Therm-a-Rest Vesper 20 Quilt vs Zpacks Solo Quilt 20F
In short: The Therm-a-Rest Vesper 20 Quilt costs $29 less; the Zpacks Solo Quilt 20F is rated 12 °F colder on the figure each maker publishes; the Zpacks Solo Quilt 20F saves 0.7 oz; the Zpacks Solo Quilt 20F carries the bigger loft budget at 12.3k cubic inches; only the Therm-a-Rest Vesper 20 Quilt publishes a lab temperature rating at all.
| Spec | Therm-a-Rest Vesper 20 Quilt | Zpacks Solo Quilt 20F |
|---|---|---|
| Approx. price | ~$460 | ~$489 |
| ISO comfort | 32 °F | not published |
| ISO limit | 20 °F | not published |
| Rating on the label | 20 °F | 20 °F |
| Honesty gap | 12 °F | — |
| Rating standard | EN 13537 | manufacturer |
| Weight | 1 lb 3 oz | 1 lb 2.3 oz |
| Warmth per ounce | 1.47 °F/oz | — |
| Fill | 900 fill power down | 900 fill power down |
| Fill weight | 12.5 oz | 13.7 oz |
| Loft budget | 11.3k in³ | 12.3k in³ |
| Shape | quilt | quilt |
| Shoulder girth | 49 in | 60 in |
| Zipper | none | none |
| Shell fabric | 10D nylon ripstop | 10D DWR nylon |
| Hydrophobic down | Yes | Yes |
| Packed size | 5.5 × 8 in | 6 × 12 in |
Shaded cells mark the row where one has a measurable advantage. Weight, thickness, girth and shape are left unshaded on purpose: heavier is sometimes tougher, wider is sometimes warmer, and calling a winner on those would be an opinion dressed as a measurement.
What each one does well, and costs you
Therm-a-Rest Vesper 20 Quilt
- 19 ounces including a snap-closed footbox — competitive with cottage quilts from a brand with a repair department.
- Publishes EN comfort and limit figures, which almost no quilt on the market does.
- 900-fill goose down, RDS-certified and PFAS-free hydrophobic-treated.
- SynergyLink straps hold the quilt to the pad without flattening the down against it, and come off entirely when you want a blanket.
- Packs to 5.5 × 8 inches, small enough to disappear into the bottom of a 40-litre pack.
- The 32 °F comfort rating is twelve degrees off the name — plan the trip around 32, not 20.
- $460 for a quilt is at or above the custom cottage makers, who will let you specify overfill and width.
- 10-denier shell is delicate; this is not the quilt to drag over granite or use around a fire.
- 49-inch width is narrow for a side sleeper who moves, and drafts are the predictable consequence.
- No width options at all — one girth, two lengths.
Zpacks Solo Quilt 20F
- 18.3 ounces with 13.7 ounces of 900-fill down in it — one of the best down-to-shell ratios in the catalogue.
- Twenty-one sizes, each with published shell weight, down weight and total weight.
- The same 2.5-inch target loft as the hooded Classic, so the two can be compared honestly.
- Elastic-and-snap pad straps rather than a proprietary system, so they work with any pad.
- Made in Florida, and Zpacks will re-loft or repair a quilt rather than replace it.
- No lab rating; the 20 °F figure is the maker's own and the loft spec is all there is to check it against.
- A quilt with no hood means a hat is mandatory below about 35 °F, and the draft-management is on you.
- 10-denier shell fabric wants care.
- $489 buys a wider, warmer quilt from several of the custom makers if you are willing to wait for it to be built.