Sources & Data

International energy-price references

WattCostLab can load a location-aware household electricity reference. For supported European locations the production site requests the latest available Eurostat household electricity dataset nrg_pc_204, band DC, including taxes. Where household gas is available it also requests nrg_pc_202, band D2. Values remain editable because utility tariffs vary by provider and plan.

• Eurostat household electricity prices
• Eurostat household gas prices
• U.S. EIA electricity prices
• Ofgem energy price-cap unit rates
• India CEA Tariff and Duty of Electricity Supply — March 2025

India does not receive a fabricated national household tariff: state, DISCOM and consumption-slab tariffs should be entered from the user's bill. Currency selection never performs a hidden foreign-exchange conversion.

Peer-reviewed sources for engineering calculators

• Building wall heat transfer: Paraschiv, L.S., Acomi, N., Serban, A. & Paraschiv, S. (2020), “A web application for analysis of heat transfer through building walls and calculation of optimal insulation thickness,” Energy Reports 6, 343–353. DOI 10.1016/j.egyr.2020.08.055. Used as the scientific basis of the Building Wall Heat Transfer Calculator.
• Solid fuel combustion: Paraschiv, L.S., Serban, A. & Paraschiv, S. (2020), “Calculation of combustion air required for burning solid fuels (coal / biomass / solid waste) and analysis of fluegas composition,” Energy Reports 6(Suppl. 3), 36–45. DOI 10.1016/j.egyr.2019.10.016. Used as the scientific basis of the Solid Fuel Combustion Calculator.

Engineering Guides content cluster — calculation-focused explanations that connect these peer-reviewed models to worked examples and the interactive tools.

Climate resilience and building-adaptation sources

WattCostLab uses primary public-sector guidance as reference material for its climate-resilience content. The planner does not treat these sources as a property-specific risk assessment.

• European Commission / Climate-ADAPT — EU-level technical guidance on adapting buildings to climate change
• Climate-ADAPT — climate-proofing buildings against excessive heat
• Copernicus Climate Data Store
• NOAA — U.S. Climate Resilience Toolkit
• FEMA — Floodplain Management Resources for Individuals
• U.S. EPA — Wildfires and Indoor Air Quality
• U.S. EPA — Drought Resilience and Water Conservation

Location Climate Intelligence sources

• NASA POWER — Prediction Of Worldwide Energy Resources: global solar and meteorological data services.
• NASA POWER Monthly Point API: monthly point data for 1991–2020 are aggregated by WattCostLab into the 30-year screening climatology.
• NASA POWER methodology: describes the satellite/model data and meteorological products used by POWER.
• WMO Climatological Normals: defines 1991–2020 as a 30-year climatological standard-normal period.
• European Climate Data Explorer / Climate-ADAPT: official European hazard indicators used as a verification destination, not as an automatic property-level score.
• Copernicus Climate Data Store: official climate-data catalogue for deeper analysis and verification.

Innovation & Trends sources

The Innovation section is source-dated and evidence-led. The initial V16.16 briefs use the following primary research or institutional sources:

• Fraunhofer ISE — Tandem PV Modules Reach 31.3% and 34.2% Efficiency — What It Means for Roof-Limited Solar
• Fraunhofer ISE — Perovskite-Silicon Tandem Solar Moves from Cell Records Toward Industrial Scale-Up
• Fraunhofer ISE — Perovskite-Silicon Tandem Meets Shingled Module Design at 25.6% Full-Area Efficiency
• Nature Communications — Smart Windows That Control Both Solar Gain and Thermal Radiation: A 2026 Research Breakthrough
• Nature Communications — Recyclable Aerogel Fibers Reach 22 mW/m·K Thermal Conductivity with High Tensile Strength
• Energy and Buildings — Can Insulation Become Dynamic? 2026 Study Tests Climate-Adaptive Vacuum Panels
• Oak Ridge National Laboratory / Applied Thermal Engineering — Residential Heat Pump + Thermal Storage Cuts On-Peak Electricity 38.4% in Field Demonstration
• National Laboratory of the Rockies — A Plug-In Home Battery Is Being Tested as a Drop-In Peak-Shifting Appliance
• Nature Communications — Adaptive Electrochromic Shading Points Toward Windows That Respond to Solar Intensity

Official electricity supplier-comparison sources

• Romania: ANRE / POSF electricity offer comparator — ANRE official comparator access.
• Italy: ARERA / Portale Offerte — ARERA Portale Offerte. The portal publishes open offer information; free-market electricity offers are available in XML and parameter files in CSV.
• Portugal: ERSE — official simulator and commercial-offers CSV.
• Spain: CNMC — official energy-offer comparator.
• France: Médiateur national de l'énergie / Energie-Info — official comparator.
• Texas: Public Utility Commission of Texas — PUCT Power to Choose guidance — Texas REP certification law.
• Ohio: Public Utilities Commission of Ohio — Apples to Apples, including official supplier-offer export options.
• Pennsylvania: Pennsylvania Public Utility Commission — PAPowerSwitch.
• New York: New York State Department of Public Service — Power to Choose.

Source registry last reviewed by WattCostLab: 18 August 2026. Offer data are time-sensitive; the live official source should always be checked before a switch.