Energy & Efficiency Estimator.
— Energy · BMS & lighting retrofit · BEE / ECBC / ASHRAE 90.1 / CEA
The energy case, in plain numbers.
Use-type Energy Performance Indices from BEE ECBC 2017 + GRIHA v3, BMS savings calibrated to ASHRAE 90.1 retrofit studies, CO₂ tied to the CEA grid factor. Defensible at board level; pricing follows a written estimate after review.
Saving potential
73,440
kWh / yr · ≈ 19% of consumption
Annual baseline
3,94,838
kWh at 85 kWh / m² · yr
CO₂ avoided
52 t
per year · CEA grid 0.71 kg / kWh
Use profile
12 h
× 300 days / yr
A planning link that reopens this exact configuration — not a quote.
- bms / hvac
- 34,746 kWh — scheduling, setpoints, plant sequencing
- lighting
- 24,875 kWh — LED retrofit + daylight harvesting
- tariff / pf
- 13,819 kWh — power-factor + tariff optimisation
- epi source
- BEE ECBC 2017 · GRIHA v3
- epi applied
- 85 kWh / m² · yr
- hvac share
- 55%
- lighting share
- 18%
- bms savings
- 16% of HVAC load (ASHRAE 90.1)
- led + harvesting
- 35% of lighting load
- tariff / pf
- 3.5% of total load
- co₂ factor
- 0.71 kg / kWh (CEA grid)
- standards
- BEE ECBC · GRIHA · ASHRAE 90.1 · CEA
+ Model assumptions (9)− Model assumptions
Indicative — modelled against BEE ECBC 2017 EPI bands and ASHRAE 90.1 retrofit savings ratios. A site audit calibrates against actual consumption, building envelope, weather profile and existing condition. Pricing and commercial payback follow a written estimate after technical review.
What changes this estimate
- Actual metered consumption against the EPI band
- Building envelope and glazing condition
- Weather profile and seasonal load shape
- Existing controls, plant condition and tariff structure
Engineering notes
HVAC dominates this use-type's energy — the controls layer (BMS sequencing, schedules, setpoint discipline) carries most of the achievable saving; metering and a baseline survey calibrate the real figure.
A planning link that reopens this exact configuration — not a quote.
Energy readiness report
Print-styled energy brief, ready to circulate. Energy figures only; pricing follows a written estimate after review.
BMS \u00b7 Energy \u00b7 Efficiency
Indicative energy reduction for a BMS-driven energy upgrade plus daylight-harvesting LED retrofit \u2014 kWh saved, percent energy reduction and CO\u2082 avoided. Conservative model; defensible numbers; designed for the first board conversation. Pricing follows a written estimate after review.
- Energy reduction
- 16–20%
- LED dimming range
- 30–60%
- Grid CO₂ factor
- 0.71 kg/kWh
- Model basis
- Measured kWh
Operationally sensible ecosystem
Brands grouped by engineering role — not random logos.
BMS platform
BACnet / Niagara orchestration
- Honeywell EBIMid-enterprise BMS
- Delta enteliWEBWeb-based mid-enterprise
Lighting & control
Backbone bus, keypads, drivers, dimming
- Lutron HomeWorksReference residential bus
- KNX (ABB / Gira)European hardwired standard
- RakoBritish keypad lineage
UPS / power conditioning
Single + 3-phase + transfer
- APC Symmetra LXModular 3-phase mid
- Vertiv Liebert APMModular 3-phase mid
· Starting configurations
Typology presets — pick a scenario, see the calculator.
Each preset opens a curated configuration page with the engineering reasoning behind the numbers. Then the calculator loads with the same inputs — change them and the URL stays shareable.
· Engineering advisory · Energy Estimator
What the energy-reduction figure actually represents.
The 16-20 percent energy reduction is the model's headline output, but the four notes below frame what the reduction depends on, where it gets eaten, and the operational discipline needed to realise it.
Deployment observations
- The 16-20 percent annual energy reduction comes from controls, not behaviour — sensor-driven HVAC scheduling, occupancy-based lighting, daylight harvesting in perimeter zones, plug-load control on shared circuits. The model deliberately assumes zero behavioural reduction; that is the discipline that makes the figure defensible.
- Daylight harvesting in perimeter zones is the highest single contributor — Indian commercial buildings receive enough perimeter daylight that overhead lighting can dim 30-60 percent during working hours without occupant perception. The retrofit is modest in scope; the kWh reduction compounds for the fixture's life.
- The model applies conservative midpoints of the published retrofit bands — 12-20 percent of HVAC load for BMS-driven optimisation, 30-45 percent of lighting load for LED plus daylight harvesting, 2-5 percent of total load for power-factor and scheduling discipline — never the ceilings. Commissioning gaps, sensor drift and occupant overrides are why the midpoints are the honest basis; specify a six-month re-commissioning visit in the AMC contract.
Operational notes
- Sensor calibration drifts at 3-5 percent per year on PIR / LUX / CO₂ sensors. Schedule a half-day annual sensor sweep — without it, the BMS scheduling logic gradually drifts from energy-optimal towards occupant-optimal, eating 4-6 percent of the energy reduction per year.
- The dashboard reporting is the political artefact, not the technical artefact — monthly energy reports to the FM team are what keeps the reduction honest. Without reporting cadence, the reduction is recoverable but not visible, and the next planning round forgets the upgrade.
Lifecycle implications
- LED fixture L70 life is 50,000-70,000 hours nominal — 14-20 years at office hours. The retrofit holds its kWh reduction across that whole window. The BMS hardware refresh window is 8-12 years; the LED fixtures outlive two BMS generations.
- Energy intensity, not tariff, is what the model reports — the percent kWh reduction holds whatever the tariff does. The model uses measured baseline consumption as the floor; the realised reduction tracks the building's actual load, not the bill.
· Example use
A 60,000 sq ft commercial office running fluorescent lighting and standalone HVAC controls lands on an 18 to 19 percent annual energy reduction when retrofitted with a BMS-driven control layer plus daylight-harvesting LED — the model's band across all use-types runs 16 to 20 percent. The model assumes nothing about behavioural change — the reduction comes from controls, not from staff. Pricing follows a written estimate after review.
· Frequently asked
The energy case —
what people ask first.
What is included in the BMS scope?
Sensor-driven HVAC scheduling, occupancy-based lighting, daylight harvesting in perimeter zones, plug-load control on shared circuits and a head-end dashboard with monthly reporting. Tenant fit-out lighting is excluded unless commissioned together.
Why daylight harvesting specifically?
Because perimeter zones in Indian commercial buildings receive enough daylight that overhead lighting can dim by 30 to 60 percent during working hours without an occupant noticing. The retrofit is modest in scope; the kWh reduction compounds for the lifetime of the fixture.
How conservative are the numbers?
We use audited BEE / ECBC energy-intensity bands per use-type and conservative midpoints of the published retrofit ranges — 12 to 20 percent of HVAC load for BMS-driven optimisation, 30 to 45 percent of lighting load for LED plus daylight harvesting, 2 to 5 percent of total load for power-factor and scheduling — with no behavioural-reduction assumption. Across use-types the model lands between 16 and 20 percent of annual consumption, calibrated against the site's measured kWh before any figure is reported.
Will the retrofit qualify for any incentive?
BEE, EESL and several state DISCOMs run rebate or financing programmes for energy-efficiency retrofits; some MNCs run internal sustainability programmes for aligned projects. We do not include incentives in the base energy case — they sweeten the result, they do not justify it.
Is this for new buildings or retrofits?
Primarily retrofits — the energy case is sharpest where you can compare a real "before" consumption baseline. For new buildings, we run a different model that compares the BMS-driven design against a code-minimum baseline and shows the lifecycle energy-intensity difference.
· Begin
Building an energy case
for the board?
Send twelve months of bills, the building drawings and the operating profile. We will return a written energy-reduction model within two working days, with pricing following a written estimate after review.