2.2 Energy, Water & Materials Calculator Tabs
Key Takeaways
- EDGE requires a minimum 20% performance reduction in operational energy, operational water, and embodied energy in materials compared to the Base Case.
- The Energy tab models passive envelope measures, HVAC efficiency, lighting power density (LPD), hot water systems, and solar photovoltaics.
- The Water tab evaluates low-flow indoor plumbing fixtures, efficient appliances, rainwater harvesting, greywater recycling, and blackwater treatment.
- The Materials tab assesses cradle-to-gate embodied energy for roofs, external walls, internal partitions, floor slabs, window frames, and insulation.
- The software calculates dynamic cross-tab interactive effects, such as LED lighting reducing space cooling loads or low-flow showerheads reducing hot water energy.
2.2 Energy, Water & Materials Calculator Tabs
Quick Summary: The core modeling engine of the EDGE App is split across three interactive measure tabs: Energy, Water, and Materials. Achieving EDGE Certified status mandates a minimum 20% reduction across all three categories against the Base Case baseline. EDGE dynamically models interactive effects—such as lighting power reductions lowering cooling loads, or low-flow showerheads reducing water heating energy.
1. Core Calculator Tab Interface & Navigation
The central workspace of the EDGE App displays three primary calculator tabs. Selecting a tab opens an interactive list of recognized green building measures. Each measure contains check-boxes, input fields for Proposed Design specifications, and default values displaying Base Case baseline specifications.
Key Interface Components
- Measures Checklist (Left Pane): Displays available passive, active, and conservation measures relevant to the building typology.
- Specification Input Panel (Center Pane): Allows teams to enter specific thermal, mechanical, hydraulic, or material values (e.g., U-values, COP, flow rates, material types).
- Real-Time Gauge Bar (Top Pane): Displays continuous percentage reduction gauges for Energy (%), Water (%), and Materials Embodied Energy (%).
2. The Energy Calculator Tab
The Energy tab targets operational electricity and fuel consumption. Measures are categorized into passive bioclimatic strategies, active mechanical/electrical efficiency, and renewable energy generation:
Passive & Envelope Measures
- Window-to-Wall Ratio (WWR) Reduction: Decreasing excess window area reduces conductive and solar heat gain.
- External Shading Devices: Installing horizontal overhangs or vertical fins with specific solar cut-off angles to block direct solar radiation.
- Solar Control Glazing: Specifying glass with lower Solar Heat Gain Coefficient (SHGC) and reduced Thermal Transmittance (U-value) in W/m²K.
- Roof & Wall Insulation: Adding thermal insulation (polystyrene, mineral wool) to reduce envelope heat transfer.
- High Reflectance Roof Coating: Applying paint/coatings with a high Solar Reflectance Index (SRI $\ge 78$) to reduce urban heat island absorption.
Active Mechanical & Electrical Measures
- High-Efficiency HVAC Systems: Upgrading cooling/heating equipment performance measured by Coefficient of Performance (COP), Energy Efficiency Ratio (EER), or Seasonal EER (SEER).
- Variable Speed Drives (VSDs): Equipping chillers, cooling tower fans, and water pumps with frequency drives to optimize partial-load operations.
- Lighting Power Density (LPD) Reduction: Replacing conventional fluorescent/halogen lighting with LED fixtures to lower LPD (measured in W/m²).
- Lighting Controls: Installing occupancy sensors in intermittent spaces and daylight dimming sensors in perimeter zones.
Hot Water & Renewable Energy
- Solar Water Heating (SWH): Installing solar thermal collectors (thermosiphon or pumped) to meet domestic hot water demand.
- On-Site Solar Photovoltaic (PV): Installing solar PV panels to generate zero-carbon electricity, directly offsetting grid electricity consumption.
3. The Water Calculator Tab
The Water tab models operational potable water consumption from indoor fixtures, operational appliances, and outdoor irrigation:
Indoor Plumbing Fixture Measures
- Low-Flow Showerheads: Reducing flow rates from baseline levels (typically 10 L/min) to efficient levels (e.g., 6 L/min or lower at 3 bar pressure).
- Low-Flow Faucets: Installing aerators on kitchen and bathroom basin faucets to reduce flow rates (e.g., from 8 L/min to 4 L/min).
- Dual-Flush Toilets: Replacing standard single-flush toilets (6 LPF) with dual-flush toilets (e.g., 4.5/3.0 liters per flush - LPF).
- Waterless or Low-Flush Urinals: Utilizing liquid-barrier waterless urinals or ultra-low flush (0.5 LPF) urinals in commercial facilities.
Water Recycling & Harvesting Systems
- Rainwater Harvesting: Capturing stormwater from roof surfaces. Inputs include roof catchment area (m²), runoff coefficient (typically 0.8-0.9), and storage tank volume (m³).
- Greywater Treatment & Reuse: Collecting low-contamination wastewater from showers, bathtubs, and washbasins, treating it on-site, and re-routing it to supply toilet flushing and landscape irrigation.
- Blackwater Treatment: Installing on-site sewage treatment plants (STP) to treat all domestic wastewater for non-potable reuses.
4. The Materials Calculator Tab
The Materials tab evaluates embodied energy—the cumulative primary energy consumed during raw material extraction, processing, manufacturing, and transportation (cradle-to-gate) for major structural and envelope components.
Scope of Material Evaluation
EDGE focuses on six core structural and envelope building elements:
| Building Element | Standard Base Case Baseline Spec | High-Efficiency Proposed Design Alternative |
|---|---|---|
| Roof Construction | Heavy in-situ concrete slab | Light timber truss with metal sheet, or precast hollow-core slab |
| External Walls | Solid uninsulated concrete block | Autoclaved Aerated Concrete (AAC) blocks, or hollow concrete blocks |
| Internal Partitions | Solid clay brick masonry | Gypsum drywall on light steel studs, or AAC block partitions |
| Floors Slabs | Heavy solid reinforced concrete slab | Post-tensioned concrete slab, or precast hollow-core concrete slab |
| Window Frames | Standard solid aluminium frames | uPVC frames, timber frames, or thermally broken aluminium frames |
| Insulation Materials | Expanded Polystyrene (EPS) | Rockwool, glass wool, or recycled cellulose insulation |
Cement Replacement & Recycled Content
Teams entering concrete specifications can adjust the concrete mix design by entering the percentage of Portland cement replaced by industrial by-products such as Fly Ash (pulverized fuel ash) or GGBS (Ground Granulated Blast-furnace Slag). Replanting 30% of cement with GGBS significantly reduces overall embodied energy and carbon.
5. Systemic Cross-Tab Interactive Effects
Unlike simplistic green building checklists, the EDGE App uses an integrated calculation engine where measures in one tab dynamically alter calculated performance in another tab.
+-----------------------------------------------------------------------+
| CROSS-TAB INTERACTIVE EFFECTS |
+-----------------------------------------------------------------------+
| |
| [Water Tab: Low-Flow Showerheads] |
| │ |
| └─► Reduces hot water volume |
| │ |
| └─► Decreases water heating kWh [Energy Tab] |
| |
| [Energy Tab: LED Lighting (Lower LPD)] |
| │ |
| └─► Reduces internal sensible heat gains |
| │ |
| └─► Reduces HVAC space cooling load [Energy Tab] |
| |
| [Energy Tab: External Shading & Low-SHGC Glass] |
| │ |
| └─► Reduces peak solar radiation intake |
| │ |
| └─► Downsizes chiller capacity & cooling kWh |
| |
| [Materials Tab: Precast Hollow-Core Slabs] |
| │ |
| └─► Reduces structural concrete volume per m² |
| │ |
| └─► Reduces embodied energy % [Materials Tab] |
+-----------------------------------------------------------------------+
Key Interactive Mechanics
- Lighting LPD & HVAC Cooling Load: Lowering Lighting Power Density (e.g., from 12 W/m² to 5 W/m² via LEDs) reduces internal sensible heat gains. In warm climates, this directly shrinks the space cooling load, dynamically reducing total chiller kWh consumption.
- Low-Flow Showerheads & Energy Use: Installing 6 L/min showerheads reduces daily domestic hot water volume. The EDGE software automatically calculates this volume reduction and transfers the energy savings directly to domestic water heating energy in the Energy Tab.
- Passive Solar Controls & HVAC Sizing: Installing external window overhangs lowers solar heat gain entering space, reducing required HVAC cooling capacity and annual cooling energy requirements.
What is the mandatory minimum percentage reduction required across ALL THREE categories (Energy, Water, and Materials) to achieve basic EDGE Certified status?
How does the EDGE App calculation engine handle internal heat gains when a design team selects high-efficiency LED lighting with a reduced Lighting Power Density (LPD)?
Which of the following structural or envelope building elements is evaluated under the Materials calculator tab in the EDGE App?
If a project design team installs low-flow showerheads (6 L/min vs 10 L/min baseline), in which calculator tab(s) will performance improvements be calculated?