of additional insulation in the attic. and a few duct mounted fans for the upper floor controlled by thermostats. That was the hardest part.but the upstairs and downstairs were much more even. The duct fans are cheap and depending on your house construction the hardest part is getting the wire to them. Usually in your type of system if hot air there is a central duct on the lower floor that feeds the upper floors and some dampers on the lower floor. The fans fit in the ducts that come off the main trunk. it does mean a hole in the ceiling to expose the duct, but easy to patch using the same piece of sheetrock. It is amazing how they made a difference in both summer and winter. The complete job was less than a grand.

sometimes you can fix your issues with balancing the registers (dampers). Those closer to the fan/cooling source get a higher pressure, so they should be opened LESS than dampers farther from the fan.

Filters must be clean for HVAC to work as designed. Does it get better when you take the filter out temporarily? Maybe you have the wrong type/too-restrictive for your system.

Lower attic temp can help reduce system load.

Ceiling fan in the room, can reduce need for cooling, and they are cheap to operate.

You may even be able to select a higher speed termination on your existing fan motor. Note that speed might be too much flow for your ductwork.

Otherwise you could try smart vents and do time scheduling of rooms. Fun.

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I change the filters religiously. But will check if it gets better with the filter out temporarily.

When I had my HVAC guy service my new home AC and Hot Air system he told me that the Filtrate filters put a strain on the fan as they restrict flow way to much. He suggested the less expensive filters and change monthly instead of every three months. It did make an improvement. But as I had mentioned before return and supply vents in the proper locations and booster fans were needed did the trick for me.

So I was browsing the community for “high temperature” and found this thread. My ask is somewhat related, looking to you all for advice/recommendations. I’m looking for a way to monitor attic temperatures. Background: I live in Phoenix, AZ in a 2 story home, and I have concrete roof tiles. During the summer my roof temp can exceed 170° F, and attic temps in excess of 140°F. I prefer a sensor system to be run on 120v vs battery. The sensors I’ve been looking at either cannot accurately measure/register temps over 125°F or the sensor itself cannot be located in an environment over 104°F. My primary use is monitoring. Secondary would be to control an attic fan through a Z-Wave outlet. Any information would be useful. Thanks in advance. Eric