Issues in The Product Characteristics Database (PCDB)

At the time of writing, the methodology for EPC assessments of existing dwellings is RDSAP 10. A significant methodology overhaul from RDSAP to the Home Energy Model (HEM) is proposed for 2026. In addition, government consultations indicate future changes to the format of EPCs and minimum rating levels required for private rental properties. Methods for improving EPC ratings will therefore change in the future.

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:

• Gas/Oil Boiler
• Heat Pump
• Compensating Heating Controls
• High Heat Retention Storage Heaters
• Mechanical Ventilation Systems
• 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 submit applications to the BRE to get their devices initially listed in the PCDB, and also to get entries for their devices modified.

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 criteria.

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 make some basic checks yourself, beforehand.

Issues might include:

• You are unable to identify the exact make and model of your device, in order to look it up in the PCDB
• You have identified your make and model of device, but it is simply not listed in the PCDB
• Your device is listed in the PCDB, but there is a problem with its listing.

If your energy assessor is unable to identify the exact make and model of your device, 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 device, but it 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.

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

For High Heat Retention Storage Heaters (HHRSHs), if they cannot be located in the PCDB, the assessor has to list them as fan assisted storage heaters instead.

For Compensating Controls for heating systems, FGHRS and WWHRS systems, if they are not present in the PCDB they cannot be included in an EPC assessment.

The PCDB does contain a comprehensive list of Boilers and Heat Pumps, so it should be an unusual situation where a device is not listed, but it is worth checking your devices, before calling an energy assessor in, just to make sure.

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.

If a device is not listed in the PCDB, the most likely cause is that the manufacturer has not registered their product with the BRE for enty in the PCDB. The following page details the process of registering devices and indicates that all enquries in this situation should be made to the manufacturer:

https://www.ncm-pcdb.org.uk/sap/page.jsp?id=38

For boilers and heat pumps, where a generic heating code is used in an assessment to represent the device, the efficiency figure used for that device is defined in the assessment methodology. For RDSAP 10, the situation is described in the Specification document:

https://files.bregroup.com/SAP/RdSAP10-dt13.02.2024.pdf

Turn to page 48, section 11.1 and the paragraph of interest here reads: “Main heating systems are either identified via the Product Characteristics Database or are categorised on the basis of the generic types in Tables 4a and 4b in SAP10.2.”.

So, looking at the document for the underlying methodology of SAP 10.2 available here, and turn to page 163 where Table 4a starts:

https://bregroup.com/documents/d/bre-group/sap-10-2-14-03-2025

Examples include:

Electric Ground/Air Source Heat Pumps = 170%

Condensing gas combi boiler with automatic ignition (1998 or later) = 84% (Winter) / 75% (Summer)

For Heat Pumps, there is a slight uplift available in the efficiency figure if you have an MCS certificate for the installation available for the energy assessor to see. The 'uplift' is described in section 9.2.7 on page 28 of that last document, and depends on the type of heat pump.

The above figures are likely to be somewhat lower than you might expect, and this makes it worth double checking your devices in the PCDB to make sure you're not being limited by this type of issue.

It is possible for a device to be listed in the PCDB but not useable in an EPC assessment.

Consider an example where you have a device such as a Weather or Load compensating control for your boiler. Devices like these are recorded in the PCDB along with a list of compatible boilers. If your boiler is not on that list, even though it is actually compatible with the control, then you can't claim the benefit of that device. The assessment will only be able to proceed using the underlying codes for standard or zoned heating controls. 

If you do have a load or weather compensating control, it is worth seaching for it in the PCDB, firstly to check it is present, and secondly to make sure 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 a small margin 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 they can seach for the device in the PCDB.

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 to get the issue resolved. The BRE will not accommodate direct communication from an end customer.

Also, as you will see in the next section, from my experience the BRE are unbelievably ineffective in communication, and your device manufacturer might be very reluctant to rise to your cause.

I have an Alpha InTec2 28X condensing gas combi boiler in my home. This is listed in the PCDB, and I can record the presence of this successfully in an EPC assessment.

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

However, in the EPC assessment software it is not possible to select either of these 'Compensator' devices as being fitted to my Alpha Intec2 28X boiler due to an error in their PCDB listings.

If I try, I see the following error message:

"The control product selected by PCDF is not compatible with the main heating system product selected by PCDF. Control requires: Condensing boiler, Modulating burner control, Compatible with Alpha Climatic controller or External probe."

The PCDB listings for these compensating devices contain a list of boilers with which they are compatible. 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.

Either way, it should be straightforward for Alpha to contact the BRE to get the Alpha Intec2 28X added onto the list of boilers that are compatible with these devices. I'll would then be able to add the compensators to my EPC assessment (although possibly only one of them, because the EPC software can only accomodate one compensator in the assessment).

My EPC rating should improve by 1 SAP point on a re-assessment once this has been done, 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.

Achieving this, however, relies on:

• Alpha Therm taking action to contact the BRE
• BRE taking action in responding to Alpha Therm

The Results:

Initial contact with Alpha Therm Ltd. was frustrating. Despite presenting a very clear description of the underlying issue, my request was initially blocked from getting up the chain of command by their first line technical support staff.

After a number of further messages and a written letter to Alpha, they eventually assigned a product engineer to contact the Building Research Establishment (BRE), who host the PCDB.

The BRE however failed to respond to Alpha's communications (I was cc'd into all the repeated emails), and after a few months, the product engineer at Alpha left the organisation before the issue was resolved.

Further email and written correspondence to Alpha Therm's main office went unanswered.

A written letter to Alpha Therm's Finance Director, Michael John Wilson, went un-answered.

A written letter to Alpha Therm's Managing Director, Andrea Carmeli, also went un-answered.

I was approached by a potential client with a property on which an EPC had been recently conducted.

The rating of that EPC was really poor, particularly considering the quantity of insulation in the walls and loft, and the owner was were keen to get the rating up to a C because it was a rental property.

A gradde C rating would give them 10 years to work out if further work was required to 'pass' the potential increased requirement for MEES that was aired in recent government consultations.

After a quick review it was clear that the IVT ground source heat pump that was fitted to the property back in 2012 was not listed in the PCDB. In fact at the time of the enquiry there were no IVT ground source heat pumps present in the PCDB at all.

The heat pump could be accomodated in the assessment using a generic heating code, but a default efficiency of 170% would be used in the calculation of the rating, rather than the actual efficiency of the device itself.

There was no solution to this problem.

This particular product is not listed in the PCDB, although the Paul Novus 300 is listed.

Consider looking up your boiler and any other devices listed towards the start of this page, in the PCDB, before your energy assessor comes out to your property. This way you might be able to spot an issue in advance.

Unfortunately, from my experience, if you have an issue, the likelihood of being able to resolve it is probably very low.

Click here to return to our 'Improve Your EPC' main page, and see if there is another way you could improve your EPC rating.