Sealed, winter and minisplits?

What's up guys?

I have a sealed room atm and as of right now the room is staying cooled perfectly fine. I lost my veg room a few months ago, so I am currently vegging in my flower room. Right now, the open hood 1000w HPS that I am using for vegging is doing a fine job keeping the room warm. When it reaches over 80 degrees, I have a thermostatic outlet that kicks the exhaust fan on and cools the room back down pretty well, hardly ever kicks on till my dehuy does, that brings the temps up pretty fast.

This room is very well insulated as it is an underground room, so it doesn't take a whole lot to heat or cool, thank god.

My question is, I will be running co2 (bottled) in a few weeks when I flip, and I will go from one 1000w HPS to 4 lights, I am gonna have to cool the room while keeping it sealed. I have a 24,000 btu minisplit already installed, have used it since last spring through summer but not during the winter yet. Will I be able to run this unit during the winter??? The outside unit is in an enclosed (cinderblock) walk way, through the summer it did fine I just put an 8 inch fan behind the unit and exhausted all of the hot air outside of the lung room/walkway. But I am not sure how the ac will perform on really cold nights. I know your traditional HVAC central air units cannot run during the winter, so not sure about minisplits ???

One thing I do feel that is gonna allow me to run it during the coldest months is that since my outside unit is in the enclosed walkway, the heat will kinda be trapped instead of being vented away and in return it will keep my coils from freezing? There are a couple exhaust ports in the walkway as well that I can just open up so it doesn't get too hot in there. I can control the walk way temps pretty well I believe.

What do you guys think??

Look for the low ambient spec, that will tell how low they can go. Some mitsubishi's I have seen go down to -23f.

When buying mini's I always spec low ambient operation and restart on power outage. those two features are critical for growers. As you already have your minisplit, you need to look up the model number and see what it's specifications are.

The inverter design in most minisplits means that they can run the compressor and condenser fan just as hard as they need to, that's also why they are more energy efficient, set them on auto cool and set the temp, then they just run hard enough to keep the room cool instead of kicking on and off all the time like normal units do. Also when it's cold you will note your outdoor condenser fan isn't really turning and the compressor is also slowed down based on the temperature differential.

They use these in server rooms where computers need cooling regardless of the temperature outside.

Also, use your ventilation system as a backup, set it to come on if the minisplit doesn't hold the temperature as it normally does. This prevents a crop loss due to a low charge or other fault.

I use my autopilot controller for this, it has my fan hooked to it and is set to cool just a few degrees above where my AC holds it. If there is a AC failure it stops co2 enrichment when it vents the room.