Climate at 5,000 Feet

The greenhouse fights two battles every day — too much heat and not enough humidity.

That’s everything the greenhouse consumed over the selected time range — kilowatt-hours of electricity, therms of natural gas, gallons of water — and what it cost per day to keep 234 square feet of plants alive at 4,979 feet elevation.

What’s Been Running

The equipment state grid shows every piece of hardware and when it fired. In winter, the heaters dominate overnight. In summer, fans and misters fight for airtime all day. The pattern tells the story before any chart does.

Indoor vs Outdoor

Left: temperature. On sunny days, indoor peaks 15–25°F above outdoor — that’s 55,600 BTU/hr of solar heat pouring through glazing with an SHGC of 0.66. The cooling system can reject 27–40% of that. The rest becomes higher temperatures. Right: humidity. Longmont drops to 14% RH on spring afternoons. The greenhouse fights to stay above 40% with misters and fog pushing against bone-dry intake air.

VPD Heatmap

This is the signature visualization. Each cell is an hour of VPD data — green is comfortable (0.8–1.2 kPa), yellow is stressed (1.5–2.0), red is emergency (>2.0). The pattern is counterintuitive: March has more red hours than August. August has monsoon moisture at 55% outdoor RH. March has 14% outdoor RH with strong solar heating — the worst combination.

Zone Behavior

Three distinct microclimates in 234 square feet. South hits 100°F+ at solar noon — it’s the exhaust side with the most direct sun exposure. East stays 9°F cooler thanks to the tree shadow and patio door ventilation. The heat spot rotates: south at noon, north by 2 PM (house thermal mass releasing), west by late afternoon as the setting sun hits the longest wall at the best transmission angle.

The Systems

The greenhouse manages climate through five interconnected systems:

• Heating — 80,120 BTU/hr combined capacity. The Lennox furnace is a sledgehammer, but at 0°F outdoor you need one.
• Cooling — Two exhaust fans at 4,900 CFM combined. Full air exchange every 27 seconds — and still can’t overcome peak solar gain.
• Humidity — Fog machine + 19 mister heads across three zones. March is the hardest month, not August.
• Irrigation — Wall drips feed plants. Misters feed the air. On hot days, 90% of water usage is humidity management.
• Lighting — 49 Barrina fixtures filling two shadow windows: the east tree blocks morning light until 10:30 AM, and late afternoon sun drops below effective transmission angle.
• Soil — Three buried probes correlating root zone conditions with the atmospheric chaos above.