Posted by: @jamespa

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Posted by: @jamespa

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Its not the check itself, its the need to interrupt progress whilst waiting for the inspector (who is not going to be standing there waiting to do his inspection). 

 

 

The key part is checking the design, there's no reason why this has to be done on-site. The installer will be preparing a quote, the details can be included with the quote and the inspector can check them offline, while the homeowner is considering it. If the inspector needs further details of the home and existing installation, they can get these from the home owner. There's no delay.

Only once the quote has been accepted otherwise the inspector has to check all 10 quotes that the householder receives.  To check the detailed design, at the level of pipe sizes, fittings and radiator schedules, independently he has to verify the input data (because that is often where the fault lies), which means doing a  survey or at least part of a survey.  It cannot be assumed that the householder can provide this information (most installers wont assume this) and even if they could inspector will likely want to verify.  So a site visit is more or less inevitable if this is to be done independently at this level of detail.

Posted by: @temperature_gradient

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And those topics you mention, the concerns, they're captured - buffer vessel type and size, controls and location, the heat demand from design calcs, the proposed heat pump model and its rating.

If you say its too difficult to expect the installer to confirm all of this, to write it down somewhere, then what you're doing is leaving it entirely up to the installer to do what they want... but that means you can't complain if you don't like their decisions and the outcome. 

I think you can complain if the design is not fit for purpose, but otherwise I agree with you.

I don't say that its too difficult to confirm the things immediately above, in fact exactly the opposite, its what I have consistently suggested on this forum that people do.  If essentially what the inspector is doing is checking that there isn't a buffer tank, that the heat loss calculations and choice of heat pump make sense given the house size and gas consumption, and that there are no external controls, then I agree that this is a paper-only exercise which can be done based on the design produced by the chosen installer and a little bit of info from the householder.

Im very happy to endorse that as an option which could be made available to a householder at a relatively small cost (subject to liability issues being resolved), and as an alternative to educate the householder to do those checks herself using eg the tool on this site.  Householders option which they choose, or to take the risk if they choose neither.

Posted by: @jamespa

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Only once the quote has been accepted otherwise the inspector has to check all 10 quotes that the householder receives.

Clearly that is not workable and I can't see anyone suggesting that, sensibly the checks would be on one design, possibly two if issues with the first quote/design couldn't be resolved, may at the extreme 3 designs at most if the second option fell through.

Posted by: @jamespa

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I think you can complain if the design is not fit for purpose, but otherwise I agree with you.

Yes, but 'not fit for purpose' is quite a high bar and topics like buffer tanks don't always meet that - there's heat pump manufacturers which recommend buffer tanks, so while they affect efficiency, you would struggle to argue it is not fit for purpose, particularly if the recommendation to use one is written down, in black and white, in the installation manual.

That's one of those discussions needed early on, between the installer and the homeowner with some expert support, to agree on what's wanted - is a buffer needed, why, homeowner accepting issues if one is not fitted, buffer vs. volumiser, or 3-port buffer etc.

I see the same thing with sizing, where a design calls for say a larger heat pump but where the modulation of the larger units are poorer affecting efficiency, so in practice the smaller unit with better modulation may be the better overall choice. Again, it wouldn't reach the 'not fit for purpose' test, it is fit, but not as good as it could be. And it's another one in the grey area, where its a trade off between efficiency/running cost vs. capacity to provide sufficient heat in extreme winter conditions and what the homeowner prioritises.

Posted by: @temperature_gradient

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Posted by: @jamespa

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Only once the quote has been accepted otherwise the inspector has to check all 10 quotes that the householder receives.

Clearly that is not workable and I can't see anyone suggesting that, sensibly the checks would be on one design, possibly two if issues with the first quote/design couldn't be resolved, may at the extreme 3 designs at most if the second option fell through.

Posted by: @jamespa

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I think you can complain if the design is not fit for purpose, but otherwise I agree with you.

Yes, but 'not fit for purpose' is quite a high bar and topics like buffer tanks don't always meet that - there's heat pump manufacturers which recommend buffer tanks, so while they affect efficiency, you would struggle to argue it is not fit for purpose, particularly if the recommendation to use one is written down, in black and white, in the installation manual.

That's one of those discussions needed early on, between the installer and the homeowner with some expert support, to agree on what's wanted - is a buffer needed, why, homeowner accepting issues if one is not fitted, buffer vs. volumiser, or 3-port buffer etc.

I see the same thing with sizing, where a design calls for say a larger heat pump but where the modulation of the larger units are poorer affecting efficiency, so in practice the smaller unit with better modulation may be the better overall choice. Again, it wouldn't reach the 'not fit for purpose' test, it is fit, but not as good as it could be. And it's another one in the grey area, where its a trade off between efficiency/running cost vs. capacity to provide sufficient heat in extreme winter conditions and what the homeowner prioritises.

Subject to the involvement of the inspector being optional for the householder and the householder being offered the alternative (ie get slightly educated), I can agree with all of that, and its broadly what I plan to push for in the retrofit strategy work I am doing.

On the DESNZ weekly mailing - Plug in  solar safety study.  I have posted some comments in the plug in solar thread.

Posted by: @jeff

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I can't speak for others. 

For me the actual visit by someone suitably qualified and not connected with the installer is the important point I was trying to make. I don't personally think a self certification process is going to work with these insulation grants , especially for relatively hard to remediate properties, including my own. 

The revised process IMHO is still too geared to redress rather than attempting to  prevent poor practice at the point of install, with limited assurance via self certification. The old self certification process resulted in the majority of the installations failing, I fear many installs will fail under the revised  process. It will be interesting to see what happens in practice. 

I agree, my point is I have seen cases where the bc inspector tries to avoid visits. 
At the end of the day, it is about paying for professionalism.