Cooling without AC

[soj]

I think you should forget that 14" attic vent fan you posted. Not big enough to make any difference in a 1200 sq ft building. I have a 40' X 45' (1800 sq ft) and have a 36" exhaust fan at the roof line, across the shop from the roll up door.

I think it is rated in the 11-12,000 CFM range. If I go in the shop during the day after it has been closed up, it is hotter inside than out. The building is insulated. I open the roll up door, turn on the fan and it "cools out" the shop pretty quickly. Yes it is hot outside air, humidity and all, but that is what you have to deal with since AC is not in your budget. With the roll up door open, this fan does not create a "breeze" you can feel. It is exhausting the hot air that is building up from the sun on the walls and roof of the building. But to feel air movement I have to lower the door to force the same volume of air through a smaller opening. So when using the fan I try to do all work as close to the door as possible. Even two of those attic fans (3240 total CFM) will never create enough air movement that you can feel. They will remove hot air from the top of the building, but the exchange rate will be so slow they will be ineffective. IMHO, you would be wasting money. Also, the fan you posted does not have a shutter. I bought my fan from Northern Tool several years ago, it is not listed on the web site now. It is a two speed, which turned out to be useless. I thought the low speed would be good for mild days, and be less noise than the high speed. There is less fan noise, but more motor noise on low speed, and not enough air movement to help. Here are the same brand (J&D) of fans they have now. Not much detail info at Northern Tool, better info at the J & D site. Made in USA fans.

Good luck with whatever you decide to do, but get the biggest fan you can afford, and not waste money on something too small to be effective. If you can't afford a big enough exhaust fan, then get circulating fans like the HF fan you posted. BTW, when I was shopping for exhaust fans, I called J & D Mfg, and an engineer told me I needed three 36" fans to properly ventilate my shop. I thought he was just trying to sell more fans, but now I can see he was right.
-jp

 

[angoetti]

I have always been tempted to get a trencher, lay tile in the ground in concentric pattern about same size of floor space with pipe beginning and ending in the building and put a puller and pusher fan on each pipe and see how well the ground covered tile 6 feet deep chills the air......what do you guys think?

 

[yhprum]

Angoetti, I have often thought about that too. Google earth tube cooling.
For the original poster, Would adding another door at the back work to get crossflow of air through the garage to at least keep the temperature from going above the outside air temp?

 

[James-W]

Lowering the temperature is one thing, lowering the humidity is another. If you lower the temperature a few degrees but keep the same humidity, it will be still be pretty hot in the shop. On the other hand, if you lower the humidity it will still be hot in the garage temperature wise, but it will actually "feel" cooler.

The opening poster has to work within his means in order to get the shop as comfortable to work in as he can. All I am saying is that I don't think fans and more ventilation from open doors or windows is the answer to his dilemma. When you live in a high humidity area you really need to lower that humidity if you want to be comfortable. Unfortunately, it will take air-conditioning to do that. Fans and other things may be of some help, but I suspect it will be like putting a band-aid on an open chest wound.

 

[Strouty]

OP, as others have said the only way you can keep the shop cooler is to switch out the hot air with cooler air. I can get away with that at my shop in the evening or early mornings. I don't have nearly the heat or humidity that you do, but I do know what my shop floor used to look like before I started running a fan all the time. It is a floor mounted fan that I aim straight up at the ceiling and it makes a huge difference.

I would recommend a couple of ceiling fans, I bought one and need to install it, but it shows that it moves way more air than the fan I am currently using. That is the best thing you can do is move the air. Other than that AC is about it, dehumidifiers will just put heat back into your shop, I played that game last year.

 

[TheEquineFencer]

Just out of curiosity...do you have a water source near you? A pond?

I've been considering a "total loss cooling system" You pump 50* - 55* well water through a cooling coil and just dump it.

I have an old well I found ,LOL, inside my shop, near the outer wall. I pulled about 40 feet of 2 inch well pipe out when I found it doing the foundation. I put a pipe around the spot in hopes of later driving one back in and using it.

I'm not sure what the cost to run a pump that long would cost. I know you need a 20* temp differential for it to work or you grow mold.

 

[pablo94sc]

I don't how tight your wallet is, but you can often find PTAC's on craigslist between $100-200. Two of those at 12,000 BTUs installed near your main work areas would be cheap and provide decent cooling with a couple box/shop fans to circulate the air once you seal the place up.

The average 480-500sqft per ton is based on 8ft tall ceilings and I believe R13 minimum in the walls/ceiling. Given the height of your building and minimum insulation I really suspect you need over 3 tons of cooling, but since this is a shop and you're not living in it, two PTACs should be more than enough to lower the humidity and cool it off to a bearable level. For example, one 11,000 BTU PTAC and 21" box fan cools my 580sqft garage pretty well in the Memphis heat and humidity.

 

[Strouty]

Just out of curiosity...do you have a water source near you? A pond?

I've been considering a "total loss cooling system" You pump 50* - 55* well water through a cooling coil and just dump it.

I have an old well I found ,LOL, inside my shop, near the outer wall. I pulled about 40 feet of 2 inch well pipe out when I found it doing the foundation. I put a pipe around the spot in hopes of later driving one back in and using it.

I'm not sure what the cost to run a pump that long would cost. I know you need a 20* temp differential for it to work or you grow mold.

I would think it would create condensation pretty bad on all the pipes. I know the other night I filled a 325 gallon tank and the condensation on that was substantial.

 

[TheEquineFencer]

I would think it would create condensation pretty bad on all the pipes. I know the other night I filled a 325 gallon tank and the condensation on that was substantial.

LOL, That's the whole idea of it, you pump cool water at 55* through a coil inside the shop and the 85*-100* air hits it, the water takes some of the heat out of the air and causes the humidity in the air to condense, this makes the air inside the shop less humid. you drain the condensation to the outside also.

 

[MTW]

Have a look here for a different point of view.
http://www.garagejournal.com/forum/showthread.php?t=211121

MTW

 

[nograin]

MTW - That is very interesting.

On a budget, within the constraints of the existing building, I think the OP's best approach is a split strategy. That is, do whatever is possible to reduce the daytime heating - add shading, venting, etc. That helps the building and the air inside from getting too much above ambient (which is already hot enough!). Then in addition, whenever using the building, have fan(s) on the people. A third log of the strategy is to do everything to take advantage of the big thermal mass below, or at least make sure its not working against you.

 

[Spdstr280Z]

I'm not going to be any help whatsoever, but I need to say two things. One, nice place, and two, you have a 2,400 square foot house, on the gulf coast of Mississippi, full electric, and your electric bill is $80 a month ? My power bill on a house half that size was slightly more than that in NC after I upgraded the heat pump to a 15 SEER unit, it was $120 or so before. That was a new construction, energy star or something rated house. Now I'm in Georgia in a house a little smaller than yours, and in the summer I'm pretty happy if the bill doesn't break $300... I have to be missing something...

 

[zurud]

That garage look like an oven in summer with sheet metal covering the whole garage. Freezing cold in winter if it up north. The sun will heat the metal and the metal will radiate the interior. It needs insulation bad especially on the roof.

 

[snrusnak]

Spdstr280Z,

Yes we are pretty fortunate with our electric bill. One thing that helps a lot is we are on a time of use plan with the electric company, so instead of paying $0.10/kWh all the time, we pay $0.05/kWh all hours except 3pm-6pm in the summer(winter is different) and we pay $0.30/kWh for these hours.

We set our thermostat to 80 deg from 3-6pm, we don't even use the electric on our hot water heaters becasue we have our AC condensor line run through a heat exchanger on the hot water so about 10 months a year we get free hot water as long as the AC is running. We don't do laundry, cook, run dishwasher, etc between 3-6pm. Try to limit the electric usage in those hours as much as possible.

Typically during the day our thermostat is around 77 and at night maybe 76.

We also have 3 attic fans on a thermostat that pretty much run all day in the summer, and never in winter (set at 90 deg). This helps cool the attic which helps the house stay cooler. We have a metal roof that is light in color which reflects heat more than dark asphalt shingles which hold heat. The house also has a lot of insulation in the roof and walls, plus it has a brick veneer so has a cavity wall. Also double pane windows.

I bought the house from the guy that built it, he really overdid things and it shows. Before we signed up for the time of use plan our highest bill was about $160/month. Now our new highest bill was this past month which was $100, but it's been the hottest month and we had company on three occasions where we used more electric during 3-6pm since we had guests.

I lived in FL before here and had a 1300 sf block home with actually the exact same AC that I have in this house, just different size, and my bill there was higher. Summer months could get up to $200+.

zurud, I think I've probably mentioned it about 3 or 4 times in this thread, my shop is insulated. The problem is insulation doesn't really do anything if it's not conditioned. So it just heats up all day then traps and holds heat all night. It's really probably working against me.

I found fans made by J&D mfg, they are affordable and seem to be good quality. What do you guys think of these:

https://www.valleyvet.com/ct_detail...Cgusb14HtJT7rogIsrFm3-DbEhrvH5M0fDRoCP6jw_wcB

Can probably go to other sites or their site directly, but this one listed a price.

 

[Spdstr280Z]

Wow, I don't feel too bad, you do a lot to manage energy, while I do nothing except yell at the wife and two kids who are there full time in the summer when they hold the doors open. The A/C stays on 70 all summer, my wife actually complains it is too cold at night.... I grew up spending hot nights in a metal trailer. A/C is one of the reasons I work....

Sent from my Nexus 6 using Tapatalk

 

[snrusnak]

lol i hear you. when I get home in the afternoons 80 is a little warm in the summer, especially when I leave work where I sometimes am in 130+ environments. But, it isn't so bad. For some reason 76 at our house is actually cold at night. But my wife wants the ceiling fan on too, of course. lol. We really don't do THAT much, just are conscious of times and what not. My house would be an ice box if I set it to 70. When we were in FL we usually had it set on 74 and it felt hotter than this system at 76.

During the spring/fall we usually just use windows at the breeze feels nice and it's cold enough outside that it's just as comfortable as the AC. We don't use heat much, but we do have a heat pump so as long as it's not below freezing it's pretty efficient. If we do use it we set it pretty mild maybe 60 or 65 at the highest. We just bundle up and usually will just heat the room we are in with a space heater.

The past couple years we really took a look at our bills and cut out things that weren't necessary. This was out of need as we were struggling with bills. We got rid of things like cable, cell phone contract plans, cut our electric bill nearly in half, and tightened up on groceries, eating out, alcohol, gas, etc. It's amazing how much you can save, we are saving hundreds every month just by being conscious of what we are spending. We got hulu to replace cable and like it better. I realized after having cable all those years I pretty much only watch over the air tv haha.

 

[pablo94sc]

lol i hear you. when I get home in the afternoons 80 is a little warm in the summer, especially when I leave work where I sometimes am in 130+ environments. But, it isn't so bad. For some reason 76 at our house is actually cold at night. But my wife wants the ceiling fan on too, of course. lol. We really don't do THAT much, just are conscious of times and what not. My house would be an ice box if I set it to 70. When we were in FL we usually had it set on 74 and it felt hotter than this system at 76.

You probably have low internal humidity levels in the house. That's a good thing for comfort levels, but don't get too low or you'll end up with a ****** nose and dry skin! I think 40% is about as low as anyone should let it get. Good to have a hygrometer on hand to know what your baseline is, and they are pretty cheap at Target.

 

[snrusnak]

Our tstat gives humidity and I think it is normally around 50-60%. I think that's pretty good but I don't really know. Never had any issues that I've noticed.

 

[pseudorealityx]

Typically, 40-60% is the happy range for summer conditions. In the winter, most people are typically in the 30-50% range.

 

[snrusnak]

Yes in the winter we definitely get low you can tell the air is dry. It's only when running the heat. I put a vent on my dryer to discharge the hot humid air into the house which works great but it's too much humidity concentrated in one room. So I'm going to remove it.

 

[Richard Mc]

It wouldn't hurt to put exhaust fan in gable but I would pull from the cooler side of the building and exhaust on afternoon sunny side.

 

[bgarrett]

OP can consider earth tubes since he has some slope. 15" pvc run under the garage 8-10 feet deep at an angle, running about 100', drawing in outside air, cooling that air as it runs thru the cooler earth, with moisture dropping out and draining out the open end.
A solar powered gable vent fan will help create 'chimney effect' to pull the air thru the tubes. Use spray foam insulation, walls and underside of the roof

 

[snrusnak]

When you say run 100' of pvc under the garage, do you mean snake it back and forth under my slab? How would I install that being the building is existing?

The two problems with that are we hit water anywhere from 2-5 feet deep, and I have no way to do that much digging to install the piping.

 

[Charles (in GA)]

That slab is a giant heat sink. That is why the building is so hot in the morning. It spends all day soaking up heat, then spends all nite releasing it.

My real feeling is that you need to be able to open up both ends of the building, to get flow thru ventilation. Add a couple or three ceiling fans to push that hot air down so it can flow out thru the doors, and you will feel much cooler.

 

[Reflex]

We're all familiar with the "heat index" making humid areas feel much hotter than it really is. This appears to be your situation. However, few people look at it the other way around. ie: If the temperature is say 100 degrees, it's possible for the heat index to be significantly less. Google the temperature/heat index in an arid climate (Needles, CA in the middle of the day). You'll find that the temperature is higher than the heat index.

So, how do we use that to your advantage? Reduce the humidity and move air in your shop. Currently I'm fortunate to have A/C in my shop. However, I use a 70 pint dehumidifier and only turn the A/C on when the temperature in the shop exceeds 90 degrees (2200 sq. ft). While my shop is well insulated and fairly tight, it's rare to have the air run more than a couple of hours daily when the temps are above 85 degrees. Believe it or not, my shop is fairly comfortable at 85 degrees and 30% humidity.

It's my opinion that you need to "feel" cooler as you can't reduce the temp in your shop at those humidity levels. Your body's natural A/C (sweat) will keep you plenty cool if it can evaporate. The lower the humidity, the faster the evaporation of sweat, the cooler you feel. The folks that walk into my shop when it's 95 degrees outside with a heat index of 105 are amazed that I don't have the A/C running. Just the dehumidifier taking the humidity down to around 30%.

Moving humid air around isn't going to do much for comfort. It's like trying to cool off by moving bath water around.

Tighten up the shop, use an adequately sized dehumidifier, and run some fans. Will it get you to 75 degrees? No way. Will it take the heat index from 117 down to something very comfortable, absolutely.

It's cheap, fast, and it works. You can pick up a decent humidifier for $200-300. I'm guessing you have a couple of 20" box fans around the house.

Problem solved!!

Reflex

 

[snrusnak]

Hey I know it's been a while but I finally came across a nice fan. The previous owner of my house gave it to me, told me it was off an electrical transformer.

It's 24" diameter I believe, the motor is a GE, 1/3hp, 950 rpm on 220v, cant really read anything else off the tag but it's model # 5k42jg2153t. Tried googling it but couldn't really find any info.