How much does hot water actually cost your business?

Hot water is an often unrecognised part of energy costs since most properties have one meter that covers both heating & DHW. This means that hot water costs are absorbed into overall energy heating costs. However, the cost of hot water can be substantial, sometimes as much as 47% of the overall bill.

Therefore making savings on your hot water costs could result in significant savings on overall consumption.

Martyn Savage, Technical Director at CircoSense explains more: “The biggest issue in a flow and return DHW system is that most of this hot water is wasted due to circulation losses. While the building is in operation the water will circulate continuously even though there will not be a continuous demand. As the water circulates, it loses heat and in some cases can be returning to the stored hot water vessel at up to 15 degrees cooler, which in turn causes the boiler to repeatedly fire up in order to maintain boiler set point temperatures”.

What can be done about it?

CircoSense uses smart technology to learn and store usage patterns forecasting probability and length of use to achieve a balance between optimal energy saving and optimal comfort level. It does so by measuring flow and return temperatures.

CircoSense provides instant and improved results as the system learns the buildings DHW demands. Since most building operators switch off boiler plant when the building is not in operation, CircoSense typically makes it savings while the site is open. This results in many small gains equating to average overall savings on DHW consumption of 39%.

CircoSense3000 was initially trialled under the supervision of the University of Strathclyde’s ‘Eco Innovation Unit (SEIU)’ for Renfrewshire Council at their Langcraigs Primary School. The trial was proven a success with energy saving empirically verified by the SEIU of a 42% reduction on the fuel to heat the Domestic Hot Water System.

How does CircoSense work?

CircoSense switches on your circulation pump only when required in three overlapping operating modes:

1) Look-ahead circulation

The CircoSense system learns and automatically stores hot water usage patterns. After regular daily consumption patterns have been recognised, CircoSense will automatically start hot water circulation in advance of the recognised usage patterns, thereby ensuring water is circulating when required.  CircoSense keeps “learning” constantly and continuously adjusts the look-ahead running times to the actual tapping times. If the usage patterns are abandoned, CircoSense of course “forgets” them again, too.

2) Random request

Should there be a call for hot water outside the normal recognised usage patterns CircoSense will immediately react to this. Our sensors will detect the call for water and will reactivate the circulation pump. Provided the boiler has been left in normal operation (i.e. it has not been turned off by a BMS or other programmed system), then hot water will be circulated immediately and be available after a short time at the outlet.

3) Circulation Cycling 

CircoSense has a built-in cycle where if there is no detected usage and no look ahead usage for a period of 24 hours, CircoSense3000 automatically circulates the water until the return temperature is steady at the maximum recorded level. This helps to ensure that HSE guidelines for water circulation are adhered to. This setting of 1 circulation cycle is automatically programmed into the system as a minimum requirement and follows HSE guidelines in this regard. Should the client request, the system can be programmed, either before or after installation, to circulate more frequently if required.

Where will CircoSense work effectively?

Although many of the installations have been in the education and leisure sectors, the table below includes information from metered Proof of Concept trials and demonstrates clearly that CircoSense works across all sectors where flow/return systems are present.

Other clients include Heathrow Airport, Emcor, CBRE, BAM, Servest, ISS Facility Services, Abellio ScotRail, Surrey Police, and many councils including Essex, Surrey, Ealing, Nottingham in the South and Glasgow, North Ayrshire, South Ayrshire, Renfrewshire & Aberdeenshire in the North.

Proof of Concept Process:

The Proof of Concept process for the CircoSense3000 allows you to try our innovative technology over a 6-week period, with peace of mind that if it doesn’t deliver as agreed in our proposal, you have no obligation to buy. Additional metering is installed on the DHW source for accurate M&V, while data logging equipment is fitted for remote visibility to ensure flow/return temperatures are being maintained. All of this information is included in the M&V report presented to you at the end of the 6-week trial.

NHS Water Quality Testing

NHS Greater Glasgow & Clyde were interested in a Proof of Concept trial at their Fernbank Health Centre to see the savings which could be achieved. Additional metering accurately demonstrated a saving of 53% on DHW consumption while data logging equipment showed flow/return temperatures being maintained however NHS Greater Glasgow and Clyde understandably advised that the safety and wellbeing of staff and patients alike was of paramount importance and that they were to instruct their own external water sampling results to ensure water quality had not deteriorated since the trial was fitted.

The test procedure started on 4th April 2017 and finished on 19th May 2017. Water samples were collected two times per week from 6 outlets and were analysed for Legionella.  There was no Legionella growth found in any of the 12 water samples collected.

Case Study 1 – Nottingham City Council Victoria Leisure Centre

CircoSense was installed at Victoria Leisure Centre in December 2016 on a ‘Proof of Concept’ basis, with heat metering installed for accurate M&V. After the trial period concluded, it was established that the CircoSense3000 had saved over 24.5% on DHW consumption resulting in a payback period of 1.78 years.  Since then Nottingham City Council have installed in a further 12 leisure sites.

James Kirkwood, Energy Project Officer at Nottingham City Council, stated, “One of my roles within Nottingham City Council is to implement energy saving projects to our buildings using Salix funding. We have several leisure centres with high hot water demands – with energy prices rising and the cost of water, as an aside, also rising, the opportunity to reduce hot water usage was too good to miss. We trialled the CircoSense unit at one of our busier leisure centres with the view that if the unit can be cope with the peaky nature of the hot water consumption here, it could be implemented elsewhere. The 6-week trial resulted not only in excellent energy savings that could easily be funded by Salix, but there were no adverse effects to the hot water demand to the user and the ‘fit and forget’ nature of the unit was welcomed by operational staff. Following this the easy decision to extend the installation to other leisure centres and high use sites was reached with several leisure centres, large offices and a theatre included. Similar energy savings were found and the professional nature of the works, the installation and follow-up measurement and verification reports were excellent and I would recommend this technology to anyone struggling with hot water demands at their sites.”

Case Study 2 – Ealing Council

CircoSense3000 was trialled at the Greenford Service Centre on a ‘Proof of Concept’ basis. Using an additional gas meter for DHW it was determined that CircoSense3000 had resulted in a 31% saving on DHW consumption. Since the initial trial Ealing Council have installed in further sites and have included CircoSense in their energy reduction strategy.

Ivan Sommerville, Building Services Manager at Ealing Council, commented, “I am pleased with the systems we have installed to date at London Borough of Ealing. We were approached by CircoSense regarding installing HWS control systems on our sites, we carried out a trial with sub-metering and the results proved the system was saving 30% on the water heaters gas consumption. We have since installed more systems and are monitoring the performances with a view of installing more systems where they are providing a below 5 year payback estimation.”

 For more information on the CircoSense device and the savings it can provide, please call on 0333 320 1000 or visit the website,