Adds two CC-BY 4.0 licensed open datasets:

Energy section — SolarCalculatorHQ open data: residential PV installation costs per watt across 10 markets (USD/GBP/AUD/CAD/EUR/BRL), optimal tilt angles by latitude (NREL PVWatts-derived), and national tax incentives (US ITC, UK 0% VAT, AU STC + Cheaper Home Batteries, DE KfW 270, FR MaPrimeRénov, etc.). Each row cites a primary public source (NREL, SEIA, EnergySage, Solar Energy UK, Clean Energy Council, Bundesnetzagentur, ADEME, IDAE, GSE, ABSOLAR).

URL: https://solarcalculatorhq.com/data/

Architecture section — RoofingCalculatorHQ open data: residential roof replacement costs by material (asphalt / metal / tile) per m² across 10 markets, X/12-to-degrees pitch conversion table with slope factors, and SMACNA Architectural Sheet Metal Manual + AS/NZS 3500.3 gutter sizing tables. Cites NRCA, NFRC, Master Builders Australia, CRCA, ZVDH, CAPEB, ANDIMAT, Confartigianato, Eigen Huis, ABRAS.

URL: https://roofingcalculatorhq.com/data/

Both datasets:

• Released under CC BY 4.0
• Distributed as direct CSV downloads with documented columns
• Include Schema.org Dataset JSON-LD on landing pages for Google Dataset Search
• Updated quarterly with last_updated per row