Adding AC to a workshop

[AK Caster]

I get a lot of pretty good common sense advice from this forum so hoping for more. My workshop is just over 1000 square feet. Ceiling is 10 feet, its insulated pretty good and both the walls and ceiling are covered with sheet rock.
Have a gas fired heater in one corner and it works great. Two windows in the shop but both are built with glass block so neither can be opened.
What are some good options to add AC? I spend a good deal of time in there during the summer. Cant' get crazy and spend a fortune so would like to keep the costs under $1500 but could go up to $2000 if I had to. The AC will only be run 10-15 minutes before I go inside then will be turned off when I left. Object of the AC would be to get the temperature down to 75 or so.

[farmbif]

you probably don't want my advice as there are no building codes where I live but having more time than money I would get a window unit, 5000 0r 6500 btu cut a hole in the wall and have air conditioning for just a couple hundred dollars.

[Neverhome]

Looks like roughly a 2 ton unit would world. I just glanced at Home Depot’s site and it appears prices vary widely. Some well under your budget and some well over. Most of the more expensive ones are also heat pumps which you wouldn’t necessarily need with your current heater. Looks like you can get a ac only unit for under 1000. Of course then it needs to be wired, ductwork installed, etc...

A portable ac unit would make it considerably more comfortable in your shop but you still need to rig exhaust ducting and empty the condensate regularly or otherwise rig a drain.

[country gent]

I put a mini s[lit in my new shop, covers both heat and cooling but was more than you want to spend. One quick way would be to frame in a window on an outside wall and use a window AC unit. there are also some smaller free standing units. You could do this on an inside wall but heat and condensation will be put into the building then.

My shop is 16'x30'x10' for 480 square feet, finding a unit for that size was tricky. The mini split was the best option for me. since this is a room inside a building the actual unit is outside the room inside the building, this keeps it put of the blowing dirt and crud and out of the weather. It also will help heating since the building will warm with winter sun on the roof. The "cartridge in the room is very quiet with a simple vane set up to distribute air.

I believe I would look at one of the wall mounted or free standing units around 1 1/2-2 tons the freestanding may be able to be moved around some even free room where needed. I wouldn't recommend the chiller type as they put a lot of moisture in the air when running and could cause rot and rust problems.

The big plus to the mini is there is no duct work to be ran on a new install. 3 lines thru the wall 1 drain 2 fluid. 1 power line. On mine the drain runs to the tray under the external unit which is drained to outside the building. Very quiet running and really does a good job. The contractor thinks with the insulation the room wont change to much overnight. I have 4" in the 2 inside walls 6" in the 2 outside walls and 12" on the ceiling with a big airspace between it and roof of building. 2 windows 2 doors insulated also.

[Dapaki]

I would seriously consider a ductless mini split, 2 ton system for your shop. You can find them from all the box stores (online) as well as Amazon for about $1k.

a 18,000 BTU window AC unit will run 1/2 of that but they also dont normally even have a SEER rating bur expect a SEER of 9-11 for window units and up to 19 for a ductless mini split.

This is really how efficient the unit is and how many BTU you get per kW.h. If you AC for a few hours a day, the window unit may be your best choice but if its left on 24/7, you will make up the difference money wise very quickly.

[osteodoc08]

I would seriously consider a ductless mini split, 2 ton system for your shop. You can find them from all the box stores (online) as well as Amazon for about $1k.

a 18,000 BTU window AC unit will run 1/2 of that but they also dont normally even have a SEER rating bur expect a SEER of 9-11 for window units and up to 19 for a ductless mini split.

This is really how efficient the unit is and how many BTU you get per kW.h. If you AC for a few hours a day, the window unit may be your best choice but if its left on 24/7, you will make up the difference money wise very quickly.

Agree with this.

Also, if you keep temps at a reasonable level, your humidity level is also brought down with the AC unit which may be beneficial depending on what you have in the shop. You don’t have to keep it on 70 when you leave. Raise to 78.

[Dapaki]

BTW- I installed a Climate Right unit in my wife's she-shed as it provides both heat as well as cooling for the same price of a window unit and attaches with hoses making it portable. Once I get the wood boiler trenched to her shed, I will buy a small mini-split and cool with that.

[AK Caster]

As I mentioned before, the AC will not be running when I leave the shop. The only time it will run with no one in the shop is maybe a 10 minute cool down before I enter.

[Neverhome]

If that was all you’d run the unit for then you’d actually need a bigger unit if you expect it to cool down in such a short time.
If you turn your household unit completely off in the summer for some reason, it takes forever for it to come back down to your target temp. Maintaining temp is much easier and requires less btu than making a huge change in temp all at once.

Totally possible to do what you want! But if you want to come down from 90 to 75 in 10 minutes you’re going to need a unit sized bigger than typical btu/ton calculators say for your size space

[Kraschenbirn]

I recently installed an LG window AC unit (8000 btu) in my well-insulated workshop (about half the size of yours) and it meets my needs quite adequately. Rather than turning it off completely when I'm not actually in the shop, I just bump the thermostat up a few degree and leave the unit in the 'Energy Saver' mode which kicks on the fan every three minutes for air circulation but doesn't bring the compressor online unless the sensor detects that cooling is actually required to maintain the set temp.

Bill

[jsizemore]

I live with a window unit in a small space. I framed a hole slightly larger then the unit so when it goes bad I'm not stuck with having to buy the exact same unit. You have to run a dedicated circuit with either a mini-split or window unit. Since you plan on turning both off when you leave, you might need to clean mold buildup if your sensitive to that kind of thing. The mini-split requires a service tech to hook it up. You'll have to provide space on a wall or the ground for the mini-split condensing unit. The mini-split requires a hole through the wall for the line set and condensate line. Good Luck

[NyFirefighter357]

As I mentioned before, the AC will not be running when I leave the shop. The only time it will run with no one in the shop is maybe a 10 minute cool down before I enter.

What people don't realize is your not just heating or cooling the air with your climate control device. Lets say your shop is 90F, everything in the shop is 90F. The tools, equipment, wall coverings and anything else inside. In the case of A/C you might be able to cool the room/air off in 10 minutes but then the mass inside the building will give off it's heat into the room warming it back up to 89F. A small 8-10K BTU set to energy saver & left set on 75-80F will maintain a temp and dehumidify as well as enable you to drop the room temp 5F or so in a reasonable time. A 12-15K btu unit will enable you to cool the area quickly if it's for short spurts but won't get all the humidity out. Either way I think your not going to maintain 75F just by running the unit for 10 min. A 12K btu high energy efficient window/wall unit and mounting it through the wall high 7'-8' off the floor will work. Window units like this run about $500-& $600, wall units will cost more but would be easier to replace if needed. Your going to have to frame this into the wall. Depending on the siding & skill set it may cost very little to a couple of hundred dollars to install. I have a 10K btu window unit in my shop I set to 70F while I'm not using the shop with the energy setting on & the fan on low. I turn it down to 65F while working in their & with the econo setting it doesn't run much as it only gets early morning sun. I got this unit for free but I'm also looking to change to a mini split at some point.

A 1 ton/12k btu mini split is about $1,000, a unit like this has a high seer as high as 21.5. It is also the appropriate size for your shop. The majority of the install can be done yourself and you can get someone for a few hundred dollars to make the final connections. These require a small hole through the wall for the line set & a plastic or concrete pad for the cassette case or can alternately be hung on the outside wall with a bracket. They can use 110v or 220v depending on what model you get. They use about 9amp of electricity which is less than a window/wall unit but the seer is much higher making it much more energy efficient.


https://www.homedepot.com/p/Pioneer-Inverter-Energy-Star-12-000-BTU-1-Ton-Ductless-Mini-Split-21-5-SEER-Wall-Mounted-Air-Conditioner-Heat-Pump-WYS012AMFI22RL-16/311759954

https://www.homedepot.com/b/Heating-Venting-Cooling-Air-Conditioners/12000-BTU/N-5yc1vZc4meZ1z180zk

https://www.homedepot.com/b/Heating-Venting-Cooling-Ductless-Mini-Splits/12000-BTU/N-5yc1vZc4m1Z1z19b6s

[smoked turkey]

AK Caster you have gotten a lot of good advice here I think. I would only add that it is important that your electrical supply be adequate for the compressor. I would imagine that your shop is adequately wired to support a unit like the mini split as described in the Home Depot link above. It is desirable to connect heavy equipment to a 240 VAC circuit when at all possible. This will help insure against "low voltage" which is always a concern with equipment that draws up to 5X the current on start up, often listed as the LRA(locked rotor amps) as compared to the running amps.

[country gent]

When I just had the AC leak fixed the tech told me to expect 3-4* an hour cooling down. Sometimes your better off to leave run and just raise temp some while out. Same with heating up a room. from 6o* to go to 70* isnt to bad or long but from 50-70 is awhile.

[Dapaki]

I live with a window unit in a small space. I framed a hole slightly larger then the unit so when it goes bad I'm not stuck with having to buy the exact same unit. You have to run a dedicated circuit with either a mini-split or window unit. Since you plan on turning both off when you leave, you might need to clean mold buildup if your sensitive to that kind of thing. The mini-split requires a service tech to hook it up. You'll have to provide space on a wall or the ground for the mini-split condensing unit. The mini-split requires a hole through the wall for the line set and condensate line. Good Luck

Not so, in most cases the line is precharged with QD's on both ends, the end user can do this themselves with no license or technical know-how.

[NyFirefighter357]

Not so, in most cases the line is precharged with QD's on both ends, the end user can do this themselves with no license or technical know-how.

You are incorrect, the line is not charged. After being installed you need to evacuate the line set before you release the refrigerant from the compressor. This removes the air & humidity from the line & head as well as tests for leaks at the connections which are flared.

"Vacuuming down a mini split system is necessary before releasing the refrigerant. It also is the main way a unit is tested for leaks"
https://www.hvachowto.com/how-to-vacuum-down-a-mini-split-and-release-refrigerant/

[Dapaki]

I will correct my wording from "in most cases" to "you can find readily available units where they (https://iwae.com/promo/mrcool-diy/ Cooper & Hunter as well as ClimateRight) have precharged line-sets as well.

I'm a licensed HVACR tech, I understand how one purges and evacuates a line set.

The trend is to do DYI installs, the ClimateRight is the one I suggest the most as it is idiot proof.

[Gtrubicon]

Mini split

[gwpercle]

Based on my past profession , 1000 sq. ft. area and 10 foot ceilings ...I would use a 2.5 ton unit .
Through the wall is old school go with a Mini Ductless Split System A/C Unit .
Much better and not that expensive , a small condensing unit sits outside and inside , mounted on the wall or ceiling , is a small air distribution unit (air handler) that has the supply vents. There can be two or three of the supply units depending on size of the unit .
There is no duct work and they work well for one room , for an application like this ...it's a good choice , check them out .
Gary

[gwpercle]

Mini split

Bingo !!!! We Have a Winner

[NyFirefighter357]

I will correct my wording from "in most cases" to "you can find readily available units where they (https://iwae.com/promo/mrcool-diy/ Cooper & Hunter as well as ClimateRight) have precharged line-sets as well.

I'm a licensed HVACR tech, I understand how one purges and evacuates a line set.

The trend is to do DYI installs, the ClimateRight is the one I suggest the most as it is idiot proof.

I don't install A/C but I have been around a lot of it as I am an oils heat tech. I haven't seen any of those self install units. Most of the houses here use ducted A/C in conjunction hydro air or hot air furnaces. Most of the splits here are in commercial spaces or installed in house additions. Thanks as I'm looking to do the A/C in my house with splits.

[Dapaki]

Then you may like the ClimateRight as it also has heat, 1700W.

[NyFirefighter357]

Then you may like the ClimateRight as it also has heat, 1700W.

That's what I'm looking for something I can use for heat as it's tough to work in a freezing garage or wait an hour for a kero heater to start warming the place.

[Dapaki]

I would use fuel if you have access but electric only, this is pretty affordable. This will be our first winter using it in the she shed, if it cant keep up, I will trench to the outdoor wood boiler and bring in heat that way.

[country gent]

I was recommended the mini split in the new shop by the contractor. he had several reasons for this 1) no duct work to deal with. 2) more efficient than other units. 4) no chimneys or vents needed and last was in a small shop fume build up from solvents and open flames can be a bad combination. I put mine in late this spring and have only used it a little bit since the shop isnt finished.

My external unit is in the garage area of the building and only the cassette is in the room high on the wall taking very little wall space and up high where its normally not used. Its very quiet running only the fan is heard. I would definitely use one for a "cold" room, addition or new room. the power units may be capable of running 3-4 cassettes even.

I was looking at a propane furnace and Regular AC unit. most were bigger than I needed, required duct work chimneys vents and drains. It went in quick and easy ( installers were knowledgeable and professional). $4000 unit labor and materials,start to finish.The remote can be programmed to start and stop at given times a set temp held. Fan speed can be set or auto. the distribution vanes programmed to oscillate or fixed position. My main unit is on a concrete stand with a tray under it drain to outside of building and the cassettes drain runs to this tray.

I would talk to several reputable heating cooling services and the stores people( home depot, lowes, menards ) and see if a self install can be done. my lines were precharged and there is a small coil up above of the extra ( so they didnt require cutting and losing the charge). They did check it but I dont recall them adding any. the unit cassette and lines were all flushed purged and filled from factory. If you can get this from a local store you may be able to do complete installation. The other issue will be wiring and adding the needed breaker to your box for it.

[AK Caster]

My shop has its own dedicated power so it shouldn't be difficult to wire in. Now that I have an idea of what to use and costs I'll call the company that installed the HVAC system in my house this winter.

[MrWolf]

I have installed four mini split units. At the time they were around $700 and come pre charged. Have both heat and cool. As long as you have electric that can be run to it you should be good to go. They are quieter than you would think.

[Dragonheart]

I have a couple of LG 14K BTU units set in the upper portion of 9' wall, operated with remotes. I purchased these from Home Depot for under $1K. They do a great job of cooling down my 800+SF shop quickly. Quite, 115V, easy to install.