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Interior temperature sensor and alarm

15008 Views 44 Replies 22 Participants Last post by  jamesmicah99
We constantly travel with our dog (heck, the dog is one reason we buy vans) and we frequently have to leave her in the van while we do other things, like sight seeing or hiking where dogs aren't allowed on trails. And of course, we get worried about heat. We have an AC unit when we're in a campground, but units fail, fuses blow. She always has water and we can leave the windows open slightly. (Only operable windows are in the front.) We do not have a vent fan.

I'd love to put some sort of temperature control with a warning light outside the van, with a little sign that reads "Dog inside. If light is flashing call us at 123-456-0987. If we don't answer it's OK to break a window."

Anyone have any ideas? My cousin makes industrial thermometers and he's never heard of anything like it. I already have a smoke and carbon monoxide detector in the van, where can I get a temperature detector?
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My dog hangs out in my van when I am at work. We insulated well and installed great ventilation (Maxair fan, two floor vents, and window vents). We also have black out covers on the windows and reflectix on the windshield.

I use a kestrel temp recorder inside the van and one outside the van to confirm that the temp inside is never more than 4 degrees hotter than outside even with the fan off. With the fan on, the inside is often 3 or 4 degrees cooler than outside for the whole 8 or 9 hour work day.

The window vents are available here (they make a version for the transit):

The kestrel temp recorders are expensive. But it gave me piece of mind to know that my dog won't cook inside the van. I'm also a data geek and it is fun to see how the van reacts to different sun/shade/temp conditions.
As a point of reference, today in Portland, OR, my external Kestrel thermometer measured 94.5 while my inside Kestrel thermometer measured 97.1. This was at the end of the day with the van windshield directly exposed to the western sun. i also parked my van without installing the window vents or the insulated windshield shade. I had the roof vent open, but the fan was off. It is reassuring to me to know that the inside temp will be very close to the outside temp even with the van in the sun, the fan off, no window vents, and a thin cover over the front windshield. Based on this, I do not feel the need to have an alarm to warn me of high internal temps. It is pretty clear that the temp. inside my van will never exceed the outside temp by more than a few degree, which is better performance than my 1924 Bungalow.

Sure. We have the transit 150 medium roof. It came with the black plastic load protection panels in the cargo area.


I used 1" rigid foam foam on the ceiling taped between the metal struts with aluminum tape. Eventually I will cover that with 1/8 paneling. I talked with Van Specialties in Tualatin, OR and followed their recommendation to use fiberglass batten behind the panels an the walls. I basically split each 4" sheet into two 2" sheets (one with paper backing and one without) and placed that behind the panels. I also used 2" fiberglass batten (water heater wrap) to insulate the ceiling above the cab area.

I also used clear Gorilla tape to cover all the small holes in the doors, struts, and columns. I figure it might help keep moisture of of those areas and provide some small amount of insulation with the air inside the voids.

On the side and back door windows, We used thick dark fabric from Ikea to make black-out curtains. We use super magnets to hold them tight against the glass when deployed and rolled up at the top of the doors when stored. We also installed cellular pull down shades from Ikea. The idea is to stop the light and heat outside the window and then the shades provide some insulation between the warm glass and the air inside the van. Inside, we used a similar piece of thick Ikea fabric as curtain between the cab and the cargo area.

On the cab windows and windshield, I used ESP Low-E® EZ-Cool Car Insulation to make window covers. EZ-Cool is polyurethane foam sandwich between mylar foil. It is a little less tha 1/4 thick. I use two suction cups on each side window to keep it tight to the glass. On the windshield, I taped a layer of reflectix to the EZ-cool. I put the reflectix side facing the windshield to keep a thin layer of air between the EZ-Cool and the windshield. The visors hold it in place.

I added carpeting to the floor directly on top of the factory vinyl, which has a thin layer of wool felt insulation. Someday I will add a wood sub floor, but the carpet seems to keep things coolish and quiet for now.


I had Van Specialties install a MaxxAir fan soon after we bought the van. I was too chicken to cut a hole in the brand new roof. I'm braver now.

I followed someone else's idea and installed two 3" vents inside the rear corner columns. I used 3" mylar dryer duct inside the columns and irrigation grates and some black ABS pipe fittings outside the van to keep the bigger critters out. The vent on the inside exit where you access the tail lights. Outside they exit where that 4" plastic cover is located. I removed the cover and used strong water proof aluminum tape to seal voids. On the passenger side, I used black ABS pipe to locate the intake away from the exhaust. With the roof vent open, you can feel the air flowing through the floor vents. The vents seems to do a good job drawing cool air in through the floor so warmer air can escape through the roof.

Recently we added the cab windows vents that I ordered from Eurocampers. They let you keep the windows rolled down a bit with some sense of security.

With the MaxxAir fan running on low, the inside temp. rarely exceeds the outside temp. At lower outside temps (less than 80 degrees) it is almost always cooler inside than outside.

With the fan off, it seems like the inside temp. can be a few degrees higher than the outside. I was pleasantly surprised to see the data yesterday that showed on a 2.6 degrees temp. difference on a hot day because I did not have my windshield insulation in place. I only had a thin windshield sunshade ( to reflect the sunlight from the windshield.
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I will try and get some photos tomorrow after work. Here is the link to the kestrel drop temp recorders:

I was a bit concerned about carbon monoxide poisoning from the exhaust, so I installed a cheap CO detector. I haven't had any issues, even when idling in traffic.

I was also concerned about dust entering through the vents when driving on gravel roads. I just use a zip lock bag with four super magnets to cover the vent opening on the outside. On the piped vent, I use Velcro to secure a Ziploc bag over the end of the vent pipe. No issues so far.
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