Air Source Heat Pump - RHI Scheme Metering for Performance vs Metering for Payment

[newhome]

Changes to the RHI scheme earlier this year mean that ASHPs must be metered in order to be eligible for RHI payments. There are 2 types of metering. The first is 'metering for performance' where performance is monitored but it does not affect RHI payments that are based on the expected heat demand. If that cannot be 'accurately assessed' then 'metering for payment' is required. 

 

Having read the rules on this (again!) I'm still not 100% sure when metering for payment is required. I am still looking at an ASHP to replace my electric boiler. Currently my set up is that I have a thermal store that provides for both DHW and UFH. That TS is also connected to a solar thermal system. It's not working currently but assuming it was does this still meet the criteria for metering for performance rather than payment? It looks as if Solar Thermal is only eligible for RHI payments if it provides DHW only, ie any provision for space heating makes it ineligible (as an aside any guesses as to why that is? ).

 

From the various RHI documents:

 

SOLAR THERMAL There are two types of solar thermal technologies eligible for the Domestic RHI – evacuated tubes and liquid filled flat plate collectors. Solar thermal technologies must be designed and installed only to provide heating for domestic hot water. Solar thermal systems designed or installed to provide space heating, heating to a swimming pool or for any purpose other than heating domestic hot water will not be eligible for the Domestic RHI.

 

So I can't claim RHI for the ST. I'm ok with that but does the fact that it is installed mean that I have to have metering for payment for the ASHP? 

 

How do you know if you need metering for payment?

 

Metering is not required for solar thermal systems. For the other eligible technologies, these are the three most common situations where your renewable heating system will need to be metered for payment:

 

1. If you have back-up heating  

 

You have a renewable technology eligible for the Domestic RHI, e.g. a biomass boiler, and also a fossil fuel source of heating, e.g. a backup oil boiler;

 

Using solar thermal for heating hot water doesn’t count as back-up heating;

 

So reading this as my ST feeds the same TS that provides DHW and space heating does this mean that I have to have metering for payment?

 

In addition I have a 3kw immersion heater attached to the TS. The only time I ever switched it on was when the boiler broke down as it's pretty inefficient at heating 475l of water anyway, but does this also mean that I have to have metering for payment too?

 

So my conclusion is that if I disconnect both the ST and the immersion heater an ASHP is eligible for metering for performance but if either is connected I have to have metering for payment, however I've read this too many times and have gone word blind now! Anyone able to make more sense of it please? 

 

[Stones]

I had a read of the info and agree it's far from clear.  It's your electric boiler (or say an oil boiler) that would be considered back up heating.  If you chose to retain the boiler and keep it connected / used it, then metering would apply rather than deemed payments.  Immersions form an integral part of most systems and are not included.

 

I think all approved ASHP now have on board metering for performance which is enough to tick that particular box.  I believe metering for payment requires extra kit.

[ProDave]

2 hours ago, Stones said:

I think all approved ASHP now have on board metering for performance which is enough to tick that particular box.  I believe metering for payment requires extra kit.

My LG one does not, unless it is something hidden and not documented in the installer or user manuals.  Irrelevant to me as I am not claiming the rhi but you would think many using that heat pump would be,.

[JamesP]

I am having an ASHP ( Same kit as @Stones ) supplied and fitted in January and on the quote is an electricity meter which will measure performance only.

I have been reassured it will not effect the RHI. Site visit by supplier in December so will confirm again.

Also will have RHI on Solar Thermal.

[newhome]

18 minutes ago, JamesP said:

I am having an ASHP ( Same kit as @Stones ) supplied and fitted in January and on the quote is an electricity meter which will measure performance only.

I have been reassured it will not effect the RHI. Site visit by supplier in December so will confirm again.

Also will have RHI on Solar Thermal.

 

How is your ASHP being set up? Direct to the UFH and DHW into a tank where the ST is also connected or is the TS feeding the UFH too? Do you have a backup immersion? 

 

[Stones]

2 hours ago, ProDave said:

My LG one does not, unless it is something hidden and not documented in the installer or user manuals.  Irrelevant to me as I am not claiming the rhi but you would think many using that heat pump would be,.

 

Does your ASHP pre date the ERP compliance? Just wondering if that's when it changed.

[ProDave]

19 minutes ago, Stones said:

 

Does your ASHP pre date the ERP compliance? Just wondering if that's when it changed.

You heard the saga of how I came by this one supplied "new" as a replacement for the previous faulty one. Chances are it is an old model and they were glad to offload it as it would not comply with the latest rules.

[JamesP]

Hi There

AFAIK the 300l twin coil unvented domestic hot water cylinder is fed by the ASHP and ST. The hot water and heating (UFH) are then drawn off from the cylinder.

My solar thermal installation is eligible for the RHI.

[newhome]

6 minutes ago, JamesP said:

Hi There

AFAIK the 300l twin coil unvented domestic hot water cylinder is fed by the ASHP and ST. The hot water and heating (UFH) are then drawn off from the cylinder.

My solar thermal installation is eligible for the RHI.

 

That's interesting thanks as it negates the view I formed from the RHI documentation that ST could not supply space heating alongside an ASHP without metering for payment kicking in instead of metering for performance. Due to the size of my house and the fact that there is only me living here I believe that I would do better on a metering for performance basis. I also read in the RHI bumf that ST is only eligible for RHI if it only heats DHW and of course a combined tank doesn't tick that box. I'm confused as hell now if your ST qualifies lol. My ST isn't eligible for RHI as it's been installed too long anyway but it would seem crazy to disgard it just because of the quirky RHI rules relating to ASHPs IMO. 

 

Here is what the RHI guide says re ST eligibility:

 

Solar thermal heat delivered through a liquid medium can only be used for heating domestic hot water.

 

I just can't fathom why is isn't (supposedly) allowed for space heating.

 

[JamesP]

@newhome I will confirm this as we have a site meeting on the 11th. 

I am not sure about the interpretation, whether its hot water for washing or heating its all domestic hot water.

Both my Dad and brother installed ST some years ago and claim RHI.