Bedroom Blackout Strategy

Cassette roller blinds with side channels — for true sleep-cave darkness
Soluna — Koh Phangan
🌙

Design Goal

Bedrooms are sleep caves — dark, cool, quiet. Automated blackout blinds follow circadian rhythm via Home Assistant: close at sunset, open at sunrise. No manual intervention, no dead batteries, no light leaks.

The System: Cassette + Side Channels

A cassette roller blind with side channels is the most effective way to achieve near-100% blackout without external shutters. The cassette headbox hides the roller tube and motor, while aluminum side channels act as guides that trap the fabric edges — eliminating the light gaps that standard roller blinds have.

WALL SURFACE WINDOW double-glazed safety glass WOOD FRAME CASSETTE HEADBOX hides motor + roller tube BLACKOUT FABRIC 100% light block WEIGHTED BOTTOM BAR — seals against sill SIDE CHANNEL blocks side light leaks SIDE CHANNEL aluminum guide rail M ZIGBEE MOTOR wired 220V inside tube ~130cm (window 120cm + 5cm each side)
Front view — cassette system mounted outside window frame on wall surface
How it works The blackout fabric rolls down from inside the cassette headbox. Its edges are guided by the aluminum side channels on each side, creating a seal with no light gaps. The weighted bottom bar presses against the window sill for a complete seal at the bottom. The motor (hidden inside the roller tube) is connected to Zigbee smart home and runs on schedule.

Cross-Section: Layer Order

From outside to inside, here's how the layers stack at each bedroom window:

1
Outside
Deep roof overhang blocks direct sun
2
Window
Wood frame
Double-glazed
safety glass
3
Screen
Retractable plissé mosquito screen
4
Blackout
Cassette roller
+ side channels
Zigbee motor
5
Room
Sleep cave
Dark & cool
← inside
Mounting note for architect The cassette headbox needs ~12–15cm of flat wall surface above the window head. With bedroom window heads at +2.65–2.73m and ceiling at ~3.0m, there is 27–35cm of clearance — plenty of room. The side channels need ~5cm on each side of the window frame. Confirm wall surface is flat and solid (concrete/masonry) at these points for bracket mounting.

Motor Selection

Two options for the Zigbee motor that drives the blackout roller:

Not recommended

Chain Motor (Battery)

~1,800 THB / unit
  • Clips onto roller blind chain externally
  • 12V rechargeable battery — 3-4 day standby
  • Solar panel + USB charging included
  • 10kg max load
  • No wiring needed
  • ✗ Battery dies — automation fails
  • ✗ Solar panel useless behind blackout fabric
  • ✗ Retrofit product, not built-in
  • ✗ Motor unit visible outside the cassette
Recommended

Tubular Motor (Wired 220V)

~2,200–5,000 THB / unit
  • Fits inside the roller tube — completely hidden
  • 220V AC — always powered, never dies
  • Zigbee built-in (e.g. Zemismart ZM35E)
  • Fits standard 40mm / 50mm cassette tubes
  • Needs 220V outlet behind cassette
  • ✓ Reliable daily automation
  • ✓ Invisible — fully inside cassette
  • ✓ Stronger, quieter, faster
  • ✓ No charging, no maintenance
Electrical requirement Each bedroom window needs a 220V outlet positioned behind where the cassette headbox will be mounted (above the window, hidden from view). This must be on the electrical plan. The outlet will be invisible once the cassette is installed.

Bedroom Windows from Schedule

From Eliya's Window Schedule sheets (dated 28.01.26), the bedroom windows requiring blackout:

Window Type Width (cm) Sill Height Head Height Window Height Location
W1 ~120 +1.12 – 1.20m +2.65 – 2.73m ~150cm House bedrooms (Sheet 13)
W2 varies +1.15 – 1.20m +2.70 – 2.73m ~150cm House bedrooms (Sheet 13)
W5 ~150 +0.30m +2.30m ~200cm Office / pool room (Sheet 14)
Cassette sizing The cassette system will be made-to-measure. For W1/W2 bedroom windows (~120cm wide, ~150cm tall), the cassette width will be approximately 130cm (window + 5cm overlap each side). For W5 windows in the lock-off bedroom (~150cm wide, ~200cm tall), the cassette will be approximately 160cm wide. Confirm final dimensions with blind fabricator after window frames are installed.

Window count for blackout

Verify the total count of windows needing blackout cassette systems:

Room Est. Windows Window Type Notes
Parents bedroom 2 W1 / W2
Kids bedroom 1 1–2 W1
Kids bedroom 2 1–2 W1
Kids bedroom 3 1–2 W1
Lock-off bedroom 1–2 W5 Taller window (200cm)
Guest cabin 1–2 TBD Not on current schedule
TOTAL (est.) 8–12 Dashboard currently says 8 — may be low

Smart Home Integration

Home Assistant automations Zigbee Zigbee Hub Tuya gateway Parents bedroom Kids bedrooms Lock-off / Guest ☀ sunrise → open 🌙 sunset → close 📱 manual override
Zigbee tubular motors connect to Home Assistant for automated scheduling and voice/app control

Each blind motor joins the Zigbee mesh network. Home Assistant handles automations:

Action Items

1

Confirm wall surface above bedroom windows Carlos

Is there 15cm+ of flat, solid wall above each bedroom window head for cassette mounting brackets?

2

Add 220V outlets behind cassette positions to electrical plan Yuki

One concealed outlet per bedroom window, positioned at head height (+2.65m or above), behind where cassette headbox will mount. Outlet will be hidden by the cassette.

3

Finalize bedroom window count for blackout Eliya

Confirm exact count of windows per bedroom. Dashboard currently estimates 8 — may need 10-12. Include guest cabin if applicable.

4

Account for cassette + side channel depth in window reveals Eliya

The cassette system adds ~8cm depth from wall surface. Side channels add ~5cm width on each side. Ensure this doesn't conflict with curtain rods, AC units, or ceiling fans near windows.

5

Source local cassette blind fabricator Carlos

Find a made-to-measure blind supplier (Surat Thani or Bangkok) who can supply: aluminum cassette headbox, aluminum side channels, 100% blackout fabric, compatible with 40/50mm tubular motor. Measurements taken after window frames are installed.

6

Order Zigbee tubular motors Sean

Zemismart ZM35E or equivalent. Zigbee 3.0, fits 40/50mm tube, 220V AC. Order after confirming cassette tube diameter with blind fabricator. Lead time: ~2-3 weeks from AliExpress/Lazada.

Open Questions from Window Schedule Review

Additional items flagged while reviewing Eliya's window schedule sheets (12–14):

Topic Question Owner Priority
Frame material Drawings say "solid wood" — dashboard says "wood-look aluminum." Which is it? Major cost & maintenance difference. Eliya High
Clerestory type Living area notes say both "louvre" and "awning." These are different — louvre = slatted glass blades, awning = single hinged panel. Which one? Eliya Medium
Child safety W5 windows (office/pool room) have +0.30m sill height — near floor level. Need window restrictors for child safety if these rooms are accessible to kids. Carlos Medium
Mosquito screens Retractable plissé screens selected. Confirm mounting provisions in frame design — screens go between window and blackout blind in the layering. Eliya Medium
Window type legend W1, W2, W5, W7 are referenced across sheets but no consolidated dimension table exists. Request a summary schedule with all types, sizes, and quantities. Eliya Medium