🌤️ ShadeHunter
Solar Obstruction & Hour-Loss Calculator
Tree, chimney, or neighbor’s roof blocking sun? Find out exactly how much energy & money you lose — and if it’s worth trimming.
📘 User Guide
How to Use ShadeHunter & Why It Matters
Turn shade uncertainty into a clear financial decision — in under 60 seconds.
⚡ Why This Calculator Exists
Most homeowners with solar (or shopping for it) have a nagging suspicion: "That tree probably costs me money, but how much?" Installers often dismiss small obstructions because they can't easily quantify the loss. ShadeHunter closes that gap. A single tree blocking sun from 1–3 PM can steal 300–500 kWh/year – that's $50–$80 annually, or $1,200–$2,000 over 25 years. This tool turns a vague annoyance into a clear ROI decision.
🧭 How to Use – 60 Second Guide
1.
Point phone compass at roof → enter Azimuth (South = 180°).
2.
Measure distance to tree / chimney (feet or meters – use toggle).
3.
Estimate height angle (hold phone at panel height, sight treetop).
4.
Select roof tilt & seasonal leaf coverage (crucial for trees).
5.
Enter electric rate ($/kWh) + system size (kW).
6.
Add tree removal cost → get “Trim or remove?” YES/NO verdict.
⬆️ After filling the calculator above, click "Calculate My Solar Shade Loss" — results include lost hours, annual kWh, $ loss, and a sun path diagram.
📐 The Math Behind the Magic
🔹 Lost Hours per Day = (verticalAngle/75) × distanceFactor × azimuthPenalty × 4.5
Example: 30° tree at 20ft, south roof → 0.4 × 0.7 × 1.0 × 4.5 ≈ 1.26 hours lost (before seasonal/type adjustment).
🔹 Annual kWh Loss = (lostHours/6) × annual unobstructed yield (approx 1400 kWh/kW × system size × tilt factor)
Example: 6kW system, 1.5h lost daily → (1.5/6) × 7800 kWh ≈ 1,950 kWh/year stolen by shade.
🔹 25-Year Dollar Loss = annual kWh loss × electric rate × 25 years.
Example: 350 kWh/year × $0.16 × 25 = $1,400 lost over lifetime → if removal costs $900, trimming pays off (+$500).
⚙️ The "Trim or remove?" logic compares 25‑year loss vs. your local arborist quote. Simple, powerful, and installer‑friendly.
❓ Frequently Asked Questions
🤔 How accurate is ShadeHunter?
Within ±25% — precise enough for a "cut or leave" decision, but not an engineering-grade simulation. Use as a financial guide.
🍂 What if my tree loses leaves in winter?
Use the Seasonal Leaf Coverage slider at 20-30% for bare branches. The calculator automatically scales loss based on canopy density.
🏠 Does roof tilt really matter for shade loss?
Yes. A steep roof (35°+) catches ~8% less total annual sun, so absolute shade loss is slightly smaller. ShadeHunter accounts for tilt in the base production estimate.
📏 Can I use this BEFORE installing solar?
Absolutely — that’s the best time. Test different roof faces or decide if tree removal is worth it before panels go up.
🌳 What if my obstruction is a chimney or neighbor’s wall?
Select “Solid obstruction” — the calculator applies a full-block multiplier (no diffuse light passes through).
💡 Why does the sun path diagram show a shaded arc?
That red/black arc represents the portion of the sun’s daily path blocked by your obstruction. The longer the arc, the more peak hours lost.
💡 Real-world example: A homeowner in Texas with a 6 kW system, a 25ft oak tree at 35° above panels (full canopy) lost 1.9 hours/day → 470 kWh/year → $75/year → $1,875 over 25 years. Removal cost: $1,100 → ✅ “Trim or remove? YES” — net gain $775.
ShadeHunter — Solar Obstruction & Hour-Loss Calculator | Estimates for guidance only.