Community Forums

Pavetack · 02-07-2021, 10:12 AM

For those with a 40' do you find that two 15K air conditioners are adequate in 90+ degrees? We are leaning toward a 40' but third AC in the 43' is very appealing.

zzotte · 02-07-2021, 11:05 AM

Quote:

Originally Posted by Pavetack

For those with a 40' do you find that two 15K air conditioners are adequate in 90+ degrees? We are leaning toward a 40' but third AC in the 43' is very appealing.

I find that my two 15 works well in hot weather, but you need to know when to start cooling, if you fall behind you done ( we like the cool nights so we turn off the AC) also for long periods of over 90 I don’t think it can cut, I wish I could have three on my 40’

Zzotte

**pasdad1** · 02-07-2021, 11:13 AM

I almost never use all three in my 43’

I really wanted three however for the redundancy. If you only have two, and lose one, you are in trouble.

wjohnson913 · 02-07-2021, 11:13 AM

I have a forty foot coach with 3 units. Most of the time 2 would be adequate but in extreme temps 3 is the way to go.

Capt. Bill · 02-07-2021, 11:35 AM

Quote:

Originally Posted by Pavetack

For those with a 40' do you find that two 15K air conditioners are adequate in 90+ degrees? We are leaning toward a 40' but third AC in the 43' is very appealing.

85-90% of the time you will probably be ok with 2 A/C units. However, if you get into some really hot weather- 90+ with the coach in the direct sun, you'll wish & need 3 units. Remember- 3 X 15,000 Btu each = 45,000 Btu divided by 24,000 Btu/ton = 1.875 ton of A/C. That's just a little above adequate for ~ 640 sq.ft & 4,480 cubic feet of air in high temperature - direct sunlight conditions in a minimally insulated structure.

Be safe & go with 3 units- you won't regret it!

Happy Trails

Dutch Star Don · 02-07-2021, 11:44 AM

This is one of my pet peeves with Newmar and their two A/C policy! I would like to make the executives hold a four hour meeting inside a 40' coach in 105 degree weather. I think they might change their mind about what's needed. The Allegro Bus has three A/C's!

Out west and especially on a travel day, two A/C's will struggle to get the coach down to high 70's. My two A/C's only work when we're parked, have everything closed up and start them early in the morning. If it's over 100, you'll only stay cool if you don't move around inside the coach.

Now before someone says theirs works great, you need to know what they think is great. To me, great would the ability to get the coach down to 70-71 degrees in about an hour at any time in the day. A temp that makes my wife put her sweatshirt on would also be acceptable.

I'm guessing those that have three A/C's and say they can get by with two most of the time, have the ability to run all three until the coach is cooled down and switch to just two, or maybe only have two cycling on at once.

Think about it.....the 43' coaches are only 3' longer, yet are getting 50% more air conditioner size. If the 40's don't need three A/C's, why does the 40' Mountain Air come with three A/C's.

One of the issues, is that a larger generator is technically needed to run three A/C's. I would have been willing to acknowledge or sign a waiver that they would install three A/C's on a 40' with an 8K generator and only wire two A/C's to the generator. This could easily be a build special. sometimes they can't get out of their own way to resolve an issue.

Okay....did that sound like a rant??

vito.a · 02-07-2021, 04:01 PM

I agree with Don. Three 15K BTU A/C's are necessary in the southwest. Our coach is 42' and we can get by on two if the temp is 90 or below, the humidity is low, and we are parked in the shade. If any of the parameters are above that, we use all three.

The worst situation is to be traveling in 110 degree heat with bright sunlight and then arrive at an RV campground in the afternoon. The big engine has heated up the bedroom and the big windshield heats up the front area. It takes all three A/C units to cool down and even then it will not get nice until dark.

A side note to the OP. I used to fly with Pave Tack back in the day. We (F-111) were the only ones that could self designate.

Ken C · 02-07-2021, 06:08 PM

Don is spot on. I have mentioned before I tried to get Newmar to install a 3rd A/C as a special, but no go. We spend a fair amount of time in the So Ca desert and 2 15K units are not adequate when temps exceed 100. Labor day weekend last year reached 118 for 2 days. Coach facing north so no sun on the windshield, Magna shades on drivers and Passenger side windows, window and Girard Nova awnings deployed. The temps inside reached 88 with both A/Cs running constantly.

While I agree Newmar insulation is better than most, 2 A/Cs are not adequate for a 40' coach if your spend any amount of time where temperatures exceed 100 degrees

saddlesore · 02-07-2021, 06:24 PM

Go with 3..

GWBGE · 02-07-2021, 06:38 PM

If you spend time in the south in the Summer, there is no such thing as too much A/C.

mbrooking · 02-07-2021, 07:19 PM

Three AC's is one of the reasons we went with the Mountain Aire 4018 over the Dutch Star 4018...

**Lt Dan** · 02-07-2021, 07:35 PM

Have had a 39' coach with two and now a 40 Phaeton with three (standard on the 40 Phaeton). Like said, most of the time two is adequate but on an extremely hot day the third is nice to keep the others from running full time. And it's nice to have the third for a backup in case you lose one.

JFXG · 02-16-2021, 10:21 PM

I’m always puzzled by these threads. I have noticed, though, that a number of those who decry the use of only two a/c units on a 40 ft coach seem to imply by some remark or other that they actually turn the system off at night, or don’t keep the units running while traveling, or some other operating method that allows the coach to become heat soaked. And then express disdain when it takes the system several hours to expel all that heat and humidity that they themselves let in!
It is far, far easier to KEEP the coach cool than it is to MAKE the coach cool. If you’re in a hot place, or heading for one, turn the system on and let it run!
I mentioned my puzzlement (above) because we only have two units in our 02 DS, but we stayed the last two summers in central Texas, with damn near every day from mid May to mid-Sept over 95*, and the majority of them over 100*. Thermostats set at 70 and the system never got shut off. Just the normal cycling, and we were nice and comfy, temp held at 70-72 by my infrared gun. Ceiling temp near the return register was ~79*, and the output air temp was ~ 50-53*. Is it possible the older Newmar’s were better insulated than the new?

Dutchstar411 · 02-19-2021, 05:59 AM

Unfortunately, in my 2002 Dutch Star with two 15,000 BTU Penguins and with all windows blocked from the sun, especially the windshield, in 95 degree Temps that coach would never hold 72 degrees. If the air return is 79 then the air in the coach overall is 79 degrees. It might show cooler near the cold air ducts of course, but the body of the coach using temp gun showed otherwise. We live in Florida and early morning or later in the day when the sun went down would be the only time we'd see steady mid 70 Temps.

Also ac's are on 100 percent of the time, from when we startup the coach until we park it when we're done with our trip and back home. Coach came with 13,5's but I changed them both out with the 15's.