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Plan it · Check it · Track it

The honest math
for your roof.

Residential solar is sold on 25-year promises built from optimistic assumptions. We run the numbers independently — hourly physics, Monte Carlo on rate paths, every alternative your capital could be doing instead. No installer affiliations. No lead-gen.

Start free forecast Audit my proposal · $79no signup to start · address + utility bill
Sample household · Boulder CO · 7.2 kW
25-year cumulative net wealth
n = 28 sims
Median NPV
$31,400
discount 5.0%
Crossover yr
yr 9
solar > grid $/kWh
P10 outcome
$8,200
rate path stagnant
Disc. payback
11.2 yr
vs installer claim 7
vs HYSA 4.5%
$12,900
opportunity cost
P90 outcome
$58,700
rate path historical
── one engine, three questions ──
01 · Explore
free

Should I go solar?

Address + a utility bill. We run an independent production model and a Monte Carlo across rate-escalation paths. Output is a distribution of 25-year outcomes, not a single headline number.

PVWatts v8 · Sunroof shading · NSRDB
02 · Audit
$79

Check this proposal.

Drop your installer's PDF. We diff their math against independent benchmarks — where the year-1 kWh, escalator, dealer fee, or DC:AC ratio drift, by how much, and which levers drive the gap.

Vertex AI extraction · NREL baseline
03 · Track
$9 / mo

Did it actually work?

Post-install. Bill ingestion + Enphase / SolarEdge / Tesla monitoring. Monthly variance vs. the forecast you were sold — bill-level and production-level.

green button · monitoring api · TTL 25 yr
8760
hours simulated per year, every year, for 25 years
n=500
Monte Carlo paths across weather, rates, degradation, hold
0%
affiliate revenue · lead-gen handoffs · referral fees
NEM 3
net-billing tariff modeled hourly, post-Apr 2023 CA