What Is Energy Management in BMS?

The Founder's Explanation (Teach Exactly This Way)

"Consider in home — when we are growing, when we are getting out of home, we need to power off the lights, fan, AC. When water tap is opened we have been instructed to close it immediately. Even single drop of water we do not allow to flow. This is not only a saving practice — this is part of life with social responsibility.

This we have to do in big buildings — called energy management. To do that we need to measure all those energy. Like how we do EB meter reading when the lineman comes for reading — we curiously ask how much cost for this month's EB bill and how many units consumed. Then we plan at home — the next month immediately the parents will tell us to be careful while using and we plan how we can save. That is called energy management."

Teaching the Concept

The EB Meter Story

Any home. Any Indian city. First week of the month.

The EB lineman arrives. Opens the meter box. Reads the number. Leaves a slip.

Both parents pick up the slip. Eyes go wide.

"1,847 units this month?! Last month was 1,200!"

Everyone is called. The investigation begins:

"Who left the AC running all night?"
"The geyser was on all morning again"
"Lights left on when going to school"
"The old refrigerator is consuming too much"

The plan is made:

"Switch off AC at 11PM — use fan after that"
"Geyser timer — 30 minutes only"
"Last person leaving a room switches off lights"
"Next month we replace that old refrigerator"

Next month — 1,380 units. Parents smile.

That entire process — measuring, understanding, planning, acting, reducing — is Energy Management.

Buildings do the same thing. Just at a much larger scale.

Why Energy Management Is Social Responsibility — Not Just Cost Saving

When parents told you not to waste water — they did not just say "water costs money." They said: "Do not waste. This does not come from nowhere."

In a large building:

One office tower in Chennai
Running 10 hours a day
Air conditioning alone consumes enough electricity
to power 400 homes for the same period

When a building wastes energy:

More coal burned at power plant
More CO2 released into atmosphere
More demand on the grid
Less power available for homes, hospitals, schools
Higher carbon footprint for the city

Energy management in buildings is the same responsibility parents taught at home. Close the tap. Switch off the light. Do not waste what the world provides. Scale it to a building — and the impact on the city is enormous.

BMS as the Parent Closing Every Open Tap

Variable speed drives on pumps and fans — controlled by BMS — run only as hard as needed.

A chilled water pump running at full speed all night while only 2 floors are occupied is the tap left running. BMS closes it — reduces pump speed based on actual demand. Automatically. Every night. Without being asked.

Five BMS Energy Strategies:

1. SCHEDULING
   Problem: AC runs 24 hours though office is 9AM–7PM
   Solution: BMS starts 30min before, stops 30min after
   Saving: 30–40% reduction in HVAC energy
VARIABLE SPEED DRIVES (VFD/VSD)
   Problem: Pump at 100% speed when 30% flow needed
   Solution: BMS reads demand → reduces pump speed to 40%
   Physics: Fan at 50% speed uses only 12.5% of energy (cube law)
   Saving: 40–60% on pump and fan energy
DEMAND CONTROL VENTILATION
   Problem: Fresh air fan at full capacity even at 11PM (2 guards)
   Solution: BMS reads CO2 → adjusts fan speed accordingly
   Saving: 25–35% on ventilation energy
CHILLER SEQUENCING
   Problem: 3 chillers at 30% load each — highly inefficient
   Solution: BMS runs 1 at 90% or 2 at 45% — better COP
   Saving: 15–25% on chiller plant energy
TENANT SUB-METERING
   Problem: Shared bill — nobody responsible for wastage
   Solution: Individual meters per tenant — direct accountability
   Human behaviour changes when people see their own number
   Saving: 10–20% just from accountability alone

Related Topics

• What is BMS integration? — how a BMS connects with VFDs, energy meters, BACnet/Modbus devices and other building systems
• How to design a BMS system step by step — the complete BMS design methodology covering site survey, IO list, controller selection, sequence of operations
• What is a Building Management System (BMS)? — fundamentals of BMS controls and architecture for HVAC, lighting, energy and access
• What is BMS commissioning? — the disciplined commissioning process that turns a BMS install into a working building brain
• Browse all Energy Management topics — more from this section of the EnSmart BMS Library