Entered-value methodsSource-labelledPlanning scopeFree tools

Building Energy
& Thermal Calculators

16 released calculators for bounded conversion, normalization, and entered-value comparisons. Each route states what it calculates and what it cannot establish.

Released calculators

Entered

Project/model values

Separate

Standards and schemes

Automatic certification

Energy Calculators

Choose the method matching your available evidence. Do not treat a conversion or entered-target comparison as a whole-building simulation, code check, or certification.

energy

Wall Assembly U-Value

Layer build-up (ISO 6946) → assembly R and U-value

Calculate →

energy

Condensation Risk

Temp + RH → dew point and surface condensation risk

Calculate →

energy

Thermal Bridge

Linear heat loss (Ψ·L·ΔT) + fRsi mould-risk check

Calculate →

energy

Roof U-Value

Insulation + layers (upward flow) → roof U-value

Calculate →

energy

Window U-Value

Glass + frame + edge → whole-window Uw (ISO 10077)

Calculate →

energy

Passive House Criteria

Selected PHPP/test values vs verified project criteria

Calculate →

energy

Solar Payback

Cost − incentives ÷ savings → payback period

Calculate →

energy

Embodied Carbon by Material

Σ (mass × A1–A3 factor) → cradle-to-gate kgCO₂e

Calculate →

energy

R-Value ↔ U-Value

Convert thermal R and U between SI and imperial units

Calculate →

energy

Spray Foam Coverage

Area + thickness → board feet, R-value, and sets to order

Calculate →

energy

Building Site EUI

Annual site energy ÷ matching floor area → EUI; comparison targets remain separate

Calculate →

energy

Annual Heating Demand

Completed model result ÷ matching area vs verified target

Calculate →

energy

Energy Demand

Completed model needs ÷ matching reference area

Calculate →

energy

U-Value

Homogeneous wall layers → series R-value and U-value; no automatic compliance verdict

Calculate →

energy

Daylight Factor

Room and window geometry → early-stage daylight-factor screening, not certification

Calculate →

energy

Window Size for Daylighting

Room depth + target daylight factor → minimum glazing area

Calculate →

Keep calculations, codes, and certification schemes separate

An arithmetic conversion, energy-model output, adopted energy code, and voluntary certification assessment answer different questions. The applicable baseline and evidence depend on jurisdiction, scheme, edition, project type, and selected compliance path.

Confirm the adopted energy code or named assessment scheme and its exact edition.
Use compatible model boundaries, floor-area definitions, fuels, units, weather data, and time periods.
Treat user-entered targets as inputs unless the method explicitly sources and selects them.
Use the complete governing method and qualified assessor where compliance or certification is claimed.

EUI and heating demand are not interchangeable

They can use different scopes, boundaries, floor-area definitions, and model procedures. Compare only values produced on a compatible basis and retain the source of every input.

A U/R conversion is not an assembly check

The reciprocal relationship applies within a compatible unit system. Assembly performance can also depend on layers, surface films, direction, repeating thermal bridges, framing, installation, and the governing calculation method.

Source and review basis

Hub claims reviewed 2026-08-30.

Energy Guides

Technical references connected through canonical hub metadata.

ashrae-90-1

ASHRAE 90.1-2019 Air Barrier Requirements: Leakage Limits and Verification

Building Energy& Thermal Calculators

Energy Calculators

Keep calculations, codes, and certification schemes separate

Source and review basis

Energy Guides

Building Energy
& Thermal Calculators