Huh? Yes it is -- that's what insulation sheathing is for, a layer in between the wood and the exterior. They're the gigantic pink foam panels you see covering buildings under construction.
Balloon framing is extremely thermally efficient, which is why it's used in places like the northeast US which have freezing winters!
Most american buildings talk about R10 to R15, and occasionally you might get up to R20 if you build it well. Verticals of balloon framing are usually ~R5.
New buildings in England need to have walls of R32 as an absolute legal minimum (and more for ceilings and floors). And England has pretty mild weather compared to much of the USA.
(Edit: never mind, deleted misinformed comment as londons_explore helpfully explained that I was comparing US imperial units to European SI units. Thanks, londons_explore!)
R values in Europe are metric, whereas the US is imperial. The conversion factor is 5.67. All values in my post are in imperial units to be consistent with the original poster and most of the HN readership.
Eh, kind of. Builders in the northeast didn’t choose balloon framing because it’s thermally efficient - they just didn’t have alternatives in the same cost range. Many homes in that region were build with masonry claddings as well to increase thermal mass and R value of the wall.
The foam sheet insulation you speak of is relatively new to the industry, at least for middle class homes. Having a continuous layer of insulation outside the framing definitely makes stick framing more energy efficient than it would be with traditional fiberglass batt insulation in a wall cavity.
Balloon framing is extremely thermally efficient, which is why it's used in places like the northeast US which have freezing winters!