# A QUESTION FOR AC PROS,AC IN THE SHOP



## a1Jim (Aug 9, 2008)

Hi Friends
Living in southern Oregon we have pretty mild weather but of late our summers and now late spring we have had some pretty hot days(for our area)a hundred degrees. this has brought me to the point that I'm considering putting AC in my shop. I've gone online and have done a little homework but I'm still confused as to what to do.I.ve found some pretty reasonably priced split unit AC's online that have good reviews from $1000-$1200 with all the items needed to install it.
I'm a 30 year contractor so it does not seem too scary installing a unit like that,but as a contractor, I also know it's not what you know that hurts you it's what you don't know that bites you in the rear,so this is why I'm seeking some AC pros advice out there. In my research, I find these kinds of units cool and heat,I already have good gas heat in my shop. My questions involve: what brands are best ? Is these type of unit good for a shop environment ? Is it possible to install this type of unit myself ? What size to get ( my shop is about 28×30 with 14' high ceilings with a guest apartment built above),the largest units in my price range seem to max out at 2200 BTU units and some online calculators put my shops needs at close to 48.000 BTU's ,if i go smaller than my needs will it still take longer to cool or just not cool at all ? What about one or more wall units instead ?

Here'sone unit I'm looking at.
http://www.amazon.com/22000-SEER-Inverter-Ductless-System/dp/B00HAQTHHY?ie=UTF8&psc=1&redirect=true&ref_=ox_sc_act_title_3&smid=A2WHKDJR2GZYM

Some details 
Max budget $1400
I have 12 dual glaze windows 12"x2' at the top of my ceilings and one 10'x10' insulated shop roll up door.
I have 220 power every 6'around the perimeter of my shop.
I have 2×6 walls with R-19 insulation

Thanks for your help
Jim


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## waho6o9 (May 6, 2011)

Interesting system Jim. I can't help you with your concerns but I was reading the Q&A on Amazon and it said:

Question: Can the indoor unit be mounted on a ceiling?

Answer: No, it has to be mounted on a wall, preferably 3 to 4 inches from the ceiling. 
By Boca Supply on March 14, 2016

I was unaware the inside return was that close to the ceiling for install, not sure if you knew that if you were going to install it yourself.


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## a1Jim (Aug 9, 2008)

Yes I read that too Jimmy ,I can find a place to mount it up that high,it kind of makes sense since cool air drops down.
Thanks for making that point,it's good to factor into the whole equation.


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## waho6o9 (May 6, 2011)

Where is Boca Supply? All I could find was this:
"Here at Boca Supply, we focus on providing our customers with high quality products shipped directly to your doorstep. In the e-commerce business since 2006, we know what it takes to keep online shoppers happy by providing quick shipping, excellent products and great customer service.

We're a real business with an actual real store front, you can even stop by to look at our products in person to take a look at the quality before purchasing. We'd actually love to tell you more about our products in person! Our wide range of products vary from natural products to electronics such as mini splits -single zone systems, to multi zone ductless systems and even do it yourself machines. Everything we sell has independant certification and comes with a manufacturer's warranty. "

Sounds good and all but if you need a part or a warranty call and they go belly up what do you do?
I'd feel better if they had an address with phone number and email etc….


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## a1Jim (Aug 9, 2008)

Never heard of them either but there's a certain amount of protection by buying through Amazon but that's short term,that's why I asked for best brands by AC guys.


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## TheFridge (May 1, 2014)

I wired a couple of these up before. I've heard the Mitsubishi brand was pretty good. Daikin as well. I've only wired up Daikin commercial models. Was told you had to follow their instructions to a T amd if not there were kinda fussy to startup. Once you got them going they were excellent.

That's about all I know. Was told this by the AC guys installing the units.


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## DocSavage45 (Aug 14, 2010)

Jim,

WAAAAAY LOOOOONG ago I worked in ac. So I have some rusty knowledge. I installed the heating ( forced air) in my shop. This was after I received several quotes from heating and ac folks who had their own brand to sell. I found someone who consulted and I did the rest.

I recently bought a 12000 btu ac unit window unit from Sears for the shop as it is about the size of a one car garage. We have a couple upstairs in our old Victorian house to supplement an existing and badly ducted ac unit. Mine is sized to the shop but it works too hard.

My problem where I am is extreme humidity. The unit keeps the shop area relatively cool but the humidity remains high . I humidify in the winter in my shop/small barn, and I'm looking at a dehumidifier as a supplement.

If the btu's are too low the machine will disappoint you. And it will not meet the cooling requirements. If your ceilings are high like mine maybe you can use some reflective plastic that has come out of the aerospace program as a solution?


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## JBrow (Nov 18, 2015)

a1Jim,

I am not a heating and air guy nor have I tackled the problem A/C in the shop; so for what it is worth…

The mini-split system you are considering is nice but pricey. Since you already have shop heating covered, my thought to be to first look at window A/C units. A quick look shows that Sears offers a window A/C rated at 25.000 BTUs for $600. I am sure there are other brands at this rating. Two of these units would put you over the 48,000 BTUs your estimate and still be within budget. These could be installed in existing window openings or, since you are a contractor, perhaps dedicated openings could be created (or required).

http://www.sears.com/search=kenmore%2025%20000%20btu%20room%20air%20conditioner?sid=ISx20140327xNonBrand&psid=414x103687&knshCrid=4600843&k_clickID=68fa78dd-de2a-45c4-b025-38ea4915c9da&gclid=COrjsu-zkc0CFQiqaQodnFsG0A

On a side note, the central A/C that services a 1000 sf apartment conked out a couple of years ago. One small window A/C in a bedroom keeps the entire apartment surprisingly comfortable in mid-80 to mid-90 degree weather. It has 8' ceilings and R13 in the walls and maybe R32 in the ceiling.


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## TheFridge (May 1, 2014)

The mini splits have many options as well depending on brand.

The Daikin units I wired had a central compressor outside that had 4-6 of the fan units inside tied into it. Pretty neat stuff. I believe they were wired by zones so they could come on in different sections (1 set for hall and another for each classroom). Really neat stuff.


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## Blackie_ (Jul 10, 2011)

Jim, have you considered a 240 window unit? The split system is going to eat up some real estate on your wall more so then a window unit.

I'm surprised to hear you're already hitting triple digits up there in Oregon, down here in central Texas our highest this year has been but only 83 - 85 degrees, but Texas is known to have strange weather though.


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## waho6o9 (May 6, 2011)

If it's not too humid maybe a swamp cooler would work for you and save you some money as well.


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## Finn (May 26, 2010)

Another rusty, former AC pro here. I have a 300 square feet shop in a west Texas desert. I installed two window units and it keeps me cool as I need when it is 100+ degrees out there. My shop is insulated. The problem with air conditioning a woodshop is the dust. Need to keep the coils clean. If you have a situation where the temp is down but humidity is still up, this can be caused by too large a unit. Sounds silly but it is true. The fix is to run that AC unit 24/7 all summer long. That will dry out the shop.


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## clin (Sep 3, 2015)

I'm not an AC expert but am an engineer and did a lot of studying on this before having a mini-split in my shop.

The ONLY, ONLY, ONLY, got that, ONLY way you can know how much capacity you need is to run a Manual J (or equivalent) calculation on the space. Many AC contractors don't do this at all, and those that do often say they do it after you sign the contract. if the calculation says you need a larger unit, they'll pay the difference. But, the rule of thumb calculations are almost guaranteed to oversize the system

They don't get people calling them back when they have too much AC. So that's why they oversize. The problem is the larger system cost you more and it will be less efficient. It will also be less comfortable. This is especially true in humid locations.

You have a 28×30 = 840 sqft shop. The rule of thumb is 1 Ton of AC per 600 sqft. So based on that you would need 1.4 Tons of AC. 1 Ton = 12,000 BTU/hr. Anything telling you you need 48,000 BTU = 4 Ton is just plain wrong. Unless your shop is un-insulated. If that's true, insulate the shop first, then get the AC.

I've run a manual J on my shop and my whole house. My house is 3,600 sqft and I live in the southwest and have pretty hot summers. Manual J says I need less than 4 Tons. My house, came with 2X5 = 10 Tons of AC. Even on the hottest days, it short cycles (only runs a short time before turning off).

Like I said, AC contractors like to err on the high side.

Again, you really need to run a Manual J calculation. That term "Manual J" is because it literally is call "Manual J Residential Load Calculation" published by the Air Conditioning Contractors of America (ACCA). They are the recognized authority on heating and cooling.

You can get an Excel spread sheet from them at (it's free no sign up or anything needed):

http://www.acca.org/standards/speedsheets

Now, without the actual Manual J, you really won't have the info you need to fill in the spreadsheet. It is actually simple in concept, but very detailed. Wall thickness, siding, insulation. Type of floor, insulated slab, type of ceiling, roof etc.

You can buy it at Amazon for about $90 (that's right they don';t give it away). In my case I was also having AC added to part of our house and spent something like $7,000, so spending $90 and some time to make sure I got what I needed was money well spent.

http://www.amazon.com/Manual-Residential-Load-Calculation-8th/dp/1892765357/ref=sr_1_1?s=books&ie=UTF8&qid=1465151953&sr=1-1&keywords=manual+J

My guess is they don't make a mini-split too SMALL for your needs. Like I said the rule of thumb suggests 1.4 Tons (~16,800 BTU/hr). And that rule of thumb is almost always too much.

Okay, now for some general comments. As with an AC system, you have to drain the condensate away. So make sure you have a way to drain the water that comes from the INDOOR unit.

I did not install mine myself. Physically the installation is simple and you clearly have the experience to do that. The only real catch is you need to evacuate the refrigerant lines connecting the indoor and outdoor units. So you need a vacuum appropriate for that and the gauges to indicate the level of vacuum. This is also needed to detect leaks.

The outdoor unit will come precharged with refrigerant. So you don't have to add any (unless your lines are real long). There are some other things you have to be careful of, like the height difference between indoor and outdoor, and I think you need to keep the refrigerant lines in some height range. Though I'm not sure. I didn't get into those details much, once I decided to not install it myself.

If you know an AC guy, you could buy him a case of beer and have him do that final steps.

As for brands, Mitsubishi , Fujitsu, Daikin are probably the best. LG is supposed to be good, but I heard in more than one place, that parts are hard to get for those.

Be aware, that some warranties require that the unit be installed by a licensed AC contractor.

In my case I had one outdoor unit put in (on my roof) and this feeds 3 indoor units. The installation crew was two people, and they spent a good two days doing it. But perhaps you have a simpler setup where you can just place the outdoor unit on the ground outside the wall the indoor unit is attached to. Keep in mind you need to get 240 AC to the outdoor unit. The indoor units get power from the outdoor unit.

Something else to wrap you head around is the way mini-splits are meant to work. You do not typically raise and lower the thermostat. They work best running 24/7. Without starting a whole new topic, turning back a thermostat has at best a 6% reduction of energy in an ideal situation (that's what I recalled the studies showed). Much less in more realistic conditions.

Think of a mini-split like a car cruising down the highway. As compared to a typical on-off AC system that functions like a car racing to the next red light. Mini-splits have variable speed compressors, so they can throttle back when needed rather than cycling between full on and full off.

Now, if you are a weekend warrior and know you won't be in the shop 5 days of the week, then it would make sense to turn it off while you aren't there. But keep in mind that sizing of AC systems is based on average heat and cooling. Not based on how quickly it can cool a space that is already really hot.

While no AC system is going to work great if your expectation is to come into a sweltering shop, turn on the AC had have it comfortable in minutes. A mini-split is particularly ill-suited to doing that.

Because mini-splits are designed to run 24/7, they don't typically come with fancy programmable thermostats. I'm not saying none do, but I don't recall seeing that.

In a shop, the only special thing I would keep in mind, is like any AC unit, you don't want them filling with dust. That has not been an issue for me. But, if I know I'm going to make a lot of dust for an extended period of time (like ripping boards for an hour). I'll just turn it off. Also, my Jet room filter happens to blow right at my mini-split, so the mini-split is typically getting filtered air blown its way. I also think being near the ceiling helps as obviously dust is going to fall downward. And with something located 4" from the ceiling, there's not a whole lot of up for dust to fall down from.

I know I've thrown a lot at you, but I hope some of it made sense and is helpful.


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## a1Jim (Aug 9, 2008)

Thanks for the info Don
Thanks Tom Sounds like you have you shop handled
Yes Randy I've thought about that too,just not sure if more than on unit will end up fighting each other. Yes we are surprised too,these temps are breaking records for our area.
I did think of a swamp cooler Jimmy but I'm concerned about all that moisture being pumped it to my shop and rusting everything.
Thanks guys for your ideas.


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## DocSavage45 (Aug 14, 2010)

Clin.

Thanks for your contribution to Jim's post!

Great info! Wish I'd had it. I did calculate total volume as I have an additional triangulated space as my roof joists are the ceiling of my shop. Which is how I came up with my calculations. And that was 12,000 btu which is just adequate because I have heat loss and gain due to doors to the shop and my shop is well insulated.

A dehumidifier will keep the rust down and the ac keep me adequately cool. I usually start it up with a timer at the early/cool part of the day to make sure the cool down is over time.

Jim….Good luck!


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## a1Jim (Aug 9, 2008)

Thanks Jim and Clin that's a lot of great information answering a great deal of questions I had. I appreciate your links Clin but I get lost in spreadsheets never could figure them out. In considering my shop size did you take into account my 14ft ceiling as to how many BTU unit I need ?


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## clin (Sep 3, 2015)

> Thanks Jim and Clin that s a lot of great information answering a great deal of questions I had. I appreciate your links Clin but I get lost in spreadsheets never could figure them out. In considering my shop size did you take into account my 14ft ceiling as to how many BTU unit I need ?
> 
> - a1Jim


Jim, I did not factor in anything about your shop other than square footage to make some general comments.

To be clear, I'm NOT telling you what you need, just some general things, like 4 tons (48,000 BTU/hr) sounds like way too much.

While I know it's not the answer you want to hear, it's just not that simple to figure. There are too many variables. All the specifics of how the shop is constructed, amount of walls that are exterior vs shared interior walls. Window types and sizes. Even the color of your roof. It's a long list. It's a whole bunch of little things that add up.

Anyone who tells you you need this or that exact size, without running a Manual J or equivalent, doesn't know what they are talking about. Unless it happens to be someone living near you that has a shop built just like yours, and ran a Manual J calculation on their space.

And even local AC contractors shouldn't be taken at their word. Not that they are being dishonest, but you will likely hear things like "around here, we use 1 ton for 550 sqft". This type thing is nonsense. It is only workable if the home/shop whatever is built the same, is oriented the same north to south and so on.

Running a Manual J calculation takes time. Now in your case, it wouldn't be as complex as a whole house, but it still takes some effort. An AC contractor can't do it standing on your porch. And understandably, they can't do it for free. So I think most just oversize confident they won't get complaints.

Then you get my house, with more than 2X the AC capacity it needs with $500/month cooling bills in the summer. And it still worked like crap which is why I had to add the mini-splits to one end of the house (along with my garage turned shop). I'm sort of hoping the old system fails so I can put in something that is better matched. But it's still cheaper to run the inefficient system, than to replace it before it is worn out.

Something else to consider in your case, this is for a shop space. If you err on the side of a bit too small, the worst thing you'll have is a shop that is a bit warmer than you want a few more days of the year. You're not trying to sleep in it, and you won't have your significant other complaining that they are too hot.

There is a program you can "buy", that is more or less doing a Manual J calculation. It just sort of walks you through the calculations. Perhaps you would find that easier. When I say "buy" it's because you do buy it, but it only works for 2 months. So you are really renting it. But it is relatively cheap and once you've run your calculations, you won't need it again.

The nice things about using a spreadsheet or a program is it is quick and easy to see the difference in some choices. For example, maybe you have no idea whether your windows have E coating or not. Try it both ways and you might see that the difference is small for your total cooling demand and therefore you know you can ignore that.

Also, you can't select AC systems by small fractions of capacity. So once you have an idea what you need, you'll have to chose the next larger or smaller size. Point is, while all the little details sum to give the cooling load. Any one of them is not likely to be the determining factor in what you need. So you just do the best you can with the calculations. But any calculation, actually based on your shop, is better than doing nothing much beyond guessing.

Anyway here's the link to the program (HVAC-Calc):

http://www.hvaccalc.com/main.asp

Unlimited use is almost $400, but it looks like $49 for the limited time use. Maybe that will work for you. Keep in mind that a little time and a few $$$ upfront may save you significant money up front, and a little more on your electrical bill when you run it.


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## a1Jim (Aug 9, 2008)

Thank you very much more great info Clin


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## mikethetermite (Jun 16, 2009)

I have been looking into a Mitsubishi Ductless Air Conditioner/heating. You can get it Just as AC or just heating. I now have a window AC and an electric ceiling mounted heating unit. My current monthly electric is really high. They say it would cut my bill in half. I have a shop 24×30x9 that is well insulated.

Does anyone have this type of unit? PROS/CONS?


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## a1Jim (Aug 9, 2008)

Interesting Mike,does the just Ac model cost less ? Did you find them onLine?


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## nkawtg (Dec 22, 2014)

If you want to spend a little more look into a hybrid solar mini-split.
http://www.hotspotenergy.com/solar-air-conditioner/


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## b2rtch (Jan 20, 2010)

I have been using an LG window (but installed in the wall) unit since I built my shop, I live in Utah, I need an AC. I am very happy with it. 
My shop is 800sq feet wit 10' wall, my unit works just fine.
If I needed it , this unit also include an electric heater. 
So far I never used it


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## Boxguy (Mar 11, 2012)

*Jim*, is your ceiling well insulated? That might be a good first investment. It will help year round. Even in warm, humid weather here in Indiana I find that I can work for 2 or 3 hours with the cooler evening air inside. I also find that since I can make my own hours, it is easier for me to just adapt to the very hottest days by working at night and sleeping more during the day in our air-conditioned house.

My experience is that the inside heat exchanger parts get covered with condensate and that they combine with any dust to quickly coat the coils or fins in the inside unit. With this coating of dust and moisture, the indoor part of the unit quickly becomes very inefficient. Have you considered this so that you have an easy way to quickly clean the inside unit every two or three weeks?


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## a1Jim (Aug 9, 2008)

Al I have a guest apartment above my shop and it's roof is insulated.good point.


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## b2rtch (Jan 20, 2010)

When I built my shop I had someone come to insulate the attic.
He asked me " how much insulation do you want?" I answered "fill it up" this is exactly what he did" 
I really can feel the difference both in the winter and in the summer.
In addition I have 6" of fiber glass in the walls.
I wished that my house was that well insulated.


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## clin (Sep 3, 2015)

> Al I have a guest apartment above my shop and it s roof is insulated.good point.
> 
> - a1Jim


Is this guest apartment air conditioned? If so, your cooling requirements are much lower, if not, I don't want to be one of your guests during the summer.

Even if that space is not air conditioned, it is still acting as more than just distance between you and the insulated roof. It acts as more insulation. This again is one of those details a Manual J calculation factors in.

For example, when doing this calc for my shop, it shares a wall with my garage (having actually been part of the garage I walled off). Having a wall with another space on the other side that is neither exterior, or conditioned interior makes a difference. Same with what's over your head.

The good news is having that over top of the shop, means the shop will need less AC. Less is good.


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## a1Jim (Aug 9, 2008)

No AC upstairs so I'm afraid that won't help.
Thanks


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## j2dawson (Feb 14, 2016)

i installed a Mitsubishi mini-split in my 750 sq.ft. shop last fall and it is fantastic. I'm in south central Illinois and we get some cold days and hot days. When it was 0 degrees it had no problem getting the shop to 75. When it was 90 it got it to 70 with no problem. My last shop was the same size and had conventional heat and air. The heat required a 60 amp breaker, the mini-split needs a 20 amp breaker and it shows in the power bill.

I installed the unit myself and hired an HVAC guy to hook up the lines as required by Mitu's warranty.


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## a1Jim (Aug 9, 2008)

Thanks for the info Jim a couple questions if you don't mind,Did you install it yourself? what size unit dud you buy? 
opps just read the last line about you installing it yourself.


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## Lazyman (Aug 8, 2014)

I cannot answer any of your questions or offer technical advice but I can tell you how a lazy man thinks about it. I was wondering why not window units? Based upon the unknowns related to how many BTUs you really need, window units might provide the ability to more easily add incremental cooling In smaller steps should that be needed. They are also easier to remove and sell later if you decide you don't like them. You can buy 2 25,000 BTU cooling only window units for about the price of the 22,000 unit you mentioned on Amazon and should be much easier and cheaper to install, especially if you don't have to worry about adding 220V. You can start with one unit and add another later if needed which might also give you better cooling by putting units on opposite sides of the shop. Just seems like more flexibility and bang for the buck.

BTW, you probably understand this better than I do, but don't forget that you might not want or be able to run your AC unit on the same 220 circuit as your other large power tools. You said that you have 220 around the shop but didn't mention whether they are all on different circuits.


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## bruc101 (Sep 13, 2008)

Where I live in the north Ga. mountains the county motto use to be…Where Spring Spends the Summer"...that has since been dropped and everyone is asking, where has Spring gone? We've been noticing our white oak trees are beginning to die, the answer that we got for that is drought. We use to have the 2nd highest rainfall of several other counties in the US. Where has that gone? No one had a/c in their homes, now almost everyone has one.

Or milliwork shop, 1000's of sq.ft, use to be comfortable to work in even with all the cnc machines in it. It got to the point where it became almost unbearable to work in during the middle part of the day. It was way to costly to even think about putting a/c to the building even in the cnc section.

We bought some very large fans and set them in the doors and turned them on about 6am when it was cool. The fans zapped about 5 degrees out of the cnc section during the hottest part of the day. We have sun on the building on the average of 3 hours a day and it's gone behind a mountain by about 3pm.That still was not enough but made things a little better for our employees and the machines.

Our building is well insulated so we ran a test. We bought 4 of the largest house attic thermostat controlled fans we could find at the time and installed them in the roof over the cnc section. When we turned them on the fist time we could feel a drop in temperature going down soon afterwards. We discovered if we didn't keep the large doors completely open it helped even more.

We used this setup for one summer and it made things much more comfortable in the shop. During the winter months we installed 8 more of those fans throughout the building. On our hottest days which can now reach 95 to a 100 degrees. In the mornings it's very cool in the building and in the afternoons it's comfortable enough not to hear anyone complaining how hot it is in the building. The fans are doing a great job of sucking the hot air out of the building.

I know several more woodworking shops here that have done the same things after coming to our shop and seeing the difference those fans have made. The fans are doing a great job is what my friends are telling me.


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## wuddoc (Mar 21, 2008)

I can not remember the manufacturer but at one of my former school CNC labs we had two units mounted on a 14' wall. about 10' from the floor. The room was 26' long and 18' wide.

The contractor installed acoustical tile at the 12' level with rolled insulation above. Living in the South we have more HOT days than mild or cool. They put one unit towards the front and one naturally towards the back with both on the same outside side wall. I do remember they each had remote controls and the vents had the capabilities of turning up and down automatically if you pressed the appropriate button on the remotes. The units also included at the remote an adjustment for the temperature and blower speed. The reason for two remotes was we could leave one unit off on a mild day be it fall or spring. We blew them out periodically. This kept the lab comfortable until we turned on the dust collector.

The problem with the system involved the dust collector drawing the cool or warm air out in a very short time. To compensate for that they installed a return air system from the dust collector but we were always clogging the dust collector filters in a few hours when a lot of machine work was going on.


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## a1Jim (Aug 9, 2008)

Lazy
I appreciate your suggestions, a couple problems, my windows don't operate and they are 1ft x 2ft at the top of my 14ft wall and no other lower windows, making the only possibility through the wall units which involves cutting holes framing etc. in the wall eliminating the idea of selling them if I don't like them, also the 25000 units I looked at are around $700 ea and runs on 220 volts. From what I can tell these type of units cost twice the amount to run. Yes, I have separate circuits 10 altogether. Thank you for you ideas.


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## a1Jim (Aug 9, 2008)

Bruce
Thanks for your ideas,unfortunately, I don't have floor space for fans and the guest house over my shop with the gambrel roof eliminates the idea of roof mounted fans.thanks for your input.

Wudduc
The false ceiling might work for some folks but I have shelving and lights all the way up to the 14ft level.
Thanks for you ideas.Just wondering was that a split unit system you had to keep blowing dust out of ?


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## Lazyman (Aug 8, 2014)

Then I'll offer some personal experience with cooling my garage shop and one more crazy idea. 
I live in the North Dallas, Texas area and we usually get many 100 degree days per year. From about June on, we usually see at least mid 90's with humidity over 50% at a minimum. However, it usually doesn't get there until noon or so, though in the the hottest part of the summer, sometimes the temp doesn't get below 90° overnight. My 2 car garage shop is about 20×20 with about 10' ceiling and a metal 2 bay garage door facing west. That door usually hits about 120° by late afternoon so I have some 2" styrofoam insulation on it. Even with that kind of heat, I am able to cool it to bearable levels with one of those 13000 BTU roll around units running on 120V. I usually turn it on first thing in the morning and it keeps the shop relatively comfortable until about 4 or 5 PM when the sun really starts bearing down on that garage door. I simply have the exhaust hose for the portable AC venting under the garage door and plug the gap under the door with 2×4's. BTW, the AC was a Craig's list find and was only a little over $200 used and works as a heater in the winter.

So here is my crazy idea. Look for a used window unit on Craig's list, put it on wheels so you can move it to sit under your garage door only when the heat gets extreme. You can make a temporary wall with 2×4's and ply wood to fit under the garage door to close the gap. Based upon my person experience, that would be enough to take the edge off on the days when the heat gets extreme.


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## smithcreek (May 24, 2016)

Jim I am a 30+ year vet of the HVAC field, I highly recommend shying away from the mini splits, I would recommend the linked unit, I have one and have been very happy with it. I bought and installed it to survive while replacing my central unit but it has performed so well and runs cheaper so we use it most of the spring and summer.

if you go with a split I would recommend Goodman. you may want to look at SEER ratings that are being phased out too, a buddy bought a Trane 13 SEER 2 weeks ago for just a couple hundred more than the Goodman.

I am not very brand loyal because they all produce problem machines from time to time, I at one time was a pretty big Carrier fan but I spent a couple of years replacing in warranty coils and compressors that had the fusible plug blow out and was cured.

the reason I would go Goodman is one of my friends had one that froze up 2 or 3 times ( his fault, dirty evap coil ) and totally encapsulated the compressor in ice and it wouldn't die. when he moved the unit was probably 15 or 16 and still kickin.

happy hunting.

creek

http://www.homedepot.com/p/Frigidaire-25-000-BTU-Window-Air-Conditioner-with-Heat-and-Remote-FFRH2522R2/205870217


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## smithcreek (May 24, 2016)

http://www.homedepot.com/p/LG-Electronics-24-500-BTU-230-208-Volt-Window-Air-Conditioner-with-Remote-and-ENERGY-STAR-LW2516ER/206999017

linked the wrong unit the first time Jim, it's the one above, no heat.

creek.


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## a1Jim (Aug 9, 2008)

Lazy thanks for your creative ideas
Creek 
Glad to hear from a HVAC pro ,I'm a little surprised you say that the Linked unit is more efficient than the split unit. Do you mind explaining what you feel is wrong with split units? Goodman is a brand name I've never heard of perhaps it's a regional issue . Do you feel the unit you sent a link for would be sufficient to cool my shop by itself or would I need two of them?
Thanks for your help


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## j2dawson (Feb 14, 2016)

> Thanks for the info Jim a couple questions if you don t mind,Did you install it yourself? what size unit dud you buy?
> opps just read the last line about you installing it yourself.
> 
> - a1Jim


Jim, I'm out of town until late tonight. When I get home I'll find the info and post it.


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## jonmakesthings (Feb 28, 2016)

Mini splits are great. I've installed many and had one in my previous residence. And honestly, I don't think you're going to find any AC unit more efficient than a mini. Fujistsu and Mitsubishi are some of the top brands, I believe mine was a Fujitsu. I just don't like window units and portable ACs, they're usually really inefficient.

You can install them yourself but keep in mind they can be pretty tricky to do yourself and I can think of a few specific points of install where you would really want an extra pair of hands. Maybe watch some YouTube videos on installing them to get an idea what you're in for.

Then you have the evacuating/possible charging of the lineset which was mentioned before in earlier comments, that really should be done by an AC guy.


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## a1Jim (Aug 9, 2008)

Ok Jim I appreciate you input
Thanks for your help Jon I will check it out on you Tube.


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## MrRon (Jul 9, 2009)

I installed the old whole house furnace/air conditioner in my 1200 sq ft shop when I upgraded the house heat/AC system. The only problem is furnace/AC filters. In a wood shop, these filters clog up real fast. I now use a big fan. You don't see many commercial wood shops using A/C, only large fans.


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## smithcreek (May 24, 2016)

> Lazy thanks for your creative ideas
> Creek
> Glad to hear from a HVAC pro ,I m a little surprised you say that the Linked unit is more efficient than the split unit. Do you mind explaining what you feel is wrong with split units? Goodman is a brand name I ve never heard of perhaps it s a regional issue . Do you feel the unit you sent a link for would be sufficient to cool my shop by itself or would I need two of them?
> Thanks for your help
> ...


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## smithcreek (May 24, 2016)

> Mini splits are great. I ve installed many and had one in my previous residence. And honestly, I don t think you re going to find any AC unit more efficient than a mini. Fujistsu and Mitsubishi are some of the top brands, I believe mine was a Fujitsu. I just don t like window units and portable ACs, they re usually really inefficient.
> 
> You can install them yourself but keep in mind they can be pretty tricky to do yourself and I can think of a few specific points of install where you would really want an extra pair of hands. Maybe watch some YouTube videos on installing them to get an idea what you re in for.
> 
> ...


excellent point on installation Jon, as far as I know any split sold to the general public will be shipped charged with dry nitrogen, not a home owner project .

Ron raises a good point as well and there is no getting around dust but you could use 4 inch high efficiency pleated filters behind a rolled media or even foam and reduce it a good bit by keeping the first stage clean. I would also check the evaporator every month or two and maybe even hit it with a self rinsing evaporator cleaner like Triple D, but be careful it is alkaline and I have a big scar on my left knee to prove its strength. Triple D runs around 16 bucks a gallon and if you stay ahead of it a gallon will last probably a year or more.

In the interest of full disclosure I am a card holding cheap skate, I always look for a way to get the end result with less $$$.


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## a1Jim (Aug 9, 2008)

Thanks again Creek


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## j2dawson (Feb 14, 2016)

> Thanks for the info Jim a couple questions if you don t mind,Did you install it yourself? what size unit dud you buy?
> opps just read the last line about you installing it yourself.
> 
> - a1Jim


Sorry for the late reply. This is what I bought:

Mitsubishi - 15,000 BTU 22 SEER Wall Mount Ductless Split Heat Pump System 208/230V w/ i-see & H2i Hyper Heat MZ-FH15NA

I bought it online from ComfortUp.com and had a good experience with them.


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## clin (Sep 3, 2015)

Jim,

Concerning dust. Buried in one of my long posts earlier, was the fact that I use a Jet room filter. It also happens to blow in the direction of the mini-split. So the mini-split is usually drawing in air the has just passed through the room filter.

The Jet filter moves WAY, WAY more air than the mini-split. Easily 10X more and probably more than that. Point is, if you have a room filter running, it will tend to trap the dust before the mini-split. I just haven't found it to be an issue. The mini-splits have filters, and like any system they need to be cleaned, but for me it is measured in months between cleaning and I don't see any large amounts of dust on the mini-split filter. While my Jet filter get completely loaded.

I'm not saying you don't need to give it some thought, as unquestionably, there is more dust in a shop than in a home, but I think it is manageable without excessively frequent cleanings. At least if you also run a room filter.


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## Blackie_ (Jul 10, 2011)

Jim here is what I did to solve the dust problem in my window unit.

http://lumberjocks.com/topics/103194#reply-2691026


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## a1Jim (Aug 9, 2008)

Thanks again Jim and Clin.

I was wondering if anyone has any input about this unit? I was thinking I might add heat and air to the guest apartment too,with a unit like this,just not sure about this brand. The better know brands that folks have recommended on this thread add an extra $1,000.


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## a1Jim (Aug 9, 2008)

Looks like a great idea Randy,thanks for sharing.


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## clin (Sep 3, 2015)

> Thanks again Jim and Clin.
> 
> I was wondering if anyone has any input about this unit? I was thinking I might add heat and air to the guest apartment too,with a unit like this,just not sure about this brand. The better know brands that folks have recommended on this thread add an extra $1,000.
> 
> - a1Jim


Jim, did you forget a link?

Also, I think the idea of adding AC to your guest apartment and shop at the same time is an excellent idea. You can get multi-room mini-splits. That's what I did. I have one outdoor unit, and three indoor units. One each for the shop, in-law apartment (no in-law in it thank goodness), and the apartment bedroom.

For whatever reason, the mulit-zone mini-splits don't have as high a SEER rating. And some people choose to still put in separate units. But two completely separate units is probably more expensive than a multi-zone.

Also, if unclear, with a multi-zone, even though there is just one outdoor unit, each indoor unit operates independently with it's own temperature settings. The only limit there is that both have to be set to heating or cooling. One can't be heating while the other is cooling. That of course is never an issue.

This talk of dust got me thinking that I hadn't cleaned my shop mini-split recently (as in more the 6 months). So I just check it, and rinsed it. Though I'm not sure I could see any dust in them (there are two sort of fine window screen type filters). I also hit the coil fins with some compressed air and saw ZERO, NADA, no dust kick up at all. There could have been fine invisible dust, but really just nothing.

My Jet room filter however, is just full of dust from my most recent project and I've blown that filter clean numerous times in the last 6 months.

In my case, I'd have to say dust affecting my mini-split is a complete non-issue. But I'm 100% sure that running my ambient room filter is a big part of why the mini-split stays so clean.


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## a1Jim (Aug 9, 2008)

Ha Ha
yep forgot the link.
http://www.amazon.com/Air-Conditioner-WYS030GMHI22M3-Ductless-Inverter/dp/B01EA833XS/ref=sr_1_fkmr0_1?s=home-garden&ie=UTF8&qid=1465249829&sr=1-1-fkmr0&keywords=Pioneer+Ductless+Mini+Split+INVERTER+Air+Conditioner%2C+Heat+Pump%2C+22000+BTU#Ask


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## a1Jim (Aug 9, 2008)

One more opps 
it's the same unit with two heads on the same link just listed for $1570.


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## clin (Sep 3, 2015)

Jim,

I'm not familiar with that brand. It is certainly not one of the known, best brands. Doesn't mean it isn't a fine unit.

Something to consider when choosing brands is what are your options for future repairs. For that reason, you might want to select a brand that has contractors for that brand in your area. That might make it easier to get service if you need it.

If the named brand unit is 2X the price, it's perhaps worth the risk of getting a less well known brand.

This of course is a common dilemma for many purchase decisions.

Keep in mind that, while mini-splits are still uncommon in the US, the Mitsubishi, Fujitsu and other Japanese brands have been used in Japan for years (decades maybe). That gives me some confidence that they have it down. One reason I went with Fujitsu.


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## a1Jim (Aug 9, 2008)

I understand what you're talking about Clin it is a big consideration,saving $$ now may mean I still have to buy all over again due to the inability of getting parts or service for an off brand,a very valid point.


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## jonmakesthings (Feb 28, 2016)

I'm not familiar with that brand either, but as was said that doesn't mean it's no good. I read up on them a little and people seem really happy with them. It's always a bit of a gamble to get lesser-known brands but Pioneer seems to be making decent products


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## OSU55 (Dec 14, 2012)

Apparently you've made it ~30 years without AC in the shop. How many days a year will you really have it on? If it's only a 60 days a year or so, window units are the way to go. Requires installing a larger window or a hole in the wall, which wouldn't be a huge deal.

If you decide to include the upstairs apt, a mini split may well be an answer. One downside to a mini split is the air within each space where the evaporator is installed is contained - not an issue for the shop, but if the apt has several rooms, each room should have an evap. In a ducted system, all of the air within all of the rooms is mixed, which really helps dissipate odors an eliminate hot/cold spots.

Clin gave great advice - figure out what size unit you really need, especially if you are going to include the apt. A Manual J calculation is best. Here is a site offers a sizing service, but also has a rule of thumb chart, by sq ft and climate zone, for sizing ac. The climate zone for southern OR is different, depending on east or west side of the state. Your high shop ceilings and whether or not the apt upstairs is conditioned obsolete the chart, though. Whether the apt is continuously conditioned effects the calculation for the shop area.

Goodman makes a "hang on the wall" ductless or ducted evap unit as one of their split systems, in ~ 1-1/2 to 2-1/2 ton sizes that are pretty economical and could be an answer for both spaces (2 separate units). They will require good soldering ability, a vacuum pump, micron vacuum gauge, pressure gauges for R-410A, and possibly some R-410A to properly install. If interested I can get more info. For split systems, my choice would be Goodman. It's possible you could do the majority of the install work then have an HVAC tech solder things up, leak check, and start the units vs a full install.

I've worked in the HVAC/Refrigeration industry for 25 years.


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## a1Jim (Aug 9, 2008)

Thanks OSU
How much will I need ac is a good point .
Someone said something about production shops always using fans not AC's ,at first I thought I'm always hot anyway hot weather or not so that won't work but after thinking about it plus the "how often will I need it factor",I decided to tray a fan,it's a relatively low dollar experiment and if it doesn't meet my needs I'm only out $77 not $2,000 then I'll make up my mind what brand and type of AC I'll install. I really appreciate all of the great info,I hope you don't feel like I wasted your time,but I feel like I have lots of good info if this fan idea doesn't work.
Thanks a lot gang.

https://www.amazon.com/b?ref=b2b_reg_ilm_rd2_pa?ie=UTF8&node=11261610011&pf_rd_p=2471038922&pf_rd_s=detail-ilm&pf_rd_t=201&pf_rd_i=B00KZMAX1Y&pf_rd_m=ATVPDKIKX0DER&pf_rd_r=1FG9F7ZKWT204G6E9E6R


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## smithcreek (May 24, 2016)

> Apparently you ve made it ~30 years without AC in the shop. How many days a year will you really have it on? If it s only a 60 days a year or so, window units are the way to go. Requires installing a larger window or a hole in the wall, which wouldn t be a huge deal.
> 
> If you decide to include the upstairs apt, a mini split may well be an answer. One downside to a mini split is the air within each space where the evaporator is installed is contained - not an issue for the shop, but if the apt has several rooms, each room should have an evap. In a ducted system, all of the air within all of the rooms is mixed, which really helps dissipate odors an eliminate hot/cold spots.
> 
> ...


+ one

Jim I emailed Parker Davis yesterday ( they produce Pioneer equipment, I had never heard of them either and they are based here in florida )
my question to them was weather or not I could walk into a Johnstone Supply or Baker Distributers store and get parts, their reply was NO, but said they keep a full stock of parts at reasonable prices.

I would stick with Goodman if you decide to pursue conditioning the space, you will be able to get parts and service from any reputable ac contractor.

creek


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## a1Jim (Aug 9, 2008)

Creek Thanks again for the info and research.
If I go the AC route will an AC supply company sell wholesale to a General contractor?


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## kelvancra (May 4, 2010)

Nothing requires you to run a HVAC as a heater. I bought a used one, including the pump, for seventy-five. I will be setting mine up to run the heat, but could bypass it with ease too.

The point is, there are many used units out there that will heat and/or cool our shops, and they don't cost a fortune. There are many different reasons they got removed, such as to address an addition, or just because they needed more from a unit.

I'm just running eight out to the pump and them happy. I'll have a HVAC guy twek in the details.

I get frustrated with the promotion of new units. In the end, they are simple metal boxes with a fan, some heating elements in one section, with the requisite wires and sequencers, then there is the heat pump and a wall control. Just like a stereo system, you can add to it or replace a bad section, rather than the entire thing, at it's as good as ANY new system.


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## smithcreek (May 24, 2016)

> Creek Thanks again for the info and research.
> If I go the AC route will an AC supply company sell wholesale to a General contractor?
> 
> - a1Jim


to be honest Jim, I don't know. at one time in florida a general contractor could purchase anything he/she wanted to but mechanical contractors here are aggressive in protecting their turf here so that may have changed. the units from here http://www.acdirect.com/ are pre charged for 15 feet of line set.

when I was younger I did a lot of side work, I had to if I wanted to hunt, fish or play. ask around for someone dependable and you can save a ton on mark up and have it installed.

creek


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