E3 Energy Method™

The E3 Energy Method™ is our signature, three-stage approach to designing a home or facility's energy upgrade. Instead of jumping straight to solar — the way most contractors still do it — E3 starts by understanding how your property actually uses energy, fixes the inefficiencies that quietly drain your wallet, and only then sizes the solar system.

The result is almost always the same: a smaller, cheaper solar system that delivers bigger lifetime savings, lower carbon emissions, and a healthier home. It's the difference between buying a bigger gas tank for a leaky car… and patching the leak first.

The three stages

E¹ — Evaluate

We assess your property's current performance — the age and efficiency of your furnace, water heater, HVAC, pool pump, insulation, windows, and roof. We benchmark what you have today against what is possible.

E² — Enhance

Before adding new generation, we reduce demand. High-efficiency appliances, better insulation, sealed ducts, smart controls. These upgrades typically pay for themselves through energy savings alone — and they shrink the solar system you need by 20–40%.

E³ — Energize

Now — and only now — we design the solar (and battery, if appropriate) system. Because demand is lower, the system is smaller, the panels cost less, and every kilowatt-hour produced is a kilowatt-hour you actually use. Nothing wasted.

Why efficiency-first beats solar-only

A solar-only project is a single bet: that the panels will offset the bills your existing equipment generates. Three things go wrong with that bet over time:

1. Your old appliances keep degrading. A 15-year-old furnace runs at a fraction of its original efficiency — you're paying to heat your home with a leaky bucket.
2. One day you'll upgrade anyway. When you finally replace the furnace, your "right-sized" solar system suddenly becomes oversized. The excess production gets sold back to the grid for as little as 10–20 cents on the dollar through net metering.
3. You waited. Every year of waiting costs you in higher utility rates, inflation on the future replacement, and an ~8% annual chance of an emergency repair.

E3 closes all three gaps at once.

The six benefit pillars

Every E3 analysis quantifies impact across six dimensions:

1. Financial Impact — 15- and 20-year cumulative savings, monthly bill reduction, lifetime cost of ownership.
2. Avoided Costs — the dollars you don't spend by upgrading now instead of later (the "cost of waiting").
3. Wasted Solar — the value lost when a solar-only system overproduces after a future appliance upgrade.
4. Carbon Impact — pounds of CO₂ avoided, expressed as trees planted and cars off the road.
5. Health & Safety — risks eliminated by removing combustion appliances and improving indoor air quality.
6. Property Value — the market-value lift from both the solar system and the efficiency upgrades.

The cost of waiting

Every year you wait to upgrade, three things compound against you:

• Energy waste — your degraded appliance burns more fuel for the same output (modeled with documented degradation curves).
• Inflation penalty — the same replacement costs more next year (10-yr US average: 3.2%).
• Repair risk — aging appliances carry an ~8% annual chance of an emergency failure averaging $2,500.

Multiplied across a furnace, water heater, HVAC unit, and pool pump, the cost of waiting often exceeds the cost of upgrading today.

How we score every project

Every E3 assessment produces three layered scores so you can see exactly what you're getting:

• Efficiency Index (EI) — raw efficiency optimization applied before solar, normalized to 0–100.
• E3 ROI — 20-year financial return on the combined efficiency + solar package, modeled at a 5.5% utility-rate escalation baseline (with low/mid/high sensitivity bands at 4.0% / 5.5% / 7.0%).
• E3 Energy Score™ (EES) — a composite letter grade (A+ through F) calculated as EES = (0.50 × EI) + (0.25 × Financial Return Index) + (0.25 × Avoided Cost Index).

Scores are produced over a standardized 20-year evaluation period so projects are directly comparable. Wasted overproduction from a solar-only baseline is valued at 15% of retail (the midpoint of the 10–20% net-metering range) and subtracted from the comparison ROI.

Methodology source of truth: src/lib/sdesCalculator.ts and src/lib/e3ImpactCalculator.ts. Constants reference: solar value $4.00/W (DOE/LBNL), inflation 3.2% (10-yr US avg), repair risk 8%/yr × $2,500, commercial cap rate 7%, annual health cost $150–$400 (EPA).