The European Energy-related Products Directive (ErP), introduced in 2015, is set to be tightened, with more stringent rules for the design of hot water cylinders in regulations to be introduced this September. Stuart Elsy from cylinder manufacturer OSO Hotwater comments on the major issue affecting the water heating market.
When the ErP was first introduced, manufacturers were required to provide energy labels on their products showing an energy efficiency rating ranging from ‘A’ to ‘G’. The purpose of this measure is to make cylinder efficiency more obvious to the installer as well as the end user. Experience in the boiler and white goods industries have shown that customers are looking for and are prepared to pay for superior energy ratings.
The next tier of ErP will see a significant improvement to the products in the market. In the first round, they were merely labelled their efficiency. Although manufacturers currently supply cylinders that range from ‘A’ to ‘G’, in reality the labels ‘F’ and ‘G’ are rarely seen, as they are unlikely to comply with Building Regulations’ minimum standards. From September, products must be a ‘C’ at worst, and a new band of ‘A+’ has been introduced to encourage manufacturers to further enhance their products.
ErP formalised the change over the last couple of decades of the key performance indicator for a hot water cylinder from maximum heat output to minimum energy loss. As new-build houses have become far more efficient and better insulated over time, the necessary power output of a boiler to provide central heating has reduced dramatically. There is no point in putting a 25kW coil into a cylinder to be married to a boiler which only produces 15kW.
ErP determines efficiency on indirect cylinders with standing heat loss. This has been recognised in SAP (Building Regulation Part L Standard Assessment Procedure) for years as being the most important facet of a cylinder in determining efficiency. Domestic hot water is heated to 65°C in a controlled ambient temperature of 20°C, and the energy required to maintain the DHW temperature is measured over time. The standing heat loss is that measurement, calculated either in watts or kilowatt hours per day. ERP gives performance bands within which the heat loss of every cylinder will fit, thus determining the energy rating.
Under the 2017 regulations, the maximum allowed heat loss for the most popular 210 litre cylinder will be 87W. This roughly translates to 2kWh per day – probably a daily cost of about 10p to the householder. This is a dramatic improvement over historic systems, which will enable the country and EU to achieve its 20-20-20 target to reduce energy use by 20% and increase the share of renewable energies by 20% by 2020. In addition, it provides a real incentive for a householder to invest in a modern, well insulated hot water cylinder.
The top performing cylinder range in the market is the OSO Delta, which is insulated with Vacuum Panels. It is the only range to achieve an ‘A’ rating all the way to 300 litres. Delta will save money against every other cylinder available and can save up to £78 per year for a householder in some circumstances.
For direct electrically heated units, ratings are determined by measuring the amount of energy used to deliver set hot water draw off profiles over time. These profiles are designed to mimic typical use on a daily basis, and combine small draw offs for a hand basin with larger ones to simulate a bath or shower. Profiles vary for different sizes of properties and manufacturers will test against the profile which is closest to the intended usage situation of the particular cylinder. The reality is that a well-insulated cylinder will perform a lot better than a poorly insulated one, and the draw off profiles are likely to favour these units.
Electric direct cylinders will normally have lower grades than indirect units. The ratings for electric heating reflect the inefficiencies in fossil fuelled power generation across Europe. A 2.5 times multiplier applies to electricity usage in efficiency calculation. This means that a perfect cylinder, which never lost any heat, ever, could only get a 40% efficiency. Smart control of thermostats, so that the water heater learns the usage habits of the household, are encouraged and will assist manufacturers to achieve ‘C’ and in some cases ‘B’ ratings, but again, only on a well-insulated cylinder.
It should be clarified that non-compliant products that are in the supply chain by 26th September, and have been traded within the European Union before then, can be sold through to the final customer. Products that are traded for the first time after this date must be compliant.
It is also the case that Brexit, for now, has no effect on ErP regulations. We remain in the EU and subject to its rules, and even when we leave, all European legislation will be adopted into UK law. Subsequent to that, the Government of the day can choose which former regulations they wish to dispense with. We are a long way from that yet.
