Mini split with heat pump/garage

Greenthumber · Feb 1, 2021

Looking to build a new room in a garage roughly 16-18 ft long and 6-7ft wide typical 2door garage height 8ftish, Living in the north (southern mi) have been contemplating 24,000 btu but wondering if it’s not overkill? As I run 4 head split with 18k heads per 4 luxx lighting leds in a home. My skepticism is about being in a garage and how well it will or will not cool and heat in the summer/winter times Anyone with experience with these units and or experience in garage grows any help greatly appreciated. 18k or 24k btu? Price is not the issue really more for knowledge and what should be sufficient for 18 x 7 x 8ht. 4 led at most (luxx lighting 645w) co2 burner) dual 110 dehumidifier). Well insulated when I build thanks

Raho · Feb 1, 2021

Greenthumber said:
Looking to build a new room in a garage roughly 16-18 ft long and 6-7ft wide typical 2door garage height 8ftish, Living in the north (southern mi) have been contemplating 24,000 btu but wondering if it’s not overkill? As I run 4 head split with 18k heads per 4 luxx lighting leds in a home. My skepticism is about being in a garage and how well it will or will not cool and heat in the summer/winter times Anyone with experience with these units and or experience in garage grows any help greatly appreciated. 18k or 24k btu? Price is not the issue really more for knowledge and what should be sufficient for 18 x 7 x 8ht. 4 led at most (luxx lighting 645w) co2 burner) dual 110 dehumidifier). Well insulated when I build thanks

If you insulate well, then the outside environment is not a factor right?
Mini-splits can be very efficient in operation.
Keep them clean though.

Living as far north as you do, pay attention to the low temp rating of the system you are looking at. Not all are designed you operate below freezing and may need to be upgraded (this usually comes up when looking at Mitsubishi units.)

HLG has a some nice resources to help you scale your system to the environment.

https://horticulturelightinggroup.com/blogs/calculators

Sizing the system properly will help reduce temperature swings (up/down) which can come from having an oversized unit.

Don't forget to include some capacity for any dehumidifiers you may be using.

Greenthumber · Feb 4, 2021

Raho said:
If you insulate well, then the outside environment is not a factor right?
Mini-splits can be very efficient in operation.
Keep them clean though.

Living as far north as you do, pay attention to the low temp rating of the system you are looking at. Not all are designed you operate below freezing and may need to be upgraded (this usually comes up when looking at Mitsubishi units.)

HLG has a some nice resources to help you scale your system to the environment.

https://horticulturelightinggroup.com/blogs/calculators

Sizing the system properly will help reduce temperature swings (up/down) which can come from having an oversized unit.

Don't forget to include some capacity for any dehumidifiers you may be using.

Thanks for the input raho it’s greatly appreciated I checked found a calculator similar to what you had mentioned and did some calculations for best and worse case I think a 24000 may be over shooting by a bit and may just run with the 1.5 ton. You’re right being well insulated I would think the weathering wouldn’t be an issue and just having a case of the overthinking being a garage build will be a first for me and used to growing in a home where the temperature is already regulated and not just a cold/hot box like a garage. Yeah being in mi and getting down pretty low I had already planned on getting something with a low operating temp I think the one I was looking at is rated to -22 degrees. Again thanks a ton

f-e · Feb 4, 2021

I'm having great results air-cooling LED lights. Unlike the HID cool-tubes, with LED you can actually get all the heat away. Putting your lights in shallow boxes with glass fronts might loose 10% of your light, but moving the heat away with aircon is a 25% drop in electrical efficiency. Plus the cost and the noise. The box might take a little thought but LED's are so controllable that you might not want to raise and lower them. It need not be a box either. A plastic bag weighs nothing. Further more, I don't have glass in my boxes, a have a hole the light unit plugs up. I just box the back of the light.

Such a system would leave the dehu as the biggest heat source. If it's not already. So that should be done with the split. Then your issue is a cold room. Your light extract system gets diverters and temp controlled actuators.

I'm unsure how much heat a co2 generator produces?

Just some alternatives

overbudjet · Feb 5, 2021

Little work shop :dance013:

16'x12'. 3K of cmh light/dehu/Co2 .12000 Btu a/c ,running fine last winter(-20c/-35c)

Greenthumber · Feb 8, 2021

f-e said:
I'm having great results air-cooling LED lights. Unlike the HID cool-tubes, with LED you can actually get all the heat away. Putting your lights in shallow boxes with glass fronts might loose 10% of your light, but moving the heat away with aircon is a 25% drop in electrical efficiency. Plus the cost and the noise. The box might take a little thought but LED's are so controllable that you might not want to raise and lower them. It need not be a box either. A plastic bag weighs nothing. Further more, I don't have glass in my boxes, a have a hole the light unit plugs up. I just box the back of the light.

Such a system would leave the dehu as the biggest heat source. If it's not already. So that should be done with the split. Then your issue is a cold room. Your light extract system gets diverters and temp controlled actuators.

I'm unsure how much heat a co2 generator produces?

Just some alternatives

I admire your ingenuity! But my goal is to absolutely not have to aircool my lights just more of a headache I would rather not deal with especially being a new build but mainly trying to no under shoot or over shoot the ac/heating capability too much because each will have its extreme being in Michigan close to zero in the winter at times and in the 90’s during the mid of summer. As of now I run 8 645 led a burner and 2 duhumidiers a dual 110 and a stand alone 70 Pinter with 2 18k heads and can control my environment pretty on spot to what I set it at but that’s being in a house. I think a 18k unit will run well but I think the key to it all will be going overboard on the insulating aspect of the room itself while building.

Greenthumber · Feb 8, 2021

overbudjet said:
Little work shop 16'x12'. 3K of cmh light/dehu/Co2 .12000 Btu a/c ,running fine last winter(-20c/-35c)

awesome I’m guessing you run low to mid 80s? How does it stand up in the summer time being a 12k?

overbudjet · Feb 10, 2021

Flower room temp 82 deg. July and August are break time for me so no info for this time ,my dehu is also a bit DIY, the hot coil being cooled by water instead of room air(worth at least a kilowatt in lighting,Co2 burner is also water cooled)

Greenthumber · Jul 8, 2021

A lot has changed since my last post it’s almost hard to believe but I’m actually almost up and running after working little hours here and there away from my already busy schedule but it’s starting to feel more like an accomplishment over what started as a foggy thought. will eventually be 6 lights total all led currently 4 horticulture lighting group 600 r specs 2 ton minisplit, 8 light controller 4 wall fans a high velocity scrubber and will sighting in on a high dehumidifier. Thanks to everyone for any input related to the original post. Much love

Greenthumber · Aug 23, 2021

4 days into 3 gallon pots and a little tie down and things are coming along

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Mini split with heat pump/garage

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