Physical Structure
Dimensions & Shape
| Property | Value |
|---|---|
| Shape | Elongated hexagon — 6 walls |
| Length (N-S) | 18 feet |
| Width (E-W) | 13 feet |
| Floor area | ~234 sq ft |
| Volume | ~2,000–2,500 cu ft (peaked roof) |
| Roof | Peaked along N-S ridge axis |
| Floor | Concrete slab (significant thermal mass) |
| Built | ~1995 (~31 years old) |
| Elevation | 4,979 ft |
| Coordinates | 40.1672°N, 105.1019°W |
Walls
| Wall | Approx Length | Notes |
|---|---|---|
| North | 13’ | Shared with house. Interior door. Equipment zone only. |
| East | ~15’ | Patio door at NE corner. Hydro system + 3 shelf bays. |
| West | ~16–17’ | Longest wall. 6 shelf bays. 15× overhead 4FT grow lights. |
| Southwest | ~5–6’ | Small angled wall. 2 shelf bays. Best light transmission angle. |
| Southeast | ~5–6’ | Small angled wall. 2 shelf bays. |
| South | ~8–10’ | Narrower (hex tapers). 4 shelf bays. Exhaust fans. |
Glazing
All surfaces are Gallina PoliCarb 2P — 6mm twin-wall polycarbonate with an opal (frosted) finish, installed December 2023. No glass anywhere in the structure. The opal finish fully diffuses all incoming light — no direct beam ever reaches a plant.
Doors
| Door | Location | Type | Seasonal Use |
|---|---|---|---|
| House door | North wall | Interior → bar/sunroom | Always closed. Passive thermal buffer. House heat leaks in (~68°F floor overnight). |
| Patio door | East wall, NE corner | Glass + screen combo | Winter: glass insert for insulation. Summer: glass removed → screen or fully open for ventilation. |
The patio door is the single most important manual climate variable. Open = cooling (cross-ventilation) but humidity loss. Closed = humidity retention but temps climb.
Surroundings
| Feature | Location | Impact |
|---|---|---|
| House | Northwest | Connected via north wall. Thermal buffer ~68°F overnight. |
| Large tree | East side | Shades east + SE walls in morning. Sensor blind spot until ~10:18 AM. |
Thermal Envelope
| Metric | Value |
|---|---|
| Heat loss rate (glazing) | ~390 BTU/hr per °F delta |
| Peak solar heat gain | ~55,600 BTU/hr |
| Total cooling capacity | ~15,000–22,000 BTU/hr |
| Cooling deficit at peak | 60–70% of heat can’t be rejected |
| Overnight retention | 5–8°F above outdoor without heaters |
The defining tension: The glazing’s SHGC (0.66) exceeds its visible light transmission (0.57). The greenhouse lets in more heat than light. Shade cloth blocks proportionally more heat than useful PAR — almost pure upside.
Floor
The concrete slab is a thermal battery. South zone stays 2–4°F warmer overnight from stored solar heat. On moderate nights (50°F+ outdoor), the slab’s retained heat plus poly insulation plus house connection mean the greenhouse holds above 67°F without any heater assistance.