Swamp Coolers for garage cooling... your thoughts and advice much appreciated.

[billdeserthill]

On my first house I had a split unit & if I wanted to work in the garage when it was hot I had to turn on the Ac a day before. The cost of running it all summer long woulda been crazy high. This was in Desert Hills, Arizona so over 100-110 in the summer.

Plus if I opened the garage door all that cold air was lost

It worked for me but I usually know a day or two in advance if I'm gonna be spending a lot of time in the garage & my garage was half the size of yours

 

[SteveM]

Would an evaporative cooler work well with outdoor temp of 100-105º, similar inside the garage temp, and humidity around 20%? (I have no idea about dew point.)

Dhart reference the blue Air cooler Index chart above for expected results About 81 degree inside if 105 outside. it was 103/15% humidity up here today, rooms where 78 to 81 inside.

But you'll need a 4500-5000 cfm for that large of a garage.

As stated early one can expect 20 to 25 degree drop in temp between inside and outside when working efficiently

You don't need to know the dew point, you'll feel it when it's high. AND that all you'll here on the local weather cast for the next 2 months. LOL My weather station do the math for me these days

 

[11Charlie]

Would an evaporative cooler work well with outdoor temp of 100-105º,

The simple answer to this is NO!!! I tried a mobile one in my garage yesterday so I could get some stuff done. PHUCK THAT!!! It got not just hot but it added humidity to the garage. So now your not just hot but humid.

 

[Stomper]

Some people just won't be told....

 

[11Charlie]

Some people just won't be told....

OH I believed you brother I just had to try. Its so phucking hot in that little garage you can't do chit!!! I am working on a portable AC unit since we are renting.

 

[Ura-Ki]

Temps will effect the evap rate, ( Exchange Rate) faster once the temps and humidity reach a certain apex, the hotter the temp, the faster the humidity will "Flash off" which is why the typical swamp cooler becomes useless! Thin dry air will transfer heat/cool faster then dense/moist air, so you get a faster exchange when thin and dry! The same applies with cooling, only it takes more energy to go down then up!

 

[Havasutom]

I've been a HVAC/R service tech/mechanic/installer for 30 years...


My favorite ductless split brand is Diakin, and I'd go with a heat pump instead of just straight cooling only equipment (yes, they make both) so your garage will be comfortable year round even if it gets nippy

If your garage is insulated figure about "1ton" (which is 12k btu/hr per "ton") of cooling per 600-800 sq ft.... I'm in Oregon so we can get away with 800 sq ft, Arizona you better go with 600 sq ft to be safe. If your garage isn't insulated you better figure 500 sq ft per ton .... so a 1.5-ton (18k btu/hr) to 2-ton (24k btu/hr) will do ya.... personally I'd go 2-ton.

The beautiful thing is going with the larger size unit, the cost difference is negligible and the cooling capacity ramps up and down to accommodate light and heavy cooling loads.



That's my 10 cents, my two cents are free!

 

[DHart]

Some people just won't be told....

Some people really appreciate being told - then work to clarify, confirm, and ponder. I'm the kind that needs to really understand all the ins outs and ramifications before making a decision. Drives my wife crazy because I tend to think things over deeply for a good bit of time before making a move - slow mover. She's the type that jumps impulsively and acts with a small bit of information or recommendation - not much exploration nor deep thought to it.

I also like to listen to a number of different opinions on things before making a decision. With enough input, often a consensus of reasoned and educated opinions rises, pointing in a good direction. In the end, I choose by what makes the most sense to me - after considering all the views.

We will quite likely be going to go with ductless split AC, instead of a swamp cooler - the extra cost isn't a huge deal. Also thinking it may be wise to get a roof exhaust fan, to suck out the majority of hot air before employing the AC... does that make good sense?

 

[Havasutom]

As I stated in the forum about storing reloading supplies in an Arizona garage during the summer, go with a quality 2 TON SPLIT SYSTEM and you will never regret it. Comparing the costs associated with the quality of life received, AC wins. As I said I'm a 3rd generation Arizona Native. I'm now a retired Master Electrician and Licensed Commercial Electric Contractor with over 40 years experience. I grew up in Tucson and have spent the last 30 years in Lake Havasu City. I have a 1800 square foot house with a 600 and 900 square foot garages. I have a 5 ton AC on the roof of the house with 3 ton split systems ( not mini split ) on each garage. Each garage has a vehicle stored in it. Vehicles last a lot longer stored inside a garage and are more comfortable to start your drive from.We keep everything set at 76 degrees year round and have an electric bill of $204.00 a month averaged billing. I have a large capacitor installed in my house to help with electric cost. After working in the desert all my life I like my comfort now. By using energy efficient AC systems and good insulation the spaces don't have a chance to heat soak as happens when you only turn on the cooling system for each use. I was able to cool the house with a 2 stage Mastercool evaporative cooler to 78-80 degrees when outside temperatures were 110 to 115 degrees. When my house equipment needed replacement after 25 years I spent my money on a high efficiency AC unit and removed the evaporative cooling units. The evaporative coolers just used to much water and required to much service compared to the AC units. Our sewage bills are based on how much water we use. My lifetime's experience strongly recommends using a Mini Split AC system . Don't even think of using a "window AC unit " because the cost and noise to run one will disappoint you. I have 3 reloading presses and store all my firearms in safes in my windowless garage. I typically spend 4-6 hours a day at my gun bench and have never regretted or wanted something different than my air conditioned garages . P.S. my wife loves her air conditioned garage for laundry work and unloading groceries from her car. The bottom line is if you like it below 85 degrees and spend a lot of time in your garage then go AC. I hope this helps.

 

[DHart]

As I stated in the forum about storing reloading supplies in an Arizona garage during the summer, go with a quality 2 TON SPLIT SYSTEM and you will never regret it. Comparing the costs associated with the quality of life received, AC wins. As I said I'm a 3rd generation Arizona Native. I'm now a retired Master Electrician and Licensed Commercial Electric Contractor with over 40 years experience. I grew up in Tucson and have spent the last 30 years in Lake Havasu City. I have a 1800 square foot house with a 600 and 900 square foot garages. I have a 5 ton AC on the roof of the house with 3 ton split systems ( not mini split ) on each garage. Each garage has a vehicle stored in it. Vehicles last a lot longer stored inside a garage and are more comfortable to start your drive from.We keep everything set at 76 degrees year round and have an electric bill of $204.00 a month averaged billing. I have a large capacitor installed in my house to help with electric cost. After working in the desert all my life I like my comfort now. By using energy efficient AC systems and good insulation the spaces don't have a chance to heat soak as happens when you only turn on the cooling system for each use. I was able to cool the house with a 2 stage Mastercool evaporative cooler to 78-80 degrees when outside temperatures were 110 to 115 degrees. When my house equipment needed replacement after 25 years I spent my money on a high efficiency AC unit and removed the evaporative cooling units. The evaporative coolers just used to much water and required to much service compared to the AC units. Our sewage bills are based on how much water we use. My lifetime's experience strongly recommends using a Mini Split AC system . Don't even think of using a "window AC unit " because the cost and noise to run one will disappoint you. I have 3 reloading presses and store all my firearms in safes in my windowless garage. I typically spend 4-6 hours a day at my gun bench and have never regretted or wanted something different than my air conditioned garages . P.S. my wife loves her air conditioned garage for laundry work and unloading groceries from her car. The bottom line is if you like it below 85 degrees and spend a lot of time in your garage then go AC. I hope this helps.

Definitely helps. Our home has two Trane heat pumps on the roof - a 5-ton and a 4-ton. The roof is a flat foam roof with high parapets. Garage also has a flat foam roof with high parapets - would it be best to install some type of AC unit on the roof of the garage? I don't really want to cut into the walls. Does a split system work well roof mounted? Or would another option be better?

 

[Stomper]

Some people really appreciate being told - then work to clarify, confirm, and ponder. I'm the kind that needs to really understand all the ins outs and ramifications before making a decision. Drives my wife crazy because I tend to think things over deeply for a good bit of time before making a move - slow mover. She's the type that jumps impulsively and acts with a small bit of information or recommendation - not much exploration nor deep thought to it.

I also like to listen to a number of different opinions on things before making a decision. With enough input, often a consensus of reasoned and educated opinions rises, pointing in a good direction. In the end, I choose by what makes the most sense to me - after considering all the views.

We will quite likely be going to go with ductless split AC, instead of a swamp cooler - the extra cost isn't a huge deal. Also thinking it may be wise to get a roof exhaust fan, to suck out the majority of hot air before employing the AC... does that make good sense?

So what you're saying is..... you're an askhole!




As for the exhaust fan... remember, make-up air will have to come from someplace... and that'll be from outside the negative pressure envelope of your building. Mechanical refrigeration works on the "Delta T" principle... For "high temperature" (comfort cooling of occupied spaces) let's say you have 80*F air getting sucked into the inlet of your A/C system... you should expect 16*F - 22*F cooler air coming out of it (64*F - 58*F), as the air in the space gets cooler the inlet temperatures will also produce the corresponding cooler discharge temperatures until the room reaches the set point on your thermostat. A small amount of fresh outside air is fine so it doesn't get stuffy in the space (10-15% of your total CFM airflow), but most residential houses have enough infiltration from the outside that it's not USUALLY an issue like it is in commercial spaces.

The key to fast and efficient heating/cooling is properly sized equipment for the load, and multiple air exchanges per min/hr across your heat exchangers (furnaces) and evaporator/condenser coils (AC/heat pumps)...

 

[Stomper]

Definitely helps. Our home has two Trane heat pumps on the roof - a 5-ton and a 4-ton. The roof is a flat foam roof with high parapets. Garage also has a flat foam roof with high parapets - would it be best to install some type of AC unit on the roof of the garage? I don't really want to cut into the walls. Does a split system work well roof mounted? Or would another option be better?
View attachment 8292

From what you said, the two Trane units on the roof are called "packaged units", everything is "packaged" in one cabinet (blower, compressor, condenser section, evaporator section, etc)

A split means just that... the outdoor unit contains (basically) the compressor, condenser coil, condenser fan motor... the indoor unit contains (basically) the evaporator coil, the "blower" (moves the air), a filter rack of some sort, and will also need a condensate removal sub-system (typically a mini reservoir pump). Each end is connected to each other by refrigeration lines and control wiring (ductless splits also have the line voltage going between the two).

Since you have a flat roof, a rooftop unit (RTU) may indeed be a great choice, but you'd need to ensure the roof structure is adequate to support the weight, build a support structure (like a roof curb) for it to sit on, make roof penetrations for the supply and return air ducts, whereas with a ductless split system you'll (typically) need one penetration (typically 2"-3" round) to fit refer lines and electrical/control wiring through.

The outdoor unit can be installed on the roof, on the ground, or even with wall brackets on the side of the house if you wish.

Hope that helps!

 

[Stomper]

Ask @11Charlie ... I fixed his F-ed up 6-ton A/C system at the last place he worked last summer... the 480/208-230vac blower motor wasn't even set on the correct voltage taps by the original installers (let alone having the drive sheave adjusted to pull the correct amperage ... and he always wondered why the airflow was so lousy.... a motor set to run on 460vac wired to 230vac... yeah, it was running slow and rather hot.

 

[11Charlie]

Ask @11Charlie ... I fixed his F-ed up 6-ton A/C system at the last place he worked last summer... the 480/208-230vac blower motor wasn't even set on the correct voltage taps by the original installers (let alone having the drive sheave adjusted to pull the correct amperage ... and he always wondered why the airflow was so lousy.... a motor set to run on 460vac wired to 230vac... yeah, it was running slow and rather hot.

That whole building was F up. So glad you fixed it.

 

[DHart]

From what you said, the two Trane units on the roof are called "packaged units", everything is "packaged" in one cabinet (blower, compressor, condenser section, evaporator section, etc)

A split means just that... the outdoor unit contains (basically) the compressor, condenser coil, condenser fan motor... the indoor unit contains (basically) the evaporator coil, the "blower" (moves the air), a filter rack of some sort, and will also need a condensate removal sub-system (typically a mini reservoir pump). Each end is connected to each other by refrigeration lines and control wiring (ductless splits also have the line voltage going between the two).

Since you have a flat roof, a rooftop unit (RTU) may indeed be a great choice, but you'd need to ensure the roof structure is adequate to support the weight, build a support structure (like a roof curb) for it to sit on, make roof penetrations for the supply and return air ducts, whereas with a ductless split system you'll (typically) need one penetration (typically 2"-3" round) to fit refer lines and electrical/control wiring through.

The outdoor unit can be installed on the roof, on the ground, or even with wall brackets on the side of the house if you wish.

Hope that helps!

It helps! For my application, would it be less costly to do a split system, with the outdoor unit just sitting near an outside wall of the garage? Seems installation would be a lot less expensive. How many amps? What voltage? Would the unit need it's own dedicated line from the power box, or could I tap into a line somewhere in the garage for power?

 

[Stomper]

It helps! For my application, would it be less costly to do a split system, with the outdoor unit just sitting near an outside wall of the garage? Seems installation would be a lot less expensive. How many amps? What voltage? Would the unit need it's own dedicated line from the power box, or could I tap into a line somewhere in the garage for power?

A 2-ton unit will need its own dedicated 220vac, 20-amp (typically) circuit that is run from the breaker panel to the outdoor unit, then from the outdoor unit to the indoor unit (which can be "loomed together" with the connecting refrigeration lines). I can't tell you what location would be the most "cost effective"... too many variables that I can't see, but the cost difference shouldn't be that much either way, so IMHO go for the most aesthetic option.

 

[DHart]

A 2-ton unit will need its own dedicated 220vac, 20-amp (typically) circuit that is run from the breaker panel to the outdoor unit, then from the outdoor unit to the indoor unit (which can be "loomed together" with the connecting refrigeration lines). I can't tell you what location would be the most "cost effective"... too many variables that I can't see, but the cost difference should be that much either way, so IMHO go for the most ascetic option.

OK, thank you for all the advice. Now I pretty much know what I need to be looking at.

There will need to be trenching from the breaker panel on the east side of the house all across the entire front (or rear) of the house over to the garage on the west side. I'm thinking the exterior unit can sit behind the bush and beneath the glass block window on the north side of the garage.

2 ton unit ductless split Diakin. This one? 17, 19, or 20 seer?

24,000 BTU Daikin 18 SEER Wall-Mounted Ductless Mini-Split Inverter Air Conditioner Heat Pump System (230 Volt)

<p><strong>Elevate your expectations and get more out of your home’s indoor comfort system performance</strong></p> <p>As you think about the functionality of your home's indoor comfort system, the Daikin brand is ready to help you<br />achieve con

www.heatandcool.com

Anything else I should be looking for in the unit?

Diakin better than Mitsubishi? What would be your #2 choice after the Diakin?

 

[DHart]

Lastly, would I have to hire an HVAC company to install it? Or would most electricians be OK with taking the job (assuming I buy the unit myself?)

 

[Stomper]

Daikin

LG

Mitsubishi



I don't know what your technical/aptitude skills are, and it does require specialized tools and knowledge to properly install them. Do yourself a favor and get three bids from HVAC contractors (who can sub out an electrical contractor (99.99% of electricians don't know squat about refrigeration) that way you'll have a warranty and liability coverage.

 

[DHart]

Daikin

LG

Mitsubishi



I don't know what your technical/aptitude skills are, and it does require specialized tools and knowledge to properly install them. Do yourself a favor and get three bids from contractors, that way you'll have a warranty and liability coverage.

OK. Electricians? Or, general contractors?