Oliver insulation

[Steph and Dud B]

Here's some data that I found interesting. Our Oliver is mostly stock, with only a little extra Reflectix insulation added to the external basement door. I have a remote thermometer in the Oliver belly, near the fresh and city water inlet lines, and another thermometer hanging inside the garage near the Oliver.

I collected data from a week from both thermometers. The was no heat running in the Oliver. You can see that the average temperatures were only different by 1.1 degrees. There was a difference of 38.1 degrees from the highest temperature to the lowest temperature recorded in the garage:

and only a 16.3 degree difference recorded in the belly of the trailer:

I couldn't tell you if that's any better or worse than any other RV would perform, but those are the numbers from an unheated Oliver sitting in an unheated garage.

[Snackchaser]

Interesting data!  I ran the numbers through AI trying to get an R value, but there's not enough information.  However, it determined the swing insulating value was 57%, which is about right for Olivers claimed R-18 value.  Most RV's are lower than R-10, 20 to 30%.  

Good stuff!  

[jd1923]

Regardless of the R-value of insulation, interior and exterior temps will become equal over time. Also, when temps are in the 50s it's not the same test as when ambient temps are in the 20s, the teens or worse.

What matters most is when we add furnace heat, will the temp rear of basement by the water lines be kept above freezing? Say it's consistently below freezing outside, what should interior temp be set at to keep the rear basement above freezing?

We also keep a Ruuvi sensor in the same rear basement location (and 5 other locations), including one outdoors. Rear basement temps will not drop below freezing while camping, with our thermostat set to 63F. The rear basement temps is always above freezing a good +10 over outdoor temps.

Generally we do not store and winterize, since we "winter" camp often (but no real winter down here). Winter overnights are often down to low-mid 20s by dawn, but then it will always warm up to 50F +/- in the sunny afternoons. If it's cold just a night or two, I do not worry. If we are to have multiple consecutive cold nights, I'll set the furnace to 50F if I had not blown the water lines clear.

The Oliver could have better insulation, but it is certainly sufficient for our use. I like how it's thin so that we have room in the basement for mods. I would add more if we lived north. I did the battery bay door already. Good reminder to add some to our basement access door. 😂

[Snackchaser]

30 minutes ago, jd1923 said:

Regardless of the R-value of insulation, interior and exterior temps will become equal over time. Also, when temps are in the 50s it's not the same test as when ambient temps are in the 20s, the teens or worse.

That’s exactly what I used to think!.  However, equalization requires a constant outdoor temperature, but that never occurs in a natural day/night cycle. The 57% swing shows that the insulation is effective enough that the interior can't track outdoor changes fast enough to equalize.  

You're right, it could be better, but it's way better than some drafty old trailers that I used to own.  

[jd1923]

Yep, that’s why I wrote “over time.” To me that interesting data is that outside the temp swing/range was 38 degrees, while indoor the temp range was only 16. This shows the difference in the insulated space. The averages should be close over daily cycles.

Thank you@Steph and Dud B, many of us love seeing some performance data of our Olivers!

Edited Sunday at 06:49 PM by jd1923

[HDRider]

I sure like that core heating system that was described on here.  I can't recall his name.  That should be offered by Oliver.  

[DanielBoondock]

Looks to me like what you’d expect, just a temporal lag and smoothing. I think you don’t see the same minima/maxima because of the time lag - outside is already turned around before the inside reaches the min/max. 

fwiw tl/dr

I spent a lot of stupid time (meaning I could have been doing something more useful 😅) thinking about the insulation on this thing. It’s really interesting, it’s basically all reflective/infrared. But for the most part air gapped everywhere except the belly band, which is what you need for that to be effective.

• Fiberglass bat This primarily slows down the rate of heat transfer. If the trailer had that we’d see a larger delta in the charts above. So it doesn’t stop the heat transfer, just slows it
• Reflective with air gap (Protex) This primarily works by actually reflecting the infrared heat, not the thermal brownian heat in the air its in contact with. So it does stop heat transfer - look at the moon landers with gold foil, or the James Web infrared telescope with its many laters of foil. Both effectively eliminate heat transfer from the sun 

Bits and pieces 

• Rule of thumb I heard from an engineer in this field; reflective works better the greater the differential (outside to inside).
• Fiberglass shells are horrible insulators
• However, we have a double hull. Air gaps of 1/2” or under is as good as insulation bats (not a big enough space for convection currents. Note that seems to be about as much of the gap as we have. 
• So the double hulls act as a buffering system, both giving the Protex the air gap it needs to work, and that enclosed air gap acting generally as dead air space.  

Putting it all together, in extreme conditions (hot or cold) the trailer should perform great due to the large delta between outside and in and the dual insulation, which is what I hear from owners. But due to the .5-1” air gaps you won’t see a large time lag in an idle trailer. 

[Steph and Dud B]

I should also note that I was measuring the temperature between the hulls, in the belly by the water intakes. I wish I had placed a third recording thermometer inside the main cabin to see what the difference was between the cabin and the belly.