Post
Critique my small outdoor 1 (or 2) person sauna design please! Southern UK climate. Internal: 1.9m height, 1.35m width (bench/heater wall), 0.93m side walls. Flat ceiling. Heater: Harvia BC23. Power: 13A UK plug to junction box on the back wired to heater (2.3kw), and RCD wired to light (40w), and fan (7w). 1.35m bench at 0.95 from ceiling. 0.9m foot bench, abbreviated at heater, 0.3m below that (just above stones). Very low door: 1.4m high, to make 0.4m ceiling steam pocket. 0.85m wide. 30mm FinFoam sauna PIR insulation over timber studs, 2x3s, with Rockwool between studs. Internally clad with cheap 9mm untreated softwood matchboard ( https://mkm.com/product/softwood-matchboard-13-x-100mm-9-x-90mm-fin-t001247 ). Ceiling insulated with 2 layers of 100mm loft Rockwool. Floor of 19mm T+G redwood, hardwax oiled all round before assembly, linear drain in centre, Rockwool beneath floor, held up with chickenwire on joists. No PIR on the floor. 250mm square window in the door. Double glazed with wooden spacer (not a premade unit). Tempered internal pane, regular outer. Exhausted by conventional 100mm bathroom fan beneath bench on side wall opposite heater. Intake on side wall above heater: 100mm with aluminium duct in wall (that wall alone is framed with 2x4s to accommodate the duct). Outside, the intake is 1m below the inside termination of the duct. Sits on a typical modern UK shed foundation: Treated skids under the floor structure sit upon pea gravel levelled into plastic grids, sitting on sand. I've included my sketches below, so you can envisage the thing. https://preview.redd.it/3escxpfbqjih1.png?width=806&format=png&auto=webp&s=e98d1fba8e57846b291832546f29407946786a84 https://preview.redd.it/bch03b3eqjih1.png?width=644&format=png&auto=webp&s=f1d3df5709ab0c69caf5b9524e95cc385be784de https://preview.redd.it/gexq59ogqjih1.png?width=818&format=png&auto=webp&s=8db4e90a31d8df7d1c547976754dafda6e08d084 https://preview.redd.it/6x90kqejqjih1.png?width=750&format=png&auto=webp&s=9096dd2d213d1b736db5632c661635bd37b2d3bf
Intent Score
2
Intent
99
Confidence
Summary
The post is about designing a small sauna and does not indicate any window replacement or window problem intent.
Reasoning
This is a home improvement/design discussion focused on sauna construction, insulation, ventilation, and heater setup. The only window mention is a small window in the sauna door, which is incidental and not about replacing, repairing, comparing, or upgrading windows.
Extracted Signals
- incidental window mention
“250mm square window in the door.”
- different home project focus
“Critique my small outdoor 1 (or 2) person sauna design please!”
Model: gpt-5.4-mini · Prompt: v3 · 8/10/2026, 5:01:22 PM