BAS Schedule Control: Simple but Best


Almost all buildings, in particular hospitals, have a Building Automation System (BAS). It’s is like the brain of a building. BAS controls most HVAC devices, such as pumps, fans, boilers and chillers. It is an interconnected, centralized system of both hardware and software, like a central nervous system. BAS provides lots of benefits, including the ability to control your building from anywhere and improved energy management. It automates all your heating, cooling and air flow needs with minimum interference.


Quite a lot operators, supervisors and facility managers leave the fans and pumps running continuously. This might seem like a good idea  … the system works all the time and users would not complain any more. But this is not a good practice as the constant use will wear out motors, belts and pumps before their time. Maintenance cost will rise and the utility bill will rise even higher.

Like people, building systems need a break. The best way is to check how people use a building, and see if we can schedule control changes for the area. If an area is only used some of the time, say during business hours, we know we can power down HVAC units after hours.

We have to make sure the unit could be turned on when needed. For example, if the air handling unit is set to unoccupied mode, it does not supply any conditioned air to the space, but it will restart when the space temperature drops below the unoccupied heating setpoint or unoccupied cooling setpoint. Only when there is a good backup plan can users feel comfortable and support these energy-saving scheduling initiatives.

With schedule control, devices will run for less time. Usually we can turn it off over the weekend. Even if we need to run the unit 12 hours a day, from 7am to 7pm, we could still save 65% on the electricity of the motor. The savings grow when we factor in gas for heating or electricity for cooling.

Below is a simple trend chart for a unit.

As the unit was running continuously before, the electricity consumption was 170,792KWh annually.


After we implemented a weekday schedule, the power consumption dropped to 60,830 KWh. The users did not feel any difference.


Schedule control on an HVAC device is a straightforward and most efficient way to save energy. It could also extend lifetime of the equipment itself. That’s saving 2 ways … a real no-brainer.



AC Motors, VFDs, and Energy Savings at Toronto General Hospital

I’d like to share two recent energy projects at Toronto General Hospital, which used VFDs to achieve significant energy savings and improve control.  When I say significant I mean that the savings could buy a house, well maybe not a house in Toronto.  There is also a fairly technical explanations of motors and variable frequency drives but I’ll leave that to the end for obvious reasons.


VFDs and Harmonic Filters on Secondary Chilled Water Pumps at TGH


Project 1: Reinstate VFD operations on Air Handling Units

At TGH we had 17 old Continue reading

T8: Retrofit Day

Come with me if you want to saveYes, I am from the 90s when Terminator 2: Judgement Day was the coolest thing since sliced bread.  Since then, Continue reading

Quick Hit – Bickle Parking Lot Lighting

As all of our devoted followers know, UHN’s Energy and Environment team is constantly looking for opportunities to upgrade old inefficient lighting to highly efficient LEDs.  Over at the Toronto Rehab Bickle Centre, facilities has had ongoing problems with light levels in the parking areas, largely due to existing HID metal halide lamps burning out.  The existing lighting consisted of a mix of 400W and 250W metal halide lamps, which have an average operating life of 8,000-15,000 hours (i.e. 1-2 years).  With several lamps burning out, we had an opportunity to go with a better LED option.

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Chad at Home: Investigating Energy Waste

My wife and I were looking for a home in the hot Toronto housing market, but we had been having a rough go of it (bidding wars, hidden problems, outright lies, etc). So when a little two story semi-detached house became available for rent just down our street, we grabbed it. We moved from our tiny one bedroom apartment to remain as renters for a bit longer, just a little more comfortably. As both of us are sustainably inclined we still wanted to make it as energy efficient as possible, but what is a renter to do?

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Awards season off to a great start

Also – a bit of unexpected yet good news Monday at HealthAchieve – UHN became the first ever hospital to be inducted into the Energy Efficiency Winner’s Circle.  The award recognizes UHN’s leadership in energy management within Ontario hospitals over the years.   We also received the Waste Management Award but we lost Green Hospital of the Year by 20 votes…20 votes!!! But we were acknowledged as a finalist. Feel good…this is a sizeable accomplishment!

UHN OHA Green Awards 2014-proshot

Ed Rubinstein, Lisa Vanlint, Kady Cowan, Adeline Cohen & Stewart Dankner celebrate 3 Green Healthcare wins for UHN

OHA 2014_Fotor

Energy Winner’s Circle, Waste Reduction & Green Hospital Finalist

Water Efficiency – Is your Refrigeration Sending $$$ Down the Drain?

When we think of refrigeration, we usually think of a cold beer, yummy food, and all those miscellaneous science experiments hiding in the back.  I’d like to temporarily change all that and focus on how it works, why some commercial refrigeration wastes tons of water, and a fantastic example of a retrofit project at UHN.  Then we can go back to trying to identify that smelly mystery jar that you came across while cleaning out the bottom shelf.

Refrigeration works by Continue reading