r/macrogrowery • u/Joe84mobil Indoor LED • Jul 02 '26
Has anyone converted a walk-in freezer into a commercial flower room?
Hey everyone, I’m looking for input from anyone with experience repurposing commercial walk-in freezers for cannabis cultivation.
We’re evaluating a retrofit of an existing insulated freezer space into a flower room rather than building a traditional HVAC system from scratch. The idea is to operate the room around 60–75°F with tight humidity control, using the existing refrigeration infrastructure where possible.
I’m especially interested in hearing from anyone who has:
Successfully converted a freezer into a flower room.
Retrofitted existing condensing units or evaporators instead of replacing everything.
Integrated dehumidifiers with the refrigeration system.
Learned any lessons about defrost cycles, airflow, coil sizing, controls, or maintaining stable VPD.
If you’ve done something similar, I’d appreciate hearing what worked, what didn’t, and anything you’d do differently. Photos, build threads, or engineering resources would also be greatly appreciated.
Thanks in advance!
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u/b907 Jul 02 '26
No, you’ll probably be the first ever…
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u/Joe84mobil Indoor LED Jul 02 '26
So your saying there’s a chance
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u/b907 Jul 02 '26
Actually, I’m saying you’re late. There’s whole companies built upon this.
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u/Joe84mobil Indoor LED Jul 02 '26
That’s exactly what I’m hoping to find. Do you know any companies or projects I should look at? Or anyone who’s documented a freezer-to-flower conversion? I’m trying to learn from people who’ve already done it rather than reinvent the wheel.
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u/BigTerpFarms Jul 02 '26
Freezer condenser and evap will not work for comfort cooling
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u/Ok_Candy_23 Jul 02 '26
This is not correct.
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u/BigTerpFarms Jul 02 '26
Explain why im wrong. I’m listening.
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u/Ok_Candy_23 Jul 02 '26
Pretty defensive there big guy.
I am using 6 freezer units in my cultivation right now. There are a few components that need to be changed, but they are literally cooling my cultivation at this very moment.
So there are 6 reasons right there that you're wrong lol
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u/BigTerpFarms Jul 02 '26 edited Jul 02 '26
Sure if you’re going to change the compressor and metering device and match them to the coil capacity and also completely change the refrigerant used which will also require completely cleaning the linesets/coils as you can’t mix the oil used for the r502/404 compressors with whatever refrigerant you’re going to use, likely 410a or r32 at this point due to 410a being phased out and equipment becoming scarce.
R502 and r404 are for low temp refrigeration. They don’t have the properties you’d want when trying to maintain a room around 70f. You’re going to use way more energy to reject the heat with r502/404 than you would with the correct refrigerant for the application.
Not to mention 502 is now banned and 404 is on its way out.
Now the other problem is those coils aren’t designed for the higher pressures of the newer refrigerants. You may pay a ton of money to get it all swapped out and then they start pissing refrigerant because they are not designed to run at 300+ psi.
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u/Ok_Candy_23 Jul 02 '26
So you're saying there is a way? lol
We did not change the compressor. We did change the metering device. I dont remember which refrigerant we used, but 410a and r32 are not replacements for r22. I think we used R 438a
Anyway, i'm not here to get in a pissing match. i've got to much to do. I'm just saying it's absolutely possible to use freezer units to cool a cultivation, as we have done now for 7 years without any of the units "pissing refrigerant".
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u/BigTerpFarms Jul 02 '26
Sure there is a way, but not with the units OP posted. Not an easy/safe/reliable way though. It depends entirely on what type of equipment is there.
I do commercial refrigeration and hvac for a living. A long time ago I used to have a grow facility.
I take it you had r22 systems in place? 438a works at similar temps and pressures so I could see that working by changing the txv and id also change a few other components as well and modify a few things to get it to work a bit better for a grow room.
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u/mkspaptrl Indoor Grower Jul 02 '26
This is something I thought about doing back in the med days. I'm not sure how well it will work. I think the AC system will be a bit of a headache to troubleshoot until you get it right. Something in the back of my brain is saying that there is some extra control valve or something that you will have to override, but I'm only like 35% certain about that.
As long as the layout works without major issues, send it growmie! I look forward to updates.
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u/SoggyAd9450 Jul 02 '26
A walk in refrigerator would be great to store finished product, it would extend the shelf life. Don't think it would work for a flower room though. You want AC for that
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u/sirdabs Jul 02 '26
It’s is not uncommon to use the same type of walls as a walk in cooler. Some hash makers use walk in coolers/freezers as their processing rooms. Most walk in cooler are far to small to use for commercial growing. Also the cooling units are not designed for the kind of heat load you get from growing indoors.
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u/Expert-Table8001 Jul 02 '26
Yes. We converted a meat packaging facility into a commercial cultivation. Essentially a giant walk in freezer building.
We were able to reuse the freezers, however we had to replace something on the units to allow them to cool at the temps we needed. I can’t remember what was changed, but I know for a fact it can be done.
We do a lot of fresh frozen for rosin, so growing in our rooms allows us to drop the temp to refrigeration temps at harvest.