Switching from a window A/C to a mini split?

[RedReign]

I currently use a 25k btu window a/c to cool my 10k room. The room is sealed and well insulated. The lights are aircooled and I use a ng co2 burner and a 65 pint dehumidifier. I have been using this set up for about 9 months and I couldn't be happier with my current room conditions.

My question is, are a window a/c and a mini split (mitsubishi mr slim in this case) equally efficient at cooling a grow room?

2.5k btu of window a/c is working great for me. I'm guessing that a mini split cools a growroom much better than a window a/c. If so, how much better? 20%? 30%?

 

[Guest 18340]

I currently use a 25k btu window a/c to cool my 10k room. The room is sealed and well insulated. The lights are aircooled and I use a ng co2 burner and a 65 pint dehumidifier. I have been using this set up for about 9 months and I couldn't be happier with my current room conditions.

My question is, are a window a/c and a mini split (mitsubishi mr slim in this case) equally efficient at cooling a grow room?

2.5k btu of window a/c is working great for me. I'm guessing that a mini split cools a growroom much better than a window a/c. If so, how much better? 20%? 30%?

What makes the Mr.Slim more efficient is if you get the one with an inverter.
I have a 9k btu (not a Mitsu, unfortunately) with an inverter and it uses less power than a 5k btu window unit I used to use. My electric bills says so
Btw, great choice of brand, imo Mr.Slims are thee best. I learned the hard way that parts are impossible to find for generic brand mini splits...

 

[Hydropimp]

redreign is your window a/c in the room or in the wall like a normal unit?

 

[RedReign]

hydropimp, I have the window a/c mounted through the wall of my grow room. My grow room is in a warehouse. The exhaust heat from the a/c goes into the warehouse and then out the whirlybirds in the roof.


evlme2, thanks for the info. Besides the power efficiency, I'm curious about the 'room cooling' efficiency. In other words, will a 24k/2ton btu mini split cool a room better/faster/easier than a 24k/2 ton window a/c? Or does a 18k btu mini split cool a room as good as a 24k btu window a/c?

 

[Sam the Caveman]

2 tons of cooling is 2 tons of cooling, however the mini split will, more than likely, use less electricity.

Most window units are around 12 seer and 2 ton mini splits can go up to 17 seer.

 

[Guest 18340]

Ok I see what you mean. I tend to lean towards what Sam the Caveman said.
Stick with the same btu's, better safe than sorry.

 

[GeorgeSmiley]

I'm looking at the mitsu 1 ton mr slim 20 seer. I hear really good things about them. I plan on getting one in the fall (most likely)

Smiley

 

[beta]

.

 

[Guest 18340]

Check your pm's beta.

 

[GanjaIsMyLife]

evelme2 wheres the tutorial on installing a mini split did you ever get around to helping your buddy install his?

 

[RedRain]

I currently use a 25k btu window a/c to cool my 10k room. The room is sealed and well insulated. The lights are aircooled and I use a ng co2 burner and a 65 pint dehumidifier. I have been using this set up for about 9 months and I couldn't be happier with my current room conditions.

My question is, are a window a/c and a mini split (mitsubishi mr slim in this case) equally efficient at cooling a grow room?

2.5k btu of window a/c is working great for me. I'm guessing that a mini split cools a growroom much better than a window a/c. If so, how much better? 20%? 30%?

BTU output is the same regardless of the SEER. a 25k BTU 18 SEER will cool the same lights as a 25k 12 SEER The SEER will determine how energy efficient the unit will be. A mini split will use less power to give the same BTU.

Think about it, a larger coil size = more surface area to dissipate and absorb heat. More surface area means less power is needed to dissipate/absorb heat. Its why portables and window shakers are so inefficient, very small and compact.

Full condenser > mini split > window ac > portable ac

You cant figure that a smaller BTU load will handler the same heat load.

 

[Guest 18340]

evelme2 wheres the tutorial on installing a mini split did you ever get around to helping your buddy install his?

No, he ended up hiring a tech because his room was broken down at the time anyway. Which was cool with me 'cause I didn't want to be responsible if something went wrong during the install...

 

[farmhouse cat]

Ive been researching these inverter type mini splits and they seem to be great for a sealed room. But how would you set different temps for day and night?

My window unit i use now is hooked to a power module that has a trigger cable hooked to the room controller. The room controller powers up the ac according to what i have set. 82 lights on 72 lights off.

With these mini spit inverter models the condenser never shuts down , yet cycles to a lower btu to save energy. The remote control for these units only have a 24 hour timer, and you cant set the unit to different temps at different times.

How did you guys that use a mini split get around this?

Do you just run the same temps day and night?

 

[Guest 18340]

Ive been researching these inverter type mini splits and they seem to be great for a sealed room. But how would you set different temps for day and night?

My window unit i use now is hooked to a power module that has a trigger cable hooked to the room controller. The room controller powers up the ac according to what i have set. 82 lights on 72 lights off.

With these mini spit inverter models the condenser never shuts down , yet cycles to a lower btu to save energy. The remote control for these units only have a 24 hour timer, and you cant set the unit to different temps at different times.

How did you guys that use a mini split get around this?

Do you just run the same temps day and night?

Sent you a vm but...
I leave my mini split set @ 73. Canopy level is always hotter so that setting has my canopy @78.
When the lights are off and theirs no heat signal the mini will shut off completely if the temps are -4 degrees from what you set it, for more than 15 minutes. Thats what it's programed to do and in our case it keeps the room from being over cooled.
Also, most heat pump models have an "auto mode" which cycles the unit between heat/cool to keep the set temp within +/-4 degrees.
But yeah, I set mine to 73 and leave it there

 

[RedRain]

why not just use a full condenser and a honeywell 6000 stat, you cant replace airflow from a real full sized air handler.

Both mini splits and window shakers will not give you as much airflow as a real airhandler.

400cfm per ton is what an airhandler will give you. An AC system removes heat from a room. You condition the air. The more air you can move the quicker you will bring your room to temp.

Mini splits are picky, and expensive. Also they are hard to run in freezing temps.

A full air to air split can easily be run in -50 weather, parts are easy to find, and common. And you get air flow!

 

[farmhouse cat]

Thanks for the response and the great info! I will be running co2 and day temps at around 82-84. I wonder if i set the temps for the night time (75) it will workout as it does for you? Im in socal so dont need to worry about freezing temps.

Im definately going mitsubishi!!

 

[Guest 18340]

Only one way to find out
What I described is what works for me specifically. Play around with it and you'll find that sweet spot. Dangle a thermometer from a string tied from your hood at plant tops.
Good choice on the Mitsu. Expensive as hell but man are they reliable.

 

[farmhouse cat]

Im wondering about placement of the indoor unit. I will be runnin 2 1k bare bulbs in a vertical system.
Seen here https://www.icmag.com/ic/showthread.php?t=209861 i will have 2 squares in total, each with a 1k bulb in the center.

The way the system runs with a fan blowing up from under the lights makes me wonder if placing the indoor unit at ground level in between the 2 squares might be beneficial?

 

[Guest 18340]

My room is approx 10x5 and I have the head unit 8" from where the wall an ceiling meet blowing the long way across the room. I use two fans at the other end;one blowing across the canopy and one blowing down from near the ceiling.
I would mount a fan somewhere, blowing down.
Heat rises so I don't know haw far you'd get cooling wise with the head unit mounted near the floor.
I have 3 fans in total in my flower room to keep air moving around, that helps tremendously when trying to maintain even temps. Trust me.
Btw, on the Mitsu's , you can adjust the flaps on the head unit via the remote. So you can have the flaps pointed straight down.