Issues in The Product Characteristics Database (PCDB)

At the time of writing the methodology for EPC assessments of existing dwellings is RDSAP 9.94. The much anticipated RDSAP 10 update has not happened yet and a significant methodology overhaul from RDSAP to the Hone Energy Model (HEM) is proposed for 2025.

During an EPC assessment, references are made to an external 'Product Characteristics DataBase (PCDB)' to import detailed information about any of the following items, if you have them in your property:

• Boiler
• Heat Pump
• Compensating Heating Controls
• High Heat Retention Storage Heaters
• Waste Water Heat Recovery Systems (WWHRS)
• Flue Gas Heat Recovery Systems (FGHRS)

This Database is separate from the EPC calculation 'software', and it is managed by the Building Research Establishment (BRE).

Device manufacturers have to submit applications to the BRE to get their devices initially listed in the PCDB, and also to get entries for their devices modified.

It is possible for issues to arise when references are made to this database about the devices present in your property, and the only way you will know about this is either if your energy assessor tells you, or if you have already made some basic checks beforehand.

Issues might include:

• Unable to identify your exact make and model of device in order to look it up in the PCDB
• Your device is simply not listed in the PCDB
• Your advanced heating control ('Compensator') is listed in the PCDB, but your specific boiler is not on it's list of compatible boilers

If your energy assessor is unable to identify the exact make and model of your boiler or heat pump, then they will not be able to search for it in the PCDB, and they will not be able to get the assessment software to obtain accurate performance information about it.

Similarly if they are able to identify the exact make and model of the boiler but that boiler is not listed in the PCDB, then they also will not be able to get the assessment software to obtain accurate performance information about it.

In thse situations, the assessor reverts to entering a generic Heating Code to describe the type of boiler/heat pump you have. This generic code puts in place lower (generic) performance values into the calculation for that type of boiler and your EPC rating will be less accurate (read: 'worse') as a result.

The PCDB contains quite a comprehensive list of Boilers and Heat Pumps, so you're unlikely to find yourself in either of these situations, but it might be worth looking in the PCDB to check that it has details of your boiler, before calling an energy assessor in.

Look on your boiler for a make and model number, but in particular for the Gas Council (GC) number if your boiler has one as this categorically identifies a specific device.

Advanced Heating Controls (Compansators), High Heat Retention Storage Heaters, FGHRS and WWHRS systems can only be included in an EPC assessment if they are listed in the PCDB.

This means for example, if you have an advanced heating control such as a Weather or Load compensator of some sort, but this cannot be brought into your assessment, then you won't be able to claim the benefit of that device. The energy assessor will fall back on generic codes for standard or zoned heating controls instead.

If you do have a Compensator of some sort, it is worth seaching for it in the PCDB, firstly to check it is present, and secondly that your boiler is on it's list of compatible boilers.

Also, bear in mind that some Thermostats that do have load compensation built into them might visually appear just like a standard thermostat. Therefore you might not be aware that you have a compensating controller. The Worcester Greenstar Comfort I RF is an example. From initial looks it might appear to be just a thermostat. The controller part that fits into the boiler however has load compenstion built into it, it is listed in the PCDB, and could improve your EPC rating possibly by 1 point if it is entered correctly.

If you know, or discover that your heating controls are more than just a standard thermostat, let your energy assessor know so he can seach for the device in the PCDB.

You can search within the PCDB yourself online here: https://www.ncm-pcdb.org.uk/sap/

There are different sections for the different types of devices, and you can search the database, using various parameters.

If there is an issue in the PCDB, and either if you spot it beforehand, of if your energy assessor spots it and tells you about it, then in the long term you might be able to get it sorted out and increase your EPC rating on a subsequent re-assessment.

This might however be rather tricky because the device manufacturer would need to liaise with the BRE on your behalf to get the issue resolved. The BRE will not accommodate direct communication from an end customer. Also, from my experience, the BRE are unbelievably ineffective in communication, and device manufacturers might not be very interested in your cause.

I have experience of an issue in this area with my own home. I have an Alpha InTec2 28X condensing gas combi boiler. This is present in the PCDB.

I also have the Alpha RF Climatic Controller (3.022143) and Alpha Weather Compensation Sensor (3.022383) attached to the boiler rather than the standard Alpha Easystat (7.2000050). Both the climatic controller and weather compensation sensor are also listed in the PCDB.

However, it is not possible to select either of those Heating Controls as being fitted to my specific boiler due to an error in their PCDB listings.

Both devices have a list associated with them of the boilers that they are compatible with. Alas, my specific boiler is not on that list, even though it is actually compatible.

This omission could be because Alpha sent an incomplete list of compatible boilers to the BRE when initially registering the controllers in the PCDB or the BRE didn’t enter the list of compatible boilers correctly that was submitted by Alpha.

If I can get the PCDB listings straightened out, my EPC rating should improve by 1 SAP point on a re-assessment, and in my case take me from band D to band C because I am on the threshold of moving from a 68D to a 69C.

After some effort I managed to get Alpha interested enough to contact the Building Research Establishment (BRE) who host the PCDB but the BRE have been completely useless and the issue is still unresolved 9 months later. The product engineer that was chasing the BRE for me left Alpha, and Alpha have not responded to any of my further communication to them.

Another example – do you have a Nest smart Learning thermostat? The nest does actually have two different ways that it can be connected to a boiler (either On/Off control or OpenTherm) but either way should really add a 3% increase to the boilers efficiency within the EPC assessment. The Nest is present in the PCDB but so far I have not been able to assign it within an EPC assessment to the boilers I have seen it attached to.

In summary, I would say look up your boiler and any advanced heating controls or devices listed earlier that you might have, in the PCDB, before your energy assessor comes out to your property. This way you might be able to spot an issue in advance of any assessment.

You might also be able to check or choose an advanced heating control via the PCDB if you are re-assessing your heating system with a view to improving your EPC score. Check the list of compatible boilers for a given advanced heating control to make sure your boiler is listed. Backup that with secondary research online.

Once you have an advanced heating control that provides either Weather Compensation and/or Load Compensation, make that fact clear to your energy assessor in advance of your visit and provide the model numbers and PCDB index numbers. This will ensure that those devices are included in the EPC assessment. Some advanced controls are otherwise easy to miss if the energy assessor is in a hurry.

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