Author Topic: Heat and a/c for shop  (Read 10307 times)

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Offline cgraham

  • Posts: 51
Heat and a/c for shop
« on: May 02, 2013, 11:29 AM »
Interested in what others have in their shop for heat and air conditioning.  Had a used heat pump given to me but it uses the old freon. The price has skyrocketed for old freon and was thinking about getting a new mini split system instead. The old system would require ductwork and would evenly heat and cool the space.  Does anyone have a mini split and do they like it. Shop is 24x32 with 12 foot ceilings

Offline RL

  • Posts: 3038
Re: Heat and a/c for shop
« Reply #1 on: May 02, 2013, 12:11 PM »
For a small space like that I'd put I a wood-burning stove that would also help you get rid of your off cuts and a floor standing or wall-mounted air conditioner.

Offline Tinker

  • Posts: 3548
Re: Heat and a/c for shop
« Reply #2 on: May 05, 2013, 07:03 AM »
For a small space like that I'd put I a wood-burning stove that would also help you get rid of your off cuts and a floor standing or wall-mounted air conditioner.
Interested in what others have in their shop for heat and air conditioning.  Had a used heat pump given to me but it uses the old freon. The price has skyrocketed for old freon and was thinking about getting a new mini split system instead. The old system would require ductwork and would evenly heat and cool the space.  Does anyone have a mini split and do they like it. Shop is 24x32 with 12 foot ceilings

A SMALL SPACE!!!???  [jawdrop]
Wayne H. Tinker

Offline Paul G

  • Posts: 1913
Re: Heat and a/c for shop
« Reply #3 on: May 05, 2013, 09:40 AM »
I don't have a mini split yet but will likely do so into my garage next year, perfect solution for my needs. Regarding burning wood, I wouldn't want to lose the floor space, nor have an open flame unless I could get its air supply from outside for greater safety and efficiency, and in my area of California the govt issues no wood burn days in the winter for air quality reasons so that wouldn't be an option for me.
+1

Offline Max Fracas

  • Posts: 81
Re: Heat and a/c for shop
« Reply #4 on: February 27, 2017, 09:19 PM »
@Paul G

Following up on this old thread to see if you've installed the mini split and what your thoughts are. 

I'm building a 24x30 workshop that will have a second level with about 300sf of finished space.  With a total of around 1000 heated and cooled sf, I'm looking at a dual zone Mitsubishi mini split with 15K BTU for the ground floor and 9k upstairs. 

If I were staying in California I wouldn't worry too much about the cooling, but this workshop will be in Monroe, Louisiana where the summer temps are much higher. 

Would appreciate any advice on this, as the HVAC folks I've talked to are suggesting a traditional ducted system.  They argue that the systems will have about the same installed cost and that the traditional system will be cheaper to maintain in the long run.  That may be true, but I'm still leaning towards the mini split. 

Offline Paul G

  • Posts: 1913
Re: Heat and a/c for shop
« Reply #5 on: February 27, 2017, 10:06 PM »
Unfortunately no, I haven't done so yet. Need some extra power to the house and waiting until that is done. Since our utilities are underground it's a bit involved, especially since phone and gas are on top in the same trench as the direct burial electric. Thankfully hadn't yet poured concrete in the same area.
+1

Offline RKA

  • Posts: 916
Re: Heat and a/c for shop
« Reply #6 on: February 27, 2017, 11:09 PM »
What kind of insulation do you have in the shop?  How tight is the structure?  How many south facing windows?

My gut tells me you're a little on the light side and even if it's well insulated, you'll have an issue with airflow downstairs.  Put the unit on the short wall pointing across the length of the shop.  A ceiling fan can help aid in circulating the air. 

I have a 24K MS in my 600 SF insulated attached garage (11 ft ceilings).  On the AC side it's completely oversized, but since these inverter units scale so well it doesn't matter.  So if you want to err on the side of caution, that's what I would do.  I oversized it to get the heating output.

Many installers shy away from these for a number of reasons, especially if they don't work with these regularly.  Installation issues can arise, but it's not rocket science.  Servicing the electronics and other parts in the indoor unit might be difficult because of the tight confines, but someone familiar with them shouldn't have any issues.  I think you need to ask them more questions to assess whether their recommendation is based on their own biases and comfort level, or something more real.  Mitsubishi and Fujitsu are two of the best as far as I'm concerned.

-Raj

Offline Max Fracas

  • Posts: 81
Re: Heat and a/c for shop
« Reply #7 on: February 27, 2017, 11:26 PM »
@RKA

Thanks for the reply.  I can look at upping the BTUs for the downstairs unit, as I'm a little worried how it'll do over the 30 foot length of the shop. 

Walls will be R-19.  No south-facing windows.  Will definitely put in a couple of ceiling fans to get the air moving. 

Good advice on talking with the HVAC folks.  Looking at the hardware, I'm wondering if installing the mini split myself is an option.  Doesn't look that complicated.  Agree with you on MS and Fujitsu as reputable manufacturers. 

Offline Bob D.

  • Posts: 662
Re: Heat and a/c for shop
« Reply #8 on: February 27, 2017, 11:32 PM »
Sanyo is another quality brand to consider. I have a 1.5 ton MS in my 24x24 shop with 10.5' ceilings. But I'm near Philly so don't have as many hot, humid days as you do. We have maybe a dozen days each summer where it gets above 95°F.
You might want to bump the size and go to a 3 zone system with two units downstairs so you'll get more evenly distributed air over the large work space.
« Last Edit: March 10, 2017, 04:34 PM by Bob D. »
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It's a table saw, do you know where your fingers are?

Offline Max Fracas

  • Posts: 81
Re: Heat and a/c for shop
« Reply #9 on: February 27, 2017, 11:54 PM »
@Bob D.

Also good advice.  Going 3 zone would for sure help on the ground floor.  I'm not as concerned with the upstairs, as that's for storage.  But would make a nice area for a ping pong table so want to have some cooling up there.  I'll take a look at Sanyo.  Thanks!

Offline RKA

  • Posts: 916
Re: Heat and a/c for shop
« Reply #10 on: February 28, 2017, 06:55 AM »
Max, you can definitely do the bulk of the work yourself.  The bulk of the work can be done without specialized tools (mount indoor and outdoor units, run electrical, run piping).  The difficulty is finding an HVAC guy to do the last 3rd of the job.  That would be adding the flares to the lines, pressure test, pull a deep vac and release the refrigerant (or adjust the fill if needed).  It's those last steps that require an investment in more specialized tools and may not be worth a DIY, but if you were to do it, figure $500-600 in tools and supplies.  You have to be careful with the warranty if you go this route.  Some manufacturers are fine as long as a certified tech does the final part of the install, some get persnickety about this.

One of the things I liked about Fujitsu is they specified a range of length for the linesets (16-60ft or something like that).  I have no idea how, as most others specific a narrow range or absolute value and provide and adjustment in oz of refrigerant to be added or pulled out.  None of this matters if you're paying someone for the final install, but for DIY, it can mean you never need to open the system.  You just connect the lines, open the valve on the outdoor unit to release the refrigerant and you're done.  But with a Fujitsu you will lose the warranty if you're DIYing. I went this route 6 years ago, no regrets, but it's not for everyone.

-Raj

Offline fignewton

  • Posts: 65
  • "Fine Quality Sawdust"
Re: Heat and a/c for shop
« Reply #11 on: February 28, 2017, 07:17 AM »
I have a 3 car garage i use for shop, about 800 SF, insulated walls, ceiling, and garage doors. I have a Mitsubishi Mr. Slim that works great for heat and AC.  It's prob about 10 yrs old now and has been flawless.  No ductwork, as it comes through an exterior side wall about 7' off the floor.
TS55, MFT3+, OF1400, C12, CT-26, LR-32 system, Domino 500, RO125, MFK 700, Carvex w/ accsy, Sys-roll,  CXS, Kapex, UG with extensions, RO90

Offline cgraham

  • Posts: 51
Re: Heat and a/c for shop
« Reply #12 on: February 28, 2017, 07:38 AM »
I originally started this post a few years back. I haven't installed a system yet but I have saved about half of the cost of the system ($6500 total). I am going with a propane furnace with an ac coil. Several reasons.  Based on square footage it would require two units for a mini split.  I don't want to maintain temperatures when there is times I won't be in there for several days. The quickest way to heat is with the fossil fuel and I already have propane at my house. A ducted system will produce an even temperature throughout the shop and circulate the air better in summertime. I am in the construction business so I consulted with several hvac companies and all three came back with the same opinion for a traditional ducted system and all three were within 2-3% price of each other




Offline SouthRider

  • Posts: 91
Re: Heat and a/c for shop
« Reply #13 on: February 28, 2017, 08:19 AM »
I originally built my 1500 sq. ft. shop in south La  (Covington) with no consideration for HVAC. In fact I installed 2 large attic fans in cupolas on the roof with an open gabled ceiling (joists at 12'). I have basically a metal building with foam in the walls, but only the rolled blankets that they typically use for the roof of a metal building. My southern exposure has a large porch the length of the building.

Later installed 3 $600 heat/cool window units, and the results are fantastic. I can have the place heated or cooled in a short time, use them to remove humidity, or turn them off and open the doors on the 6 nice days we have every spring or fall here....

AND - not needing to keep a system running 24/7 sure keeps the electric bill down.

Offline WarnerConstCo.

  • Posts: 4076
    • Warner Mill Works
Re: Heat and a/c for shop
« Reply #14 on: February 28, 2017, 04:31 PM »
I heat 5500 sqft with a 190000 btu hanging furnace. Keep it at 45 at night turn it to 55 when I am working (makes me sweat any higher) about 70 bucks a month to heat.

It's a block building so it stays pretty cool most of the time. 

Offline Max Fracas

  • Posts: 81
Re: Heat and a/c for shop
« Reply #15 on: February 28, 2017, 11:40 PM »
Thanks for the feedback, everyone.  I sure hope I don't need anything near 190,000 BTU in my place!  I'm pretty settled on a Mitsubishi or similar unit with two zones.  Along with a couple of ceiling fans in the main floor, I'm hopeful it will heat and cool the 720sf downstairs.  Will post back after I have some experience with it.

Offline Holmz

  • Posts: 3980
Re: Heat and a/c for shop
« Reply #16 on: March 01, 2017, 05:22 AM »
How much can you rely on passive?
With some south wall, skylights, etc and a concrete floor one gap can get heat I out and thermal mass for storage.
Whether that costs more than power is probably the primary question.

You probably need some heat/heater, but a well sealed and insulated structure with some way to get light/heat in can do a lot of the naturally.

Offline SouthRider

  • Posts: 91
Re: Heat and a/c for shop
« Reply #17 on: March 01, 2017, 07:29 AM »
One more thing to consider for the mini splits is parts and service.

The concept is pretty new in the US, and in many areas parts and service may be limited to only a small number of dealers.

Offline mcooley

  • Posts: 174
Re: Heat and a/c for shop
« Reply #18 on: March 03, 2017, 08:51 AM »
I am building a shop now. Looks like I will be going with the Mitsubishi Mini-Split system with Hyper-Heat etc. My shop is about 1,000 sq ft so it sounds like a 6-9,000 BTU unit will be sufficient. I am still sorting out the details so these numbers may change. I know for cost the system I have been quoted is around 8K with 12 year manufacturer warranty. But this system also includes another 1,000 sq ft above in the apartment. So I'd say the cost for the shop alone should be closer to $1,500-2,000 etc.

Offline bigmoguls

  • Posts: 15
Re: Heat and a/c for shop
« Reply #19 on: July 07, 2017, 05:20 PM »
Thread is a few months old, but I have a 2 ton Mitsubishi mini-split HVAC in my garage.  I live in Houston, TX so the summer months are HOT and HUMID.  My garage is 550 sqft, it is a 2 3/4 bay garage, basically a 2 car garage with the right hand bay being 35 feet deep.  The right hand wall is non-insulated, but all other walls and the garage door are insulated.  The space above the garage is also insulated.  I spent $4k on the unit w/installation and another $250 to add a disconnect from the breaker box to the external unit.

I would not work in the garage without this thing, it is fabulous.  It is efficient and nearly silent, I think the external unit actually is silent.

Offline HarveyWildes

  • Posts: 580
Re: Heat and a/c for shop
« Reply #20 on: July 07, 2017, 06:39 PM »
Thread is a few months old, but I have a 2 ton Mitsubishi mini-split HVAC in my garage.  I live in Houston, TX so the summer months are HOT and HUMID.  My garage is 550 sqft, it is a 2 3/4 bay garage, basically a 2 car garage with the right hand bay being 35 feet deep.  The right hand wall is non-insulated, but all other walls and the garage door are insulated.  The space above the garage is also insulated.  I spent $4k on the unit w/installation and another $250 to add a disconnect from the breaker box to the external unit.

I would not work in the garage without this thing, it is fabulous.  It is efficient and nearly silent, I think the external unit actually is silent.

I have four of these units in my house because I have radiant in floor hear - no ducting for forced air AC.  They are still pretty new, but so far I like them a lot.

@bigmoguls, a question - what about filtering air that the unit blows in your shop?  Any issues with that, or with occasionally having to clean the inside where the air flow is?  Also, any issues with condensation, like wood dust caking onto the coolant pipes?  If I move and end up in a garage shop again, I would definitely consider one of these units.


Offline RobBob

  • Posts: 1164
Re: Heat and a/c for shop
« Reply #21 on: July 07, 2017, 08:33 PM »
FWIW, I also have a 2 ton Trane mini-split in my attached two car garage.  Works great in both summer and winter (Atlanta, GA).  Had it about a year with no issues.
« Last Edit: July 07, 2017, 08:35 PM by RobBob »

Offline Bob D.

  • Posts: 662
Re: Heat and a/c for shop
« Reply #22 on: July 07, 2017, 11:02 PM »
One more thing to consider for the mini splits is parts and service.

The concept is pretty new in the US, and in many areas parts and service may be limited to only a small number of dealers.

Mini-splits have been available in the US for about 10 years. I think they are firmly entrenched by now and not going anywhere.
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It's a table saw, do you know where your fingers are?

Offline bigmoguls

  • Posts: 15
Re: Heat and a/c for shop
« Reply #23 on: July 10, 2017, 09:40 AM »

I have four of these units in my house because I have radiant in floor hear - no ducting for forced air AC.  They are still pretty new, but so far I like them a lot.

@bigmoguls, a question - what about filtering air that the unit blows in your shop?  Any issues with that, or with occasionally having to clean the inside where the air flow is?  Also, any issues with condensation, like wood dust caking onto the coolant pipes?  If I move and end up in a garage shop again, I would definitely consider one of these units.

I try to have dust collection connected during most milling operations (except the Mitre Saw - what a mess it creates).  So it keeps the dust in the unit down.  It is pretty easy to clean the filters.  I have not noticed any condensation/wood caking issues.

Offline TealaG

  • Posts: 66
Re: Heat and a/c for shop
« Reply #24 on: July 15, 2017, 09:11 AM »
Guys...I have been studying this myself and watched this video: where Jay Bates talks about his minisplit and other options he's tried.

Honestly, I want a minisplit, but it's a dramatic cost.   I think I'll try to insulate the attic space above the garage.   I wanted to try these Windeevents that you install in the garage door to vent the hot air out and I heard that they work very well.   The installed cost was approx $300.  The problem was that my garage door is so cheesy that the installer said the door would no longer be structurally sound if they cut the hole.   Isn't that sad?  I tried to get a quote for a new door, but well, he wasn't excited enough to send it to me so I'm back to the drawing board.

Not having endless amounts of money...I'm now thinking of getting someone to blow insulation into the attic (relatively low cost, compared to replacing the garage door and putting in a mini split) and see how that does.  Then, I can consider the garage door option and the vents.

My other issue with the mini split is that I think I've maxed the electrical in the house.  :(   I haven't researched that issue, but it could be dramatic, cost wise..  :( 


Offline Laminator

  • Posts: 300
Re: Heat and a/c for shop
« Reply #25 on: July 15, 2017, 10:41 AM »
Attic insulation can  (will) make a dramatic difference in both heating and cooling.  I have worked in a new construction home in the 100+ Texas summer sunshine.  The A/C was running but would not get temp below about 85.  The insulation guys came and blew the attic and by the time they finished the temp was down to 75 and falling.  I was soaking wet and it felt really good but I still wish I had scheduled the job 1 day later and stayed dry... I love air conditioning! 

Go for the insulation.

I cool my 1000 sq ft shop with an 18000 btu window a/c and it works very well.

Offline RKA

  • Posts: 916
Re: Heat and a/c for shop
« Reply #26 on: July 15, 2017, 11:28 PM »
If I could spend money on anything first, it would be insulation.  If I could choose only one place to put it, I would start with the attic.  It may not be sufficient to keep you comfortable but it will drastically reduce the heating and cooling load and your recurring expenses. 
-Raj

Offline Holmz

  • Posts: 3980
Re: Heat and a/c for shop
« Reply #27 on: July 16, 2017, 07:05 AM »
If I could spend money on anything first, it would be insulation.
...

I am with you Raj.

(After that a teaspoon of concrete)

Offline Mikeoutrage

  • Posts: 9
Re: Heat and a/c for shop
« Reply #28 on: July 16, 2017, 09:32 PM »
Just remember that it will not make it cooler if anything it will keep the heat of the day longer. I have a 24x32 detached insulated shop but no A/C and the temp reached 95-96 the other day. In the morning the outside temp was 77 or so and inside temp was still 88-89. I would still insulate first. I am looking at installing a Mr Cool 24,000 btu when they are back in stock.

Offline PaulH99

  • Posts: 36
Re: Heat and a/c for shop
« Reply #29 on: July 17, 2017, 07:19 AM »
would still insulate first. I am looking at installing a Mr Cool 24,000 btu when they are back in stock.

Any relation to Mr. Fusion[cool]
-Paul
CT 26 • DF 500 • ETS 125 • KS 120 • OF 1400 • PS 430 • RO 125 • TS 55 R