Picture and question: 4k cooling via mini-split AC

[Andyo]

inverter ac

inverter ac

to large of an AC unit will cause it to short cycle. Get cold to quick and shut down before it can remove the humidity.

use an inverter AC speeds up slows down as needed doesnt switch on and off cooling ,far more efficient and better controlled temps and humidity.A

 

[queequeg152]

Heat gain calculation. Hmm. So in you opinion if you ran 4k light with no air cooling, 12kbtu AC will keep the room 70~? And going over 18kbtu risk humidity problems as it is too powerful for the space and will turn on and shut off at different intervals than a smaller more appropriately sized AC?

12k would be enough to cool the lights and nothing more.

your room itself will gain heat from solar radiation and convected and conducted heat from the outdoors.

 

[queequeg152]

Question: don't most mini-splits have low-medium-high output settings? You don't have to run an 18k at a full 18k all the time, right? I always see specs showing variable output ranges, such as 'has an operating range of 7k through 18k'. No?

most minisplits are VRF, or variable refrigerant flow capable...at least on some level.

meaning they can vary their capacity to some degree.

however if your unit is not capable of cooling on peak load days... this variability is of little use.

where VRF is hugely important is off load days... when you only need say... 8kbtuh. the vrf system can ramp down the capacity... slow down the blower, and continue to dehumidify very very well.

vrf systems are the future of premium end hvac, mark my words.

 

[queequeg152]

use an inverter AC speeds up slows down as needed doesnt switch on and off cooling ,far more efficient and better controlled temps and humidity.A

problem is that VRF systems cost around 2 grand per ton... sometimes more.

you can save a shitload of money by running a properly installed and PROPERLY SIZED single stage system.

with a decent thermostat and a variable speed air handle you can get decent dehumidification as well.

 

[tact1]

problem is that VRF systems cost around 2 grand per ton... sometimes more.

you can save a shitload of money by running a properly installed and PROPERLY SIZED single stage system.

with a decent thermostat and a variable speed air handle you can get decent dehumidification as well.

mr.slim?

 

[queequeg152]

mr.slim?

yes the slims are very good VRF systems.

VRF systems tend to be less reliable, and more expensive to fix, but in the long run... if properly sized it should pay for itself in like 10 years of normal residential use. your use case is different... id think it would pay for itself sooner, but you would have to do the math.

get the heat gain calc... and investigate the insulation situation. investigate the air tightness.
retrofit air seal where feasible, and replace any damaged insulation. if you have cellulose above this room... investigate your attic ventilation and insulation depth and quality.

Bad insulation will cost you serious money

500 bucks worth of cellulose and fiberglass( though i reccomend roxxul) is the best investment you can make in lowering long term costs associated with using a living space.

 

[queequeg152]

less reliable than a generic single stage low efficiency split system i mean... mitsubishi equipment is high... some would argue very high quality, but circuitboards and sensors will go bad just as in any system.

the VRF systems have more going on than shittier systems and as a result tend to fail more often.... its like an old air cooled traction engine verses a water cooled EFI motor.

if you get a VRF system properly installed i dont think you will regret it. just know you could get away with something much cheaper if you wanted to.

 

[tact1]

Like a Friedrich?

The issue is, I am moving and setting up the room a-priori to the grow, and keeping my existing grow going under the new house room is setup. It will be in the basement with two exterior poured concrete basement walls. So I am going to have a space partitioned for 3-4 1k lights to run as a flower, and do my veg/cloning in a tent in a separate room.
So once the wall gets put up, a door, drywall out the ceiling, and have the contractor doing the work cut holes for a closed air system that can be optional, and standard in/out sepperate holes for passive/active, into the house itself scrubed through filters first. The electrician will setup the outlets I need, then I was going to have an AC guy setup the AC and I buy it online as this seems to be cheaper.

But once it is setup:

I can't have him back for any repairs. Soooo.

 

[Andyo]

Asia ac price

Asia ac price

problem is that VRF systems cost around 2 grand per ton... sometimes more.

you can save a shitload of money by running a properly installed and PROPERLY SIZED single stage system.

with a decent thermostat and a variable speed air handle you can get decent dehumidification as well.

Less than half that price here.
Ive yet to find a dehumidfyer for sale here i guess outside RH 85% + no point ac takes care of it .
Ive noticed all new buildings running inverter AC .LG mostly
Yes definatley need facility for remote thermostat.A

 

[queequeg152]

Like a Friedrich?


But once it is setup:

I can't have him back for any repairs. Soooo.

lol, a-priori... i had to google that one. are you an english major or what? im an engineering student, take it easy with the anachronistic letin shit... it goes over my head.


the BIGGEST factor in system reliability is first... a good install then a close second... PROPER maintenance.

which ever system you get, i reccomend you get super familiar with the maintianance required, and the manufacturers recommended install procedures.

tell your hvac tech straight up-that you dont want a hack cheap install. tell him to take his time, nitrogen purge all solder joints with the proper back pressure to ensure best possible joints. consider pressurizing with nitrogen for a few hours to leak check, though most dont consider this necessary... and it adds a big chunk of time to the install.
absolutely insist on a proper low micron evacuation, make sure it holds stable below 300 or so for at least 30 minutes.

make shure he adheres to the manufacturers specifications regarding super heat super cool values... pressures, refrigerant charge weights etc.

make shure he picks proper equipment...hacks often pair air handlers to condensing units improperly.

consider adding a sight glass/moisture indicator... its generally always considered a good idea, but check with the manufacturers as its possible that its not reccomended.

tell your hvac tech you are not a tight fuck and that you will pay for the extra 2 hours of labor required to install the unit properly.

 

[queequeg152]

Less than half that price here.
Ive yet to find a dehumidfyer for sale here i guess outside RH 85% + no point ac takes care of it .
Ive noticed all new buildings running inverter AC .LG mostly
Yes definatley need facility for remote thermostat.A

im in the south, so we run ac pretty much all year, so yea we dont see many dehuys either. we also dont do basements here... there is no real engineering reason for this, its just that we like our houses cheap and shitty.

beyond 10-20 tons or so, most new refrigerant equipment is going to be 3 phase VFD systems. it makes more sense financially at that scale, and its cheaper to design VFD systems operating on three phase AC power.

eventually you get multistage + variable frequency drivers on chiller skids with these lovely pressurized oiling systems for huge cooling loads like 200k sq.ft per floor commercial buildings.

VFD equipment is absolutely excellent for multi zoned systems... most small homes dont need excellent zoning so its a harder sell getting VFD units into homes.

 

[queequeg152]

Like a Friedrich?

no. as far as i know fridrich only sells window unit ac's?

im talking about cheap single stage 13-16 seer split systems.

google the york 14 and 15 and 16 seer units. the best bang for the buck is the 13 seer goodman units... pair these cheep condensing units with a variable speed blower and you can get decent dehumidification. not as good as a VFD mitsubishi, but pretty good.

 

[tact1]

no. as far as i know fridrich only sells window unit ac's?

im talking about cheap single stage 13-16 seer split systems.

google the york 14 and 15 and 16 seer units. the best bang for the buck is the 13 seer goodman units... pair these cheep condensing units with a variable speed blower and you can get decent dehumidification. not as good as a VFD mitsubishi, but pretty good.

Like this?:

http://www.alpinehomeair.com/viewpr...from=froogle&gclid=CPjj2qT1rsYCFYdFaQodi0kCRQ

The 18k btu Seer 18 mitsu split I was looking at is $1800. That of course online, but then if I bought it through the hvac installer it would be way way more. Either way they really nail me on install, I got one quote for $2200 for installing a dual-zone split ac, though now I just want a single zone split, or possible your solution here with a legit dedicated big-boy ac though cheap and inefficient?

What do you reckon is ballpack (I am midwest) on proper installation by hvac pros of either the $1800 single-zone mitsu split vs this goodman 13 seer? Better to purchase through the installer so they install it better, or absolutely know they have all the tools for it or something?

 

[Granger2]

http://www.friedrich.com/

Mini splits
Also for self installs http://www.friedrich.com/products/residential/window/breeze
Window Units
Thru the Wall Units

 

[tact1]

Well this is where I am at now:

18k mitsu mini split, single zone as the "AC". I will not be doing co2, or running a sealed room. I don't want to drag outside debris through my hoods because of the humidity where I live so I opted to just draw some air over the hoods then out of the house from the partitioned "storage room". Word life?

https://drive.google.com/file/d/0BwXvuunYt2lnVUdwcGtvMEVRVlE/view?usp=sharing

 

[Charles-scott]

Hi Tact1
I run air cooled lights on my beds for SOG and Scrog gardens all hard piped I use insulated flex where flex is required , we tape all the seems on the AC hoods .
I would run a sealed room with c02 generator internal carbon can and we actually use very high output ozone generators to cover ambient air from filtering out of the facility in common area's we run a lot of light but same principals apply .
I worked in a research facility where we had breeding rooms each room was run on mini splits they were all sealed I found that the brand made little difference on the Mini Splits we imported a bunch from China that functioned as good as the fujitsu units that were purchased locally for 5-6 times the price .
Those Rooms were all around 4 kw bare bulbs and we used 2 ton mini Splits these roomed were on a upper level and all functioned fine with the 2 ton units .
I am not a AC expert i just thought I would share my experience with you here .
If you can afford it just buy a york or carrier household 3 ton they are great units .
You can have pre charged lines set up for you just say you need to take it to a remote cabin etc etc .

 

[tact1]

Nice setup Charlie. A pallet of shitty Chinese mini-splits, nice. I heard a lot of them are made in the same factories they just put different brand labels on them *shrug*.

 

[queequeg152]

Like this?:

What do you reckon is ballpack (I am midwest) on proper installation by hvac pros of either the $1800 single-zone mitsu split vs this goodman 13 seer? Better to purchase through the installer so they install it better, or absolutely know they have all the tools for it or something?

it varies wildly, sorry but there is no real answer to this question.

a residential hvac tech isnt just some highschool grad... they go through some vocational program... its a 1 or 2 year deal i think. they also apprentice in some states for a few years before they can practice on their own.

if i had to guess id say that they make around 30-60 bucks an hour... double that amount and you will probably arrive at your labor cost.

refrigerant... coper, silver solder, wire, thermostat wire, electrical disconnect, conduit, hangers, lineset covers... this all adds up.

IMO, you could easily pay 800 bucks for an install not including the equipment.

a minisplit SHOULD be cheaper to install. why? because there is alot less going on with a minisplit. there are no accessories to worry about, no copper work, no brazing etc. if i had to guess, id venture that you could get a minisplit installed for like 5 600 bucks? IDK. r410 is only like 5 bucks an lb.

IMO you need to get on angies list or what ever... yelp? and get bids from at least 3 REAL hvac techs... tell them straight up what you want. i cannot emphasize this enough, tell them you are not ONLY interested in the lowest bid...but in a quality install.

tell them what accessories you want installed into the equipment... line set covers, low ambient kits, new concrete pad, condensate pump, etc.

make it clear to them... the scope of the install. do they need to core out of our basement wall? that will cost you more. do they need to plumb in a condensate drain? drop wire for your thermostat?
do they need to drop new 10-3 to the condensing unit? do they need to fabricate duct? it all costs money... in labor and parts.

a huge pet peeve of mine is the fucking outrageous markups some ****s charge for r410... sometimes its like 500%. watch out for that. a 25lb cylinder of r410 is like 150 bucks MAXIMUM. a 3 ton unit will require no more than like 14 15 lbs.

ask them how they will install it. if they try to tell you that its unnecessary to nitrogen purge and evacuate properly just smile nicely and move on.
there is no point in trying to convince a hack to install something properly...because you will still have a clueless hack installing your equipment.

 

[queequeg152]

insulate that whole room if you are going to dump hot ambient air into the surrounding areas...

 

[tact1]

Damn, this is not a legal state so I cant be too straight up, of course emphasize I seek quality one-time job over saving a few hundos. I need a cover I guess in a way to justify shy I am getting the mini-split @ 18k right there. As far as all your excellent questions, could I just boiler plate read those off, if nothing else to emphasize I seek a quality install? Because I could never verify all that shit in reality I feel like.