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EG4 Mini Split - 24k BTU system

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AndreasPassat

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Joined
Aug 6, 2023
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108
Location
Sonoran Desert - Eastern
Finally got around to installing my EG4 24k BTU mini spilt system over the weekend.
First impressions, this thing is awesome. Effortlessly keeps my casita at a very comfortable 70 degrees when it's over 100 degrees outside, even with unfinished roof insulation.
Checked loads and it pulls 10amps max. Even with the current set-up of (4) EG4 LL 48V 100Ah batteries I still have anywhere from 40%-50% state of charge left in the morning.
No doubt I will get more of these for my workshop when that's completed.
 
I did try the pv panels when I had the 12k BTU unit, but as soon as some cloud cover comes around it throttled down and wouldn't keep it cool.

Seeing as I'm 100% off-grid it's running off the inverters full time.
Kind of a moot point to run it off pv panels during the day and then switch over to battery power at night. This way it has the ability to do full output without missing a beat.

The main reason for purchase is the design concept. It has a rotary compressor instead of a piston type compressor making it much more efficient.
Same concept as an industrial air compressor. A screw compressor can way outperform with cfm output vs the same horsepower as a piston type compressor. The amount of cooling power this thing has at only a 10-amp draw is amazing.
 
How many square feet are you cooling with a single 24K? Is it one large space, or separate bedroom and bath? Do you use any fans to help circulate the cooled air?
 
Currently cooling 800sq ft which isn't much really but considering my roof is NOT insulated at the moment and I'm the lower AZ desert, anybody who knows the sun here is just downright brutal and it takes quite a bit to keep something cool.
I've lived here in AZ for 6 years now and I'm still amazed at how unrelenting the suns heat is.

The indoor unit is centrally located in the middle of the casita length wise on a 50ft long wall that is facing North.
I have two rooms, the bedroom and the bathroom, the rest (kitchen, living area) is open. The unit is cooling the whole place with no fans.
I have a pretty large door leading into the bedroom and likewise into the bathroom off one end of the living area.
The temperature difference between the rooms and the rest of the building is only by a few degrees.

I was up in the loft area yesterday midday (103° outside) and the heat pushing through the roof was pretty intense.
The peek of the loft is just under 12ft, back down at 8 to 9 ft the cool air has pretty much cancelled any heat pushing down any further.
The outlet of the indoor unit is at 8ft high.
 
Thanks. Seemed like a large unit for what I envisioned as a casita. Your situation makes sense and great that it cools that much space on its own.
 
hidiyguy said:
Thanks. Seemed like a large unit for what I envisioned as a casita. Your situation makes sense and great that it cools that much space on its own.
Click to expand...

Yeah actually it is too big for the square footage.
If I were back WI where I used to live I wouldn't even think about doing something like that. When humidity is a big deal sizing the ac unit is crucial so it doesn't cool it down before it removes all of the moisture.

Down here where I'm at the humidity is rarely above 20% so humidity isn't an issue. I just needed / wanted something to power through the intense heat and make it comfortable without having to run a 100% duty cycle.

I know just enough about sizing the ac unit to understand the importance of it all, but I don't know the actual formulas involved. I think I've stumbled across the perfect combination of sq footage to BTU's this time.
 
AndreasPassat said:
When humidity is a big deal sizing the ac unit is crucial so it doesn't cool it down before it removes all of the moisture.
Click to expand...
How does that work exactly? I’ve got a 12Kbtu split that’s nearing end of life. It cycles between 200 and 400 watts (avg 225-ish?) and I wonder if a 9Kbtu might use less power, cycle less, and/or be better at humidity control.
 
AndreasPassat said:
Here are (2) online caclulators you can use. These are by no means as accurate compared to a HVAC technician, but it will give you pretty close number of what is needed.

https://www.calculator.net/btu-calculator.html

https://kobiecomplete.com/cool-tips/btu-calculator/

These calculators are getting me within a few thousand BTU's of what I have right now.
Click to expand...
Thanks, but I’m looking specifically for information on humidity control. I have a concrete house, so insulation value is low and thermal mass is high, and my primary interest is understanding humidity control versus temperature reduction.
 
AndreasPassat said:
Currently cooling 800sq ft which isn't much really but considering my roof is NOT insulated at the moment and I'm the lower AZ desert, anybody who knows the sun here is just downright brutal and it takes quite a bit to keep something cool.
I've lived here in AZ for 6 years now and I'm still amazed at how unrelenting the suns heat is.

The indoor unit is centrally located in the middle of the casita length wise on a 50ft long wall that is facing North.
I have two rooms, the bedroom and the bathroom, the rest (kitchen, living area) is open. The unit is cooling the whole place with no fans.
I have a pretty large door leading into the bedroom and likewise into the bathroom off one end of the living area.
The temperature difference between the rooms and the rest of the building is only by a few degrees.

I was up in the loft area yesterday midday (103° outside) and the heat pushing through the roof was pretty intense.
The peek of the loft is just under 12ft, back down at 8 to 9 ft the cool air has pretty much cancelled any heat pushing down any further.
The outlet of the indoor unit is at 8ft high.
Click to expand...
I live in a similar desert as you with unbearable 103 summers. I like taking my RV trailer out, but summers cut that short. I'm wondering how a 24k system with large ground array would work in an aluminum airstream trailer. Anyone who lives in the desert and spent any summer in a tin can RV knows how hard it is to keep these trailers cool. Tons of energy is wasted with 2 of those loud annoying inefficient ceiling ACs.
 
schmenkee said:
I live in a similar desert as you with unbearable 103 summers. I like taking my RV trailer out, but summers cut that short. I'm wondering how a 24k system with large ground array would work in an aluminum airstream trailer. Anyone who lives in the desert and spent any summer in a tin can RV knows how hard it is to keep these trailers cool. Tons of energy is wasted with 2 of those loud annoying inefficient ceiling ACs.
Click to expand...
How/what is the insulation in those trailers, and is there any way to improve it? Can you shade them?
 
It's a 1958 model so the mid-century fiberglass insulation is useless. Being that it's constructed of thousands of rivets that I'd have to drill out, I'm not quite ready to tear it apart to redo insulation anytime soon. Anything can be shaded, but we have high winds. Even harder to shade when camping out in the wilderness. Other's have converted their vintage trailers with 12k heat pumps, but they arent in the desert. Wondering if a modified ducted 24k would give it a boost.
 
schmenkee said:
It's a 1958 model so the mid-century fiberglass insulation is useless. Being that it's constructed of thousands of rivets that I'd have to drill out, I'm not quite ready to tear it apart to redo insulation anytime soon. Anything can be shaded, but we have high winds. Even harder to shade when camping out in the wilderness. Other's have converted their vintage trailers with 12k heat pumps, but they arent in the desert. Wondering if a modified ducted 24k would give it a boost.
Click to expand...
Can't get at the insulation from the inside? Just brainstorming, I know there are no good answers. Solar reflective paint? Ducted mini-split would probably be better than those roof-mount things, though just upgrading those to inverter style with modern SEER ratings might help?
 
AndreasPassat said:
Currently cooling 800sq ft which isn't much really but considering my roof is NOT insulated at the moment and I'm the lower AZ desert, anybody who knows the sun here is just downright brutal and it takes quite a bit to keep something cool.
Click to expand...
I am thinking about something this size for my garage. Thanks for the review, especially being from the same area I am in.

I'd be especially interested in the ACs kWh usage per day. On the worst days of the year in the Phoenix Valley, my 4 ton AC uses about 60-70 kWH of power. It runs at 4500 watts. Those numbers include both the AC on 240 volts and the blower at 120 volts. At least the mini-spit is just that.
schmenkee said:
like taking my RV trailer out, but summers cut that short. I'm wondering how a 24k system with large ground array would work in an aluminum airstream trailer. Anyone who lives in the desert and spent any summer in a tin can RV knows how hard it is to keep these trailers cool. Tons of energy is wasted with 2 of those loud annoying inefficient ceiling ACs.
Click to expand...
With RVng in the summer and living in the low desert in AZ, I have thought about a larger mini-slpit but decided against it. Too much effort and cost for me to be the first on my block to try this.

1) Any mini-split unit I've found for sale above 12k BTU is for split phase 240. Since most of what I do is boondocking, my inverter is a 3000 watt 120 volt single phase unit, so major mods would need to be done. For park camping, the park is likely wired for split phase 240, but my trailer is not. A sub panel could make it that way, but more than I want to do.

2) My camper has a 15k BTU and 13.5 k BTU, so I don't think the fifth wheel would be evenly cooled even if the BTUs would keep up. I'd actually need three or four heads to evenly cool the trailer.

3) On the fifth wheel, installation is a bit odd. I'm sure they exist, but I have not seen a whole trailer mini-spit installation for a still mobile fifth wheel.

4) The 24 k Minisplit still is less BTUs than 28.5 k BTU I have now. 28.5 k BTU will still take several hours to cool down a trailer that has been baking in the sun all day in storage or on the move. I don't want to go less BTU and hope it works out. Also, the smallest 120 volt mini-split I found was 12k BTU, so even just replacing that one AC is less BTUs than the 15k BTU I have now.
 
chrisski said:
I am thinking about something this size for my garage. Thanks for the review, especially being from the same area I am in.

I'd be especially interested in the ACs kWh usage per day. On the worst days of the year in the Phoenix Valley, my 4 ton AC uses about 60-70 kWH of power. It runs at 4500 watts. Those numbers include both the AC on 240 volts and the blower at 120 volts. At least the mini-spit is just that.

With RVng in the summer and living in the low desert in AZ, I have thought about a larger mini-slpit but decided against it. Too much effort and cost for me to be the first on my block to try this.

1) Any mini-split unit I've found for sale above 12k BTU is for split phase 240. Since most of what I do is boondocking, my inverter is a 3000 watt 120 volt single phase unit, so major mods would need to be done. For park camping, the park is likely wired for split phase 240, but my trailer is not. A sub panel could make it that way, but more than I want to do.

2) My camper has a 15k BTU and 13.5 k BTU, so I don't think the fifth wheel would be evenly cooled even if the BTUs would keep up. I'd actually need three or four heads to evenly cool the trailer.

3) On the fifth wheel, installation is a bit odd. I'm sure they exist, but I have not seen a whole trailer mini-spit installation for a still mobile fifth wheel.

4) The 24 k Minisplit still is less BTUs than 28.5 k BTU I have now. 28.5 k BTU will still take several hours to cool down a trailer that has been baking in the sun all day in storage or on the move. I don't want to go less BTU and hope it works out. Also, the smallest 120 volt mini-split I found was 12k BTU, so even just replacing that one AC is less BTUs than the 15k BTU I have now.
Click to expand...
Yes, I'd hate to be the first one on the block experimenting on my RV. But I believe there is promise with these solar units and way better than rooftop ACs.

I think I would have to add a dedicated 220v line and convert to 50amps just to run the 24k. (I do not know how to just yet)

Also having enough rooftop space for panels is another factor.

Instead of using the typical mini-split wall-mounted air handler, they sell "ducted" air handler units that can attach to smaller 3 inch vents. Since it's not wall-mounted, the unit can be concealed much better. If you are handy or creative you can run small ducts throughout the 5 wheel trailer so it cools a bit more evenly. (this is all in theory of course)

Here's an example of a non-connected "ducted" unit connected to solar at the 30 second mark.
 
wpns said:
Can't get at the insulation from the inside? Just brainstorming, I know there are no good answers. Solar reflective paint? Ducted mini-split would probably be better than those roof-mount things, though just upgrading those to inverter style with modern SEER ratings might help?
Click to expand...
One day I will renovate and replace the nonworking insulation, but these old beauties are aluminum on the inside as well and have hundreds of rivets to drill out. Not for the faint of heart. Marriages have broken up renovating airstreams. They are that hard!

Just looking for options for the next 5 years before I embark on a pricey frame-off restoration.

Another idea is to shade the trailer with a shade shelter cloth called Aluminet. Its made of aluminum mesh netting that more reflective than tarps yet breathable, see through and doesnt catch the wind like shade sails do. It's also what Burning Man festival attendees use during their week long festive in the summer desert heat in their tents and RVs.
 
wpns said:
Thanks, but I’m looking specifically for information on humidity control. I have a concrete house, so insulation value is low and thermal mass is high, and my primary interest is understanding humidity control versus temperature reduction.
Click to expand...

I'm sorry I don't have any info on that part of the equation.
I'm in pretty good with the HVAC company that services all the building s where I work. I can prod one those guys for some info.
 
@schmenkee
@chrisski

I hear you about the RV situation. Completely understand your plight.

My wife and I purchased a 1989 Bounder - solely purchased to live in during construction.
Up until late last year we were in the RV for 2 years. There were times when we'd come home after work and the RV would be above 140° inside.
Absolutely brutal! The roof top units would take hours just to get it down to 100°.
We were using (2) Honda generators (eu2200i and the eu2200i companion daisy chained) for all of our power during that time.
The generators were right at the cusp at all times and man did we burn through the fuel. To the tune of around $35 per day.

I even tried to incorporate a Renogy system to aid in power production. That system lasted a whopping 3 days before everything went up in smoke just from the heat of the sun here in the desert.

As you guys know, the heat inside of an RV, new or old is something quite difficult to deal with.

I've seen a number of RV's running around the Phoenix area where people actually mount a mini split on the back of the RV.
You could power the EG4 24k BTU mini split with solar panels only but it requires around 3200 watts of power. Not easily done if you want to stay portable. You'd basically would have to build an off-grid power system into the RV to run A mini-split big enough to satisfy your needs.

You got those YouTubers out there with seemingly endless supplies of cash building such systems into their RV, but for the common man, I just don't think it's a practical (money wise) solution.

The good thing is, this unit only pulls 10 amps (maximum on each 120 volt leg) so if hooking up to shore power, you could get away with just a 30amp connection if manage your electric use wisely.
 
AndreasPassat said:
You could power the EG4 24k BTU mini split with solar panels only but it requires around 3200 watts of power. Not easily done if you want to stay portable. You'd basically would have to build an off-grid power system into the RV to run A mini-split big enough to satisfy your needs.

You got those YouTubers out there with seemingly endless supplies of cash building such systems into their RV, but for the common man, I just don't think it's a practical (money wise) solution.

The good thing is, this unit only pulls 10 amps (maximum on each 120 volt leg) so if hooking up to shore power, you could get away with just a 30amp connection if manage your electric use wisely.
Click to expand...
THESE ARE THE ANSWERS I'M LOOKING FOR!!! Thank you so much.

3200 watts? Is that to compensate for cloudy days?

In addition to my 30 amp shore power line, I'm wondering if I should just install another independent 220v plug that connects to shore power to bypass my original wiring. This way, rather than retrofitting my 30 amp and converting to 50 amp, I keep things intact.
 
Plum Crazy Rob said:
Short answer, yes - particularly if you have no grid input. Longer answer, I have seen max of 2700W on HEAT and 2200W on COOL over my 18 months with a 24k.
Click to expand...
Thanks. Would that apply to desert environments where it rains 10 days out of the year with 350-355 days of sunshine?
 
schmenkee said:
Thanks. Would that apply to desert environments where it rains 10 days out of the year with 350-355 days of sunshine?
Click to expand...
It applied between -3F and 112F (with a heat index of 126). I checked that day, and while it was 120F in Phoenix, heat index was only 115!! It WAS a dry heat :ROFLMAO:

According to Specs, it appears "somewhat" more efficient on Cooling, but in reality I find it significantly more efficient.

Edit: Vegas?? Drive over to Airspool and chat with him. Same units...
 
schmenkee said:
THESE ARE THE ANSWERS I'M LOOKING FOR!!! Thank you so much.

3200 watts? Is that to compensate for cloudy days?

In addition to my 30 amp shore power line, I'm wondering if I should just install another independent 220v plug that connects to shore power to bypass my original wiring. This way, rather than retrofitting my 30 amp and converting to 50 amp, I keep things intact.
Click to expand...

Have to admit I didn't even consider that myself.

Yeah, installing a separate 220v plug just for the ac could certainly be a solution. Probably the easiest most economical way to go and you don't compromise the existing electrical system in any way.

I'm not a RV'er type of person. Do they have multiple outlets per site at campgrounds or RV parks?


As far as the 3200watts, that's the recommended solar power requirement to supply the mini split with enough power to run at maximum load / output.
Being cloudy or not has nothing to do with the 3200 watts of power.
However, if powered by solar only, if it does get cloudy, it will cause the unit to run at a lower output.
The 24k BTU mini split requires a minimum 90volts DC to get it to turn on and make it run.
When I first tried solar only, if I remember correctly the minimum was around 94volts before the unit actually "turned on".
 
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