Input Needed - AC for 20 x 50 Shop in Texas

[bulletpruf]

Just rented a 20' x 50' shop with 14' - 16' insulated ceilings. Owner doesn't mind if I install AC. My unit is the the middle of a row of 5 units, so the outdoor components will have to live out back.

I won't be spending a lot of time there; mostly wrenching on weekends. However, the summers here in San Antonio are brutal, and I'd like to be able to keep it in the 70's when I'm working there. FYI - I was there yesterday mid-day and the temps inside weren't bad at all.

The owner said that someone is installing two two-ton AC units in an adjacent unit for $2500 - parts and labor. That sounds crazy cheap, but if that's legit, that fits my budget.

Anyone have any input? HVAC is not my wheelhouse.

 

[mike93lx]

I'd be tempted to see the workmanship and performance of the neighbor's system, then decide if you want to use the same guy and setup

 

[racecougar]

You'll likely get more help in the Heat and AC section of the site; maybe a moderator could move this thread there.

I can't see someone furnishing all components and labor to install two 24k split units for just $2500. If you buy cheap units, the components alone will run you about $2500.

 

[bulletpruf]

You'll likely get more help in the Heat and AC section of the site; maybe a moderator could move this thread there.

I can't see someone furnishing all components and labor to install two 24k split units for just $2500. If you buy cheap units, the components alone will run you about $2500.

Yeah, that's what I'm thinking. Sounds too cheap to me.

 

[My Old Tools]

24k MrCool should do it. I use a 36k in my 30x40x12 with a 6/12 pitch. It's 22 feet tall. Set the unit about 9 feet off the floor and don't worry about the heat up high.

 

[mike93lx]

There are some scary cheap no name minisplits out there.

Make youtube work for you... Hit up Mr cool for a sponsorship deal.

 

[racecougar]

He's going to be fighting the lack of insulation and the desire to pull the temp down in a reasonable amount of time here.

 

[housewolf]

My shop is slightly smaller, ~750 sq ft w/12’ walls. All foam insulated except the OH door which has none. One 18K unit keeps it comfortable. If you’ll be using the OH door, you want to watch the dew point vs set point. You can get some pretty rapid condensation when you open that door. I keep mine set on 80 unless I know I’ll be in there a while and won’t be opening the big door. I’ve pulled a car out of the shop to see it look like it was rained on in just minutes. Pretty humid where I am

 

[Stuart in MN]

He's going to be fighting the lack of insulation and the desire to pull the temp down in a reasonable amount of time here.

Exactly. No insulation in the walls, and it appears a minimal amount of foam on the roof. I assume the overhead door is not insulated either. Without some serious insulation upgrades, trying to cool it will be like trying to bail out the ocean.

 

[mike93lx]

If the door is south facing, I'd get some insulation in it.

 

[racecougar]

It looks to be a roll up door.

 

[gregs]

IDK, trying to keep it in the 70's when its 95 and sunny outside is a pretty big ask. I have 2 - 24k window units in my 30x50x12. Worked this past weekend all day in it. If I run both of them I can keep it in the low 80's from 11am-3pm. After that they will catch up and get it down to the upper 70's in the afternoon and its no problem in the mornings and evenings. The big plus is the drop in relative humidity to around 40%. On Monday I just ran one of them and it was ok. Again the humidity got lowered and the temperature averaged around 86 inside while it was 95 on the outside. My shop is insulated, but I have 2 10x10 rollup doors that are not and face east. In the mornings its like standing next to a fire even 6-8 feet away. I need to come up with a solution for it

 

[bulletpruf]

24k MrCool should do it. I use a 36k in my 30x40x12 with a 6/12 pitch. It's 22 feet tall. Set the unit about 9 feet off the floor and don't worry about the heat up high.

I need to park something inside that's 10' tall...

 

[bulletpruf]

He's going to be fighting the lack of insulation and the desire to pull the temp down in a reasonable amount of time here.

I really need to check the indoor temps on a hot day, but as I mentioned above, it wasn't that bad when I was there yesterday at around noon.

 

[mike93lx]

It looks to be a roll up door.

Yeah, I missed that

 

[firebirdparts]

There's a lot of profit potentially built into everything these days. I'm constantly amazed by jobs that you'd do in a weekend with a shovel or a hammer and somebody on the internet says "I got a quote for $27,000"

You could potentially buy a packaged unit for a couple grand and plop it right in there. Wiring is obviously easy in that unfinished space. In a 20 by 50 space you only need one duct to run to the far end, one outlet, and done. Doesn't even have to be insulated. This is how my shop is set up and I paid $1100 BRAND NEW not $11,000. Admittedly it was a while ago. Admittedly I bought it wholesale through a friend in the business.

The modern escape route is mini splits as we all know.

I don't know how many tons you need.

PS. I once bought a wall-mount from a big surplus dealer in indianapolis with a name like USA-MFG or something that's hard to remember/nonsensical. I don't think they call it that anymore but they had an enormous catalog that you just couldn't believe. There are other businesses somewhat similar.

 

[dcg9381]

If the door is south facing, I'd get some insulation in it.

It's woefully uninsulated. I've never seen spray foam that thin, I can see the outline of the roof R panels. Given the roof is where you want insulation.

As this is a rental, you probably don't want to drop another $5-10k in spray foam. And I assume it's "occasional use" - I'd say 24k is minimum with that lack of insulation and a roll up door. This is where I'd take a 36k for sure (if I could get it). You'll need something that can cool that space down fast when you roll up on it in the evening.

Daikin 24k ductless units cost me about $1300 each, they seem to be up to $1500 now. So that's $1k for install. That's "possible" but it's sure not the market rate around here.

 

[firebirdparts]

Looks like packaged units are about $2k from liquidators or $3k from HVACdirect.

 

[bulletpruf]

The roll-up door faces northeast.

 

[bulletpruf]

I have a buddy who is an experienced HVAC installer. Waiting to hear back from him on his recommendation.

 

[danski0224]

Just rented a 20' x 50' shop with 14' - 16' insulated ceilings. Owner doesn't mind if I install AC. My unit is the the middle of a row of 5 units, so the outdoor components will have to live out back.

The ceiling height is a killer. Lots of air to condition

You will want to do a load calculation based on local temperatures and your desired indoor temperature. The result may sway your desired temperature.

Who is paying for the power?

 

[bulletpruf]

The ceiling height is a killer. Lots of air to condition

You will want to do a load calculation based on local temperatures and your desired indoor temperature. The result may sway your desired temperature.

Who is paying for the power?

Landlord is paying for power!

 

[shakenfake]

Exactly. No insulation in the walls, and it appears a minimal amount of foam on the roof. I assume the overhead door is not insulated either. Without some serious insulation upgrades, trying to cool it will be like trying to bail out the ocean.

You’re overestimating it pretty good I think. My shop is 17x30, bit smaller than this but I can keep it in the mid to high 80s on a 105 degree day with no door insulation, facing the west and a window. Only have a 12k window shaker if I remember right.

 

[dcg9381]

You’re overestimating it pretty good I think. My shop is 17x30, bit smaller than this but I can keep it in the mid to high 80s on a 105 degree day with no door insulation, facing the west and a window. Only have a 12k window shaker if I remember right.

I have crappy roll up doors too. Adding seals will help.

But this shop has almost no "other" insulation. It's also a pretty tall shop. I cool 2400 sqft with 48k, but that's with 3" of foam all the way around. And even then, in the summer, we have to start the AC about 2 hours before using the shop.

 

[mike93lx]

You’re overestimating it pretty good I think. My shop is 17x30, bit smaller than this but I can keep it in the mid to high 80s on a 105 degree day with no door insulation, facing the west and a window. Only have a 12k window shaker if I remember right.

A bit smaller? That's half the footprint, plus whatever additional height be has. Could be 4x the volume

 

[My Old Tools]

You don't live in the upper 6-8 feet of a 16 foot tall shop. Setting the unit lower and letting the upper air stratify effectively lowers the volume to be cooled. My shop is 22 feet to the peak, 7 large windows, 12x12 door facing south (insulated). 36k pulls it down pretty quick. Getting it into the 70's isn't as important as getting the humidity down.

 

[niget2002]

My shop is a 26'x50' in NE Dallas. I have a full-size residential unit in the corner of my shop. It works really well to keep the place comfortable. All my walls are insulated, but I have 3 large doors that are not and all the windows are cheap single pane.

The AC can keep the shop in the lower 90's when it's in the 100's outside. That doesn't sound like much, but if you're working in the middle of the shop the cold air blowing out of the large duct hits you and you feel ok. I also use some oscillating fans to blow the cool air around the shop.

You can see it in the back left of this photo.

 

[TxSteve]

I'll be interested to see how this goes with the minimal insulation. If you can get 4 tons for $2500 installed - go for it. That's a good price.

For comparison:

I have a 40x50 with 12' walls (~17' peak). I just installed 2 of the 'crazy cheap' Seville 24k "Leto" units in it. With the vacuum pump/set of gauges/pads/misc I think I'm in for about $2600. ($1099 each delivered plus extras). I did the installs myself. Disconnects were wired when I built the building.

I live ~ 30 miles SW of Fort Worth. I have 2" of closed cell foam in ceiling and walls. 2 insulated panel doors (8x10 and 10x12) and 2 insulated walk out doors. 4 3x4 (I think) double paned windows. Exterior roof is a "cool roof" white and the walls are "cool roof" light gray.

I set the thermostat on the units at 75 and it keeps 75 day in and day out - so far. Hottest we've had is about 96-97 and they worked great. In fact a lot of the times that I've checked in the non-peak parts of the day, one of the compressors will be shut off and the second one will be running on low. Most of the time so far, they've been running on low. I haven't had a full month to see what the electric hit is going to be, but so far, I'm happy.

The biggest advantage I saw what the reduction of humidity. I installed the first one I turned it on 'dehumidify' and overnight it was amazing the difference when I walked in the shop the next morning.

One thing to keep in mind - contents will either help or hurt you. If you keep it close to the temp you want all the time, all the contents will help keep it consistent. If you let it get hot, all the contents will also get hot, and they will be throwing off that heat as you are trying to cool it down and work against you. Similar to your fridge.

Remember - mini splits work most efficiently when you leave them on 24/7 with little thermostat change.

 

[BillK]

Just rented a 20' x 50' shop with 14' - 16' insulated ceilings. Owner doesn't mind if I install AC. My unit is the the middle of a row of 5 units, so the outdoor components will have to live out back.

I am not in Texas so keep that in the equation.
My unit is 30x60 with 15ft ceiling also insulated. I am also one of the middle units but our building is all block so that probably adds considerable insulation between units.

I have a 5 ton but its up on the roof. The air handler hangs right below it with one long duct running the length of the shop with several holes in it for outlets.

I think someone is lying about the price on the two 2 ton units.

 

[gregs]

The air temperature variation from floor to ceiling is a lot in the summer. This is one reason I never installed ceiling fans, no sense in mixing it together just let it naturally settle out. Mid to upper 80's with low humidity and a fan blowing cross ways is very comfortable to work in when its 95+ both temp and humidity outside.

 

[shakenfake]

A bit smaller? That's half the footprint, plus whatever additional height be has. Could be 4x the volume

You are correct but as another user commented you aren’t cooling the roof.
My point was is that I’m cooling a 510 sq ft room with a lot less cooling power than he plans on using, I have next to no roof insulation, an open window, noninsulated garage door, regular door, and some **** wall insulation from the 60s that keeps falling out. At my highest my ceiling I think is only 12 feet but I could be wrong, been a while. A 30k mini split should be plenty to keep it cool.
I am running my AC 24/7 however.

Jmo, I’m no HVAC tech.

I have crappy roll up doors too. Adding seals will help.

But this shop has almost no "other" insulation. It's also a pretty tall shop. I cool 2400 sqft with 48k, but that's with 3" of foam all the way around. And even then, in the summer, we have to start the AC about 2 hours before using the shop.

I would think that being in between stalls would give you added insulation of sorts. Less footage for the sun to roast you.

 

[welder4956]

Exactly. No insulation in the walls, and it appears a minimal amount of foam on the roof. I assume the overhead door is not insulated either. Without some serious insulation upgrades, trying to cool it will be like trying to bail out the ocean.

Probably be ok with just adding insulation to the front and rear walls. Side walls are exposed to adjacent spaces, not outside air. Depends on how hot the adjacent spaces get.

 

[rockcrawler]

You might look at Pioneer Mini Splits. I bought 2 24K 21 Seer for about $1,700 each. They seem to have a pretty good reputation and they will warranty DIY installs. I live East of Dallas, TX and my shop is 35x45x14 steel with 2 10x12 insulated garage doors, 2 insulated man doors and fairly thin closed cell spray foam insulation. So far, the heat and A/C have been pretty impressive. I can’t say anything about the 100 degree days yet, since we haven’t had any since the install. But we had a few pretty warm days recently and the shop stayed downright cold. With some help from this forum, reading and watching some YT videos, I completed the install myself. It took me a long time because I was not in a rush and wanted to do it right.

 

[bulletpruf]

I'll be interested to see how this goes with the minimal insulation. If you can get 4 tons for $2500 installed - go for it. That's a good price.

For comparison:

I have a 40x50 with 12' walls (~17' peak). I just installed 2 of the 'crazy cheap' Seville 24k "Leto" units in it. With the vacuum pump/set of gauges/pads/misc I think I'm in for about $2600. ($1099 each delivered plus extras). I did the installs myself. Disconnects were wired when I built the building.

I live ~ 30 miles SW of Fort Worth. I have 2" of closed cell foam in ceiling and walls. 2 insulated panel doors (8x10 and 10x12) and 2 insulated walk out doors. 4 3x4 (I think) double paned windows. Exterior roof is a "cool roof" white and the walls are "cool roof" light gray.

I set the thermostat on the units at 75 and it keeps 75 day in and day out - so far. Hottest we've had is about 96-97 and they worked great. In fact a lot of the times that I've checked in the non-peak parts of the day, one of the compressors will be shut off and the second one will be running on low. Most of the time so far, they've been running on low. I haven't had a full month to see what the electric hit is going to be, but so far, I'm happy.

The biggest advantage I saw what the reduction of humidity. I installed the first one I turned it on 'dehumidify' and overnight it was amazing the difference when I walked in the shop the next morning.

One thing to keep in mind - contents will either help or hurt you. If you keep it close to the temp you want all the time, all the contents will help keep it consistent. If you let it get hot, all the contents will also get hot, and they will be throwing off that heat as you are trying to cool it down and work against you. Similar to your fridge.

Remember - mini splits work most efficiently when you leave them on 24/7 with little thermostat change.

Ok, so the Senville 24k Leto units are $1100 each from Amazon with free shipping. Rated 4.6/5 with 6,300 ratings.

Thanks

 

[TxSteve]

Ok, so the Senville 24k Leto units are $1100 each from Amazon with free shipping. Rated 4.6/5 with 6,300 ratings.

Thanks

I ordered directly from Senville. I found a coupon (VIPPROMO10DSC) that have me 10% off that more than covered tax

 

[rharman]

Landlord is paying for power!

We'll see how long that lasts if multiple tenants are installing A/C.
I'm sure you've done your lawyer diligence stuff on the contract though.

 

[danski0224]

Landlord is paying for power!

No, you are.

 

[Joemctag]

Just rented a 20' x 50' shop with 14' - 16' insulated ceilings. Owner doesn't mind if I install AC. My unit is the the middle of a row of 5 units, so the outdoor components will have to live out back.

I won't be spending a lot of time there; mostly wrenching on weekends. However, the summers here in San Antonio are brutal, and I'd like to be able to keep it in the 70's when I'm working there. FYI - I was there yesterday mid-day and the temps inside weren't bad at all.

The owner said that someone is installing two two-ton AC units in an adjacent unit for $2500 - parts and labor. That sounds crazy cheap, but if that's legit, that fits my budget.

Anyone have any input? HVAC is not my wheelhouse.

Ceiling insulation is most important, of course, but ya gotta consider the common walls, too. Your neighbor and you might be helping each other out if they’re not insulated. ( Can’t tell ).
You know, most everywhere they sell used roofing foam from where they re-do commercial flat roofs. Often 2” thick 4x8 sheets polyiso or blue hard styrofoam. Cheap. You could stick some on those other walls, maybe the door. Without, or even with, insulation , there’s heat loss, I’m sure you’re well-aware. Sounds like you wouldn’t run it except weekends. Turn it up at night even then. AC and fans both? A little “cool room” in a corner? You’re planning on renting there long-term, it sounds like, if things work well.

 

[bulletpruf]

We'll see how long that lasts if multiple tenants are installing A/C.
I'm sure you've done your lawyer diligence stuff on the contract though.

Contract is crystal clear on that.

 

[bulletpruf]

Ceiling insulation is most important, of course, but ya gotta consider the common walls, too. Your neighbor and you might be helping each other out if they’re not insulated. ( Can’t tell ).

Walls are not insulated. There are 5 units. I thought one of the adjacent units was installing AC, but I spoke with the landlord yesterday and it sounds like the end units are installing AC and I'm in the middle. Still a pretty good chance that the units next to me will install AC, but one hasn't been rented and I don't think the other one has moved in.

You know, most everywhere they sell used roofing foam from where they re-do commercial flat roofs. Often 2” thick 4x8 sheets polyiso or blue hard styrofoam. Cheap. You could stick some on those other walls, maybe the door. Without, or even with, insulation , there’s heat loss, I’m sure you’re well-aware. Sounds like you wouldn’t run it except weekends. Turn it up at night even then. AC and fans both? A little “cool room” in a corner? You’re planning on renting there long-term, it sounds like, if things work well.

I'll probably end up with a big fan or two to help move the air at ground level.

My plan is to keep the AC going 24/7, but maybe with the thermostat at 80? Then when I'm there wrenching I can turn it down.