[Oscar]

If foil-backed fiberglass still radiates heat from the plastic duct, I seriously doubt "rags" will prevent convection from that part. It woild need to be ceramic coated, lol.

Everything radiates heat, doesn't matter what it is. If your two choices are suboptimal and less than suboptimal, I will choose suboptimal.

Take two pots of water that are boiling and set them off the stove, one with a towel over top of it and one without and tell me which one cools down faster. It won't even be close. Bottom line is you can either insulate it or not insulate it. I would say it's better than closing off half the pipe by crushing it.

True, but plastic doesn't transmit/conduct/radiate as much as a metal, so the suboptimal part is already in-place, being the plastic hose duct. The less-than-suboptimal would be the metal duct without a lot of extra work to prevent it from radiating heat, which it is excellent at doing. Besides, the hose duct is not being crushed all that much. It's not like it's 20% of it's original area. Probably around 85-90%. Now if they made that duct out of plastic it would be much better.

[Oscar]

Here look. To settle this once and for all!

As you can see, I'm not squeezing the living daylights out of it.





PLENTY of hot air coming out!

[tweake]

does that temp change if you lift the door up a bit and not squeeze it all ?

[Oscar]

does that temp change if you lift the door up a bit and not squeeze it all ?

You'll have to come and drive down so you can try it yourself to find out after removing all the foam insulation I have installed on all 4-sides, lifting the door up a bit, checking the temp, then lowing the door back down and re-installing all the foam insulation on all 4-sides. I'm not about to lose 1½ hours of my free time. Besides if you lift up the door even just a bit, the top and bottom will no longer be sealed. So it would defeat the purpose.

[motox]

Oscar,
I have mini's in my front (house) garage and in my rear smaller garage. (weld/machine shop)
the bonus is the units are up and out of the way and they keep the room at a constant temp and humidity.
i use the heat the winter to do the same job. very reasonable to operate.
Craig

[tweake]

does that temp change if you lift the door up a bit and not squeeze it all ?

You'll have to come and drive down so you can try it yourself to find out after removing all the foam insulation I have installed on all 4-sides, lifting the door up a bit, checking the temp, then lowing the door back down and re-installing all the foam insulation on all 4-sides. I'm not about to lose 1½ hours of my free time. Besides if you lift up the door even just a bit, the top and bottom will no longer be sealed. So it would defeat the purpose.

just a thought, you could test the temp at the outlet of the machine and compare that to the pipe out.

the thing to look for is how dependant on air flow is it.
some of those units can be undersized air pipes from factory. others may run higher compressor pressure to get higher temps so they can use less air flow and not be so effected by pipe size.
with that sort of outlet temp i'm picking its the later.

[Poland308]

Discharge air temps on the condenser side will depend on refrigerant used.

[JustTheDad]

Can't add anything re. A/C. I have a Daikin mini-split for our gym and rec room because they're over the garage and it's a long distance from the main house's geothermal units. The mini-split works great.

Are you actually running a 3kw tube amp in a hot garage? That really is like running a space heater at the same time as your AC. I've built lower power tube amps for guitars, and they get hot! Even the 18 watt AB ones put out a lot of heat. I'm sure your hi-fi version is a lot more efficient, but still, it's probably hotter than a half dozen easy bake ovens.

[Oscar]

Are you actually running a 3kw tube amp in a hot garage? That really is like running a space heater at the same time as your AC. I've built lower power tube amps for guitars, and they get hot! Even the 18 watt AB ones put out a lot of heat. I'm sure your hi-fi version is a lot more efficient, but still, it's probably hotter than a half dozen easy bake ovens.

Nah, the tube amp is a 15W x 2 mini-amp. Still puts out heat like a space heater though! So no, not efficient at all! Even then the small portable LG A/C is keeping temps in the upper-80s/lower-90's, so I'm still beating the heat outside! The other two amps together with the tube amp are worth over 3 kW, but I'm not using both of them. The Peavey IPR-7500 class-D is for the subwoofer, and the Peavey CS-800X is what the tube amp took over from, so it's just sitting there. Since you have tube amp experience, are you familiar with the circuits/transformers for KT-88s vs KT-100s/KT-120s? I have some questions about them.

[JustTheDad]

Since you have tube amp experience, are you familiar with the circuits/transformers for KT-88s vs KT-100s/KT-120s? I have some questions about them.

Sorry, never built anything with KT-88s. They can take some really high voltages though. My amps used 6V6 and 6L6 tubes, or smaller. Mostly smaller because I was actually mostly interested in 1-2 watt class a designs for playing at home back. Great distortion at tolerable volumes.

[Oscar]

Since you have tube amp experience, are you familiar with the circuits/transformers for KT-88s vs KT-100s/KT-120s? I have some questions about them.

Sorry, never built anything with KT-88s. They can take some really high voltages though. My amps used 6V6 and 6L6 tubes, or smaller. Mostly smaller because I was actually mostly interested in 1-2 watt class a designs for playing at home back. Great distortion at tolerable volumes.

Yeap, totally different classes that I am headed into.

[G-ManBart]

Mitsubishi is the gold standard in mini-splits....pretty much everybody has borrowed their inverter technology, and some big name companies actually use their internals.

If having the outside unit visible won't be unsightly, I think they make all the sense in the world.

I partitioned off part of my shop building, insulated it and added liner panel walls and ceiling so I could heat and cool it. I installed a Mitsubishi Mr. Slim with the heat pump option in that section a couple of years ago and it's been awesome. It's very, very quiet and even in the dead of summer I don't see much of a change in the electric bill (separate meter). I've been around some of the other brands and they were all much louder...but usually a fair amount cheaper.

At the same time we added a 24K unit to the loft in our house because it never really cooled properly (adjacent to the great room with 21' ceilings. You can't hear that one running and it's lowered our overall summer electric bill a bit...win-win.

[motox]

be aware, mini's do not like a lot of dust.

[Oscar]

be aware, mini's do not like a lot of dust.

Yes, recently I have given it a lot of thought, having ran my portable AC in the garage for a few weeks. I've had to add filter layers in front of the unit's filter screens, and they get very filthy quickly. There's no way a mini-split would have appropriate protection against dust/fumes. So I will resort to plan B/C. Custom-made filtration with carbon-filters to clean the air and then cool it down before being recirculated back in. Naturally I will be utilizing unused attic space for all this. Plus I can get a lot more cooling capacity using several portable A/C's than I can with a mini-split. ~$1500 will get me 42k BTU's of cooling capacity.

[motox]

if you don't need heat, portable units work great. had them in my old shop in nj,