Acceptance Testing resulted in excellent block level performance

Low return temps across the network minimises risk of overheating

Prevented debt risk

“The FairHeat support on this project has been excellent. The properties were handed over with installation and performance of the systems as per design, which led to limited resident complaints for the heating and hot water systems. The ongoing maintenance has been a very effective way of keeping performance at a suitable level, ensuring that any issues are addressed as quickly and efficiently as possible.”

Communal Heat Manager

Housing Association


The client is one of the largest providers of affordable housing and care in England. The project entailed a development of 140 units located in London, with a mix of tenures (affordable rent and private). The heat network, with heat distributed from a plant room containing boilers and CHPs, serves heat interface units (HIUs) in every dwelling providing heating (via radiators or underfloor heating) and hot water. The development consists of Guru Hubs installed in every dwelling and at block level to facilitate metering & billing and remote monitoring


In 2016, the site was a brand-new residential development project undergoing construction. FairHeat was engaged with the purpose of verifying LTHW installation, commissioning and operation at a dwelling level prior to occupation, as rectifications and remedial works post-occupation can be much more tricky and costly to organise.
The client, a housing association, had had issues with poor dwelling level performance post-occupancy on several previous sites so wanted to ensure that this did not occur here, as poor performance can have negative knock-on effects, including elevated tariffs, corridor overheating and heating/hot water delivery outages.
Two years after the development handover, HIU servicing was required to ensure operation remained consistent and any parts that were faulty were replaced.

FairHeat Solution

The housing association engaged FairHeat to carry out Acceptance Testing at the project site to verify dwelling level installation, commissioning, and operation. The purpose was to ensure that design intent was being met and resident comfort was factored into the overall installation.

FairHeat utilised results recording software to undertake Acceptance Testing within every dwelling, flagging any result or installation outside of a set of pre-agreed performance criteria, for rectification by the M&E contractor. Any ‘failed’ test was then re-carried out subsequent to the contractor rectification. Tests included installation inspections and analysis of the HIU and tertiary side performance during hot water draw off, heating and zero demand.

Guru Pinpoint data visualisation software was then used to confirm dwelling performance during the testing period. Any anomalies in performance were then investigated and fixed prior to resident occupation.

FairHeat was also engaged by housing association to monitor post-occupation dwelling level performance to flag issues and poor performance. Periodic reviews were carried out using Guru Pinpoint, analysing dwelling level performance in all properties and highlighting properties where remedial action was required. This process kept a track of which HIUs should be prioritised for servicing based on the HIU manufacturer’s biennial HIU servicing requirement.

The use of Guru Pinpoint enabled FairHeat to quickly highlight poorly performing HIUs to client’s maintenance contractor so they could attend the property to fix the issue and carry out a full service of the unit during attendance. This proactive maintenance reduced likelihood of resident complaints and ensured that if poor performance did affect network efficiency it was not for a long duration. If residents complained about a lack of heating, Guru Pinpoint was able to be used to diagnose the issue.

It was recommended post-Acceptance Testing scope completion that block level and plant room meters should be installed and connected to Guru Hubs, to enable performance analysis in a wider level. These meters were also analysed in the maintenance checks to identify performance issues that could not be picked up using the dwelling level meters.


Acceptance Testing resulted in excellent block level performance with blocks having return temperatures less than 40 °C for vast majority of the time

Block level heat meter

Low return temperatures across the network minimises risk of overheating (by reducing heat loss) and increases plant room generation efficiency

Ongoing maintenance highlighted connectivity issues with Guru Hubs – preventing debt risk to the client

Dwelling issues were fixed during ongoing maintenance, thus lowering HIU return temperature during all modes of operation, reducing bills for resident, and ensuring correct temperatures at taps and heat emitters

Dwelling heat meter with recommissioning of hot water and space heating on 31 Jan 2019

An HIU flushing bypass was identified using block level meters. Access was gained in order to shut the bypass which dropped the block level flow rate from 6 m3/h to 2 m3/h and the block level return temperature from over 60 °C to less than 40 °C, thus increasing generation efficiency and reducing heat loss on the network

Dwelling heat meter (top) and block level heat meter (bottom). The flushing bypass was closed at roughly 8 am


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