The price of gas is the most obvious driver of energy bills, but one driver that is often overlooked is boiler efficiency. Inefficient boilers can cost residents over £500 more per year.

On paper, boilers perform at around 90-91% efficiency, but field trials repeatedly show that performance in the home is often much worse. A 2009 trial by the Energy Saving Trust found that boilers perform on average at only 82.5% efficiency, with some boilers performing as low as 68.6% efficiency.

Guru Systems monitors gas boilers using Guru Heat Smart, and we’ve seen the same results. Boilers that are expected to perform at around 90% efficiency often only reach efficiencies in the low 70s.

Inefficient boilers cost residents

The price cap which protects customers who heat their homes using gas boilers had already risen by 12% in October, and will rise again by an unprecedented 54% from April.

It’s possible to see the impact of boiler inefficiency on prepayment customers by comparing the price to heat a home at different efficiency levels.

To demonstrate the impact of inefficiency on price, we’ve used Ofgem’s figure of £983 for the average annual gas bill and assumed that the boiler is older (see graphs below), so only performing at 88% efficiency. The cost of energy then rises as efficiency decreases because gas is wasted to achieve the same level of comfort in the home. This is a hypothetical scenario, but the impact on annual bills is clear – a boiler working at 75% efficiency is £171 more expensive to run than a boiler working at 88% efficiency.

Act before the next heating season

While many local authorities and housing associations are beginning to plan to replace gas boilers with heat pumps, the cost and carbon savings associated with this change won’t be realised in time for the next heating season.

To protect residents from price rises (as well as reducing carbon emissions), the aim must be to ensure that gas boilers perform as well as they can until they are replaced.

With proper monitoring and subsequent interventions, gas boilers can perform better ahead of next year’s heating season – something that will disproportionately benefit the poorest households.

Boiler inefficiency is often caused by high return temperatures

Boilers cannot condense when the temperature flowing back from the radiators to the boiler is too high. This can happen when radiators aren’t balanced, or when the thermostat or boiler settings aren’t at the right level – problems that are often easy to solve.

These two graphs show how efficient a domestic boiler can be at different return temperatures. The graph on the left shows a standard boiler, and the graph on the right shows an older boiler.

Source: Real-time monitoring energy efficiency and performance degradation of condensing boilers, by Simone Baldi et al. (2017)

You can’t manage what you don’t measure

Most local authorities and housing associations don’t yet have visibility or control over their boiler fleet – this is why we created Guru Heat Smart.

Guru Heat Smart allows property managers to monitor and remotely control individual gas boilers (or heat pumps). The accompanying software displays performance data, ambient temperature and humidity data to help predict the risk of mould growth.

The Guru Heat Smart device captures detailed performance data from the heating system, including return temperatures from radiators, to help identify and resolve performance issues, and reduce maintenance callouts.

Here’s an example of what gas boiler performance looks like on the Guru Heat Smart web platform:

Data from this boiler shows that the difference between the flow temperature (orange) and return temperature (yellow) is almost non-existent. In practical terms this low Delta T means that very hot water is rushing around the heating systems only imparting a small amount of useful heat to the dwelling via the radiators on each loop.

It also shows that the boiler regularly receives water with return temperatures of over 70°C. When water returns from radiators to the boiler this hot, the boiler can’t condense properly. In this situation the resident is paying too much for their heat to achieve the same level of comfort in their home.

This cost difference may be enough to push households into fuel poverty, especially when prices are high. It also means unnecessary carbon emissions.

Data-led interventions

Performance data means that problems can be identified, and the appropriate interventions can be made. There a number of interventions that could be made ahead of the next heating season, including:

• Installation of flow limiting Thermostatic Radiator Valves (TRVs)
• Reducing the flow temperature of the boiler, especially outside of peak heating season
• Rebalancing radiators using existing radiator valves to reduce return temperatures
• Improve boiler, cylinder or heating pipework insulation
• Improving radiator sizing
• Make sure replacement boilers are appropriately sized

Data on how a resident is heating (or not heating) their home may also be useful for resident liaison teams. Data may help guide conversations around fuel bills or fuel poverty.

Underheating and mould growth

Not only are high fuel bills difficult for many residents, but when a house is cold and poorly ventilated, the risk of mould growth is much higher.

Guru Heat Smart captures ambient temperature and humidity data to help predict the risk of mould growth. This information, when viewed alongside boiler performance, can help local authorities and housing associations to support vulnerable customers in a more holistic way.

Better performing boilers use less fuel..

.. and less fuel means lower resident fuel bills.

If you’re interested in learning more about how to improve gas boiler performance, please contact our Sales team via sales@gurusystems.com or 020 8050 4305.

We all know that it’s best to design heat networks for the lowest whole-life cost – but sometimes project budgets are so constrained that CAPEX must be kept to an absolute minimum.

Recognising this reality is what inspired us to create Guru Hub 3 Core – monitoring hardware for heat networks. It’s the innovation and quality that you expect from Guru Systems at a price that’s comparable to a wired M-Bus system. Guru Hub 3 Core is now being installed across the UK, including in Brent where it’s being used as a low-cost credit billing solution.

Guru Hub 3 Core is just one way that we reduce costs for clients. Here we explain how we’ve created a collection of hardware and software to help our clients keep costs down, without compromising on the service they provide to residents, or on the quality of data being captured from their heat networks.

• Guru Hub 3 Core – our credit billing hardware that’s price comparable with wired M-Bus
• Free networking hardware, like gateways and repeaters
• Hardware agnostic technology, meaning clients save money on equipment like meters, valves and HIUs
• Cost-effective accompanying software for credit billing to keep operating costs low

Guru Hub 3 Core – our credit billing hardware that’s price comparable with wired M-Bus

The cost of running M-Bus cabling and installing data loggers is usually estimated between £175 – £250 per dwelling – and that’s for a system that’s prone to communications faults due to broken wires or shorting. It also risks GDPR non-compliance because data traffic is not encrypted.

Guru Hub 3 Core captures and communicates encrypted data every five minutes – and the price is comparable to the cost of installing a wired M-Bus system on site. Our first screen-free domestic device, it’s been designed as a low-cost credit billing option for clients who want to use this data to provide their customers with a monthly bill.

But unlike other screen-free options, it doesn’t compromise on the frequency it captures data, the number of utilities it can monitor (four) or its ability to remotely open and close supply valves or switch loads on and off.

Free networking equipment, like gateways and repeaters

Guru Systems hardware uses 868 MHz wireless mesh communications to ensure high reliability, including in areas where SIM cards won’t work due to lack of signal. This kind of network requires at least one gateway (allowing data to be communicated out of the building), and can require repeaters depending on the layout of the site. If a site needs more gateways or repeaters, that’s on us. Networking equipment like gateways and routers are free when buying either Guru Hub 2 or Guru Hub 3 Core, again reducing CAPEX costs.

Hardware agnostic technology, meaning clients save money on equipment like meters, valves and HIUs

Guru Hubs are HIU, valve and meter agnostic. This can help clients to save considerable sums per dwelling i.e. by buying less expensive HIUs or meters.

For example, inexpensive but good quality meters can be used with Guru Systems hardware, costing around £135. Instead, some other solutions only work with expensive meters costing £170 or more.

It’s important to consider the entire price of the bundle, i.e. the HIU, heat meter, automatic meter reader and networking equipment when working out what is most cost-effective for a site.

Cost-effective accompanying software for credit billing to keep operating costs low

Ongoing costs associated with metering and billing are a key consideration for clients. However, cost-effective solutions are available.

The accompanying software to Guru Hub 3 Core structures the data captured on site ready to be accessed online via Guru Platform, and/or sent to your chosen metering and billing provider via SFTP or email. Costs are lower because this system focuses entirely on the effective communication of data instead of on features and systems to support pay-as-you-go billing.

This system is in place in Brent, where it was chosen to keep costs lower for credit billing customers on a development of socially rented flats.

“Brent is piloting credit billing in a brand new 100% socially rented block of about 235 flats.

Credit billing was favoured because it spreads heating cost across the year helping families to budget. Receiving meter readings from an AMR service provider like Guru allows us to monitor payments against consumption and to prepare accurate heat statements every six months using in-house resources.”

Francesca Campagnoli, District Energy Manager – Brent Council

To find out more about our lower-cost hardware and software solutions, please contact our Sales team via sales@gurusystems.com or 020 8050 4305.