Insulation of ac unit increases cooling?

[jsk]

I did not see the chosen pic. I may not have privileges yet. Sorry.

[Jopopsy]

Originally Posted by schrederman

Run the air for a few minutes and insulate the cold one...

Excellent idea. I will do this over the weekend as I get the rig ready to roll for our trip next week.

[Camper_bob]

Originally Posted by Campbellizer

snip...

I've also noticed that there is some leakage between the ducts and the ceiling around then vents. In other words, leaking back into the ceiling. So I used aluminum tape to seal up the area between the duck and the ceiling. The vents themselves have a round plastic piece that extends upward and is supposed to seal all that up. They do not seal completely and appear to block some of the airflow too (since some of mine were nearly touching the top of the duct). Two of my ducts had very little air flow coming out (with one of them being in the bedroom ). I snapped the round piece off of the vents and reinstalled them. I can definitely feel an increase in airflow from those two vents now.

...snip

How exactly did you seal the vent holes in the ceiling to the vent holes cut in the duct? I looked at mine yesterday and found some of the same issues you have (not a great seal, and the "sleeve" sticks up into the duct blocking flow), but I'm not quite sure how to solve them yet. I was thinking of removing the cylindrical sleeve and just running foil tape from the ceiling into the hole in the duct. That would seal off the attic space completely. But I'm afraid there won't be enough ceiling to get the tape good adhesion. And there would be nothing behind the tape to support it. There is no insulation around the vent holes. I guess I could put something there? And I guess my adhesion fears would be mitigated when I screw the vent "fascia" back up?

I also have a problem with my last frontward duct opening, in the "master" bedroom. My unit was originally equipped with "2nd AC Prep", so that duct goes on after that last opening in the bedroom. I assume this is to allow the second unit to be ducted into the existing duct work. I would like to temporarily close that off, but I don't quite know how. I was thinking I could tape a piece of cardboard up to block it off? Whatever I do, I want it to be easily removed as I am seriously considering putting in a second unit next year.

All this, and I haven't even approached insulating the outside of the unit ... yet. I have all the stuff to do it, and I'm hoping to get to it tonight, but so far it's not looking like I'll get to it. I also need to wash the coils up top, and wash the roof and inspect my seals. I've got A LOT of work to do!

[Levinehikeski]

Originally Posted by Campbellizer

Yes, I'd say you summed it up perfectly.

That actually is a pretty good upgrade. A/C giving you that much more of a difference in temperature (5-6 degrees) provides quite a bit more cooling. You probably gained the most by sealing the ductwork.

For a home (window) unit you would need to go to a much larger unit

[Camper_bob]

Originally Posted by Camper_bob

How exactly did you seal the vent holes in the ceiling to the vent holes cut in the duct? I looked at mine yesterday and found some of the same issues you have (not a great seal, and the "sleeve" sticks up into the duct blocking flow), but I'm not quite sure how to solve them yet. I was thinking of removing the cylindrical sleeve and just running foil tape from the ceiling into the hole in the duct. That would seal off the attic space completely. But I'm afraid there won't be enough ceiling to get the tape good adhesion. And there would be nothing behind the tape to support it. There is no insulation around the vent holes. I guess I could put something there? And I guess my adhesion fears would be mitigated when I screw the vent "fascia" back up?

I also have a problem with my last frontward duct opening, in the "master" bedroom. My unit was originally equipped with "2nd AC Prep", so that duct goes on after that last opening in the bedroom. I assume this is to allow the second unit to be ducted into the existing duct work. I would like to temporarily close that off, but I don't quite know how. I was thinking I could tape a piece of cardboard up to block it off? Whatever I do, I want it to be easily removed as I am seriously considering putting in a second unit next year.

All this, and I haven't even approached insulating the outside of the unit ... yet. I have all the stuff to do it, and I'm hoping to get to it tonight, but so far it's not looking like I'll get to it. I also need to wash the coils up top, and wash the roof and inspect my seals. I've got A LOT of work to do!

So last night I gave it a go, and it worked out just fine. I just tore off a bunch of 3" strips of foil tape and ran it from the inside of the duct opening to the outside of the ceiling opening. I stuck the tape to the ceiling such that it did not protrude from the trim of the vent and is thus hidden.

Result was great. Those sleeves were sticking up about 1/2" into the duct work, and now without them, the air flow is much smoother and higher in perceived volume (?).

I was only able to seal off 2 of my 4 vents last night. If I don't get to finish the other two tonight, I'll get to them this weekend.

Now all that's left is to seal off the "dead end" past the master vent, and get up on the roof to clean the coils and insulate the box.

Then I'll be confident I've done just about everything I can do to help my current system along, and it's on to insulating the other areas of the trailer...

[Griswald One]

We are getting the first real test of our newly insulated A/C unit. I can only report on comfort level because the reading on the thermostat continues to be completely useless. This is day four down here and temps have reached as high as 100 degrees and we are in full sun. The A/C has functioned well with no evidence of freezing up. I have also noticed a distinct lack of condensation on the interior cowl which was previously an issue for us. The temperatures inside have been consistently cool. The thermostat has read as high as 85 but my bride and I agree that the true temperatures have been in the mid 70's... I am currently feeling very cool in shorts and a t-shirt and it is just past noon.

We did discover that using the direct flow vents instead of the ceiling conduit was far more efficient and actually kept the entire RV much cooler. With the direct flow vents open my plan is to try it out with only the ceiling vents over the bunk and the master bed open tonight and see if that keeps us all comfortable.

[Campbellizer]

That's exactly what I did Bob. Just used 3" foil tape to seal up between the ceiling and the duct. I cut slits in the tape every inch or so I could fold it down onto the duct and ceiling without it pulling up. Like you said, without the rings attached, there was a noticeable increase in airflow out of the vents afterwards. One thing I don't like is you can see the foil if you look up into the ceiling vents now. Nobody else notices it, but I do. I will probably go back and paint the foil off white at some point.

For what its worth, in the daytime, I leave the ducted ceiling vents and the direct flow vents open. And, I also close the bedroom doors. At night, I close off all of the ducted ceiling vents except for the one in the bedroom. That seems to work for best for us.

[Sunflake]

I can only imagine how much better things would work if everyone sprayed out the condenser coil!!!!! The one on the outside.

[Dustdevil]

Just did the Reflectix wrap on the cold air boxes on both of my AC units on the Seneca. Remains to be seen how that works out. Also wrapped the suction lines on both. We're headed toward 110-112 degree humid heat for a few days soon, and I wanted to be prepared. The remainder of the Reflectix roll I bought at Lowe's I used to make window covers for the windows that weren't already sized up for it. We'll need to cover all the windows in that sort of heat. Used that method in my old toy hauler, and it worked well. That unit didn't have as good an insulation as the Seneca either. Aluminum siding, loosely hung fiberglass insulation and wood studs in the walls was the standard construction in that thing. Held up well, but I'm sure the AC was working overtime to keep up.

[Camper_bob]

Originally Posted by Sunflake

I can only imagine how much better things would work if everyone sprayed out the condenser coil!!!!! The one on the outside.

Doing it tonight if it's not raining. Some time this week for sure.

[Dustdevil]

OK, so a trip report on the AC insulation issue. We cut our trip short. Not because of anything with the AC or the motorhome. But because there were no darn birds in Blythe. But I digress.

As it turns out, the AC insulation trick was awesome! We landed in Blythe on Wednesday in the heat of the day, about 109 degrees with moderate humidity. Had started the AC earlier on the road by running the genset, but it was still about 88 degrees in there. When we parked, we plugged in, and the temp gradually decreased about maybe 6 degrees an hour inside until it met the preset of 75 on the thermostats. Both AC running, with the rear AC blowing forward. Front AC unit is ducted throughout the coach body. So, in a few hours, it was very cool, and the sun was going down. AC actually cycled at night. Just left it on early yesterday as we left the campground. It stayed cool the entire time. Yesterday was projected to be hotter than Wednesday, but the morning actually felt cooler (maybe only 102 or so). But so far, my assessment is that the insulation worked like a champ in very high temps. Most of the motorhome was in direct sun. We did have reflectix covers on all windows except one, including the cab side windows and windshield. That helps tremendously.

This was a great mod to do, and it makes the AC system work less to keep up with the heat. It's a fair amount of work if you want to do it right, but very much worth the effort, and the $25 expense.

[Jopopsy]

Originally Posted by Camper_bob

How exactly did you seal the vent holes in the ceiling to the vent holes cut in the duct? I looked at mine yesterday and found some of the same issues you have (not a great seal, and the "sleeve" sticks up into the duct blocking flow), but I'm not quite sure how to solve them yet. I was thinking of removing the cylindrical sleeve and just running foil tape from the ceiling into the hole in the duct. That would seal off the attic space completely. But I'm afraid there won't be enough ceiling to get the tape good adhesion. And there would be nothing behind the tape to support it. There is no insulation around the vent holes. I guess I could put something there? And I guess my adhesion fears would be mitigated when I screw the vent "fascia" back up?

How are you guys removing the little louver circular vent piece from the ceiling to even see inside? I'd like to take mine apart to see if I can tighten it up too.

[Bassdogs]

This thread is starting to sound like the governments justification for "climate change". So far several people have done the mod and only a couple have given the AC a hard test since it was installed. There reports range from seems to have helped to a definite helped a lot. Even the helped a lot said it took the AC running for a while via the onboard genny and then several hours to get the coach down to to 74. Since all of this completely lacks any scientific proof all we have is speculation or I think it did. What I would like to hear is something like a previous experience in similar temps to the after the mod results. Something like 4 hours to get to set point vs 6 or more hours.

No offense but RV'ers are pretty much always looking for ways to help with cronic issues but this one still sounds like "its pretty easy and low cost to do so why not give it a shot".

[Dustdevil]

Originally Posted by Bassdogs

This thread is starting to sound like the governments justification for "climate change". So far several people have done the mod and only a couple have given the AC a hard test since it was installed. There reports range from seems to have helped to a definite helped a lot. Even the helped a lot said it took the AC running for a while via the onboard genny and then several hours to get the coach down to to 74. Since all of this completely lacks any scientific proof all we have is speculation or I think it did. What I would like to hear is something like a previous experience in similar temps to the after the mod results. Something like 4 hours to get to set point vs 6 or more hours.

No offense but RV'ers are pretty much always looking for ways to help with cronic issues but this one still sounds like "its pretty easy and low cost to do so why not give it a shot".

I don't have a previous trip into 109 degree temps to compare to, but I do have a previous experience to use as something of a comparison. In temps of around 92 degrees, the front AC, which is ducted to the entire coach, was not able to reduce the temps more than about 2 degrees in two hours, despite about half the windows (all the large ones) covered with reflectix.

So, do I have an identical experience to compare in a fully scientific test? No. Do I realize this is a fairly dramatic improvement? Yes, I think that's what I'm conveying. Doesn't mean everyone's results will be the same. Depends heavily upon the ducting itself (the ducting in the older Senecas is constructed in the "attic", and has its own internal factory-included insulation setup on the inside of the ducts. It also depends upon whether the AC system(s) itself is adequately sized. In our case, it's a 34 ft unit with one 15k and one 13.5k system on the roof, which requires a 50 amp connection (or the genset, which is adequately sized to run both under most conditions).

I think for those who are venturing into temps of high-90s, and expecting the system with these mods to get them down to the 70's internal temp range, this mod will not only help make that possible, but will likely result in the compressor not having to run continuously. These are temps of 109, which most people will never see, and with the coach almost entirely in direct sunlight.

Personally, my past experience is with a trailer with aluminum siding (transfers far more heat than fiberglass) and loose fiberglass batting (vs the styrofoam and vacuum bonded construction that Jayco uses on these units). That single 13.5K AC unit was adequate, but required about half a day to eventually bring down temps, and ran continuously.

Each system is different in various models of RV. I think everything we can do to improve cooling and insulate hot from cold is a help with these units, regardless. So, everyone who has different Jayco models and years will likely experience different results. I think it also depends very heavily upon how clean the coils are in the condenser coil. Mine were pretty clean, so I didn't bother to hose them out. Your results may vary.

[Bassdogs]

MY 2014 W Hawk is sitting in my back yard in direct sun. Have used 2 times recently when kids visited and the wife and I moved to the RV. With temps 95 and total direct sun, I ventilated the TT for about an hour using the roof mounted fantastic fan and a couple windows opened about 6 inches in the main cabin. After an hour I fired up the 15k AC unit and set the digital tstat to 76. I started all this at about 3pm with the AC coming on around 4pm with outside temps still in mid 90's. At 6:30 I took went out to set the DVR to record a couple thing that evening and the unit had cycled off after meeting the 76 degree set point. Actual AC run time 2 1/2 hours and don't really know when it cycled off. At that point I lowered the set point to 73 for the night.

I have not tried the instillation mod so can't say if it would help, but 2 1/2 hours plus an hour of venting to suck out the 100 degree temp inside the closed up TT is pretty darn good that would not justify this mod for me.

[Dustdevil]

Originally Posted by Bassdogs

MY 2014 W Hawk is sitting in my back yard in direct sun. Have used 2 times recently when kids visited and the wife and I moved to the RV. With temps 95 and total direct sun, I ventilated the TT for about an hour using the roof mounted fantastic fan and a couple windows opened about 6 inches in the main cabin. After an hour I fired up the 15k AC unit and set the digital tstat to 76. I started all this at about 3pm with the AC coming on around 4pm with outside temps still in mid 90's. At 6:30 I took went out to set the DVR to record a couple thing that evening and the unit had cycled off after meeting the 76 degree set point. Actual AC run time 2 1/2 hours and don't really know when it cycled off. At that point I lowered the set point to 73 for the night.

I have not tried the instillation mod so can't say if it would help, but 2 1/2 hours plus an hour of venting to suck out the 100 degree temp inside the closed up TT is pretty darn good that would not justify this mod for me.

One good thing about living in a free country is that each can decide for themselves.

[PR Travelers]

This is what I did to mine. I was surprised at how shallow the duct is in the ceiling.

[Dustdevil]

Originally Posted by PR Travelers

This is what I did to mine. I was surprised at how shallow the duct is in the ceiling.

The ducts in my Seneca are fairly shallow also. The difference is that in the Seneca, there is no space or air gap between the hole in the ceiling panel and the hole in the duct. It's just as if they are the same panel. No tape is required.

[Dustdevil]

Originally Posted by Jopopsy

How are you guys removing the little louver circular vent piece from the ceiling to even see inside? I'd like to take mine apart to see if I can tighten it up too.

Not sure what you are referring to. IF it's the outside, the cover over the AC is held on with three screws. In the rear unit, the round louvered cover is taken off first, then the main cover can be removed also, by lifting straight up. Front AC has a similar overall look, it's louvered cover is largely a part of the rest of the A/C cover.

If it's the inside, then my covers are rectangular, with a thin open cell foam material inside as a filter. They come off with just four screws or four quick panel anchors. Either way, it's pretty easy to get them off and review what's up in the box. Your units may vary significantly.

[Camper_bob]

So, I insulated the top, cold side of the AC unit along with the cold coolant hose. I don't have scientific conclusions, but things seem to work better in our trailer.

One of the reasons I can't really say whether the insulation on the AC unit helped is that we changed A LOT of things on the trailer at the same time. I sealed off each vent directly to the duct work, I sealed off the return side of the unit from the "cold" side, I closed off a dead end on the front duct, we removed a wall, and I performed the insulation mod and rinsed off the coils while I was up there.

So, after all of those items, the AC seems to be working better. It was pretty hot last weekend, but it was VERY humid. We've camped in hotter weather though. The AC was able to cool the trailer to a set temp of 75 within a few hours of setup (the unit cycled off before sunset, we arrived around 3:00 pm) with an outside temp in the mid 90's and a "feels like" of over 100. We had shade for all but an hour or two during the day, so I'm sure that helped as well. We also kept the awning out almost the entire trip, and that side of the trailer was facing West, so I'm sure that made some difference.

So, while I don't have "scientific" results, I will say that there is an improvement. Certainly worth the cost (which was basically $0 for me since I had the materials already, and that's for ALL the stuff I did) and the time and effort. Even if you have to buy the materials, and it helps a little, it's worth it IMO.

The coils weren't really that dirty, but I think I'll add this chore to my annual maintenance list. It can't hurt to keep them clean, right?