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With phrases such as Carbon Footprint and Sub metering being banded about so much these days it is easy to get confused about what you might be required to meter. Add to that all the almost daily “we can save you money” phone calls and it gets more than a little confusing as to what might be the best path to take. This article aims to give a general introduction to Submetering and Part L of the building regulations.
Explanation
So first of all what is Sub metering? Sub metering is when you split energy usage into different parts and meter each part individually. For example if you were metering an office building you might put the lighting on one sub meter and the air-conditioning on another. By splitting these systems onto different meters it is possible to find out if one of the systems is wasting money. If your air conditioning is still running at 3am then unless your employees work very late it is probably wasting energy. This type of sub metering is often referred to as Automatic monitoring and targeting (AM&T).
AM&T systems are usually splitt into three parts:
- Meters and Transducers
- A means of capturing, retrieving and storing data electronically
- Analysis/Production of consumption management reports
Benefits
So that is the definition but what does that mean to a business? Can sub metering actually save you money? The simple answer to that is probably.
The first thing to note is that by installing sub metering alone you will not save money. To save money a metering system must be actively analyzed to find out where energy is being wasted and then the information acted on accordingly. Also if your company is already very efficient in terms of energy usage then you will also not save much, if any money.
It is however reckoned that on average AM&T can typically result in 5-10% savings and sometimes more.
Also to add to this 100% of first year Enhanced Captial Allowances (ECA's) are available on AM&T systems*. This is usually around 7-8% of the cost of the equipment.
The Regulations
Part L of the building regulations covers energy efficiency requirements. Since 2002 part L has recognised the role of sub metering by including requirements for non domestic buildings to be sub metered. In new buildings installing sub meters to account for at least 90% of the estimated annual energy expenditure is considered reasonable. In some cases existing buildings might be required to have this also.
To enable proper use of an AM&T system the building owners or occupiers should be provided with sufficient meters and sub meters as well as instructions on use and an overall metering strategy showing how to attribute energy consumptions to end uses.
Conclusion
In conclusion whether you are required to have it or not AM&T can probably save you money on your energy bills. Add to that the ECA benefits and the whole proposition starts to look rather attractive. Be it to seriously cut down your carbon footprint or to print off reports to show you clients that you are trying to make a difference sub metering would seem to provide an answer. If you would like anymore information on sub metering or AM&T systems please contact B&S Group at www.bsgroupltd.com
References and Useful Sites
The Chartered Institute of Building Service Engineers (CIBSE)
* for full details see the official website at: www.eca.gov.uk
Last Updated: May 01, 2008
