How come there are no high SEER RV air conditioners?

[Luke Johnson]

My Dometic AC is acting up again. This time I want to replace it but cannot bring myself to replace it with another 10 SEER unit. There is a nice unit that claims a whopping 20% increase in efficiency (https://www.upfittersresource.com/co...-benz-sprinter) but I really am looking for 20+ SEER that can more than double the cooling power for the same energy. They are readily available for home use and with so many people solarizing their RV rig, I would think there was a high demand there. Been searching and as far as I can tell you simply cannot buy a high efficiency AC unit for an RV for any money. I have a nice solar setup and a high SEER AC unit would enable me to boondock in my airstream in the middle of Arizona summers with AC comfort. I would pay a lot for that! I suspect I am not alone. Build it, we will come!

[Bubba L]

Luke, do manufacturers even make a high seer HVAC unit that’s not 220vac? I know in the mini splits the higher seer units are 220. Our 55 mini split is 12k BTU. With a lot of heat transfer I would over compensate with a high BTU. Good luck

[ITSNO60]

Boondocking in the Arizona desert makes you the perfect candidate for a 12 volt roof top evaporative cooler. I've had 2 of these in the past, they work great. Low water and power usage and enough CFM to really cool things. Fits right on an existing hatch. https://www.turbokool.net/

[88Limited]

HVAC tech here...

The reason you won't see the 20+ SEER rated units is likely package size. The higher the SEER rating, generally speaking for non-mini split units, the more surface area the condenser coil and evap coil need (along with other things).

Mini split units can hit the higher SEER rating as the outdoor unit and indoor unit are variable speed and communicate. As the load increases/decreases the compressor and indoor blower will ramp up/down to meet the load.

I've been waiting and looking to replace the 20yr old R-22 unit on our AS, but won't until they come out with a mini-split type (variable speed) unit. I can keep this one running until then.

Along with the one you posted, there's also this one (I think they're the same unit): https://www.recpro.com/rv-air-condit...te-non-ducted/. The unit may be a multi-stage unit, but their marketing info doesn't come right out and talk about multiple speeds and I can't find any of the tech/repair documents for it. It does list having a PTC Soft Start Technology - but that tech has been around a loooong time and is not a soft start. The best explanation I can give is here: https://hvacrschool.com/this-is-not-a-soft-start/.

[jcanavera]

I think part of this is the size of the units. After living in the same home for 35 years, I am currently on my 3rd A/C unit. I've always gone with the higher SEER outdoor units and I started with a SEER 10 back in 1982. The standard at that time was SEER 8. The second unit was a SEER 12 and my current is a 14. Most likely the next one will be a 16.

The current home unit I'm using now uses a scroll compressor and the entire outside unit is using about 20 amps of power. It is interesting that the 15K unit on my 2004 Classic is using between 18-20 amps of power.

What I have noticed in my home units is the size of them. As the efficiency has gone up so has the size of the cabinets. My current Trane is twice the height of my original Trane. All that size is in the coils, and other than compressor technology it seems that if you can provide more coils you can expel more heat to the outdoors. I use single stage units so my compressor and fan run the same speed all the time. So my SEER rating for all intents was not affected by the multiple fan and compressor speeds available on the high end units. With an RV that profile is important and with the minimal coil exposure you can't be as efficient as a home unit.

The other issue is demand, and as long as the cost of electric is bundled into a campsite rental, folks just aren't interested in energy savings unless they are boon docking. It always burns my craw to see the folks who are running both air conditioners with their doors and windows open. In many cases we are subsidizing those folks in the cost of our campground sites.

Jack

[88Limited]

Originally Posted by jcanavera

I
What I have noticed in my home units is the size of them. As the efficiency has gone up so has the size of the cabinets.

Yep, that's one of the more cost effective ways of meeting the SEER requirement. Once coil size maxes out, it's multi-stage/variable speed fan motors and compressors.

[MTDSilver71]

I too have been searching high and low for something other than the standard rooftop units. I have decided to go the route that Bubba and others have done with a mini split. There is a LG unit (LSU120HXV2) that is a 12k BTU that runs on 115v that is relatively small. I believe it is around 19 SEER. It is a wall mount air handler, which I am not a huge fan of the look of it, however, Bubba has repurposed his into a ducted system, which I may end up trying. Many mini splits can be used with ceiling cartridges (around 2’ x 2’) but all that I can find are 230v units. My HVAC guy is currently searching his suppliers for a 115v ceiling cartridge setup. But he is doubtful. The ceiling mount way would also necessitate some fancy shroud work on the roof.

I agree that this would be in high demand for all brands of campers if one company could be convinced to create that setup.

Keep us posted if you find something and I’ll do the same😃

Ted

[uncle_bob]

Hi

Part of this will always get around to "what would you pay?". I suspect a limited number of folks would pay 10X to hit 20. Making a business around those 8 to 10 people likely isn't going to work. Toss in a non-standard ( = much larger) size and weight, the cost of the unit may only be a fraction of what's needed to install it.

If you look at what people buy, the RV market is very much cost driven. Finding "upgrade" anything for an RV is problematic. The market is simply to small.

Bob

[switz]

Just installing American Standard (same production line as Trane) 5 and 2 ton units at the home. Condensor cabinets are much larger both in diameter and height that the ten year old units. The motors in the confessors and air handlers are all DC and are synched for speed. We went with heat pumps to get rid of the gas furnaces in the attic.

I would suggest serious attention to servicing the inside air filters and cleaning the cooling fins on the outside to get the maximum performance out of the still used 90s designs for roof top RV units. Lots of dust and bug guts can accumulate in those cooling fins...

With our 600 amp hour lithium battery, we can stop for lunch and run the one A/C from the battery for 30 minutes. Takes the rest of the day for the nine 100 watt solar panels to replenish the battery.

Maybe the future battery technology will be able to power an AC unit for longer, but the recharge is still an issue. No free lunch.

[mtbmitch]

Originally Posted by ITSNO60

Boondocking in the Arizona desert makes you the perfect candidate for a 12 volt roof top evaporative cooler. I've had 2 of these in the past, they work great. Low water and power usage and enough CFM to really cool things. Fits right on an existing hatch. https://www.turbokool.net/

How much water do they use if you have the turbokool on medium for 8 hours?

[ITSNO60]

Originally Posted by mtbmitch

How much water do they use if you have the turbokool on medium for 8 hours?

It's been a few years but we used to leave the TurboKool on all day in my Lance camper while we were out on Apache Lake and my water supply was a 3 gallon bug sprayer, it never went dry as long as we were sitting still. If we were driving it used a lot more which I suspect was splash, or forced air coming in I don't know which, I just know that sitting still was amazingly efficient. Keep in mind an evaporative cooler will use more water in dryer air as the water evaporates faster which is where you get the cooling. The air at Apache Lake was dry desert air most likely single digit humidity.

[MTDSilver71]

Originally Posted by uncle_bob

Hi

Part of this will always get around to "what would you pay?". I suspect a limited number of folks would pay 10X to hit 20. Making a business around those 8 to 10 people likely isn't going to work. Toss in a non-standard ( = much larger) size and weight, the cost of the unit may only be a fraction of what's needed to install it.

If you look at what people buy, the RV market is very much cost driven. Finding "upgrade" anything for an RV is problematic. The market is simply to small.

Bob

Hi Bob
I thought much the same thing initially but have since learned I was wrong regarding the pricing and weight issues. It definitely is a larger opening for a mini split ceiling cassette (23 x 23 versus 15 x 15) but this can easily be spec’d out during the build. And I think that one outdoor compressor unit can run two interior air handlers, even bringing the overall weight down further. Check out these specs I quickly looked up:

LG mini split. Cool and heat
97 lb total weight (both pieces included)
Approximately $900.00 - 1000
44 db max interior level
12k btu. 19 seer

Atwood 15k btu w/ heat pump
88 lb total weight
Approximately $1500 - $1600
66 db max interior level
Unknown SEER

Coleman Mach 8 w/ heater
90 lbs (one site says 109lbs)
Approximately $1100
13.5k btu. Unknown SEER
Cannot find published DB

My thoughts are that the industry would profit greatly with the use of a mini split unit versus the older style ac. Much more efficient and quieter to boot. Now that is music to my ears!

Sometimes I think it is just a ‘fear of the unknown’ for the manufacturers that drives them to continue with the ‘if it’s not broke’ attitude. Hopefully we’ll see some change here soon.

Ted

[uncle_bob]

Originally Posted by MTDSilver71

Hi Bob
I thought much the same thing initially but have since learned I was wrong regarding the pricing and weight issues. It definitely is a larger opening for a mini split ceiling cassette (23 x 23 versus 15 x 15) but this can easily be spec’d out during the build. And I think that one outdoor compressor unit can run two interior air handlers, even bringing the overall weight down further. Check out these specs I quickly looked up:

LG mini split. Cool and heat
97 lb total weight (both pieces included)
Approximately $900.00 - 1000
44 db max interior level
12k btu. 19 seer

Atwood 15k btu w/ heat pump
88 lb total weight
Approximately $1500 - $1600
66 db max interior level
Unknown SEER

Coleman Mach 8 w/ heater
90 lbs (one site says 109lbs)
Approximately $1100
13.5k btu. Unknown SEER
Cannot find published DB

My thoughts are that the industry would profit greatly with the use of a mini split unit versus the older style ac. Much more efficient and quieter to boot. Now that is music to my ears!

Sometimes I think it is just a ‘fear of the unknown’ for the manufacturers that drives them to continue with the ‘if it’s not broke’ attitude. Hopefully we’ll see some change here soon.

Ted

Hi

A mini split is not going to drop into the existing structure on a trailer. You will need a very different design to accommodate it.... Since a big part of their efficiency gain is from the "split" they do need to be done properly to get the published numbers.

Bob

[Bubba L]

Ted, I agree that the mini split technology will be designed into future RVs. And I also think that as long as people are buying RVs knowing the HVAC systems perform with minimum efficiency in certain situations, manufacturers will continue to install the rooftop units. I don’t believe it would take much engineering effort to design a mini split for an RV. We’ll see what technology and profits hold for the future.

[MTDSilver71]

I would hope, Bubba, that this change won’t take too many years. I argue for it, not just for the efficiency but because I am partially deaf and the quieter system is a Godsend! I am sure that many would benefit from a quieter world.

Ted

[TouringDan]

Originally Posted by uncle_bob

Hi



A mini split is not going to drop into the existing structure on a trailer. You will need a very different design to accommodate it.... Since a big part of their efficiency gain is from the "split" they do need to be done properly to get the published numbers.



Bob

Bob



I don’t believe the changes to install a mini split are all that major. I am installing one on our son’s and dil’s 78 Caravanner in Texas. The compressor is essentially the same size as 2 30 Lb propane tanks and there will still be room for a 10 Lb horizontal propane tank behind the compressor. 10 Lb of propane will be adequate as it will only be needed for cooking and hot water. They are installing a compressor fridge and the 12k mini split should provide adequate heat.



For the air handler, you loose a wall cabinet and the 8x12x32 air handler is installed in front of that cabinet. It will just take some getting used to it being there.



I am installing a Cooper and Hunter Sophia model 12k unit. The specifications are impressive:



- 21.5 SEER

- 36 dB noise level inside

- provides 12k heat down to -13F.

- maximum electrical consumption of 1,120 watts

- very low start up current.



I believe this is definitely the future HVAC for RV’s.



Dan

[Luke Johnson]

Originally Posted by Bubba L

Luke, do manufacturers even make a high seer HVAC unit that’s not 220vac? I know in the mini splits the higher seer units are 220. Our 55 mini split is 12k BTU. With a lot of heat transfer I would over compensate with a high BTU. Good luck

They do. I have a 120V 12000 BTU split unit in service on my shed right now.

[Luke Johnson]

Originally Posted by switz

Just installing American Standard (same production line as Trane) 5 and 2 ton units at the home. Condensor cabinets are much larger both in diameter and height that the ten year old units. The motors in the confessors and air handlers are all DC and are synched for speed. We went with heat pumps to get rid of the gas furnaces in the attic.

I would suggest serious attention to servicing the inside air filters and cleaning the cooling fins on the outside to get the maximum performance out of the still used 90s designs for roof top RV units. Lots of dust and bug guts can accumulate in those cooling fins...

With our 600 amp hour lithium battery, we can stop for lunch and run the one A/C from the battery for 30 minutes. Takes the rest of the day for the nine 100 watt solar panels to replenish the battery.

Maybe the future battery technology will be able to power an AC unit for longer, but the recharge is still an issue. No free lunch.

I have 4064 amp hours of battery and 10 250W panels which gets me through 3 days if parked in the shade. Could go longer but batteries are lead-acid and I don't discharging below 50% to extend their life. If I could cut the power demand of the ac by half I think I could get make it work (hence the thread).

[Luke Johnson]

Originally Posted by TouringDan

Bob



I don’t believe the changes to install a mini split are all that major. I am installing one on our son’s and dil’s 78 Caravanner in Texas. The compressor is essentially the same size as 2 30 Lb propane tanks and there will still be room for a 10 Lb horizontal propane tank behind the compressor. 10 Lb of propane will be adequate as it will only be needed for cooking and hot water. They are installing a compressor fridge and the 12k mini split should provide adequate heat.

Thanks for sharing. I was considering a similar arrangement but was not so optimistic on the reduced propane needs. The refrigerator in my airstream consumes 400W 24/7 when running on electricity so I use propane for that when boondocking to save the electricity for cooling. Maybe I should consider upgrading the fridge, too...

[uncle_bob]

Originally Posted by Luke Johnson

I have 4064 amp hours of battery and 10 250W panels which gets me through 3 days if parked in the shade. Could go longer but batteries are lead-acid and I don't discharging below 50% to extend their life. If I could cut the power demand of the ac by half I think I could get make it work (hence the thread).

Hi

Ok, 4064 AH of 12V lead acid batteries is roughly 40 100AH cells. Last time I picked one of those up it was a bit over 60 pounds. 400 of them gets you to 24,000 pounds. I don't have a trailer that will handle that sort of weight ....

Bob