Blog & insights
Practical guidance on building energy modeling, certification and the codes that shape modern buildings.
The 2D finite-element workflow for thermal bridges in THERM 8 — psi-value extraction, the temperature factor fRsi for condensation risk, and ISO 10211 / BR 497 conventions.
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How WINDOW 8 computes whole-window U-factor and SHGC, how it pairs with THERM for frame and edge-of-glass bridges, and how to handle window installation psi-values.
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AutoPSI's online, template-driven workflow for UK psi-values — BS EN ISO 10211 and BR 497 conventions, temperature factors, and when custom psi beats default values in SAP.
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The Prescription Act 1832 and the 20-year rule, the Waldram 50% / 0.2% sky factor test, why the 45-degree rule is a myth, and injunctions vs damages from Colls to Coventry v Lawrence.
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A private legal easement vs a planning matter under the BRE Guidelines (BR 209) — VSC, APSH, NSL, the 25-degree rule, and why planning permission never extinguishes a Right to Light.
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The developer's playbook — early modelling, designing out injury, negotiated releases, Right to Light insurance, Light Obstruction Notices, Section 203, and keeping injunction risk low.
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The standard (formerly 209P) that turns energy modeling into a design tool — the energy charrette, the simulation plan and the 11 modeling cycles from concept to post-occupancy.
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Savings can't be metered directly. The three M&V approaches, the NMBE and CV(RMSE) calibration criteria, and where Guideline 14 fits in retrofits and performance contracts.
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HDD, CDD and the balance point — how the oldest tool in energy analysis still powers weather normalization and quick estimates, and where it breaks down vs hourly simulation.
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LL97 limits tighten sharply in 2030. The compliance periods, the good-faith decarbonization plan, and how to plan retrofits before the cliff.
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An ASHRAE Level 2 audit and retro-commissioning every 10 years, the Energy Efficiency Report, deadlines and fines — and how the findings feed Local Law 97 retrofit planning.
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Who's covered, the May 1 Portfolio Manager deadline, fines and public disclosure — and how benchmarking feeds your energy grade and Local Law 97 planning.
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What NYC's A–D energy letter grades mean, how the ENERGY STAR score and EUI are calculated under Local Law 33/95, and how modeling helps improve them.
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How electrification and heat pumps cut NYC Local Law 97 carbon — the declining electricity coefficient, the beneficial-electrification credit and the pre-2027 double credit.
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What LL88 requires — tenant sub-metering and lighting upgrades to code — deadlines and fines, and how the data supports Local Law 97 compliance.
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How New York City's building energy laws fit together — Local Law 97 carbon limits, LL84 benchmarking, LL87 audits, LL88 and the NYC Energy Code — and where energy modeling keeps you compliant.
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What plug and process loads are, how they're modeled, why they're hard to regulate, and why they're decisive for NYC Local Law 97 carbon compliance.
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What regulated and unregulated loads are, how ASHRAE 90.1 Appendix G treats them, and why the distinction is critical for NYC Local Law 97 carbon compliance.
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LEED v5 centres occupant health — an occupant needs assessment, validated air-quality testing or monitoring, low-emitting materials and the new Occupant Experience credit.
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LEED v5 makes embodied carbon mandatory — a Quantify & Assess Embodied Carbon prerequisite, the Reduce Embodied Carbon credit, optimized products and zero-waste planning.
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LEED v5's biggest category is rebuilt around operational carbon — a new decarbonization-plan prerequisite, electrification, grid interactivity and renewables.
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A whole-building approach to water — combined indoor/outdoor prerequisites, the up-to-8-point Enhanced Water Efficiency credit, alternative water sources and leak detection.
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LEED v5's Sustainable Sites category moves from basic landscaping to ecological restoration — biodiverse habitat, rainwater management, heat island reduction and resilient site design.
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How LEED v5 reshapes Location & Transportation — compact connected development, electric vehicles and transportation demand management — to cut transport carbon and support equity.
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LEED v5 elevates the integrative process into its own category of upfront assessments — climate resilience, human impact and carbon. Here's what changes and where energy modeling fits.
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A practical guide to Appendix G's Performance Rating Method, baseline vs proposed building models, LEED energy modeling and common compliance mistakes.
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Compare COMcheck and whole-building energy modeling for commercial energy code compliance, including when each path works best and what documentation teams need.
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Compare DesignBuilder, EnergyPlus and OpenStudio for building energy modeling, including strengths, limitations and when each tool makes sense.
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Learn how LEED EAp2 and EAc2 energy modeling works, how ASHRAE 90.1 Appendix G is used, and what architects and LEED consultants should prepare before submission.
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Understand LEED daylight analysis, including spatial daylight autonomy (sDA), annual sunlight exposure (ASE), glare control and how daylight modeling supports better design.
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A practical guide to thermal comfort modeling using PMV, PPD and ASHRAE 55, including inputs, comfort risks and how simulation supports WELL, LEED and HVAC design.
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Learn how energy modeling helps NYC building owners understand Local Law 97 emissions exposure, evaluate retrofit measures and reduce carbon penalties.
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A practical guide to 179D energy modeling, eligible commercial building systems, ASHRAE 90.1 Appendix G, inspection requirements and documentation for tax deduction studies.
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How existing building energy modeling supports retrofit planning, decarbonization, energy-cost reduction, utility incentives and capital improvement decisions.
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A clear checklist of drawings, schedules, HVAC data, envelope inputs and project information needed to start a building energy model.
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A practical guide for architects on when to start energy modeling, what drawings and inputs are needed, and how early modeling reduces redesign and compliance risk.
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The 10 WELL concepts, certification levels, on-site performance verification, how WELL differs from LEED, and how thermal comfort, daylight and ventilation modeling support it.
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Florida's hot-humid energy code explained — the 2023 FBC-EC (IECC 2021-based), its prescriptive, performance and ERI compliance paths, and what the climate means for design.
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California Title 24 Part 6 explained — the 2025 code (effective Jan 2026), prescriptive vs performance paths, CBECC software and the state's 16 climate zones.
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How EnergyPlus's heat-and-moisture methods differ — CTF, EMPD, Simple Steady-state Moisture Flux and the fully-coupled HAMT — and how to choose for accuracy vs run time.
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NCC 2022 lifted new homes to 7 stars plus a Whole-of-Home energy budget. How NatHERS works, what changed, and how HERO accredited software models and certifies a compliant home.
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What thermal bridges cost you, how psi-values and y-values work in SAP, the fRsi condensation safeguard, and how junctions are modelled in THERM for Part L compliance.
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LEED v5 makes embodied carbon mandatory. A clear look at the new Life-Cycle Assessment prerequisite (MRp2), the Reduce Embodied Carbon credit (MRc2), and what teams must do.
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USGBC's LEED v5 puts decarbonization at the center — shifting energy modeling from cost savings to carbon, with a new operational-carbon and decarbonization-plan prerequisite.
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The 2025 NYC Energy Conservation Code takes effect for jobs filed on or after March 30, 2026. Here's what's changing — electrification, tighter HVAC and lighting — plus how it ties into Local Law 97.
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A clear comparison of the 2016 and 2019 editions — lighting power density, envelope, HVAC and Appendix G — and what the differences mean for your energy model.
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A plain-English introduction to whole-building energy simulation: what it is, how it works, and why it's the key to passing energy codes and earning green-building certifications.
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