A Reliable Metre to Accurately Demonstrate a Home’s Energy Efficiency

The challenge with any energy efficient renovation project is demonstrating performance. How do you know that the renovation delivers the promised energy savings?

Barry Lynham is Managing Director and Quentin Galland is Public & Regulatory Affairs Director at Knauf Insulation.

To answer that question, Knauf Energy Solutions (KES) has developed a pioneering energy efficiency metre. Called the Negawatt Hour Metre, this innovation makes it possible to demonstrate the energy savings delivered by the renovation measured in real time. Just like you can metre how much energy your new rooftop solar panels deliver, our metre shows homeowners how much energy is being saved. 

To do this, the KES solution couples sensor data, such as indoor humidity and temperature, with actual gas and electricity use, as well as data on the efficiency of the installed heating system. Next, external weather data on outdoor temperatures and humidity gathered from a local weather station is added to the mix. 

Our cloud-based machine learning algorithm then analyses all this data to calculate the home’s exact energy efficiency, providing the resident with a simple report comparing the energy efficiency of their home before and after the renovation – a sort of energy performance certificate if you will.  

Enticing Data

The Negawatt Hour Metre enables the metering of real energy performance. It also allows for the benchmarking of improvements because of the renovation, which in turn helps to build trust between homeowner and contractor. 

Being able to provide a homeowner with clear data that a particular solution does what the label says it will do gives the homeowner confidence in their decision making – and a confident consumer is more likely to go through with a quality energy efficient renovation project. 

Enticing more homeowners to renovate their inefficient homes is of fundamental importance to achieving the EU Renovation Wave Strategy’s goal of renovating 35 million building units by 2030 – a figure that, if achieved, would put a substantial dent in the building stock’s total energy consumption. 

Energy efficiency metres provide such enticing data.  

Measuring a Home’s Heat Pump Readiness 

Energy efficiency metres also allow homeowners to make decisions based not on some generic benchmark, but on the unique performance of their actual house. 

Having access to such tailored information could become key to supporting the roll out of heat pumps. For example, to be a viable alternative to gas boilers, heat pumps must be able to heat a home or building at a comparable cost. That means achieving a ratio of around 4 units of heat for every 1 kW of electricity. By understanding the actual energy demand of their house, homeowners will be better positioned to choose the right heat pump, increasing the chance that the expected savings are delivered. 

In addition to choosing a heat pump, such information will also help homeowners decide whether they could benefit from improving the energy efficiency of their home. If measured to be inefficient, it may make sense to install a cost-appropriate, whole-house insulation specification to improve home efficiency while also sizing the heat pump and radiators to meet that now reduced space heating need. 

By providing such measurements, energy efficiency metres help ensure that when an owner installs a heat pump, they get both the promised efficiency and cost-saving benefits.  

Alleviating Europe’s Capacity Challenge

Even when an energy efficient renovation is done, an energy efficiency metre’s work continues. 

By providing ongoing, up-to-date data on the energy efficiency of one’s house, smarter decisions can be made about energy use. For instance, with an energy efficiency metre, it will be possible to understand whether a house can be preheated at times of the day when electricity is cheaper, yet still stay comfortable and warm. This could allow a house to be heated during the middle of the night when electricity is cheaper as opposed to during expensive peak periods.   

Such smart energy use would help alleviate Europe’s electricity generation capacity challenge – a challenge that begins when the heat in most homes kicks on at around 6:00 p.m. While this isn’t a problem when everyone is using a gas boiler, it may well become an important issue when everyone starts heating with electricity. 

Energy efficiency metres can improve the ability to use price signals, such as time-of-use tariffs, to help reduce peak demand, reducing the need to overbuild grid generation capacity.

Benefiting Industry and Government Too

But the benefits of energy efficiency metres are not limited to homeowners. They also benefit the building and renovation industry. The transparent data these metres provide can help drive the market to deliver higher performance and better-quality solutions. By allowing us to better understand the real impact of a solution, metres can help us identify the most cost-effective measures for decreasing energy use, thus helping reduce the overall cost of renovating the building stock.  

Furthermore, with energy efficiency metres, we can now measure energy efficiency the same way we measure energy produced. This means governments can, for the first time, start treating energy efficiency like they treat energy production. Instead of paying for kilowatt of energy produced, in the case of energy efficiency, they would pay for the kilowatt of energy saved.

Ready for Use Today 

These benefits aren’t hypothetical. Energy efficiency metres are already available – and in use. In fact, Knauf Energy Solutions installed them as part of a renovation project of homes in Tienen, Belgium, where over 160 units received an energy renovation package. 

The metres allowed us to verify that our insulation measures were achieving the promised energy savings. Specifically, we could show a 36% average improvement in energy efficiency per home, which translates to EUR 1000 saved per household per year – a direct win for this community. 

Time to Measure Europe

Of course, energy efficiency metres could deliver a direct win for all of Europe. But that would first require that the EU take specific steps to maximise the use of such technology across the Continent. 

Knauf Insulation believes that an important step towards doing so is to develop and implement pay-for-performance schemes that reward renovation savings, as these directly contribute to savings in capacity generation. The good news is that there are already opportunities within the Energy Performance of Building Directive that would allow for the gradual use of such measurement tools.

Savings in capacity generation should also be rewarded on the electricity markets: metres allow one to demonstrate the exact savings and should be fairly rewarded as such within the framing of the revision of the Electricity Market Design Regulation.

Leveraging the Power of Data

The data we need to truly embrace the energy efficiency first principal is out there, residing within the walls, roofs, windows, and appliances of homes across Europe. 

Energy efficiency metres give us the ability to extract, analyse and use this data to improve energy efficient home renovations.

Now all we need is for the EU to take the necessary steps to tap this technology’s full potential, leverage the power of data and let the digitalisation of energy efficiency drive Europe’s energy transformation.