Help with mystery air conditioning inefficiency in home garage shop

ClimberD · May 20, 2013

Greetings,

I run a small niche automotive parts upgrade business out of my home's garage. Love the forum, browse it often whenever a tool decision or garage layout question comes up. I have done a ton of research on this problem, and have found nothing to answer my dilemma.
The issue is that almost regardless of outside temperature, which commonly ranges from 40* to 100*F here in Dallas, my garage is always hotter than my 72*F home above, even in the dead of night.

My question is, Have any of you ever seen heat come up in heaps from the cement floor? Garage will naturally climb to 75*F when it is 40*F outside, and 68*F in my home. I have had to open the door to cool it off, but cannot do that with summer here. Garage naturally tops out at about 85*F, regardless of summer heat or time of day/night.

-23' x 18' x 10.5' ceilings; 415sq ft
-Direct sunlight only on garage door, only from 9am-11am. (Townhouse)
-3 walls are reasonably well insulated with a rock wool product.
-Double garage door is insulated with 1.5" thick R-Max foam sheet insulation in all 4 rows of hinged garage door panels, R9 in total.
-Ceiling is very well insulated, with my 72*F home on top.
-Cement pad floor.
-No windows.

What I have tried so far:
I run a 9000btu portable A/C, which draws 72*F air in from my cooled house, and pumps 150*F air outside through an insulated exhaust vent.
This unit blows a 30*F temperature drop.
Result, it drops the room temp maybe 3*F, cannot do any better.

I am now considering a 13000 or 18000 BTU mini split.
I cannot decide! My gut says to get the 18000, but with 414sqft am I crazy? Would 18000 make it into a swamp or would the constant influx of mystery heat cancel out the larger unit so that all would be normalized?

Any experience about this phantom heating is very welcomed.

Thank you in advance!

rlitman · May 20, 2013

Do you live over a hot spring? Or a native american burial ground perhaps?

I'd look at your heating system more closely.

tdkkart · May 20, 2013

When the bodies finish composting, things will cool off, take it from an exp.......oh never mind.

Tell us where you live, if you live in Hawaii on top of an active volcano we can't help you much, other than to center your efforts more towards quality BBQ rather than home brewed beer.

rlitman · May 20, 2013

He did say Dallas.

egnorant · May 20, 2013

Does your garage have any appliances? Water heater, freezer, washer drier?

Do you park your car in there after driving it around?

Home AC/Heat run off gas and an uninsulated vent pipe?

Find how the heat is getting in first.

Bruce

ford33 · May 20, 2013

How about locating the source of the greater heat using an inexpensive digital thermometer? Or if you have access to a digital heat viewing device (not sure what they are called) use that to find the hot spots in the room.

Boyd · May 20, 2013

That slab is getting heat from somewhere. Which direction does your house face? It sounds to me like you're getting quite a bit of thermal transfer between your driveway and garage slab.

jtbinvalrico · May 20, 2013

For reference, I use a 12k window unit in my two-car shop. Insulated door. One and a half walls bound the house, one and a half walls are uninsulated cinder block bounding the great outdoors here in mid-Florida. I have zero attic insulation. I can set the AC to 75 and within fifteen minutes I have significant cooling, and a solid 75-76 in the shop while it's in the 90's outside.

Let me make sure I'm understanding you correctly. It sounds like you are using a 9k portable unit to draw cool air from inside your residence, and to exhaust hot air to the outdoors. As a result you are getting a stream of cold air blowing from the unit into the garage, and this cold air is 30 degrees colder than the ambient temperature of the garage.

If this is the case, I think the problem is that you should be drawing air from the garage into the unit, not from the house into the unit. The way it's set up now, you aren't removing any moisture from the garage air, you're just blowing cold air into it. The great benefit of air conditioning is that it dries the air out, which combined with the introduction of cool air, can make your garage as comfy as your house.

Hopefully I haven't misunderstood your setup and this helps.

:beer:

benjammn · May 21, 2013

jtbinvalrico said:
For reference, I use a 12k window unit in my two-car shop. Insulated door. One and a half walls bound the house, one and a half walls are uninsulated cinder block bounding the great outdoors here in mid-Florida. I have zero attic insulation. I can set the AC to 75 and within fifteen minutes I have significant cooling, and a solid 75-76 in the shop while it's in the 90's outside.

Let me make sure I'm understanding you correctly. It sounds like you are using a 9k portable unit to draw cool air from inside your residence, and to exhaust hot air to the outdoors. As a result you are getting a stream of cold air blowing from the unit into the garage, and this cold air is 30 degrees colder than the ambient temperature of the garage.

If this is the case, I think the problem is that you should be drawing air from the garage into the unit, not from the house into the unit. The way it's set up now, you aren't removing any moisture from the garage air, you're just blowing cold air into it. The great benefit of air conditioning is that it dries the air out, which combined with the introduction of cool air, can make your garage as comfy as your house.

Hopefully I haven't misunderstood your setup and this helps.

This was my exact thoughts on his situation. He is not actually removing the hot air from the garage and removing the moisture properly. I too believe that if he uses the unit as directed to pull the hot air from the garage and blow it out it will work better. But I do believe there is some heat source that is missing here. An infrared scan should show the major heat source and then allow for a better diagnosis of what should be done to remove the heat.

benjammn · May 21, 2013

One other note: if you are drawing in cold air from the house the air conditioner may be seeing that it is already cooling the room even though it is not.

Larosa · May 21, 2013

better to check of its compressors that would have got out of order. its better to take it to service center as soon as possible

kursplat · May 21, 2013

benjammn said:
One other note: if you are drawing in cold air from the house the air conditioner may be seeing that it is already cooling the room even though it is not.

that's what it sounds like. depending on what mode your running the A/C in, the fan can continue to run even if the compressor is off. since it's pulling through cool inside air it's thinking it's cold enough.
i'd like to see some pics of the duct work for this

Falcon67 · May 21, 2013

12K unit is plenty for that space if it's properly insulated - which it sounds like. I'm 200 miles west of you and mucho hotter (since it's drier here) - I can hold 70s with 16K BTU in 960 sq/ft easy. Portable units are - IMHO - useless. We've tried to use 9K units at work on a temp basis for emergencies in areas that need AC (computer closets, etc) and they don't work well at all.

pseudorealityx · May 21, 2013

Lights and equipment are likely the cause of the "mystery" heat. Portable units are awful, and since you set it up wrong, it didn't do you any favors.

+1 on Falcon's response. You don't need 18,000 btu in that space unless you're doing something you're not telling us about... which, if the garage is 75 when the house is 68 and the outdoors are 40.... might be something to look into.

ClimberD · May 21, 2013

Thank you guys for your replies!

egnorant said:
Does your garage have any appliances? Water heater, freezer, washer drier?
Do you park your car in there after driving it around?
Home AC/Heat run off gas and an uninsulated vent pipe?
Find how the heat is getting in first.
Bruce

No house appliances are in the garage; all are upstairs in the kitchen.
I have lots of heat-producing equipment, but none get powered on for a week at a time; so ruled that out.
The hot room temperature is consistent with and without any appliances running. I have a dehumidifier that keeps humidity ~40% so nothing rusts.
But turning the dehumidifier off for a day made a insignificant difference to heat situation.

ford33 said:
How about locating the source of the greater heat using an inexpensive digital thermometer? Or if you have access to a digital heat viewing device (not sure what they are called) use that to find the hot spots in the room.

Ordered an infrared temp gun from Amazon, will report the findings.

Boyd said:
That slab is getting heat from somewhere. Which direction does your house face? It sounds to me like you're getting quite a bit of thermal transfer between your driveway and garage slab.

I would bet this is it. Townhouse is within a large structure, my outside wall faces East, with 2 hours of direct morning sunlight. However, my garage cement is connected to the outside drive cement, which gets a lot of sunlight.

jtbinvalrico said:
For reference, I use a 12k window unit in my two-car shop. Insulated door. One and a half walls bound the house, one and a half walls are uninsulated cinder block bounding the great outdoors here in mid-Florida. I have zero attic insulation. I can set the AC to 75 and within fifteen minutes I have significant cooling, and a solid 75-76 in the shop while it's in the 90's outside.

Let me make sure I'm understanding you correctly. It sounds like you are using a 9k portable unit to draw cool air from inside your residence, and to exhaust hot air to the outdoors. As a result you are getting a stream of cold air blowing from the unit into the garage, and this cold air is 30 degrees colder than the ambient temperature of the garage.

If this is the case, I think the problem is that you should be drawing air from the garage into the unit, not from the house into the unit. The way it's set up now, you aren't removing any moisture from the garage air, you're just blowing cold air into it. The great benefit of air conditioning is that it dries the air out, which combined with the introduction of cool air, can make your garage as comfy as your house.

Hopefully I haven't misunderstood your setup and this helps.

Nice. Good point of reference, thank you.

So on the right side wall of the garage door is the door to the house, so I prop that open.
On the opposite (left) side wall is the portable A/C, with an exhaust vent above the garage door.
So any portable A/C has an exhaust, and this one moves a LOT of air. So to make up the air flow difference back INTO the room, it will either come from any air gaps in the garage door (sucking in outside hot air), or if I prop open the house door then it will also draw pre-conditioned air. I went with the house draw option. You can feel the air being drawn in from the house.

benjammn said:
One other note: if you are drawing in cold air from the house the air conditioner may be seeing that it is already cooling the room even though it is not.

Crossed that off the list; the portable a/c is set lower than the garage temp (has digital display indicating compressor is on).

Larosa said:
better to check of its compressors that would have got out of order. its better to take it to service center as soon as possible

portable a/c blows a 30*F temp drop, which is as good as it gets.
A/C's vent outside temp measures to 150*F, so system is quite inefficient (given the following realistic example):
Garage temp: 85*F
System cooling output: 55*F
System exhaust: 150*F.
Thus, inside temp drop: 30*F,
with heat production of: 65*F
Thus 46% efficient.

I did not realize until now how terrible that is.

Falcon67 said:
12K unit is plenty for that space if it's properly insulated - which it sounds like. I'm 200 miles west of you and mucho hotter (since it's drier here) - I can hold 70s with 16K BTU in 960 sq/ft easy. Portable units are - IMHO - useless. We've tried to use 9K units at work on a temp basis for emergencies in areas that need AC (computer closets, etc) and they don't work well at all.

I'm at the point of complete agreement. I am yet to see a portable work well, and I have owned a couple portable units by now.

pseudorealityx said:
Lights and equipment are likely the cause of the "mystery" heat. Portable units are awful, and since you set it up wrong, it didn't do you any favors.

+1 on Falcon's response. You don't need 18,000 btu in that space unless you're doing something you're not telling us about... which, if the garage is 75 when the house is 68 and the outdoors are 40.... might be something to look into.

Under normal circumstances, I agree completely. But room only has two multi-bulb flourescent T8 fixtures that can be off for a day without affecting room temperature.
I look forward to playing with my new infrared temp sensor gun to see what the heck is going on.

Thank you all for your questions and information, and willingness to help me out :beer:

I may post pictures if it gets to looking like that will help.

ClimberD · May 21, 2013

This is coming:
http://www.amazon.com/Kintrex-IRT0421-Non-Contact-Thermometer-Targeting/dp/B0017L9Q9C/ref=sr_1_6?ie=UTF8&qid=1369161199&sr=8-6&keywords=temp+sensor+gun

pseudorealityx · May 21, 2013

That dehumidifier you've got is spitting out quite a bit of heat, at least in summer. No reason to put it at 40% RH. Raise it to 55-60% and you'll save a bunch of money and you still won't rust anything.

ClimberD · May 21, 2013

IR thermometer came in fast, so played with it today.
Conditions: Thunderstorms and rain, 71* cement outside, trees closer to 65. (Dallas)
Results:
-Surprisingly no hot spots, except around dehumidifier, which produces wall surface temperatures of 2-3* over ambient. Again, when I turn it off for a day, room is about the same temperature, maybe just a couple degrees cooler at most, but such a small difference on average that I could not spot it with the room's dial thermometer. Also it was exactly the same problem for the year before buying the dehumidifier.
-Cement pad is 2* cooler than room ambient today (81pad vs 83+/-1*).
-Metal of garage door is 73 outside, 79 inside.
-Foam sheet insulation in garage door facing inside is 83.
-Ceiling and walls are all around 83*, with subtle variations.
-Home side of door to garage is 72, as is the inside of my home.

Summary: It's 71 outside, 72 inside my garage, no sun this afternoon, and 83 in my garage.

Conclusions...
Best I can come up with is that my cement floor is being heated from underneath.
I now believe that the insulation in the garage ceiling and walls next to living areas (adds up to about 2 full walls out of 4 total) are actually keeping heat in.
If I was planning to stay in this space for a decade, I might try a thermal decoupling layer of material on the garage floor.
But instead, I will just pump out the heat with a... heat pump (mini split a/c).

Do any of you have different measurements of the relationship between ceiling, walls, garage door, and cement floor?

pseudorealityx said:
That dehumidifier you've got is spitting out quite a bit of heat, at least in summer. No reason to put it at 40% RH. Raise it to 55-60% and you'll save a bunch of money and you still won't rust anything.

Good tip, thank you.

ClimberD · May 21, 2013

Passively Googled humidity to get more details.
http://www.surplusrifleforum.com/viewtopic.php?f=80&t=62001
http://www.thehighroad.org/archive/index.php/t-24411.html
http://www.ehow.com/how-does_5325633_humidity-black-mold-start-grow.html
Going to bump the level up to 45%.
I personally really like how dry it has been in there since I bought the dehumidifier a year ago. I am concerned about a lot of things each day, but anything related to moisture (including mold, coating my Grizzly lathe, metal in my tool chest, etc) has not crossed my mind at all in one year, with zero problems.
http://www.wikihow.com/Sample/Kilowatt-Hours-Calculator
I calculate it uses between $160 and $320, which for me is more than reasonable to keep every tool and machine I own completely dry.

Maybe considering this addition to the garage will be useful to someone. Thank you for getting me thinking about it. The difference between 35-45 is already going to be a huge savings.

ClimberD · May 21, 2013

Ordered a 18,000 BTU, 13 Seer mini split http://www.highseer.com/13-seer-mini-split-ductless/ductless-mini-split-heat-pump-wyd018g.html
It's also for sale on Amazon, but shipping costs more.

Chose 18,000 instead of 13,000 for one main reason:
I do NOT, yet again, want to buy twice. I can grow into a future bigger space and still be covered with this unit.
I also have the unknowns: I know the garage naturally receives heat from somewhere, and I believe now that it is coming from the worst possible direction: directly below. I know the temperature, but I do not know the rate at which BTUs are rising into the room. However, the room can heat up back to its ambient within 30 minutes of dumping the heat by opening the garage in the winter. So I know it's pretty serious. Thus a big unit is also a hedge. And other benefits, like I can blast cooling after a hot vehicle pulls in, that much faster.

I think the first and second guy were right: ancient indian burial ground over a hot spring

pseudorealityx · May 22, 2013

ClimberD said:
Passively Googled humidity to get more details.
http://www.surplusrifleforum.com/viewtopic.php?f=80&t=62001
http://www.thehighroad.org/archive/index.php/t-24411.html
http://www.ehow.com/how-does_5325633_humidity-black-mold-start-grow.html
Going to bump the level up to 45%.
I personally really like how dry it has been in there since I bought the dehumidifier a year ago. I am concerned about a lot of things each day, but anything related to moisture (including mold, coating my Grizzly lathe, metal in my tool chest, etc) has not crossed my mind at all in one year, with zero problems.
http://www.wikihow.com/Sample/Kilowatt-Hours-Calculator
I calculate it uses between $160 and $320, which for me is more than reasonable to keep every tool and machine I own completely dry.

Maybe considering this addition to the garage will be useful to someone. Thank you for getting me thinking about it. The difference between 35-45 is already going to be a huge savings.

You can easily go above 45%. The inside of your house is no doubt higher than 45% during the summer. Does steel in your house rust?

ClimberD · May 22, 2013

pseudorealityx said:
You can easily go above 45%. The inside of your house is no doubt higher than 45% during the summer. Does steel in your house rust?

I don't have a single bit of untreated or un-coated rust-able steel in my home. No iron LSX coffee table or wine rack. Not even the knives are 10% as rust-able as the iron and steel in my garage. But its also air conditioned 24/7/300ish days a year. I will measure indoor humidity, am curious now what it is.

ClimberD · May 22, 2013

Relative humidity inside home is ~60%.
That would explain why my existing portable A/C setup would kick on the dehumidifier full time. It would draw more humid air from the house into the less humid garage.

I'm not an avid gun collector, but the guys I do know who keep guns in cabinets and safes in their air conditioned homes often do extra things to manage humidity. Lots of oiling, and lots of coalescent material. Maybe they're over-doing it, maybe they're not. I do not know, and I am not too worried either way.

Falcon67 · May 22, 2013

Chose 18,000 instead of 13,000 for one main reason:
I do NOT, yet again, want to buy twice. I can grow into a future bigger space and still be covered with this unit.

Smart plan. Also - I lived a long time in Fort Worth but I tend to forget you have a lot more humidity over there than we do. Sunday here the RH was 8%. That's eight percent. Normal to be in the teens or single digits. My tools and steel won't rust unless I leave them out in the rain.

I would add that out house garage is only 22x21 and it'll be 95~100 in there but only 85~90 in the big shop. Doors both face south, both have walls facing due west that get really (130F+) hot. The main difference is that the house garage has that long driveway in front and the shop has dirt/grass. There is also 64,000 lbs of concrete in the shop floor so that mass changes temp a lot slower. So you could well be picking up heat from conduction out of the driveway.

Nice price on that 18K unit.

ClimberD · May 23, 2013

Falcon67 said:
Smart plan. Also - I lived a long time in Fort Worth but I tend to forget you have a lot more humidity over there than we do. Sunday here the RH was 8%. That's eight percent. Normal to be in the teens or single digits. My tools and steel won't rust unless I leave them out in the rain.

I would add that out house garage is only 22x21 and it'll be 95~100 in there but only 85~90 in the big shop. Doors both face south, both have walls facing due west that get really (130F+) hot. The main difference is that the house garage has that long driveway in front and the shop has dirt/grass. There is also 64,000 lbs of concrete in the shop floor so that mass changes temp a lot slower. So you could well be picking up heat from conduction out of the driveway.

Nice price on that 18K unit.

8%?!

Amazed at such a difference from just 200 miles west, and only 100 more miles from sea. I always thought Dallas was the dry city (compared to Austin and especially Houston), but then I guess everything really is relative.
That said, my girlfriend wants to be in Houston and having kids in the next few years, so I may soon be looking back at Dallas' 50-70% humidity with envy

I will continue to test correlation between inside and outside cement temperature. AND when I eventually have a more permanent place, I will make a point to decouple the driveway from the garage floor with some material that has high insulation properties, which should not be much trouble. That is a great takeaway from this thread, thank you.

Flyguy30263 · May 23, 2013

ClimberD said:
Ordered a 18,000 BTU, 13 Seer mini split http://www.highseer.com/13-seer-mini-split-ductless/ductless-mini-split-heat-pump-wyd018g.html
It's also for sale on Amazon, but shipping costs more.

Climber, I'm very interested in this system you bought and I'd like to hear any and all feedback you can provide when you get it and once it's installed. Thanks

72Anthony · May 23, 2013

The reason your garage is getting so hot is due to the lack of air circulation. It is the same as a car parked in the sun: the outside temp may be 90 degrees, but the car with the windows closed will reach 130 to 140+ because there is no air movement and heat input results in a rise in temperature.

The mini split should make a world of difference.
Good luck and let us know how it works out.

kursplat · May 24, 2013

ClimberD said:
So on the right side wall of the garage door is the door to the house, so I prop that open.
On the opposite (left) side wall is the portable A/C, with an exhaust vent above the garage door.
So any portable A/C has an exhaust, and this one moves a LOT of air. So to make up the air flow difference back INTO the room, it will either come from any air gaps in the garage door (sucking in outside hot air), or if I prop open the house door then it will also draw pre-conditioned air. I went with the house draw option. You can feel the air being drawn in from the house.

i know this is moot since your getting the mini-split, but where, now that you created a vacume in the house, was the air that was being passed through the garage and out the portable A/C exhaust, entering the house from? i thought central A/C setups recirculated the air within the house

ClimberD · May 24, 2013

72Anthony said:
The reason your garage is getting so hot is due to the lack of air circulation. It is the same as a car parked in the sun: the outside temp may be 90 degrees, but the car with the windows closed will reach 130 to 140+ because there is no air movement and heat input results in a rise in temperature.

The mini split should make a world of difference.
Good luck and let us know how it works out.

Makes total sense. Makes me wish I could cut a hole in the ceiling to tie into the fireplace vent. Not realistic, but would help in such a situation where the heat has nowhere to go, so it just builds up instead.

kursplat said:
i know this is moot since your getting the mini-split, but where, now that you created a vacume in the house, was the air that was being passed through the garage and out the portable A/C exhaust, entering the house from? i thought central A/C setups recirculated the air within the house

Exactly, that's the major flaw in a portable A/C, that the input air must come from somewhere. The good portable A/C units have two big flex hoses that go in the window: one input, one output. That way it can function more like a mini split, by not adding or removing air from the room.
The compromise I made with mine, drawing air from the house, was this:
Hot air being sucked through the numerous points that did not have perfect seals (along windows, doors, fireplace, vents) would raise the temperature of the house, but then the home A/C would just flip on and manage it. The house never felt any different as a result of doing this. I agree it is a silly roundabout way of cooling.
The mini split should solve all of that.
Plus, then I'll have the portable A/C's soon-to-be-available vent, which I can plumb into with a flex duct and fan, or my shop vac's output, so I can draw out harmful fumes from a small area of the garage, such as where I'm spraying parts with brake cleaner, spray paint, epoxy, pretty much anything that I really don't want to breathe.

dave*99 · May 30, 2013

ClimberD said:
Plus, then I'll have the portable A/C's soon-to-be-available vent, which I can plumb into with a flex duct and fan, or my shop vac's output, so I can draw out harmful fumes from a small area of the garage, such as where I'm spraying parts with brake cleaner, spray paint, epoxy, pretty much anything that I really don't want to breathe.

If I understand this correctly you are looking to have your AC system **** up these fumes and vapors. This may degrade the equipment, coat the fins, reduce performance, longevity etc.

Flyguy30263 · Jun 5, 2013

Climber, have you received the mini split system yet? I'm interested in your thoughts if so. THanks

ClimberD · Jun 12, 2013

dave*99 said:
If I understand this correctly you are looking to have your AC system **** up these fumes and vapors. This may degrade the equipment, coat the fins, reduce performance, longevity etc.

I should have been more clear. I was thinking of the potential to get a separate vent fan to pull air outside the garage via 4" dia flex hose. So I could do something like spray brake cleaner wherever I'm working and not have it turn my garage into a brain cell killing chamber. Would only be used like twice a month, would not be a big investment.

Flyguy30263 said:
Climber, have you received the mini split system yet? I'm interested in your thoughts if so. THanks

I have it, have bought all the wiring accessories, just need to install it. Though it's 240V, it does not have a crazy amp draw, so 14AWG extension cord running to the outlet for my air compressor and future welder will be spliced in.

I'm going to make a wood table base to make the outside look more discrete:
http://house-pet.blogspot.ca/2010/09/hide-that-ugly-ac-unit.html?m=1
This design offers better air flow than most other designs I have seen online. Will give the chop saw a workout.
Might paint it white.

Falcon67 · Jun 12, 2013

ClimberD said:
8%?!

Amazed at such a difference from just 200 miles west, and only 100 more miles from sea. I always thought Dallas was the dry city (compared to Austin and especially Houston), but then I guess everything really is relative.
That said, my girlfriend wants to be in Houston and having kids in the next few years, so I may soon be looking back at Dallas' 50-70% humidity with envy

I will continue to test correlation between inside and outside cement temperature. AND when I eventually have a more permanent place, I will make a point to decouple the driveway from the garage floor with some material that has high insulation properties, which should not be much trouble. That is a great takeaway from this thread, thank you.

Lived in Houston - you don't know humid yet. :bounce:

90F there is like 110F+ here. Or worse. It's real sticky here now - 41%. It's what you are used to. But I never got used to it down there. You bust a sweat walking the 20' from the house to the car. Best advice - get a pool. And after you mow the yard, get in it. Don't change clothes, just get in it.

SiGmA_X · Jun 12, 2013

That Minisplit is dirty cheap! How are those Pioneers rated? It is many, many times cheaper than I expected to see. (Compared to the top-quality, Daikin) Can you easily get replacement parts? I see absolutely no mention of warranty on highseer.com which makes me think none of their sales have any warranty, possibly because they aren't a Pioneer authorized vendor? I'm just shooting in the dark, I assume you'll have the answers for me being you researched and bought it! :rocker:

ClimberD said:
Exactly, that's the major flaw in a portable A/C, that the input air must come from somewhere. The good portable A/C units have two big flex hoses that go in the window: one input, one output. That way it can function more like a mini split, by not adding or removing air from the room.
The compromise I made with mine, drawing air from the house, was this:
Hot air being sucked through the numerous points that did not have perfect seals (along windows, doors, fireplace, vents) would raise the temperature of the house, but then the home A/C would just flip on and manage it. The house never felt any different as a result of doing this. I agree it is a silly roundabout way of cooling.
The mini split should solve all of that.
Plus, then I'll have the portable A/C's soon-to-be-available vent, which I can plumb into with a flex duct and fan, or my shop vac's output, so I can draw out harmful fumes from a small area of the garage, such as where I'm spraying parts with brake cleaner, spray paint, epoxy, pretty much anything that I really don't want to breathe.

Is your portable a 2 hose? If so, one is the condenser intake and one is the condenser exhaust. The evaporator unit recycles in-room air. So you really should have been using outside air for both hoses, there is no point in making your central HVAC work harder than needed. But that is a moot point now. Minisplit FTW!

dave*99 said:
If I understand this correctly you are looking to have your AC system **** up these fumes and vapors. This may degrade the equipment, coat the fins, reduce performance, longevity etc.

I think that is just something everyone who has HVAC in a shop accepts as a potential problem. Every benefit has a cost, and this is definitely an acceptable one.

ClimberD · Jun 13, 2013

SiGmA_X said:
That Minisplit is dirty cheap! How are those Pioneers rated? It is many, many times cheaper than I expected to see. (Compared to the top-quality, Daikin) Can you easily get replacement parts? I see absolutely no mention of warranty on highseer.com which makes me think none of their sales have any warranty, possibly because they aren't a Pioneer authorized vendor? I'm just shooting in the dark, I assume you'll have the answers for me being you researched and bought it!

It does have a warranty, but I am not too concerned about it past the first few weeks of operation.
Perhaps far more important than a warranty, I have the power of my Amazon.com review, where HighSeer advertises these. They would spend a certain amount on me to avoid a scathing review, just in case the unit is DOA.
Either it leaks a little or doesn't, works or doesn't. The Pioneer appears to have a better reputation than all the bottom barrel Chinese units out there.
The way I look at it is that either I spend 4x as much, and still have a huge headache if something breaks, or pay 1/4 for the Pioneer and just have a huge headache at 1/4 the price.
For work I have had a LOT of A/C repair work done at single family homes, by many different contractors, both in and out of warranty. I still do not see any price difference between the two. It's all labor and technical skill in the end, even on a 5-ton Goodman heat pump system.
This should be an appropriate purchase for non-living-area, non-permanent cooling.
In short, there is no guarantee any way I go, so this made the most sense for me and my specific situation.

Your mileage may vary.

Flyguy30263 · Jul 22, 2013

Climber, Do you have your system up and running yet? If so I wanna hear your thoughts. I'm very close to buying the same unit and would love some feedback. Thanks

Milton Shaw · Jul 22, 2013

This may sound silly but check to see if you have any circuit breakers drawing about 12 -15 amps all the time. I have seen electric slab heat in some locations you would not expect to find it. Model homes were prime for about anything weird you could think off.
If the slab is staying 83 all the time you must have a heat source in there, find it and turn it off is about the only thing that is going to work long term. Saw electric heat in a church basement slab one time, never could figure what it was there for.

RKA · Jul 22, 2013

LOL, reminds me of a similar story someone posted on these forums...someone down south buys a home and can't figure out why his electric bills are through the roof. After 2-3 years an electrician discovers a circuit that has been heating the driveway all that time (snow melt system)!

Help with mystery air conditioning inefficiency in home garage shop

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