How much of a BMS upgrade directly results in energy savings?
Energy efficiency and hardware end of life are two common reasons for BMS upgrades. If the BMS controllers are failing or are no longer supported, then a complete upgrade may be required. However, in many cases a complete upgrade is not required as part of an energy efficiency upgrade.
The table below lists the BMS upgrade tasks as a cost percentage* that do not directly result in energy savings, in other words, the money that you spend doesn’t directly translate into an increase in NABERS rating or reduction in utility bills.
For example, the electrician physically replacing the current controller with a new controller does not save energy. Rebuilding the graphics, database, alarms, trends and user accounts does not save energy. The cost of the physical BMS controllers does not save energy. Project management costs do not save energy. Sales overhead and margin do not save energy.
The table below lists the BMS upgrade tasks as a cost percentage* that result in energy savings. For example, designing new energy efficient control strategies does save energy.
Approximately 70% of the cost to upgrade the entire BMS does not directly result in energy savings, only 30% of the cost results in energy savings. Therefore, if your primary driver is to save energy, improve your NABERS rating and attract higher profile tenants, then only upgrade the control strategies.
The commissioning cost in the table above is to commission each input and output point once the controller is replaced. Technically, we don’t need to recommission the points if we don’t replace the controller, however, in this comparison I have kept the 20% cost to commission the new software control strategies.
If demanding energy improvement targets have been set over the next 12 months you could consider delaying BMS periodic preventative maintenance for 12 months and redirecting some of the maintenance budget towards control strategy optimisation.
* The cost percentages above were averaged from four office tower BMS upgrades from the same tier one BMS manufacturer, in the range of $500,000 to $700,000. The purpose of this comparison is to give you a feel for where the money goes. Depending on the building type, building grade, geographical region, type of BMS company and scope will vary the percentage of each break up.
If you are a BMS engineer, see this previous blog for a bit more about control strategy training: BMS Training: Advanced Control Strategy Optimisation
If you are a building owner or facility manager, then please reach out to discuss a BMS energy efficiency strategy. Which is typically a combination of the following:
BMS Specific maintenance specification
BMS Control strategy upgrade specification
Facility manager training
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