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HVAC: Cost matters

18 November 2015

HVAC (heating, ventilation and air conditioning) systems can devour more electricity than anything else in commercial premises, but how can you measure and control these costs? Advanced Engineering considers the question and outlines a solution


The single biggest consumer of energy in a typical UK commercial building is the  (HVAC) system. 


Over an average year, the air con system alone could guzzle more electricity than a building’s annual heating bill, all the PCs and office equipment combined, or two or three times the amount of energy used by the building’s entire lighting system.

Setting out the scale of the problem, Stephen Matthews, chief executive of CIBSE (Chartered Institution of Building Services Engineers), explains: "Air conditioning systems can use as much as 30% of the electrical demand of a building, so a poorly performing system will be wasting a large amount of energy.”

That’s why for service and building managers, keeping air conditioning equipment serviced and maintained to run at peak efficiency is one of the easiest ways to: 

•  Significantly reduce a building’s overall energy usage

•  Enhance your corporate reputation by lowering your carbon footprint 

•  Make major gains in your energy efficiency 

•  Reduce costs associated with breakdowns, callouts and unplanned maintenance


Minimum Energy Efficiency Standard (MEES)


To compound the problem, with changes on the horizon for Energy Performance Certificates (EPCs), air con efficiency will come under increasing scrutiny. An EPC is a legal document which details a building’s energy efficiency rating from A (very efficient) to G (inefficient). Changes involving EPCs are coming as part of a new law; the Minimum Energy Efficiency Standard (MEES), which as of 1 April 2018 will require rented commercial premises to have a rating of at least an E. 


Buildings currently rated with an F or G will need to improve efficiency in order to comply, and estimates suggest about a fifth of UK business properties could be in the F & G rating brackets.


Monitoring role

One of the simplest ways for managers to check air con efficiency over time is to insist that service engineers are using the right equipment to provide this information. Help is at hand through a new intelligent manifold that produces instant reports on exactly on the energy efficiency of the air conditioning system.

While some digital gauges currently used by A/C service engineers don’t have this facility, one example that does is the Imperial iManifold, an 'intelligent' digital manifold from the US that has won awards on both sides of the Atlantic


The iManifold calculates a system’s capacity, evaporator performance, system electrical efficiency, dehumidification, and so on during a routine air con service.


From these calculations, the iManifold can produce a range of technical reports on a system’s efficiency and performance, including instant measurements of the EER (Energy Efficiency Ratio) of an air con system using dynamic, live system data.


The EER is a ratio calculated by dividing the cooling capacity of a system in Btus per hour, by the power input in watts, expressed in Btu/h per watt.


This information can be plotted on live graphs in the field, and detailed reports can be emailed immediately to building managers as a permanent record of an A/C system’s energy efficiency at a particular moment in time and stored in the cloud for future reference.

Importantly, because this data is precise and the measurement is instantly repeatable, these reports can be compared over time, allowing supervisors and managers to spot trends throughout the year or over much longer periods, giving them all the information they need to monitor and control the efficiency of their air conditioning system forever.


The iManifold won the RAC Cooling Industry Awards’ Innovation of the Year Award and two Product of the Year Awards this year, one at the ACR News Awards and another at the National ACR Awards. It is distributed in the UK by Advanced Engineering.