A fridge is a a heat pump machine. It does not “create” cold; it extracts the heat from inside and releases it to the outside. Our Novakool R5810 fridge is designed to disperse the extracted heat via a series of coils in the back (in fact it’s the case for most refrigerators). The heat inside the fridge is transferred into the ambient air in the cabinet via these coils. If that heat is not evacuated from the cabinet, the coils cannot do their jobs of dispersing the heat. To compensate, the compressor will runs constantly and electrical consumption will increase (not to mention the the fridge lifespan is decreased!). The refrigerator is the most energy-using appliance in the van; let’s make things right and add some ventilation!
Here is the idea: we will add a floor vent. Fresh air enters by the floor hole (because the roof fan creates a negative pressure in the van), rises up along the fridge coils, exit the cabinet through the gap near the drawers and is finally pushed outside the van through the Maxxair Roof Fan.
All ideas are made of other ideas, right? We were totally inspired by the super-famous Orton hole-in-the-floor. Credit to him.
TIME SPENT ON THE JOB: 8 hours
TOTAL COST : $40 USD
MATERIAL:
- Valterra Slip Hub, 3″ (Buy on Amazon)
- Powertec Splice, 4″ (Buy on Amazon)
- Aluminum Tape (Buy on Amazon)
- Silicone II (Buy on Amazon)
- Wire Mesh (Buy on Amazon)
- Mosquito Screen (we used leftovers)
TOOLS:
- Power drill (Buy on Amazon)
- Drill bits (Buy on Amazon)
- Milwaukee 4″Hole Saw (Buy on Amazon)
- Milwaukee Hole Saw Arbor, 3/8″ (Buy on Amazon)
RESOURCES:
PRE-REQUISITE:
First, we need to make sure the hole will no interfere with a frame or something. We used the vertical frame (bottom left) to locate the hole, because that frame is also under the floor (bottom right).
We started with a small pilot hole, fine-tuned the center of the hole, then proceed with the full-size 4″ hole.
Seeing our floor layers really got us emotional! We almost felt like archaeologists going back in time, almost.
Drilling into the van metal floor exposed edges to corrosion, so as usual we sanded the bare edges and applied primer + paint + clearcoat. We sourced them from our local Auto Parts Store (It’s better to use a can. Spray into a jar and use a Q-Tip to paint the edges). No pictures here 🙁
Now, if we were to leave the hole as it is, water could ingress into the layers of the floor. We will therefore “seal” the hole using a Valterra 3″ Slip Hub & a Powertec 4″ Splice. We did as follows:
a) Temporary install the Valterra 3″ Slip Hub under the van (the flange is outside the van);
b) Temporary install the Powertec 4″ Splice inside the van;
c) Add tape around the splice to mark where to cut it (or mark it with a pen…);
d) Cut the splice using a metal saw (or any other tool of your choice);
e) Tape the Slip Hub & the Splice together using aluminum tape (or other type of tape that works);
f) Install the assembly, from under the van. The flange is screwed into the van floor using 4 metal screws.
g) Seal the top with Silicone:
h) To prevent critters or killer bees from crawling inside the van, we added wire mesh and mosquito net:
We’re not done yet! We want to be able to close the vent for winter or when we hit dust roads.
We used some leftovers of 1/8″ thick MLV (that we sourced here) to fabricate a gate. The MLV is flexible, so we enclosed it in a guide that we built from 1/8″ thick russian birch plywood:
Here is a closeup on the guide:
Since the MLV is flexible, the “handle” can be folded back on itself and hidden under the fridge. That’s why we used MLV instead of wood!
Here it is in action!
ON SECOND THOUGHT
The floor vent does improve venting of the fridge. When the Maxxfan is running, some air is pulled through the vent. That being said, just to set the expectations straight, it’s not enough to cool down the whole van. If your goal is to cool down the van, an extra window or second fan would definitely work better. And on the downside, dust is sucked in through the floor vent. On our next van, we’re not sure if we will do another floor vent…
What fantastic information. These considerations are important. I think a good solution would be to elevate the fridge an inch or two and allow to vent into the interior. The fan system or A/C will then cool the air and remove mosture.
Hi Antoine,
Love your contribution to the van build community.
I have been interested in the concept of putting ventilation holes through the van deck for the van living area, propane enclosure and now that you mention it… the refrigerator.
My concern is that if the vehicle goes through a big puddle of water or backroad drainage wash will water potentially flow into the van. especially if a hydroplane incident occurs. Do you think this is a valid concern?
I am thinking of putting a waterproof tub (like a plastic wash tub) in the propane enclosure and sealing the drain through the bottom. If water gets into the tub, it can drain back out without getting into the cabinet / floor system.
Perhaps a similar approach could work for the refrigerator?
Perhaps the van community has some ideas as well?
I don’t think we would go for a floor vent again. It sucks quite a lot of dust inside. I’d recommend windows or a second fan instead if your goal is to cool down the van.
I see where the air comes in.
Not clear how it gets out. Does the hot air exit rearwards over your drawers to be dumped under the side of the bed? I think I see a slot in the rear of the cabinet, maybe? (when I say rear, I mean rear of the van)
There’s a slot (gap) over the drawers, air makes its way in the garage further back.
Hi!
I Didn’t know where to post this. But:
In your cutout for the refrigerator that I can see above (the “Seeing our floor layers really got us emotional!” picture), do I see extra insulation on the driver’s side of the refrigerator?
I know you can’t add insulation on the back of the unit, but on the sides and top you could. Did you?
Cheers, Don
We did add some XPS foam board on the sides.
antoine
I’ve read your Floor Vent post as well as this Fridge Floor Vent post and both are great. I have a slightly different issue I would like address, namely I want to have a fan that exhausts air from a small kitty litter cabinet that we are creating. From your experience do you think something like this is worth it (in front of the rear wheels) or would it be more hassle than helpful? Cheers!
The litter will quick get saturated and would require constant refresh. I don’t think it’s worth it personally.
Wanted to leave an update that the “Hole in the Floor” url has changed: https://www.ortontransit.info/floor-vent
Hi, there! I know it’s been a while since you posted this up so I’m hoping you will still be able to see this.
You spoke of the upper fan creating negative pressure and therefore sucking air out from the fridge cabinet. This seems less than ideal as you are drawing the warm air out from your fridge into the rest of you van. What if you were to have your floor vent sucking air out of the cabinet? It could be drawing fresh air from your cabin into the cabinet and forcing the hot air out. I was thinking of combining this cabinet space with our compost, trash, and (nearby) toilet as to all use the same vent(and thus less holes drilled). Any opinions on if this would work out?
Finally someone understands the refrigeration cycle! So many people think we create cold! Great site!