Ac cooling advice

Hello everyone this is my first post. I can really use some cooling advice. I'm in socal somewhat coastal
My set up
Two 12x12 bedrooms side by side.
One is used for veg with 4'x6' grow area running two sun system lec 315's
Other room runs 4 air cooled 8" magnums 1000's and 4 solis tek digital ballasts. Up to this point I have only ran two of the lights in flower and am going to need to start running the other two very soon. I am running a can 150 carbon filter in the room with a 14" max fan on top then splitting into two 8" ducts running through two lights each then exhausting outside.
For intake I have an 8"filtered duct going into each room in closet with doors removed. The air is being pulled from the garage. I don't have any fans in the ducts. There is also an 8"duct connecting the rooms which exhaust into a wall mounted fan opposite side of the room of the exhaust fan.

Current temps are fine below 80 in the flower room and maxing about 82 in veg room. Although it has not gotten very hot outside yet.

I've really been wanting to get a whole house ac and already have ducting for 3ton central heat.
Is there anyway a whole house ac works in this set up? Should I just get a mini split and house ac separate? Pros and cons?
What is a good quality and efficient minisplit for this set up? I'm thinking 18,000 btus.
The exhaust cfm is about 1200 which mean I'm dumping the room air about every minute. How does this come into play when trying to cool a room? Where is the best place to put the minisplit? My exhaust fan is close to the door. I'm guessing opposite the exhaust fan. Would a cassette type work well here?
I have a 220v 20 amp power source ready for a split system.

Any help would be appreciated and passed on. Thank you.

The temperature of the entire house would need to be 68° or lower to compensate for the heat the lights give off in the two rooms.

I run central heat and air and have cabinets in a smaller bedroom. 5000btu A.C. keeps it at 68-71°f.

To cool that room with the central air conditioner. It'd take cooling the whole house. Even on cooler days to where you can open windows and don't need the whole house at a balmy 68. Plus it'd take a lot more $$$ for electricity.

SouthCross said:

The temperature of the entire house would need to be 68° or lower to compensate for the heat the lights give off in the two rooms.

I run central heat and air and have cabinets in a smaller bedroom. 5000btu A.C. keeps it at 68-71°f.

To cool that room with the central air conditioner. It'd take cooling the whole house. Even on cooler days to where you can open windows and don't need the whole house at a balmy 68. Plus it'd take a lot more $$$ for electricity.

Click to expand...

I was thinking I could close the vents in the house and maybe duct a second ac intake into the flower room and put the thermostat in the flower room.
then just open the vents for the house in the summer months.
I'm wondering if this can make sense. Probably not. If the ac runs all day it would make more sense to run a smaller dedicated unit.
Can Anyone with ac experience tell me if this is a bad idea?

The whole house system ducting system is designed to run most efficiently with all the duct outlets open. If you choke down the duct outlets and try to feed only a couple of rooms, the main AC compressor will be oversized for the load and won't work well.

A dedicated system designed around the grow loads will be more efficient and cost effective over time, especially with southern California electricity costs.