Soluna AC Plan

AC Types We're Using

Ducted (Concealed)

AC UNIT

only slim grilles visible

Hidden in roof void. Only elegant slot grilles in ceiling. Quietest, cleanest look. Maintained via roof access.

Main house + Airbnb

Cassette (4-Way)

PANEL ← → ↓

flush panel in ceiling

Flush ceiling panel, 4-way airflow. No ductwork. Needs lowered ceiling with void above.

Office

Wall Split (High-Wall)

UNIT

wall-mount, no void needed

Wall-mounted. Only option for vaulted ceilings. Simple, any local tech can service.

Guest cabin (vaulted)

How Dampers Work

Zoned Ducted System with Motorized Dampers

┌──[DAMPER]──▸ grille ──▸ Master Bed ◂── thermostat │ ├──[DAMPER]──▸ grille ──▸ Kids Bed 1 ◂── thermostat [Outdoor Unit] ──▸ [Ducted Unit] ──┤ (in roof) ├──[DAMPER]──▸ grille ──▸ Kids Bed 2 ◂── thermostat │ ├──[DAMPER]──▸ grille ──▸ Kids Bed 3 ◂── thermostat │ └──[BYPASS]──▸ return air (pressure relief)

One ducted unit serves multiple rooms through branched ductwork
Each room gets a motorized damper — opens/closes based on that room's thermostat
Bypass duct relieves air pressure when rooms close off
Inverter compressor throttles down when fewer rooms active = energy savings
Smart home: dampers + thermostats integrate with Zigbee / Home Assistant

Ducted + Dampers in Thailand — Feasibility

Commonality

Uncommon residential

Feasibility

Doable with right contractor

Parts supply

Daikin/Mitsubishi + Thai damper mfg

Island service

Limited — Samui/mainland contractors

Ducted systems standard in Thai hotels/luxury villas but uncommon in typical homes (95%+ use wall splits)
Motorized zone dampers are specialty — need contractor familiar with zoning, not just ducted install
Tropical humidity is the main risk — closed-cell elastomeric foam insulation with vapor barrier required (NOT fiberglass)
Salt air corrodes damper mechanisms — specify stainless steel or PVC (Duct Asia Engineering manufactures both)
If a damper actuator fails, parts from Bangkok/Surat Thani (1-3 days). Not a crisis — room just stays open.

Equipment suppliers:
Duct Asia Engineering (dampers, est. 1977) ENM Smartfarm (IoT dampers, Modbus) Daikin Thailand (ducted units) Mitsubishi Electric TH (City Multi)

Samui-area HVAC installers:
Managing Samui (ducted experience) Rungruangchai Samui (Daikin dealer, 15yr) Samui Air Conditioning & Plumbing

Zone Plan — 5 AC Zones

Based on Eliya's Ceiling & Lighting plan (Feb 18). Current plan: 4x mini-central + 8x high-wall splits. We're consolidating into 3 ducted zones with dampers, 1 wall split, and 1 cassette.

🏠

Zone 1 — Main Living + Kitchen

Main house, open-plan common area

Ducted 36,000–48,000 BTU

Single ducted unit on structural supports in roof void. Multiple linear slot diffusers across the open area. Already planned as mini-central in Eliya's ceiling plan — no change needed. May need high static pressure model (Daikin FBFC) for the large space.

🛏️

Zone 2 — All Bedrooms (Master + 3 Kids, with Dampers)

Main house, 4 bedrooms sharing one ducted unit — sleep schedules aligned

Ducted 4x Dampers 36,000–48,000 BTU

One ducted unit with 4 motorized zone dampers — one per bedroom. Each room has its own thermostat. Bypass duct for pressure relief. All bedrooms in the same wing → short duct runs. Adults and kids sleep at the same times → single shared unit is practical. Inverter throttles down when fewer rooms active.

🏡

Zone 3 — Airbnb Unit (Living + 2 Bedrooms, with Dampers)

Entire lock-off unit — one ducted system, independent from main house

Ducted 2x Dampers 36,000–48,000 BTU

One ducted unit serving the entire Airbnb: living/kitchen area always-open, 2 bedroom branches with motorized dampers. Guests typically cool the whole unit when present. Completely independent system — own outdoor unit, own controls. Bypass duct for when bedrooms close at night. Simpler for guests than managing separate AC units per room.

🏕️

Zone 4 — Guest Cabin

Standalone cabin, vaulted ceiling (thatch roof, no ceiling void)

Wall Split 12,000–18,000 BTU

High-wall split — the only option for a vaulted ceiling with no void. Slim inverter model (Daikin FTKF / Mitsubishi MSY). Simple for guests, any local tech can service. Smart home via Tuya ZS06 Zigbee IR blaster.

💻

Zone 5 — Office

Standalone office, lowered ceiling

Cassette 12,000–18,000 BTU

Ceiling cassette — clean look for work space. Lowered ceiling provides the void. No ductwork. Simple, effective, easy to maintain.

Changes from Eliya's Current Plan

Room	Current Plan	New Plan	Change
Main Living + Kitchen	Mini-central	Ducted	No change ✓
Master bedroom	High-wall split	Ducted Damper	→ Zone 2
Kids bedrooms (x3)	3x High-wall split	Ducted 3x Damper	→ Zone 2
Airbnb living	Mini-central	Ducted	→ Zone 3 (merged)
Airbnb bedrooms (x2)	2x High-wall split	Ducted 2x Damper	→ Zone 3 (merged)
Guest cabin	AC (unspecified)	Wall Split	Defined (vaulted)
Office	AC (unspecified)	Cassette	Defined ✓

Budget Estimate

Thai market prices, inverter models. Includes unit + standard installation. Ductwork, dampers, insulation, and diffusers additional.

Zone	Type	Indoor	Outdoor	Est. Cost
1. Main Living	Ducted	1	1	100K–150K ฿
2. Bedrooms (x4)	Ducted 4x D	1 + 4 dampers	1	120K–180K ฿
3. Airbnb (full)	Ducted 2x D	1 + 2 dampers	1	100K–160K ฿
4. Guest Cabin	Wall Split	1	1	20K–30K ฿
5. Office	Cassette	1	1	35K–55K ฿
TOTAL ESTIMATED			5 outdoor	375K–575K ฿
~40,000–61,000 ILS \| ~$11,000–17,000 USD

5 indoor units + 6 dampers + 5 outdoor units. Down from 12 indoor + 7+ outdoor in original plan.

Ko Pha Ngan Considerations

🧂 Salt Air Corrosion

Gold Fin / Blue Fin coated outdoor units required. Stainless steel or PVC dampers only. Rinse outdoor units monthly. Position leeward.

💧 Duct Condensation

PRIMARY RISK. All ductwork: closed-cell elastomeric foam insulation + vapor barrier. NOT fiberglass. Any gap = mold. Annual duct inspection.

⚡ 3-Phase Power

250m² with 5 AC zones likely needs 3-phase (380V). Confirm with PEA. Already in Carlos's scope.

🔧 Roof-Access Maintenance

Ducted units on structural steel in roof void. Maintained via roof hatch — no ceiling access panels. Plywood catwalks along maintenance paths. Optional slim filter slots only.

📱 Smart Home

Ducted: Daikin WiFi adapter → Home Assistant. Cassette/wall: Tuya ZS06 Zigbee IR blaster (~600฿). Dampers: zone controller with Modbus/IoT.

🏗️ Ceiling Void

FC board at 3.00m, roof peak ~6m = 3m void. Ample for units + ductwork. Steel frames hung from trusses (Yuki to spec). Guest cabin: vaulted = no void → wall split.

Action Items

#1 Priority: Find HVAC Contractor with Damper Experience

Ask Carlos and Yuki if they have HVAC contacts with ducted + zone damper experience. Key questions: Have you installed motorized zone dampers? Can you service on KPG? What duct insulation do you use? If no suitable contractor can be found, we drop the dampers and revert to the current plan — wall splits for bedrooms, ducted only for living areas.

📋

For Carlos / Yuki

Structural supports for ducted units in roof void (Yuki to engineer steel frames)
Roof access hatch location + plywood catwalks for maintenance
Plan duct routing — keep runs short (bedroom wing ideal)
Outdoor unit placement — leeward, screened, Gold Fin coating
Confirm 3-phase power with PEA
Damper material: stainless steel/PVC (Duct Asia Engineering)
Closed-cell elastomeric foam insulation for ALL ductwork (non-negotiable)

✏️

For Eliya

Update ceiling plan: replace all 8 high-wall splits with 3 ducted zones
Mark supply grille positions (linear slot diffusers) — Japandi aesthetic
Guest cabin: wall split position (vaulted ceiling)
No ceiling access panels — maintenance via roof access only