Why You Should Use a Sleeping Quilt – Thermarest Vesper Quilt

Like most sleeping quilts, it features an enclosed foot box like a sleeping bag, an open upper and no zip closure. The details that set the Vesper apart from other quilts are a drawstring cinch at the top, a simple snap closure for a wrap feel, and what Thermarest calls SynergyLink Connectors, basically pad straps that offer a quilt-to-sleeping pad connection.  

Collar Cinch and Snap Closure

A downside of a quilt is the inability to cocoon or fully seal up on a cold night. The collar cinch and snap on the Vesper address this by creating a partial seal that helps retain heat. I found the snap the most useful and think that it adds nice functionality without compromising weight or packability.

SynergyLink Pad Straps

The SynergyLink straps are designed to keep the quilt and your sleeping pad aligned, which also helps create a more thermally efficient sleep setup. The idea makes sense, and functionally, they do the job well. Personally, I prefer the freedom of no straps. Maybe it’s because I move a lot at night. Regardless, they are a well-designed solution. It just happens that they address a problem that doesn’t really exist for me. The good news for me is that the straps are removable. It’s more evidence that Thermarest knows its business well. Some people want them. Some people don’t.

900-Fill RDS-Certified Hydrophobic Down

Down quilts and sleeping bags can be stereotyped by their fill power rating. The Vesper quilt’s 900-fill rating is at the top of the down rating scale. The number reflects the quality, aka the loft, of the down used. Generally, the higher the fill power number, the higher the loft and warmer the sleeping bag or quilt. The Vesper uses 900-fill RDS-certified (responsibly sourced down) down that is hydrophobic, which means it resists damp conditions longer and dries faster than untreated down. 

Fill power is calculated by placing one ounce of down in a graduated cylinder and measuring the volume it occupies in cubic inches. You can compensate for lower fill power with more down, but doing so adds volume and weight. I’d call 600-fill average, 800-fill high-quality and 900, top-tier quality. 1000-fill exists, but is not commonly used in sleeping bags.

Packability

The Vesper owes its compressibility and lightweight to its 900-fill down and 10-denier ultra-light ripstop fabric. It easily fits into most bikepacking handlebar bags with plenty of room to spare for more gear. I generally forgo the stuff sack when packing my sleeping bag for a bikepacking trip to maximize compression and packing versatility around other gear. I just stuff it directly into my handlebar or seat bag. That said, the Vesper includes a really nice compression stuff sack with a lightweight build, designed to take advantage of the quilt’s maximum compression. 

Temp Rating

The Vesper is billed as a 20-degree sleeping quilt. Thermarest clarifies that its comfort limit is 20 degrees and its comfort rating is 32 degrees. While I have not used it in consistently cold, 20-degree temps, I am impressed with its warmth. Sleeping bag ratings are somewhat subjective, with everyone having different tolerances and needs. I believe the Vesper 20 is ideally rated for general three-season mountain use.