racecougar
Well-known member
Does the landlord have any idea what electric bill he/she is in for once all five tenants install AC and let it run 24/7 without insulation? Whew!
Input Needed - AC for 20 x 50 Shop in Texas
- Thread starter bulletpruf
- Start date
OP
bulletpruf
Well-known member
I don't think it will be as bad as you think. The temp inside is actually not bad during the day. I haven't been there at 3 pm yet, but at noon, it's tolerable.
BillK
Well-known member
One of my customers installed mine and that is what he told me to do. He said to not even bother turning it up or down. Same with the heat. So I dont
I really dont think it makes much difference in the electric bill. You will be surprised at how cool even 80 will feel because it gets rid of the humidity. I keep mine at about 75 and when its in the 80's outside it almost feels cold inside at that temp
OP
bulletpruf
Well-known member
Ok, so I'm going to go with a pair of mini-splits. The only issue at this point is whether I go with a pair of 2 ton units for $1,100 each or a pair of 3 ton units for $2,000 each.
They'll both be mounted on the back wall; that's really my only option since I'm in the middle unit and I can't place one up front. The outside unit will be on brackets above the ground a few feet.
Any thoughts on 2 or 3 ton?
Thanks,
Scott
They'll both be mounted on the back wall; that's really my only option since I'm in the middle unit and I can't place one up front. The outside unit will be on brackets above the ground a few feet.
Any thoughts on 2 or 3 ton?
Thanks,
Scott
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OP
bulletpruf
Well-known member
Using the BTU calculators online, I'm getting around 4 tons for my space - 20' x 50', 15' ceilings, poor insulation.
The guy who is doing the install thinks I could get away with using a single 3 ton, but I like the idea of going with a pair of 2 ton units.
The guy who is doing the install thinks I could get away with using a single 3 ton, but I like the idea of going with a pair of 2 ton units.
mike93lx
ALLIANCE MEMBER
Won't hurt to go bigger as Mini splits are inverters and will vary output, but a $2k difference isn't nothing.
I'd be tempted to do a single 3k and see how it does. Then add another as needed.
Wonder if you could get the landlord to split the cost of proper insulation?
I'd be tempted to do a single 3k and see how it does. Then add another as needed.
Wonder if you could get the landlord to split the cost of proper insulation?
dcg9381
Well-known member
When I installed, I found that 2 x 24K units were less expensive than a single 48k unit.
I like the idea of 2 units, especially on applications like this where you may need "hurry" cool down, but can run one unit to maintain temperature.
You may find (as I did) that when it's really cold in Texas (you know, 2-4 days every 2 years) that your heat pumps will not keep up... So just be aware.
racecougar
Well-known member
That depends on the unit you buy. Some do fairly well in "cold" weather. Mine impressed the heck out of me last winter: https://www.garagejournal.com/forum...-whats-your-setup.524811/page-4#post-10501872
dcg9381
Well-known member
Absolutely, but some of us don't pay attention to heating in Texas until we figure out that some of the Daikins don't do well below freezing. I was so focused on cooling, I didn't even consider the heating side of it.
OP
bulletpruf
Well-known member
Yeah, I think 2 x 24k units will run me about $2,700 installed. A 48k unit will cost around $4,300 installed.
I like the idea of having two for redundancy -- if one shits the bed, you still have one operational unit.
Shiftless
Well-known member
And also, how much does electricity cost per kilowatt-hr?
TxSteve
Well-known member
This is what I have also for the same reasons
OP
bulletpruf
Well-known member
$1300. Just over $1/sf per month.
OP
bulletpruf
Well-known member
Landlord pays for electric.
I have a 36x32 shop with open cell foam and triple-insulated doors. 36k senville (2- 18k units) and when it's close to 100 degrees outside I can almost get it to 65 degrees.
The sun is on the doors around noon and it seems to not bother the garage.
I'm in Tennessee.
The sun is on the doors around noon and it seems to not bother the garage.
I'm in Tennessee.
TxSteve
Well-known member
I kind of wish I'd gone with open cell under the roof. Closed cell does nothing to dampen the rain noise.
3 ton, if you build later you'll have a good start in the hvac. That first year's lease and A/C is a chunk of dough. Does each shop have its own power service?
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OP
bulletpruf
Well-known member
The power is potentially an issue. There's a 200A box on the back of the building that services all 5 units. Each 20' x 50' unit has a 125A box.
I'm not an electrician, but I think the main box should be 400A. Thinking about installing a 200A box in my unit, but not sure that this makes sense given the 200A box for the entire unit.
Thanks
TxSteve
Well-known member
My 24k mini splits spec a max 30A breaker.
For a general shop - I can't imagine you'll ever need more than 125A. I've got 100A going to mine, and never have issues.
OP
bulletpruf
Well-known member
For power, look into what machines and equipment you have now and also what you might add on soon/later.
Two minisplits each with 30A 240V double pole breakers is four panel slots right there.
Air compressor, anything 'decent' and you are using another two panel slots for a 240A breaker.
Welder? Another two slots for the 240A breaker.
Lighting? Suggest at least separate two circuits.
Utility or general use outlets? Again, at LEAST two separate circuits.
Already up to 12 slots in the breaker panel.
Landlord paying the electrical? Put in an EV charging station.
That's another 2 panel slots for the two-pole 240V breaker.
Make sure you have enough slots in the panel! Some 125A subpanels only have 8/16 slots.
Barring trying to run a big old transformer-based 'industrial' welder, you can run a big/decent 'modern' welder on a 50A 240V breaker. Again, short of full-out 'industrial' type stuff.
Two minisplits each with 30A 240V double pole breakers is four panel slots right there.
Air compressor, anything 'decent' and you are using another two panel slots for a 240A breaker.
Welder? Another two slots for the 240A breaker.
Lighting? Suggest at least separate two circuits.
Utility or general use outlets? Again, at LEAST two separate circuits.
Already up to 12 slots in the breaker panel.
Landlord paying the electrical? Put in an EV charging station.
That's another 2 panel slots for the two-pole 240V breaker. Make sure you have enough slots in the panel! Some 125A subpanels only have 8/16 slots.
Barring trying to run a big old transformer-based 'industrial' welder, you can run a big/decent 'modern' welder on a 50A 240V breaker. Again, short of full-out 'industrial' type stuff.
OP
bulletpruf
Well-known member
Gotcha. Install on these will happen in the next several days.
Ok, haven't figured out whether I'm moving my 80 gallon Quincy from home or not, but I'll have a big compressor one way or the other.
Running a Miller 211, so I'll need 240 for it.
Yep. Will need a few.
Already up to 12 slots in the breaker panel.
Landlord paying the electrical? Put in an EV charging station.
Make sure you have enough slots in the panel! Some 125A subpanels only have 8/16 slots.
This one has 16 slots.
Just a Miller 211. Looks like anywhere from 30A - 50A will work, so I'll go with 50A.
Thanks
Two minisplits on 30A breakers should be max 24A draw each. That's 48A right there.
Air compressor kicks on, maybe another 24A for that (not counting in-rush current when the motor first kicks on).
And you are welding at the same time. Maybe another 20A there if you are running the 211 hard.
That's about 90A current being pulled just there. And that's a use case easily done by just one person in the shop. With no lights or other things being run at the same time. Air fan to blow some air around to cool you off or get the welding fumes away from your face, a fridge for a cool drink, etc.
125A doesn't necessarily go that far when you add in HVAC to the shop space and just a couple of amp-hungry devices like a welder and a bigger air compressor. Just an FYI and to be aware of how quickly the amps can add up even with just one person in the shop.
Air compressor kicks on, maybe another 24A for that (not counting in-rush current when the motor first kicks on).
And you are welding at the same time. Maybe another 20A there if you are running the 211 hard.
That's about 90A current being pulled just there. And that's a use case easily done by just one person in the shop. With no lights or other things being run at the same time. Air fan to blow some air around to cool you off or get the welding fumes away from your face, a fridge for a cool drink, etc.
125A doesn't necessarily go that far when you add in HVAC to the shop space and just a couple of amp-hungry devices like a welder and a bigger air compressor. Just an FYI and to be aware of how quickly the amps can add up even with just one person in the shop.
racecougar
Well-known member
Yep. That's further justification for improving insulation, at least in cases when you own the building and have to pay the electric bill. I run a single 24k unit in my 30'x60'x13', often times while running the air compressor, welding, etc. While I'd love to have more, I only have 60A service. It has not posed a problem (never kicked out) in the five years that I've been working out there. Good insulation and envelope sealing allows you to get away with far less heating/cooling load.
OP
bulletpruf
Well-known member
Thanks for the input. Will likely need to unplug the compressor while I'm welding.
You can get open cell sprayed on top. That's what I did and yeah, made a huge difference.
Fair warning that will be an issue if you ever do plasma cutter.
My 33x60x14 has 2" closed cell all around, another 5.5" open cell in roof. 4 ton Mr. Cool with 3 18k heads. Last Summer it couldn't keep up and go below 80 on the hottest days, but otherwise fine. Hoping another round of insulation and some double bubble on the roll up doors will help this year.
Jealous of San Antonio Rent prices
OP
bulletpruf
Well-known member
Pallet of stuff showed up a few days ago from Amazon.
HVAC crew showed up today to install. Three hombres, but not a ragtag crew. Had the requisite tools and equipment to complete the job. Price to install each unit went up from $350 to $480; according to the boss, they needed more supplies than they expected when they installed a pair of 24k units two doors down.
Not a huge fan of the particle board they hung the inside units on, but if it looks like it's sagging, I'll either brace it or replace it with 3/4" plywood.
Took them about 4.5 hours to complete the job. Install looks fine to me, they cleaned up after themselves, and both units working fine.
It was 97 in the shop before the install - hot, but not unbearable. Some air circulating would have made it much better. Anyway, temps dropped to 90 before I headed to the house, but if I stayed in the area where the cold air was blowing, it was quite comfortable.
HVAC crew showed up today to install. Three hombres, but not a ragtag crew. Had the requisite tools and equipment to complete the job. Price to install each unit went up from $350 to $480; according to the boss, they needed more supplies than they expected when they installed a pair of 24k units two doors down.
Not a huge fan of the particle board they hung the inside units on, but if it looks like it's sagging, I'll either brace it or replace it with 3/4" plywood.
Took them about 4.5 hours to complete the job. Install looks fine to me, they cleaned up after themselves, and both units working fine.
It was 97 in the shop before the install - hot, but not unbearable. Some air circulating would have made it much better. Anyway, temps dropped to 90 before I headed to the house, but if I stayed in the area where the cold air was blowing, it was quite comfortable.
racecougar
Well-known member
If I read the OP's post correctly, I believe he paid $960 for the install. Still quite cheap for the install of two units. Though that install is about as easy as it gets.
theoldwizard1
Well-known member
That is a JOKE for insulation in TX ! For a metal roof in TX, you need at least 6" of insulation, 12" better !Just rented a 20' x 50' shop with 14' - 16' insulated ceilings.
You can cool it, but you will need a MUCH LARGER A/C !
OP
bulletpruf
Well-known member
Yes, they took some measurements before installation, so they're symmetrical.
It was $480 per unit for a total of $960.
Thanks
OP
bulletpruf
Well-known member
Correct.
OP
bulletpruf
Well-known member
I really don't think I will need a larger AC. The HVAC guy thought I could have gotten by with a single 3 ton unit, but I went with a pair of 2 ton units instead.
TxSteve
Well-known member
I've got 2" of closed cell all over in my 40x50 with two 24k units. It works great. Laser thermometer on the inside of the roof shows ~80-81 degrees with outside temps in the mid 90s. It's also a white roof.
TxSteve
Well-known member
These are the same units I have. OSB will be fine. The interior units aren't very heavy.Pallet of stuff showed up a few days ago from Amazon.
HVAC crew showed up today to install. Three hombres, but not a ragtag crew. Had the requisite tools and equipment to complete the job. Price to install each unit went up from $350 to $480; according to the boss, they needed more supplies than they expected when they installed a pair of 24k units two doors down.
Not a huge fan of the particle board they hung the inside units on, but if it looks like it's sagging, I'll either brace it or replace it with 3/4" plywood.
Took them about 4.5 hours to complete the job. Install looks fine to me, they cleaned up after themselves, and both units working fine.
It was 97 in the shop before the install - hot, but not unbearable. Some air circulating would have made it much better. Anyway, temps dropped to 90 before I headed to the house, but if I stayed in the area where the cold air was blowing, it was quite comfortable.
Congrats! I love having the cool work space.
dcg9381
Well-known member
Yea, that's cheap. Takes me at least 6 hours to install one of these in a shop.
I see some issues though:
- Brace that OSB, just like you mentioned, OP. 2x4s should do fine. You can get 2x4s up there between the gurts and frame it behind the OSB. Tie the framing into the gurts with vertical metal-attachment screws.
- Are these hung on a single screw through the gurt? I'm not a fan. I always use uni-strut between gurts then tie to that.
- Make sure they put the vibration dampners in.. I don't see them, might be there though:
- Get rid of these kit water lines. They are going to plug up. Install 3/4" PVC water lines.
OP
bulletpruf
Well-known member
I am so excited about having a cool workspace!