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root cellar ventilation

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nailkiller1

· hurtlocker
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Discussion starter · #1 ·
I have a customer that would like a root cellar
I have a 12x12 room in the northwest corner of a basement
Exterior Basement walls are exposed
The rest of the interior walls and ceiling are insulated

My question is how to handle the ventilation

And do I need to add something to moderate the temperature
 
Discussion starter · #7 ·
They are exposed on the inside
Underground on the outside

my concerns are with the ventilation
and if the temp will need to be adjusted

I think i will try fh's theory
pvc pipe High and low
put a ball valve on it so I can play with the air flow and temp
Add equipment later in needed
 
#8 ·
Yes, I get it.

The ground temperature in MN is about 47°F. My cellar (not a basement) is in the 50s most of the year. It can be well ventilated with a 12" chimney up the center but it stays fairly humid without the vent open.

The air temperature is easy if closed tight, but humidity is harder to control without affecting temperature. If you are trying gravity ventilation, like hydraulics it may take a bigger pipe than you think. My intake comes down an outdoor staircase and vent off the center of a 10x20' room 4+ feet below the surface.

There is precious little information on proper root cellar design let alone HVAC.
 
#9 ·
A few things which may surprise you. Unless the basement wall above ground level i insulated, expect to see temps in the high 30s on the inside in cold weather. The rim joist especially can get cold, but I'm assuming it's insulated. Air leakage at the sill plate can make it pretty cold too. I think this area will wind up being much colder than you expect.
 
#10 ·
This is a point well taken. We install a lot of high density (2lb.) foam in the rim joists and down the walls at least to the frost line. Thus my point to the "exposed" walls, I now understand to be unfinished.

My cellar is just that, and no exposed walls and only earth above. If you have a conditioned space above your root cellar, it is still a basement and a minimum R-value would have to be added to the floor joist above to keep the heat from traveling down to the cold slab below.

This is why I use Wrightsoft for all my design work. Somebody has to do the math.
 
#11 ·
A big consideration for this is getting condensation in the ceiling of the room because of air infiltration into the ceiling from the room above. It really has to be air sealed.

I worked on a commercial cooler that was made in a basement with conventional fiberglass ceiling insulation. Worked great until temp and humidity conditions caused condensation in the ceiling. Water was dripping out of the light fixture:blink:
 
#12 ·
I think you need to approach this from another angle.

first this will not be a root cellar it would more accurately be classified as a basement pantry.

This distinction is important. The customer needs to recognize a cool room in the basement does not a root cellar make.

Now for something constructive, consider a dehumidifier, best a split but the cost may be prohibitive.
 
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BadgerBoilerMN
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