How many blankets do I actually need?
I have a fair number of blankets. Almost certainly more than I need.
Almost.
But I'm working on a vanlife build right now, and so, in theory, I should be able to calculate my insulation needs.
Let's start with climate.
Climate
Did you know that in the US, the EPA has published recommended insulation levels based on where you live?
According to their map, I live in region 5A. Futhermore, I do my best to avoid traveling during the cold season, most particularly to colder regions of the country (regions 6-8).
So it's probably pretty safe for me to take their recommended insulation ratings as my upper limit, as far as total insulation between both my van's built-in insulation and my blankets' insulation.
For regions 5, 6, and 4C, the EPA recommends:
- R60 for ceilings and attics
- R5-10 for walls
- R30 for floor
Realistic Expectations
Now, I'm building a van. Actually trying to install insulation that highly rated is completely unrealistic. I could fill the van with high-loft insulation and probably hit R60 without too much weight... but there'd be no room left for me to live in.
Realistically, I think I'll probably put 1 to 1½ inches of XPS in the ceiling and likely close to the same in the walls. My floor will be a little more complicated, but I'm currently looking at cabinets built out of XPS (plus some extra stuff to make it load bearing) with an effective thickness between 2 to 3 inches, as well as 1½-2 inches of aircrete (for my standing-room). Add a thin sheen of thinsulate to all sides and that puts me at roughly:
- R5-8 for the ceilings
- R5-8 for the walls
- R8-15 for the floor
Blankets
Disclaimer: I have used an LLM to help with my estimates, but I've double-checked its assumptions and math to the best of my ability. The LLM was used strictly for calculating estimated R-values based on published information for each of my blankets, and was not used to write any portion of this blog entry.All the words and opinions contained herein are exclusively mine.
Rumpl Original Puffy Double
I currently have a single Rumpl Original Puffy, which I regularly sleep with in the winter time (albeit indoors, in a mostly-well insulated house). It's wrapped around me burrito-style, so the part beneath me is compressed but the part above me is mid-loft.| State | Midpoint | Likely Range |
| Compressed | R2.5 | R1.6-3.8 |
| Mid-Loft | R6.5 | R6.0-7.4 |
Rumpl NanoLoft Double
I also own a NanoLoft, though I'm frankly rather disappointed in it. The insulation has clumped quite severely and I've been unable to un-clump it. I mostly use it as a privacy cover in my car since it's black, and otherwise relegate it to emergency use to gain just a little bit more insulation where needed.| State | Midpoint | Likely Range |
| Compressed | R2.3 | R1.6-3.3 |
Rumpl Original Puffy Single
I have two Puffy Singles, one from their National Park collection (it's Arches), one orange fade pattern. I tend to use one exclusively for keeping my feet and lower legs warm in the winter, and the other has been deployed as both an underquilt (hanging underneath my hammock) and as a shroud (suspended over my ridgeline). These are generally kept at mid-loft (the one at my feet will suffer mild compression, but in practice it feels insignificant; the two hanging modes either above or below suffer no compression).| State | Midpoint | Likely Range |
| Compressed | R2.5 | R1.6-3.8 |
| Mid-Loft | R6.5 | R6.0-7.4 |
Rumpl Merino Softwool Queen
Yes, I'm something of a loyal customer, how'd you know?This was actually the result of a lottery. I bought a single "surprise me" the one year I've seen that offer, and since this was the result... I'm very likely to buy in again if they ever repeat the grab-bag option (I haven't seen it yet, but I'm keeping my eyes peeled).
This is very different from my other Rumpls in that it's not down or synthetic down. Compression is a minimal concern.
| State | Midpoint | Likely Range |
| Pressed/Typical | R1.8 | R1.4-2.1 |
| Fluffed | R2.9 | R2.4-3.5 |
Gravel Layover Travel
I honestly rarely use this as a blanket. Most often it's treated like a pillow (ergo, compressed), though when it gets cold, I'll also wrap it around my head (still mostly compressed).| State | Midpoint | Likely Range |
| Compressed | R2.6 | R1.8-3.3 |
| Mid-Loft | R6.5 | R4.3-8.5 |
(I don't think those lofted values are accurate, considering it scores so close than my Original Puffy, but the Layover is a considerably thinner and lighter blanket. For my calculations, I'm going to use the low estimate, R4.3, instead of the midpoint.)
Miscellaneous Blankets
Everdell Cozy Critters Throw | ||
| State | Midpoint | Likely Range |
| Any | negligible | R0.02-0.11 |
Homemade Dual-Layer Fleece | ||
| State | Midpoint | Likely Range |
| Any | R2.8 | R1.2-6.4 |
Totals
| Blanket | Compressed | Lofted |
| Rumpl Original Puffy Double | R2.5 | R6.5 |
| Rumpl NanoLoft Double | R2.3 | (n/a) |
| Rumpl Original Puffy Single (both) | R5 | R13 |
| Rumpl Softwool Merino Queen | R1.8 | R2.9 |
| Gravel Layover Travel | R1.8 | R4.3 |
| Everdell Cozy Critters Throw | R0 | R0 |
| Homemade Fleece | R2.8 | R2.8 |
| Total | R16.2 | R31.8 |
Summary
Well now, how about that.
All my blankets and I cracked R30.
Admittedly, that's assuming I'm surrounded perfectly by all of them, which isn't even the best case scenario, so I think the R16 is a better gauge of the situation. After all, it's probably better to assume less so I can better plan for the worst case, since it's easier to discard layers than it is to add more that I don't have.
Add that to my built-in insulation plan, here's how we look:
| Side | My Van | EPA | Offset |
| Ceiling | R21-24 | R60 | -39 to -36 |
| Walls | R21-24 | R5-10 | +16 to +19 |
| Floor | R26-31 | R30 | -4 to +1 |
I do think, for the time being, I will keep a second Original Puffy Double on my wishlist where it's been for several years, but whether I actually acquire one will remain up in the air.
Leave a comment or continue reading: other vanlife posts.
