RetrofitIQ · Residential Renovation Decision Support
Multi Criteria Optimization Based Sustainable Renovation Decision Framework for Residential Buildings: Integrating Life Cycle Energy, Carbon and Cost Performance
A digital decision-support application for evaluating residential renovation alternatives through life-cycle energy, carbon and cost performance.
Prepared by
Yahaya Hassan Labaran
Structural Engineering Division
Supervisor
Prof. Dr. Nihat Atmaca
Head, Structural Engineering Division
Academic unit
Structural Engineering Division Department of Civil Engineering Gaziantep University
Research focus
Life-Cycle Energy · Carbon · Cost Renovation Decision Support
From building inputs to a defensible retrofit decision.
Evaluate energy, represented life-cycle carbon and life-cycle cost across the complete 72-package universe—then stress-test the decision, compare alternatives and document every assumption.
The active Knowledge-Based Engine remains independent from the future Thesis-Verified Engine, allowing like-for-like comparison without hidden calibration.
Guided assessment
Build a traceable renovation case.
Start with transparent archetype defaults or switch to Expert Mode for technical overrides. Every value remains visible in the calculation record.
Knowledge-Based Engine
KB-2.0.0
ACTIVE
Calculation engine
Recoverable assessment draftA locally saved draft is available.
1 · Building
2 · Envelope & systems
3 · Goal & scenarios
4 · Review
No assessment calculated yet
Complete an assessment first. Your result will remain available while you navigate between the application sections.
Knowledge-Based Engine result
Renovation assessment
Knowledge-Based Engine
CALCULATED
Energy reduction
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Formal decision · annual delivered energy
Represented life-cycle carbon
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Formal decision · reduction vs baseline
Initial investment
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Formal decision · 2026 TRY price basis
Life-cycle saving
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Formal decision · baseline LCC minus package LCC
Input evidence profile
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Input completeness
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Direct user / expert
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Model-derived / default
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Balanced solution
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Key performance
Decision intelligence brief
Why this package?
FORMAL RULE
Reproducibility
Calculating…
A fingerprint of the engine version, controlled data version, formal inputs and formal decision.
Alternative decision views
Visual analytics
Baseline vs viewed package energy
Annual delivered energy by carrier.
Viewed-package carbon breakdown
Operational and represented embodied carbon over the selected analysis period.
Viewed-package life-cycle cost
Present-value comparison of baseline and the package currently being explored.
Cumulative financial position
Knowledge-based cumulative package saving relative to the baseline.
Cost–carbon package landscape
Budget-feasible packages. Pareto-efficient packages are emphasized; the selected package is highlighted.
Package comparison
Package
States
Energy kWh/y
Energy reduction
Represented LC carbon tCO₂e
Initial TRY
LCC TRY
LCC saving
Applicable
Pareto
Professional assessment report
No calculated assessment yet.
Complete an assessment first. RetrofitIQ will then assemble the building profile, selected renovation package, alternatives, energy, carbon, cost, scenario robustness, assumptions and scientific-engine metadata into one public-facing report.
Report Center
Assessment Report
Gaziantep University
Faculty of Engineering
Department of Civil Engineering
Multi Criteria Optimization Based Sustainable Renovation Decision Framework for Residential Buildings: Integrating Life Cycle Energy, Carbon and Cost Performance
Prepared by Yahaya Hassan Labaran
Supervisor Prof. Dr. Nihat Atmaca
Assessment ID—
Project—
Engine—
Report date—
Executive Summary
Decision / reference package
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Energy reduction
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Represented life-cycle carbon reduction
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Life-cycle saving
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Engine status: This report uses the independent Knowledge-Based Engine. Its outputs are transparent decision-support estimates and should not be interpreted as calibrated EnergyPlus simulation results or certified engineering design.
Building & Assessment Inputs
Decision / Reference Renovation Package
Visual Performance Summary
Energy
Represented Life-Cycle Carbon
Life-Cycle Cost
Cumulative Financial Position
Alternative Packages
Decision view
Package
Energy reduction
Carbon reduction
Initial cost
Life-cycle cost
Scenario & Robustness Summary
Case
Winner
Same as base
Represented LC carbon
LCC
Assessment Quality & Assumptions
Methodology, Data Status & Limitations
The Knowledge-Based Engine estimates transmission heat transfer from envelope U-values and areas, ventilation/infiltration from air-change assumptions, annual heating/cooling demand from transparent climate-demand relationships, and HVAC energy from efficiency/COP. Retrofit states modify these parameters and all 72 packages are recalculated. Life-cycle calculations use a single annual cash-flow ledger for upfront outlay, maintenance, age-aware replacements, energy expenditure and residual value. Represented life-cycle carbon includes operational energy carbon plus the embodied impacts of retrofit and replacement components currently represented by the Knowledge-Based Engine; it is not a complete all-module whole-building WLCA.
Public-use limitation: Knowledge-Based results are decision-support estimates, not a substitute for a detailed building survey, certified energy audit, structural assessment, tender pricing or final engineering design. Project-specific surveys, calibrated simulation, detailed engineering checks and current market quotations may be required before implementation.
Reproducibility fingerprint:— This identifier is generated from the application/engine/data versions, formal inputs and formal decision. Matching fingerprints indicate matching recorded assessment state; it is not a digital signature.
Scenario & robustness analysis
Calculate an assessment first.
After an assessment is available, RetrofitIQ will rerun the project under predefined climate, price, discount-rate and grid pathways and show whether the preferred renovation package remains stable.
Scenario & robustness analysis
How stable is the decision?
The same building and package universe are recalculated under nine predefined knowledge-based cases. This page distinguishes a stable decision from one that changes materially when assumptions change.
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Base-case decision package
Selection stability
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Distinct winners
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Across nine predefined robustness cases
Budget feasible
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Central selected package across all cases
Decision status
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Knowledge-based robustness indication
Robustness matrix
Decision trace
Formal package rank across robustness cases
BASE DECISION HELD FIXED
This view reports whether the formal base-case package remains feasible and where it ranks under the declared decision rule. It does not silently replace the formal decision.
Decision-package life-cycle cost by case
The base-case decision package is held fixed while assumptions change.
Selected-package represented life-cycle carbon by case
Operational grid pathway and climate assumptions change lifecycle emissions.
Scenario detail
Case
Winner
Same as base
Selected package energy
Selected package Represented LC carbon
Selected package LCC
Budget
Project workspace
Save and reuse assessments.
Saved projects stay in this browser. You can load, duplicate, delete, export or import project files without changing the scientific engine.
Local project store
0 saved projects
Advanced decision analysis
Calculate an assessment first.
Once an assessment has been calculated, this section compares multiple retrofit packages side by side, filters the package universe, exports CSV data, explores sensitivity, and summarizes ranking stability across robustness cases.
Advanced decision analysis
Compare packages and explore trade-offs
Compare up to five packages, filter the full package universe, export results, and examine how the selected solution responds to changing assumptions.
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Current results-screen selection
The thesis-engine comparison architecture remains preserved elsewhere in the software design. This page focuses on richer analysis of the active Knowledge-Based results.
Select packages to compare
Analysis snapshot
Applicable packages
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Pareto-efficient
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Compared now
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Use the package picker to compare the selected package with its most relevant alternatives. The explorer below can filter the full package universe by budget, performance and measure states.
Preference laboratory
Explore decision priorities without rewriting the assessment
This sandbox uses the same feasible package universe and the same min–max normalization as the formal balanced rule. It is exploratory only; the formal result remains unchanged.
EXPLORATORY ONLY
Exploratory leader—
Adjust the emphasis sliders to explore.
Top packages under current emphasis
Side-by-side comparison
Delivered energy comparison
Lower bars indicate stronger energy performance.
Life-cycle cost comparison
Costs are present-value Knowledge-Based estimates.
Represented life-cycle carbon comparison
Lifecycle carbon combines represented embodied and operational impacts.
Selected-package sensitivity
One-at-a-time tests on the current selected package, shown as change in life-cycle cost relative to the base case.
Ranking stability across robustness cases
Ranks are computed under the current objective rule across the nine predefined robustness cases. Lower average rank is better.
Package
Average rank
1st-place cases
Worst rank
Ranks by case
Advanced package explorer
TRY
%
Filtered packages shown: —
ID
States
Measures
Delivered energy
Energy reduction
Represented LC carbon
Initial cost
LCC
Pareto
Research audit & reproducibility
Every result should be traceable to a recorded state.
Inspect controlled model assumptions, current assessment inputs, version identity, methodological boundaries and reproducibility fingerprints from one audit workspace.
Assessment fingerprintNo assessmentCalculate an assessment to generate its reproducibility fingerprint.
ApplicationRetrofitIQ V2.7.1
Scientific engineKB-2.2.0KB-2026.10-R1
Active data source—External dataset or embedded fallback
This ledger is generated directly from the active engine object and current formal assessment record. It is not a manually maintained display table.
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Category
Parameter / path
Value
Unit
Status
Transparent scientific architecture
Methodology & data
RetrofitIQ separates the application interface from the scientific engines. The Knowledge-Based and Thesis-Verified engines can therefore coexist without silently sharing calibrated outputs.
Interface adapter and output schema are installed; the verified thesis dataset is still pending.
Comparison engine
Standby
Activates automatically when the thesis engine becomes available.
Reproducibility metadata: price base year 2026 · analysis base year 2026 · first operational carbon year 2027 · active scientific data source is shown above. The Knowledge-Based carbon result is explicitly bounded to represented components and operational energy.
Glossary
U-value
Rate of heat transfer through an element. Lower values generally indicate better thermal insulation.
WWR
Window-to-wall ratio: window area divided by gross external wall area.
COP
Coefficient of performance: useful heating/cooling delivered per unit of electricity consumed.
Life-cycle cost
Present value of investment, maintenance, replacements and energy, less applicable residual value.
Embodied carbon
Greenhouse-gas impact associated with producing and replacing retrofit components represented by the engine.
Pareto-efficient
A package for which one objective cannot be improved without worsening at least one other objective.
Discount rate
Rate used to express future costs in present-value terms.
Robustness
How stable the preferred decision remains when key assumptions or scenarios change.
Knowledge-Based energy model
Envelope transmission uses H = Σ(U·A). Ventilation/infiltration uses a declared volumetric heat-capacity coefficient multiplied by ACH and volume. Annual heating and cooling loads are estimated from degree-day demand, glazing solar gains and declared utilization factors. All numerical method constants are stored with the engine configuration rather than hidden inside the decision functions.
The 72 packages are generated from W0/W1/W2 × R0/R1/R2 × G0/G1 × S0/S1 × H0/H1. No fixed package-saving percentage is used. Every calculated package must also pass physical-invariant checks before it can enter the decision set.
Lifecycle model and boundary
Life-cycle cost is calculated from one annual cash-flow ledger containing gross upfront outlay, maintenance, replacements, energy expenditure and terminal residual value. The same ledger is used for LCC, discounted payback and the cumulative financial chart. Retained windows, heating and cooling systems have separate age inputs. Monetary outputs use the price-base metadata declared by the engine.
Represented life-cycle carbon includes operational energy carbon plus embodied impacts for the retrofit and replacement components currently represented by the Knowledge-Based Engine. It is intentionally not presented as a complete whole-building, all-module WLCA until the thesis-verified LCA boundary and dataset are installed.
Data status
KB climateIndependent model assumptions for Gaziantep calculationReplaceable JSON
KB envelopeArchetype U-values, ACH and glazing propertiesReplaceable JSON
Thesis LCA/LCCAFinal doctoral data and rulesPending final freeze
Future update path: installing the verified thesis JSON/model replaces the scientific engine data without requiring a redesign of the application screens, charts or reporting structure.
Scientific software verification
Engine diagnostics
RetrofitIQ runs an internal verification suite covering data integrity, the 72-package universe, building physics invariants, lifecycle accounting, budget logic, Pareto filtering, scenario calculations and edge cases.
Important: a passing diagnostic result verifies software consistency against declared Knowledge-Based equations and test cases. It does not mean the KB model has been empirically validated, certified, or thesis-verified.
Current self-test
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Run verification to evaluate the engine.
Tests passed
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Tests failed
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Packages checked
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Runtime errors
0
About RetrofitIQ
Sustainable residential renovation decision support
RetrofitIQ is developed from a doctoral research framework integrating life-cycle energy, carbon and cost performance for residential renovation.
Research team
Researcher
Yahaya Hassan Labaran
Structural Engineering Division Department of Civil Engineering Gaziantep University
Supervisor
Prof. Dr. Nihat Atmaca
Head, Structural Engineering Division Department of Civil Engineering Gaziantep University
✓
Verification completed
All internal verification checks have completed.
RetrofitIQ Research Intelligence
A decision-support workspace built around traceability.
Three principles shape this release: the formal decision is never silently overwritten, exploratory analysis is clearly separated from the formal result, and every assessment can be reproduced from recorded inputs and versioned model data.
01AssessQuick or Expert inputs with recoverable local drafts.
02ExplainFormal rule, runner-up margin, robustness and budget headroom.
03AuditLive assumption ledger, fingerprints and research export.
