# HVAC in a garage woodshop



## MJClark (Sep 19, 2018)

I took a few months off as I acquired some new tools including a used 220v delta unisaw, dust collection system, and a few other things. Now that I have my shop layout situated, I am running into a much different issue. Heat and humidity. I living in the Raleigh NC area and it gets kind of warm.

Given that my shop is in a garage, I was wondering what others do for HVAC for their garage shops? Do you tie into the house HVAC, leave the door into the house open, ignore the climate and build, or do you do something else?


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## clin (Sep 3, 2015)

DO NOT tie into the home HVAC system or open your house to the shop. This could spread fine saw dust throughout your house. This can present a health hazard.

I put a ductless mini-split in my shop. If you are unfamiliar with these, these are refrigerated air systems. They are split, which means the compressor is located outside and the evaporator/air handler (head) is mounted inside. A pair of refrigeration lines runs between them.

They are meant to condition large rooms or small areas of a house. Or in some case an entire apartment.

Quality mini-splits are EXTREMELY efficient. They use variable speed compressors. So instead of just off and full on, they can throttle down. This is much more efficient. They are designed to run 24/7. Or if you were a weekend warrior, you might turn it on Saturday morning, and run it through the weekend. It's sort of like a car cruising on the highway (good gas mileage) rather than going full throttle to a stop and back up at every stop light.

How well this works depends on the ratio of shop to garage use. If it is more a shop that WAS a garage, then the mini-split is really good. If on the other hand, it is more a garage then a shop and the garage door is being opened often and a hot car rolled in, then nothing is going to work that great except some sort of grossly oversized system that can remove a lot of heat quickly.

A mini-split, being an AC unit, it will also remove humidity from the air. They are again very good at that. Many regular AC systems are way oversized for homes, and cool the house so quickly, they don't have time to remove the humidity. Most mini-splits also run in reverse for heating in the winter.

There's really no downside to them other than perhaps cost. You need to take some care to keep them from clogging with dust. But you should be keeping your shop air clean with a good DC and perhaps room air filter. In this way you shouldn't need to clean the mini-split filter excessively often.

Other cooling options are to get a window type AC unit and fit it to a window if available or put it through a wall. I think there are also units specifically design for thru-wall mounting. A typical window AC unit won't be nearly as efficient as a mini-split, but it would be much less expensive. So may still be the most economical choice if you don't use it a lot.

Also, if not already, insulate the garage. First step in controller temperature is to insulate.


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## John_ (Sep 23, 2013)

Mini Split is the way to go if it is within your budget

I installed a 18k Mr Slim about 4 years ago and it is one of the best things I ever did. Purchased over the internet (eComfort) and installed everything myself - BUT, for warranty purposes, I had an authorized Mitsubishi dealer come out and start it up (Check lines for leaks, inspect everything and then release the freon)

Mini Splits are becoming very popular. There is a DIY brand - Mr Cool that Costco is now selling. I would really recommend looking at one of their units. (The lines are already pressurized - you just connect them and your good to go)

There are pretty good prices - Home Depot and other stores also carries the brand
https://www.costco.com/CatalogSearch?dept=All&keyword=mr+cool

PS - I had a 'through the wall' type AC before the Mr Slim and it was a waste of money


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## CL810 (Mar 21, 2010)

Another vote for the split units. I installed a Mitsubishi and have had very good results. I think an underrated benefit is eliminating high humidity in your shop.


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## GR8HUNTER (Jun 13, 2016)

my shop shed is in the woods under trees in constant shade so no need for cooling my fans do a great job … my problem is heating I am in process of insulating right now …. do you guys with split systems think it would benefit me to install one just for heating or just go another way them DIY mrcool seem rather cheap


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## ibewjon (Oct 2, 2010)

Mini split is a great option. Installed my LG 4 years ago, along with hour meter and kwh meter to monitor power usage. I can keep my shop, 16×22 x10' ceiling cool and DRY for 25 cents a day. It is a 28 seer for AC, and I think 14 for heating, and works down to 10 below zero, which you will never see. As long as your dust collector does not vent outside, it will do the job cheaply for you. I got it from supply house ,com, many suppliers out there. It also has internet control, which is handy if away for extended periods.


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## ScottM (Jul 10, 2012)

No one, that I saw, mentioned insulation. For the guys with mini splits, are your shops insulated?


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## ibewjon (Oct 2, 2010)

Absolutely. I would never consider trying to heat or cool in Illinois without insulation. 6" fiberglass in the walls, 10" fiberglass in the ceiling. Also housewrap under the siding. Three outside walls, the fourth, downwind side, is against the unheated garage.


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## bmerrill (Mar 14, 2018)

Another vote for a mini split.

Live in eastern North Carolina.
Have a 2 ton Mitsubishi Mini-Split in an insulated 2 car attached garage/workshop to the home with an insulated 18'x7' OHD. Garage is 680sf with 12' ceilings and 2 tall windows.
Room above the garage is conditioned space. 
The south and a portion of the east wall adjoin the house. 
Garage also has a fridge and a separate freezer.
Unit is very efficient in heating and cooling the space. 
If the system has been off for sometime it will take a while to bring everything in the space upto temperature. 
Once everything is up to temperature, opening the door does let in cold or heat, but the air temperature recovers fairly quickly.


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## bigJohninvegas (May 25, 2014)

So I did a mini split last year and love it. 
First off, I have a fully insulated, 3 car garage/workshop, about 600sqft. And I am in Las Vegas, Nv. My summer temps in the afternoon when I get most of my shop time range from around 100 to 115. And my only cooling was to open the door to the house and put a large fan to draw A/C air from the house. And like others said. I got saw dust in my home. And 80 seemed to be as cool as I could get.
As you can see from all the replies. Mini split seemed to be the way to go. 
So three bids later form the pros, and they all came back at around 6k. Sticker shock!
That's way out of my budget. 
So I had already read about a DIY mini split units, And decided to go for it. 
https://www.homedepot.com/p/MRCOOL-DIY-Enhanced-24-000-BTU-2-Ton-Ductless-Mini-Split-Air-Conditioner-and-Heat-Pump-208-230V-60Hz-DIY-24-HP-230AE/309068910

I chose this unit, and it was the same btu the pros wanted to sell me. It is a total DIY system, saying you can handle adding 220v on your own. I needed some minor help there, and had a electrician friend for asst. 
I got mine through Home depot, delivered to the store for free. I figured if there was an issue, I would be taking it back to them and having a face to face transaction, vs a 1-800 good luck phone call. 
So I have been holding off on a real review, wanted to get a full season on it. But I think I will get one done soon. My install was complete right at 7/4/18. And for the first month I would turn it on when I got home from work. Took about 45 min. to go from 85 down to 76. Then mid August I started leaving it on. Kept the shop a constant 77. To my surprise, my power bill went down about $15 that month. I can only assume working the main house A/C gave me a higher bill. As for winter, I only get a couple weeks a year, most years. The really need a heated shop. And this year a think I used the heat 3 times. worked great. 
Todays price shows it around $1650, but I spent around 2k when you count all the extras. electrical, concrete pad, and line set conduit. 
Only regret is not pulling the trigger 5 years earlier. 
good luck


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## CaptainKlutz (Apr 23, 2014)

Grin and enjoy the outdoor weather is my preference, even when it's 110F here in AZ. 
When it gets too hot, go inside and do something else.
YMMV

+1 insulation before spending money on AC. If you can keep shop closed off from warmest weather, can open it up and work when it's cooler. Plus need to spend 2X on up-sized mini-split unit and utilities without insulation.

+1 mini-split. Self installation is pretty simple with prefilled lines, as long as you can do the electrical. 
If you live in place with neighborhood Nazi (HOA), many have limitations on installation location of condensing units (typically out of site, and not heard directly from neighbors back porch).

Best Luck.


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## Bluenote38 (May 3, 2017)

I like the Mini-Split idea and will probably adopt it in my next shop. While in Memphis TN, like you, I worked in the Garage (no basements there) and had to contend with heat and humidity. No A/C so just quit working in the dead of summer… I'm happy to be back in Michigan. Best of luck in you new digs!


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## Sawdust2012 (Sep 17, 2013)

Greensboro, NC here. 1.5 ton mini split in 550 sq ft garage. It does an amazing job, probably better than the 30 yr old central unit on the house. I had one shipped to the house from Alpine Air at a great price. I had to have it installed, but if you can do that, it's absolutely the way to go. Sometimes I go out to watch the water drain out of the condensate drain tube! I sleep better knowing that my cast iron isn't rusting! Mine has a heat pump also which makes the garage as comfortable as the house. Either insulate the door or buy an insulated door. Put a couple of WiFi speakers on the wall, and some Waylon Jennings on the iPhone, and the only reason to leave is to buy scotch!
https://www.alpinehomeair.com/viewcategory.cfm?categoryID=97


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## OSU55 (Dec 14, 2012)

Won't be without HVAC in my shop - just makes it so much more enjoyable. How you use the area is important, ie keep a constant temp and occasionally open the door, or just use the shop intermittently and want the temp to come up or down quickly. DO NOT tie into your home ac or leave doors open.

Intermittent use requires a much larger unit, and depending on the cycles can be more expensive to operate vs continuous temp control over the year. Insulation is less important for intermittent.

Continuous - insulate well, including garage door. Mini splits work very well, but there are potentially much cheaper options. I happened to have a window in my garage, and put a <$200 10k window unit in. With very good insulation it maintains about a 22 deg delta vs outside in a 675 ft2 area, and dehumidifies very well. Over sizing the ac does not dehumidify well. I can keep it warm with a small 120v 1500w heater in MO.


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## rbrjr1 (Nov 2, 2017)

> Greensboro, NC here. 1.5 ton mini split in 550 sq ft garage. It does an amazing job, probably better than the 30 yr old central unit on the house. I had one shipped to the house from Alpine Air at a great price. I had to have it installed, but if you can do that, it's absolutely the way to go. Sometimes I go out to watch the water drain out of the condensate drain tube! I sleep better knowing that my cast iron isn't rusting! Mine has a heat pump also which makes the garage as comfortable as the house. Either insulate the door or buy an insulated door. Put a couple of WiFi speakers on the wall, and some Waylon Jennings on the iPhone, and the only reason to leave is to buy scotch!
> https://www.alpinehomeair.com/viewcategory.cfm?categoryID=97
> 
> - Sawdust2012


I came here to post this.. Alpine Home Air has much better pricing than MR Cool for those of you on a budget.


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## John_ (Sep 23, 2013)

> Greensboro, NC here. 1.5 ton mini split in 550 sq ft garage. It does an amazing job, probably better than the 30 yr old central unit on the house. I had one shipped to the house from Alpine Air at a great price. I had to have it installed, but if you can do that, it's absolutely the way to go. Sometimes I go out to watch the water drain out of the condensate drain tube! I sleep better knowing that my cast iron isn't rusting! Mine has a heat pump also which makes the garage as comfortable as the house. Either insulate the door or buy an insulated door. Put a couple of WiFi speakers on the wall, and some Waylon Jennings on the iPhone, and the only reason to leave is to buy scotch!
> https://www.alpinehomeair.com/viewcategory.cfm?categoryID=97
> 
> - Sawdust2012
> ...


If your looking for a Mr Cool unit - you probably want the 'DYI" models that come with the precharged lines

And, Alpine Home Air may have decent prices, but Costco is still cheaper and you can't beat their return policy or customer service

AlpineAir 1.5 ton DYI = $1,400
https://www.alpinehomeair.com/viewcategory.cfm?categoryID=319

Costco 1.5 Ton DYI = $1,300
https://www.costco.com/Mr-Cool-DIY-18K-BTU-Mini-Split-Heat-Pump-with-WIFI-Smart-Controller.product.100493414.html?langId=-1&krypto=dYz4fTilTKOfOLh0VyqkLEZzbSdi7tnLT8rtaT9zCxS5uEzj%2FOKoahcZr9qMloZHUTOxosmxj664uHV5oi6ZR%2F3z%2B9IF4ijPTifJAjK8By%2BH7lDuE3PR6JaEfqOIZoXix8VdHM4%2FOKc0deqqLyu1kZW6JEPpBw8iFiiIGg2XX49BsizwCvHZiYJVYOey4hZvEJFokhbNVyFQ6XQdv0N4VxdGvYHeI2A3MY%2BIQCnTyox8J%2FBGEjJ31474NSwxQ2ln7JHnr9vldiL1BYhaoBGPww%3D%3D


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## Woodshark (Sep 21, 2008)

Just a note to say thanks about the info that Costco sells the Mr Cool mini-splits. It saved me a few hundred bucks.


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## ajosephg (Aug 25, 2008)

18,000 BTU Lennox Mini Split in NW Arkansas in an 800 sq. ft. well insulated (including door) garage shop. Also keeps things warm in the winter.


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## tvrgeek (Nov 19, 2013)

Mini-split. I added a box with MERV 13 filters in front of it. Surprising how much fine dust it built up even with a dust collector and ambient air filter.

You can also get large window/through wall all in one heat pumps.

Mine is a Mitsubishi. My HVAC guy said they are by far the most reliable


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## CarlfromMichigan (May 26, 2016)

Based on his logo of the Upper Peninsula I suspect he is looking for heat vs Ac


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## MJClark (Sep 19, 2018)

> Based on his logo of the Upper Peninsula I suspect he is looking for heat vs Ac
> 
> - CarlfromMichigan


 Well, both actually. I was born and raised in the UP, but now live about 10 miles from Raleigh NC… so AC is a must.

Both would be perfect.


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## kelvancra (May 4, 2010)

I love the idea of a mini split, but, at about four grand, I went with a window unit for cooling and a ceiling mount heater (5,000 / 7,000 watts) for heating.

I was going to run a line off the street and go with a standard HVAC, but my buddy moved and I'm the only one in the shop these days, so don't have to worry about two of the three horse collectors and a couple of the amp hungry tools running at the same time I'm heating, cooling and lighting.

I couldn't use the shop in the winter or extreme of summer without conditioning the air. It's only about 1,800 square feet, but eight hundred is not conditioned, since it's storage and parking for one vehicle).

Though I have only a portion of the shop area rocked and the ceiling needs another 15" of insulation, the heater and air conditioner leave the shop pretty comfortable.

IF I were going a regular HVAC system, and I would have no qualms doing so, I would design my own air filter system. There is, absolutely, no reason you could not, as long as you follow a few basic rules. For example:

- pre-filter to take out the heavy dust associated with woodworking;

- use a high MERV rating to scrub the air, but design the filter system to insure major airflow (e.g., use five inch filters and use two side by side (not stacked) of a high quality (two of the same MERV rated filters can have completely different air flow, as shown by a manometer or magnehelic gauge);

- you can build your own cabinet to accomplish the above.


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## rwe2156 (May 7, 2014)

Aside from the work environment, wood behaves much better with climate control.


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## RedcarWW (Feb 3, 2021)

We are actually going to convert out whole house to mini-splits. The efficiency is well worth it. Plus our house is unique where we have forced hot air, but no cold air returns. The furnace gets it's air from a small cellar room off our living room. It's extremely inefficient and prone to massive temperature swings.

The mini-split system would put 5 zones in our house. Allowing for much better control of both the heating and cooling of the house.

The shop is in a detached house and is heated with forced hot water. The shop has it's own zone and that works well. The only thing it does not have is AC in the summer. Even with the efficiency of the forced hot water, we are considering going to a mini-split system in that house as well.


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## Barkley (Jun 28, 2019)

Had a 18k btu minisplit Mitsu minisplit installed yesterday. Seems to work soooooo much better than the window unit I've been using for years. The window just didn't have the umph to recover from running the dust collector at all.
I did notice that the minisplit has already been removing a lot of water that the window unit didn't. My shop is 14×30 and the new unit will make it about as cold as you want. I'm headed to the shop now so we'll see has it responds to the dust collector.


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## newwoodbutcher (Aug 6, 2010)

I live in Southern California, not humid but very hot summers. I have a three car garage, one slot is for my car, the two car spot is my shop. I put an inexpensive window air conditioner on the wall between my shop and the garage. I leave the garage door open when I'm running the ac in my shop to exhaust the hot air. It works like a charm. My wife's idea, she is very smart. Cools the whole shop down on a very hot day in less than 15. Min


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## dbw (Dec 2, 2013)

+1 on mini-split. Make sure you size it correctly. Bigger is not necessarily better. If the unit is too large it will bring the temperature down before it has a chance to remove humidity. There are numerous sizing calculators on the web.

FYI I have yet to find a down side to having one of these.

I have a Pioneer from HD ($1200), installation was $500, electrician was $150, extras such as equipment pad and line covers was $60.


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## Barkley (Jun 28, 2019)

Taking a break from the shop. Mini split is doing great, used the dust collector and cut a couple of boards. Temp dropped a couple of degrees and recovered in about a min. Used the planer and the temp increased from 70 to 75. It took about 5 min to recover back to 70. I didn't notice the temp change. Maybe because the humidity is quite a bit lower. 
I went with a Samsung 18K unit at my son's advice, he owns a HVAC business so install was $0. It's supposed to be very efficient. I'm hoping it'll be cheaper than the window unit and propane heat in the winter.


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## ibewjon (Oct 2, 2010)

Should be considerably cheaper than a window unit. I have an lg mini in my shop, 16×24, and it costs about 25 cents a day to keep it at 74 in northern Illinois.


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## Barkley (Jun 28, 2019)

While we're on the subject of minisplits and I had mine installed yesterday. What can I expect re. cleaning, filters. I saw a youtube vid where Jay Bates built a intake that would hold several extra filters to help keep the dust out of the head unit. Any thoughts?

Sorry I didn't mean to hijack your thread!


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## darthford (Feb 17, 2013)

> While we re on the subject of minisplits and I had mine installed yesterday. What can I expect re. cleaning, filters. I saw a youtube vid where Jay Bates built a intake that would hold several extra filters to help keep the dust out of the head unit. Any thoughts?
> 
> Sorry I didn t mean to hijack your thread!
> 
> - Barkley


Did you have an HVAC do the install? Curious on the cost to just pay a pro to install it. I googled the heck out of mini splits after reading this thread yesterday. By afternoon my garage shop is an oven this summer.


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## Barkley (Jun 28, 2019)

My son owns a HVAC company, so I paid $0. for the install. Just paid for the unit. I'll ask him and post it.

He said it would be $3600.
Have ya ever thought a DIY unit? I think it's a fairly easy install.


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## ibewjon (Oct 2, 2010)

I was lucky as well. The ac company I use told me to hang the unit, inside and out. I did the electrical. They ran the lines and did the refrigerant. Only cost $100. Since Monday be is a heat pump, efficient down to,12 BELOW zero, I built a stand for my outside unit, three concrete blocks, filled with rebar and concrete. The rebar was poured into the slab.







I ran a 3" PVC with a toilet flange on the inside wall for trim. Filled with foam after install and testing.









And yes, the images may be sideways. I post from my phone.


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## CaptainKlutz (Apr 23, 2014)

+1 mini-split

Live in Arizona and rent. AC in garage is hard to find in a rental home?

Decided I could not take heat in shop anymore this summer, and built a 'mobile' garage AC unit. So when my landlord decides to sell this place, or kick us out; have AC in next shop too. 
Named the 'refrigerator dolly" project by folks on weather thread who watched me build this the last 10 days.
Just finished the project, and fired up this afternoon. 
















It's Mirage 19 seer, 1.5 ton inverter heat/cool unit, for 550 sqft of poorly insulated space.

Had an extra 240V 20A circuit available, and connected using L6-20 twist lock connections and used a 15A fused disconnect per mfg recommendations. Added a surge protector to power line as inverters are more sensitive to voltage spikes, had an extra from VFD project. Unit only draws 7A running in quick cool/heat mode, less running normally.

Condenser is outside the door, and air handler is inside when being used. Entire 'refrigerator dolly' stored inside when not needed. All plumbing and wiring are run inside crush proof steel tubing that door rests on top of. A 12ft 2×4 is under the garage door to seal the gap in one side. The unit is not small. Condenser is 32wx22h. Air handler is 39w. The AC unit alone weighs 100lbs without ~70 lb metal dolly, so I added wheels to make moving it easier.

Has a crash barrier around the condenser, as #IAMAKLUTZ in house full of Klutz and most anything will happen.

Will likely build a decorative wrap around shroud with louvers out of cedar or something outdoor safe; attempting to hide the unit from street. The HOA has rules against noisy window AC units visible from street. Good thing my full size truck is parked in front of it?  
The outdoor unit is very quiet ~50db. Can only hear faint hum on sidewalk 35 feet away in still of night, beyond that it disappears into nature. The indoor unit is too quiet (30-45db) and make less noise than my *********************************** air filter (box fan with air filter on back).

Still gauging performance as it was 111° outside when I turned it on, and closed the garage door. Dropped to 95° in about an hour, but there is a lot of hot cast iron keeping the shop warm. Will probably have to insulate the metal door to reduce power bill.

Installation was sort of easy for me, except for some leaky 1/4 to 5/16 hose adapters from Amadud. Did engineering work on some of first variable speed controls for AC compressors at a large motor/compressor mfg four decades ago, and have most of tools/training for old school R12/22 HVAC install & repair. Sold off my vacuum pump (like an idiot) in a downsizing move a couple years ago; so borrowed one from Autozone tool loaner program. 

Spent a week fabricating the dolly. Like lumber, steel prices are horrendous compared to pre-covid prices. The dolly is a heavy, over built monster; as I found 1.5×3 and 1.5×1.5 tube in remnant bins at supplier for $1lb. Retail price on the lighter weight 14ga tube I intended to use was over $200, and I fabbed this monster for ~$80. Had some surplus Omni epoxy primer/sealer and Rustoleum Canvas (Jet) white enamel to make Ms. Dolly purdy and sort of blend with outdoor house trim colors. 

Sorry for long post, but only used one piece of wood (BB plywood) to mount the air handler to welded steel frame, so doubt it qualifies as proper LJ wood working project? Thought others might like some details. 

Cheers!


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## tvrgeek (Nov 19, 2013)

> Based on his logo of the Upper Peninsula I suspect he is looking for heat vs Ac
> 
> - CarlfromMichigan
> 
> ...


Thread still active! OK, I am in Hillsborough. Drop by and see how a mini-split works in my shop. I made the mistake of running a gas line as I though I would need aux heat. Nope. ( PM me if you wish)

BUT, a mini-split is supper efficient. To do so means the coils run 54 to 55 degrees. ABOVE the dew point. They don't de-humidify! I have to run a de-humidifier to stay @ 55%. Old low efficiency units ran about 45 degrees.


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## ibewjon (Oct 2, 2010)

My LG mini does dehumidify. It requires a drain. My shop is at 59% today.


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## Knockonit (Nov 5, 2017)

Finally i found a 2.5 ton two zone unit, had ordered several but they were so back ordered, wanted two heads in my shop to assist in distributing air thru out, do have two 60 inch fans above bottom chord of trusses to assist in air movement ( have open trusses in shop, foamed underside of roof) yesterday was in the neighborhood of 114 outside, with shop closed up only two windows for air movement, it stood at 98 degrees, no cooling YET

can't wait to get it squared away, one more coat on drywall at bath and office area and texture tomorrow
rest of shop is 5/8cc ply, almost done there two. one more week and interior will be squared away enough to move all the old shop tools in. yeehaw
rj in az


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## CL810 (Mar 21, 2010)

> While we re on the subject of minisplits and I had mine installed yesterday. What can I expect re. cleaning, filters.
> - Barkley


I went for about 18 months just cleaning the built in filter and not the fins. Big mistake. Very, very fine dust built up on the fins reducing the units efficiency.


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## bigJohninvegas (May 25, 2014)

> While we re on the subject of minisplits and I had mine installed yesterday. What can I expect re. cleaning, filters. I saw a youtube vid where Jay Bates built a intake that would hold several extra filters to help keep the dust out of the head unit. Any thoughts?
> 
> Sorry I didn t mean to hijack your thread!
> 
> - Barkley


I have had my mini split a few years now. Clean your filters every month. I also have a jet air filter that I run when using most any power tool, so that helps. Without the air filter, it would not hurt to check your filter twice a month. 
I have never seen it clogged up. But it does have a fine layer on it every time I clean it. I also gently blow out the whole unit with compressed air every time. Always a little fine dust making it past the filters.



> While we re on the subject of minisplits and I had mine installed yesterday. What can I expect re. cleaning, filters. I saw a youtube vid where Jay Bates built a intake that would hold several extra filters to help keep the dust out of the head unit. Any thoughts?
> 
> Sorry I didn t mean to hijack your thread!
> 
> ...


So I have had my mini split since 2017, or 18. Can't remember now. A few years anyway. I got three quotes from HVAC companies. All three were around 6k. Way out of my budget. I ended up with a Mr Cool DIY system. 
Total cost was around 2k for a 2 ton unit, and all the extras. Electrical and such. Turned out to be pretty easy to do. 
So.last year. February 2020, I had a new 5 ton system put on my home. No way I'm doing thst upgrade myself. Talking to the contractor when I was getting that estimate. He told me he would have done the job for about $3500. 
Still high in my budget, but j would have probably paid that. He also checked my work, found one issue. I ran a new line into my main panel, had a pro do that part. Apparently I need a shut off at the unit itself to be in code here. 
I was told only a real issue if I got to sell the house. 
My panel is only about 15' away. So for now I'm going to live with it.


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## therealSteveN (Oct 29, 2016)

I'm in SW Ohio. Summer temps get into the 90's rarely to 100, but we have full service humidity, which goes between 30 to 99% with more of the steamy stuff when it's warmer. Winters can get cold, and once cast iron ducks below 40 degrees it's a biatch to lay a hand on it, you just freeze up. So I put in heat for Winters, it is LP gas fired, and I can get toasty warm really quick, even in sub zero temps. Last year was a mild Winter, but I heated to 50 degrees all the time, and just bumped it to 65 when in the shop. Total cast for fuel was less then 100 bux from November when I put it in, to thaw.

My shop building is on a 32×48 slab, over a few tons of fill. The walls are well insulated, and the ceiling is packed with loosefill. I also have 2 pretty large ceiling fans mounted back near the tools. Running the fan I am good in the shop, UNLESS I open the overhead door, then it gets hot real quick. Just using the fans and the Man door to come and go, I can work all day, in shorts and T shirt. My belief is all that cement is a cool sink, and overnight it cools everything down nicely. Sometimes early mornings I'll carry a light jacket back, cause it's too chilly in the shop, and it's 80's outside.


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## ibewjon (Oct 2, 2010)

The disconnect is required for safe service of the unit. It is a requirement of the National Electrical Code. And in most case, a gfi receptacle is required nearby as well for servicing the equipment.


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## splintergroup (Jan 20, 2015)

Yeah, the disconnect is NEC, I think it is only required when the service breaker is not in direct view of the unit, but best practice is to have a disconnect at the umbilical connection for all hard-wired (no plug) equipment


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## CaptainKlutz (Apr 23, 2014)

> The disconnect is required for safe service of the unit. It is a requirement of the National Electrical Code. And in most case, a gfi receptacle is required nearby as well for servicing the equipment.
> 
> - ibewjon


+1
NEC 430 requires lockable disconnect method within line of sight of HVAC unit(s), which usually means less than 50ft. It also has to be less than 2m from ground level of the appliance. 
Latest code also requires the GFCI outlet to be within 25 ft of equipment for servicing.

Most new construction places the disconnect much closer, typically on wall behind unit. 
GFCI is usually right next to disconnect; unless there is another one within 25ft.

Other min-split install tips: 
Forewarned is fore armed.

The indoor air handler MAY also require a disconnect switch in line of sight. Commercial buildings are required to have wall switch power disconnect for servicing mini-split AC air handlers, just like outdoor unit. Residential mini-split installations do not require the indoor power switch per NEC; but some local AHJ or codes may require it everywhere. Check with local AHJ for details.

I found zero mini-split that specify a disconnect means between air handler and condenser, and the expensive 2HP motor rated switch plus extra wiring can add $100+ in parts to the install cost.

During my mini-split install also learned that most mini-split ship with evaporator to condenser connection cable (tray cable or SOOW) that violates NEC codes for not being allowed to pass through a residential wall, or be used inside conduit. 
The proper method is to dump the factory cable and use 14-4 armored weatherproof cable, or use non-metallic conduit with separate wires. 
This improper cable recommendation by mfg is another 'surprise' installation cost that you will not read about when looking at mini-split units. Many home owners that install a mini-split (without a building permit); do not become aware of the code violations until it comes time for insurance related home inspection (ouch) or sale of home.

HVAC equipment is heavily regulated, with a ton of rules/requirements. It is not typically a DIY task. 
Always consult your local building code AHJ before new DIY HVAC installation in your shop. 
OR hire a licensed professional for your HVAC work. 

Be safe, not sorry.


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## Woodmaster1 (Apr 26, 2011)

I have a 990sqft garage shop with 9' ceiling. I heat the shop with a 50000btu bigmax ng heater. I cool the shop with a 10000btu window air conditioner. Insulation is r19 wall and r30 ceiling. It's 90 outside and 74 inside today. The furnace I installed myself and my son in law ran the gas line. The air conditioner was free from a neighbor. So I have around $500 in my heating and air.


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## kelvancra (May 4, 2010)

Sadly, in addition to what the Capn says, one should arm themselves with knowledge of their systems and how they work because that a business is licensed to do installs does not mean they won't promote gimmicks for profit, take short cuts, or do shoddy work.

A well known local company installed ours did a crappy job on ducts (I wasn't around back then). I had to pull a couple and redo them, which doubled their air flow (they didn't cut big enough holes for the flex duct, crushing them during install).

Then there is the question of why they used insulated ducting off the main metal ducts (short cut) and reduced cost not mentioned in the original contract.

On full on HVAC systems, some companies promote UV light as part of the filtration. While UV lighting is bonafide, it's a scam for other than keeping mold down on the coils because the air moves too fast for the UV to be effective against bacteria and viruses.

On the filtration side of things, many companies do not spend any effort explaining the value of filter cabinets that can accommodate four and five inch filters, as well as running COMMON filters that are as wide and long as possible, within reason. Though much more expensive, they last far longer and, because of the greatly increased surface area, allow you to go to a higher MERV rating, for better filtration.

Another thing too few marketers and installers talk about is, filter condition monitoring means. That could mean a simple manometer (just a fluid filled clear hose in a U shape) or a magnahelic gauge.

I made the former and it worked like a charm (lots of info on them on the Net), but happened upon info about the magnahelic gauges and opted for one off the Bay. A quick glance tells you the pressure between the filter and the blower, letting you know when it's time to change filters.

Either the manometer or the magnahelic gauge can save you money (so you don't toss expensive filters too soon) and keep your system running at top efficiency.

The nice thing is, both monitoring devices are easy to install. All you need is some of the clear hose sized to fit on the device and running to a hole you drill between the filter and blower.

For the magnahelic gauge, I built a small wood box to hold it and installed a strong rare earth magnet to attach it to either the HVAC cabinet or the metal duct work. Vibration, if any (such as when a filter loads too much) has not budged it a fraction of an inch.

SIDE NOTE: When choosing a magnahelic gauge for an HVAC or furnace systems, it only needs to be able to read up to a 1.0" of water level rise.

A shop dust collector needs one that goes much higher, or a means of limiting vacuum on either version you choose to use. I

When I tested both the manometer and magnahelic gauge on my shop collector, I just moved it close to the opening, rather than going for broke and subjecting the devices to the full pressure differential of a dust collector (at the intake, since you can't really install it between the blower and filter(s)). Just getting them near the opening of any of my collectors seemed to want to peg or drain them.

For the foregoing reason, one might need a T and valve to allow direct air intake in front of the meter, to allow you to reduce the draw on the monitoring device. Alternatively, there are meters that can read much higher than the ones needed for shop and house heating and cooling systems.

The page below is just one example of a magnahelic gauge. The one I bought off the Bay has about a 3-1/2" face, so is very easy to read.

https://damnfilters.com/products/magnahelic-filter-gauge-surface-mount?variant=13421410091069&currency=USD&utm_medium=product_sync&utm_source=google&utm_content=sag_organic&utm_campaign=sag_organic&gclid=CjwKCAjwx8iIBhBwEiwA2quaq8-LxLen_pGkUzlGUEzzCcj5emPTHs-oGv8n1TZMiGcC0yrOquQTvRoCCN0QAvD_BwE


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## squazo (Nov 23, 2013)

funny this post should pop up right now while I am in the research phase of my mini split purchase.

I had my brother price check it for me and Costco has it for 600 dollars less than what I was able to find anywhere else, granted some of that is shipping, but it still saves me.

https://www.costco.com/mrcool-diy-12k-btu-115v-mini-split-air-conditioner-and-heat-pump-with-wi-fi-smart-controller.product.100573059.html

cost as of 8/10/2021 at noon was $1,099.99. I am going to become a member just for this.


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## squazo (Nov 23, 2013)

just bought it, total cost including a membership was $1211.54

about 600 dollars less than anywhere else. Between that and the weather stripping I just ordered the other day to seal up around the doors, Ill be chilling in my shop in no time. Next stop is some saws and stuff. Maybe some drills too.


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## TucsonJOA (Oct 6, 2020)

I have a mini-split in my shop (24×30). Located in AZ there is not a lot of heating required, but I am sure glad to have the AC when it is 110 outside. I've had it 15 years and really don't have to do anything to it. Clean the filter when I think of it. It is economical to run too.


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## JackDuren (Oct 10, 2015)

My shop is heated and cooled from the main furnace but is not on the the thermostat. In the summer it's nice and cool. In tge winter it is above 60 degrees. I belive this is done or wax because my main water comes in throgh this part of the house.

I put a heating/cooling unit in the garage to help bring the temperature up in the winter while I'm in tgere. Takes about 30 minutes to an hour to bring it I the 70's.

Putting in a new furnace in the spring. I will be talking to the furnace guy about putting the old heater in he garage on the opposite of the wall.


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