HVAC ideas for 40x64x16 shop?

[VtecGSR95]

Good morning all!

I am wrapping up the build of my 40x64x16' shop, and trying to get ideas for HVAC.

I am all set for 5" open cell foam in the walls, and R-49 blown in cellulose in the ceilings, covered by white sheet metal. I also plan to add a mezzanine on one end, 12' deep, and the entire 40' width of the building. On top will be storage (and a place for my furnace?), as well as half of the lower part being an enclosed bathroom/kitchenette/utility room. I also have 4 high cfm 60" ceiling fans I will be installing to keep air circulated. I have (2) 12x12 CHI commercial insulated doors (3285 series if I recall), (2) steel insulated walk-in doors, and (8) insulated 4x3 slider windows.

So essentially, a 12x20x8' enclosed room that will contain my water heater, bathroom, plumbing, incoming water line, etc., and will need to maintain temp year round to avoid freezing. The remaining portion of the shop roughly 52x40x16, plus the open storage area will need to be heated and cooled to make it comfortable in the extreme heat and cold.

I did have a friend tell me look into the mini splits for heating and cooling, but I am concerned about it being able to handle the amount of space with the tall ceilings. I originally considered running s standard propane furnace and a/c system, with a single tube down the center of the ceiling, with a few vents along the way to evenly distribute the air, and a single vent into the "finished area" to keep it where it needs to be......possibly with some sort of way to control the amount of flow in the finished area so it doesn't get too hot or cold when the system is feeding the shop.

Should I just worry about the shop for now, and use a small space heater at a low temp in the winter to keep the utilities warm? I've read so many ways to skin this cat, and dont know which is best. I am already outside my budget adding HVAC right now, so need the most cost effective method if possible.

BTW, the BTU calculator said I needed something like 61,000 BTU for cooling and 5.1ton?

Thanks in advance!

Located in central IL.

 

[930dreamer]

Are you not insulating the bathroom area because its not finished or it won't be included in the hvac plan for heat/ac? Did you look into closed cell foam?

 

[VtecGSR95]

Are you not insulating the bathroom area because its not finished or it won't be included in the hvac plan for heat/ac? Did you look into closed cell foam?

Sorry, forgot to add that! I will insulate the finished area with batt insulation, osb on the outside with drywall inside.

Regarding the foam, I did consider the closed cell, but the open cell was already pushing my budget pretty far. I figured open cell on the walls would be a great barrier, although not as strong as closed cell, but still probably better than batt insulation and house wrap. But it is rated at R-19, and being on the walls, not so concerned about moisture sitting "on" it, as I know it can absorb moisture. My local insulation contractor said they used open cell on their shop/office as well.

 

[dcg9381]

40x60x16 in Texas. 3-4" of open cell foam insulation.
Note, it hit 108 last week and due to Covid, I'm currently working and living in the barn.
We have 2 x 24K BTU ductless units. We can cool the barn into the 70s (perhaps below, I haven't pushed it) when it is 108 outside...
I have 3 x 14'x14' doors with crappy (very little) insulation.
No windows. One 4' door.

Note, ductless units are directional - we work in about 1/3 of the barn (no full walls) where the AC is focused. You'd want to move air around (fans, etc).

I wonder if your calculations are coming back high due to needing heat BTUs? Ductless often lose heat capacity as things hit zero and below.

 

[VtecGSR95]

40x60x16 in Texas. 3-4" of open cell foam insulation.
Note, it hit 108 last week and due to Covid, I'm currently working and living in the barn.
We have 2 x 24K BTU ductless units. We can cool the barn into the 70s (perhaps below, I haven't pushed it) when it is 108 outside...
I have 3 x 14'x14' doors with crappy (very little) insulation.
No windows. One 4' door.

Note, ductless units are directional - we work in about 1/3 of the barn (no full walls) where the AC is focused. You'd want to move air around (fans, etc).

I wonder if your calculations are coming back high due to needing heat BTUs? Ductless often lose heat capacity as things hit zero and below.

Not sure on the calculations. I did speak with a local HVAC guy today, he stated a 5 ton unit would be required for cooling a building that size. He thought the mini splits would be too expensive, likely requiring multiple units, but thats with him selling and installing.

He did offer to sell me a 140K btu propane furnace, 80% efficient, new in box, for $800 cash. Said it would get me by on heat, and then offered an all in one used unit to use for cooling, but its a 3 ton, but for $1200 I can have a/c, and it does have heat strips in it, but I wouldn't use those (prefer gas heat).

Not sure if I should consider the furnace for now, and add an a coil and condenser later? Or go ahead and buy both for $2000 and have a decent setup? Or would that a/c unit be so overwhelmed it wouldnt do much?

I Forgot to budget money for the HVAC system up front LOL!

 

[Balvar24]

I heat/cool my 40x60 with two 2-ton minisplits. It has a little trouble keeping up at noon on a hot day, but it's to be expected. I've only got batt insulation compressed between the framing and the siding.

If it were insulated similar to yours, I'd have no issues.

 

[VtecGSR95]

I heat/cool my 40x60 with two 2-ton minisplits. It has a little trouble keeping up at noon on a hot day, but it's to be expected. I've only got batt insulation compressed between the framing and the siding.

If it were insulated similar to yours, I'd have no issues.

Thanks Balvar! What are you using for heating BTW?

My only issue I am facing is I will have a 12x20 finished room for a bathroom and kitchenette. I have to make sure that stays warm year round.....guess I could use a space heater if I had to.

 

[Balvar24]

I'm using the minisplits currently. Not great when it's in the low 30's outside. Takes all day to get to 60F. Sometimes I run them in conjunction with the kerosene heater. I'd like to find an electric furnace on the cheap.

I'm only in the shop for a couple hours thru the week and then most of the day on Saturday, so I don't leave things running 24/7. If I did, I think the minisplits would keep up on heat as well. 1% design temp down here is 7F.

I've noticed my slab temp has a lot to do with how much heating/cooling I need. That's a lot of mass to work against.

I knew I was on the line when I sized the units, but I got an extremely good deal on the units.

 

[aschwartz]

I run mini splits in my building. The main garage area is 40x40x16 and I have two 24k btu head units. Also have a living area 20x40x8 downstairs and 20x40x8 upstairs and each have a single 18k btu head.

 

[nadogail]

IMHO, without a geographical reference all conversation about what works in one shop as compared to another is meaningless.

What works for me certainly will not have any relevance to what is appropriate for Buffalo, Cleveland or Duluth. Honolulu has very different conditions than Seattle.

 

[nsula_country]

I have a HVAC thread in my signature. 5 Ton Heat Pump.

CT

 

[BKB]

Our barns sound about the same 40x64x16 with a mezzanine 12x64 bathroom and man cave. I lifted my furnace-boiler-ac off the ground on a platform. Im installing a 5 ton AC unit right now, heat is all waste oil. Furnace is only about 70-80k BTU and keeps the barn nice and warm all winter. The boiler heats the craft room upstairs, bathroom, and i have two 8 foot baseboard units in the man cave area to add some heat. I ran pex from the barn to the house so i could use the boiler to heat the house. Insulation is not done and it burns 400 gallons of waste a year to keep it 55-60'F all winter in north east PA. Any warmer and you sweat while doing anything. Propane in my area is expensive per BTU. You will be cold with 4 tons of HP in that building if it gets much below 30 in your area. I use 2 tons of mini HP in my 3 car garage 800sq ft and it does OK. Mini splits dont work well in dusty locations, no filtering.

 

[nsula_country]

Deleted this post.

Linked pictures as URL instead of IMG.

CT

 

[nsula_country]

Mini Splits are all the rave.

Mini Split cannot compete in a shop environment in this regard...

Normal. Sweeping floor, common activities.

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2 spray paint projects.

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I buy filters by the case. HVAC runs year round. I change them every 1-2 months. Only needed 2, 20x25 for 5 Ton (2000 cfm forced air system). Made filter base to hold 3.

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CT

 

[VtecGSR95]

I have a HVAC thread in my signature. 5 Ton Heat Pump.

CT

Like the idea of what you are doing.

I may no get AC this year.......but my local HVAC guy is offering my me a 140K BTU propane furnace, NEW, for $800 cash, which seems pretty good considering I totally forgot to budget for HVAC!

Other options are radiant tube for $3200 installed, or floor heat (which I've pretty much ruled out already out due to the cost), or an all; in one outside unit, and I dont think thats a road I wanna go down.

 

[justinthurn]

No matter the price, you will pay for it forever if you settle for an 80% efficient furnace.

Sent from my SM-G960U using The Garage Journal mobile app

 

[VtecGSR95]

No matter the price, you will pay for it forever if you settle for an 80% efficient furnace.

Sent from my SM-G960U using The Garage Journal mobile app

For the money, i think its a good short term plan

 

[nsula_country]

Heat exchangers in 80% furnaces do not rot out as quickly.

CT

 

[dcg9381]

nsula_country, that's simple.. Love it.

No matter the price, you will pay for it forever if you settle for an 80% efficient furnace.

There's some wisdom there, the same thing can be said of moderate-SEER ACs, and installing less than climate-zone insulation.

Think about it - I've got a shop. I use it, lets say, on average of 1 day a week. Should I spend $18,000 on R-38+ insulation and 20 SEER HVAC? Or spend $8k on R15 and 17 SEER HVAC? It comes down to how often I'm using it and need to cool (or heat it). My guess is spending the $18k, I wouldn't see that payback in the next 20 years...

 

[nsula_country]

nsula_country, that's simple.. Love it.



There's some wisdom there, the same thing can be said of moderate-SEER ACs, and installing less than climate-zone insulation.

Think about it - I've got a shop. I use it, lets say, on average of 1 day a week. Should I spend $18,000 on R-38+ insulation and 20 SEER HVAC? Or spend $8k on R15 and 17 SEER HVAC? It comes down to how often I'm using it and need to cool (or heat it). My guess is spending the $18k, I wouldn't see that payback in the next 20 years...

I have standard 2" insulation with bubble/foil on one side and white scrim on other. 14 SEER 5 Ton Heat Pump. I'm happy.

CT

 

[VtecGSR95]

I agree guys......gotta consider how its being used, and in my case, it'll be maybe on the weekends, and possible a couple evenings at best. I think in my case, with 5" open cell foam in the walls, and R-49 cellulose in the ceiling, it should heat fairly easy for what I am doing. I dont plan to work on the floor......installing a lift for that!

I've already exceeded my budget, so I think this should be enough to get me by.

 

[nsula_country]

Dude. I went over budget. Built in spring. Sweated *** off all summer. Winter came, propane salamander type heater. Sucked. Installed air handler with AC coil, 20kw heat strips and ducting. Electric heat all winter. Spring, installed lineset, electrical and condenser unit. Rock n Roll now. 5 Tons of Heat and Cool with 20kw reserve heat for artic Louisiana cold snaps.

Keep shop at 75*-78* in Louisiana, Summer, Humid AF. $163 electric bill for July.

All electric, no gas.

CT

 

[nsula_country]

Filtration is key also.

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CT

 

[86turbodsl]

5 tons sounds huge for that building. Mine's at about 2.5 tons same size building. Southern Michigan. Not that huge a difference in climate.

 

[nsula_country]

5 tons sounds huge for that building. Mine's at about 2.5 tons same size building. Southern Michigan. Not that huge a difference in climate.

You are kidding right?

CT

 

[Black Oak]

5 tons sounds huge for that building. Mine's at about 2.5 tons same size building. Southern Michigan. Not that huge a difference in climate.

I was born in Flint Mi. , moved to Arkansas 4 years ago . Louisiana is dead south of me , I promise you it is brutal at times , nothing like mid - Michigan . It's a different ballgame entirely .

 

[VtecGSR95]

You are kidding right?

CT

I think he's right in regards to the climate. I bet we're usually within 5-7 degrees of each other. My uncle lives in northern WI., and they have been feeling the heat and humidity we see here in central IL., just not quite as many days of the real hot/humid days.

I still think its gonna take a decent size unit to cool me down......I think a lot depends on what I consider "comfortable". Some want it 80 and take out the humidity......some folks wanna see their breath!! LOL!

I just got the 5-6" open cell foam completed, working on wiring and inside metal finishing......pics to follow!

 

[Black Oak]

I was born in Flint Mi. , moved to Arkansas 4 years ago . Louisiana is dead south of me , I promise you it is brutal at times , nothing like mid - Michigan . It's a different ballgame entirely .

My Bad ! I thought the OP was the one in Louisiana . Michigan - IL. , they are close .

 

[nsula_country]

OP is in IL. Member from MI questioned 5 tons for about 2400 sq/ft. Said climate was close and they were cooling with 2.5 tons.

I thought they were saying MI and LA climate was close. Hence my comment about kidding. Believe they ment MI and IL climate was close. I thought this was the thread about guy in TX with similar size building asking about HVAC. 5 tons in LA, TX, AR for 2400 sq/ft shop is marginal.

CT

 

[VtecGSR95]

OP is in IL. Member from MI questioned 5 tons for about 2400 sq/ft. Said climate was close and they were cooling with 2.5 tons.

I thought they were saying MI and LA climate was close. Hence my comment about kidding. Believe they ment MI and IL climate was close. I thought this was the thread about guy in TX with similar size building asking about HVAC. 5 tons in LA, TX, AR for 2400 sq/ft shop is marginal.

CT

nsula,

you thinking a 2-3 ton unit might work in my application??

 

[Black Oak]

I re-read your initial post ,and think your shop is well insulated . That said , I'm still like Mini Splits for you . I think of cost to operate . I had a 4 Ton central air unit for my home in Ark. , and NOT using it for 1 season paid for the Mini Split that replaced it . My concern for you is heat . The $800 propane furnace could supplement the Mini Split from Dec. thru Feb. , if needed . The other 9 months , the AC would be cheap , heating demand minimal . Load calc said 61,000 btu. , I think 2 24,000 btu. is sufficent in a building that is so well insulated.

 

[VtecGSR95]

I re-read your initial post ,and think your shop is well insulated . That said , I'm still like Mini Splits for you . I think of cost to operate . I had a 4 Ton central air unit for my home in Ark. , and NOT using it for 1 season paid for the Mini Split that replaced it . My concern for you is heat . The $800 propane furnace could supplement the Mini Split from Dec. thru Feb. , if needed . The other 9 months , the AC would be cheap , heating demand minimal . Load calc said 61,000 btu. , I think 2 24,000 btu. is sufficent in a building that is so well insulated.

Black Oak,

You thinking the propane furnace isn't going to be up to snuff? Should I reconsider the radiant tube heater option for heat?

 

[nsula_country]

Black Oak,

You thinking the propane furnace isn't going to be up to snuff? Should I reconsider the radiant tube heater option for heat?

I believe Black Oak is suggesting have propane furnace installed to supplement the Mini Split Heat Pumps (MSHP). Two 2 Ton Mini Heat Pumps.

Black Oak mentioned load calculation of 61,000 btu (5 Ton). Which is what I also initially suggested. Two 2 ton MSHP is 48000 btu or 4 Tons. Due to your milder summer climate and claimed good insulation 4/5 of load calc will probably work.

The concern is will 4 tons of MSHP be enough heat btu. Black Oak probably only did a cool load calc. Will need one for heat also. 4 ton HP in IL winter may only output 24-36k on cold days.

CT

 

[Black Oak]

nsula country was right . mini split for cooling and heat , propane furnace just in the dead of winter if the mini splits are not keeping up . some area's propane is going up all the time , so factor that in and the mini will cost less to use . that depends on which mini you are using , and the price of propane where you live .

 

[VtecGSR95]

nsula country was right . mini split for cooling and heat , propane furnace just in the dead of winter if the mini splits are not keeping up . some area's propane is going up all the time , so factor that in and the mini will cost less to use . that depends on which mini you are using , and the price of propane where you live .

Would this still be a good idea when I only will be in there a couple days a week? I am not too familiar with the mini splits, didnt know if they needed to run a lot to get the temp up? Seems they cool well according to a friend of mine, but he doesn't use it to heat......so just curious?

Thanks!

 

[nsula_country]

Set thermostat and walk away. Personally our shop is set at 76* summer/60* winter. Do not set back. Takes more energy to raise/lower temp on demand than maintain.

As we speak it is 16:30, 99*, 52%, heat index 110*. 5 ton set at 76*, 82* indicated. Runs constant from 12:00-19:00 before catches up. I need 7-8 tons to maintain 76* setpoint in summer. My indoor humidity control is AWESOME!! Heat BTU isn't an issue in Louisiana, it is cooling BTU. Inverse in Illinois.

In my loacale, propane is about $1 a gallon cheaper in summer. We bulk up on summer price to ride through winter. I got rid of gas and went all electric. One less phone call. Heat Pump and resistive heat at house, shop and rental houses.

CT

 

[Black Oak]

Same for me . set my mini to " AC " mode and don't touch it till fall . Put it in " Heat " mode and don't touch it till spring . They work most effectively that way . They don't cost much to run in AC mode , heat will be higher . The humidity control is great . In the summer the condensate drain looks like a dripping faucet .

 

[VtecGSR95]

Any suggestions on a good place to buy these mini's? I think my buddy got his on ebay.....off brand name I think? Pioneer maybe?

 

[Black Oak]

Google Mini Split - 100's of places to buy . High Seer. com for Pioneer .

 

[VtecGSR95]

Google Mini Split - 100's of places to buy . High Seer. com for Pioneer .

Just to clarify.......you're referring to the mini split heat pump only, NOT with heat strips correct? Thats how I understood you.......my buddy read this thread and wondered?

I looked on high seer......looks like an outside unit sized for 2-24k wall mounts, plus the wall mounts themselves is about $3900+shipping. This seem like a fair price?