Gulf between TER and other 2013 building regs.

[epsilonGreedy]

In another thread @PeterWbrought the TER design assessment to my attention when I mentioned SAP and general 2013 thermal building regs. I gather that TER relates to a CO2 emission target, the EPC assessment indicates how much space and water heating will cost and the 2013 thermal building regs are a fairly low-bar standard for building's thermal performance.

 

Having looked at the model home u-value targets for TER they seem very demanding compared to other building regs. A minimum conformance with 2013 thermal regs would probably lead to a mid EPC band C score whereas a scraping passing TER score would equate to an upper EPC band B.

 

How have we arrived at a situation where the more stringent TER design assessment effectively makes other less demanding regs pointless? Must be missing something.

 

 

[Jeremy Harris]

I'm not convinced that the regs are in any way demanding, TBH.  We found it pretty easy, and not at all expensive, to exceed the requirements by a significant margin, and many others here have done much the same.  The key thing is to ensure that the design of the house, from the ground up, is optimised to improve thermal efficiency.  There are lots of details that literally cost nothing, but can reduce heat loss and contribute to improved performance, including some fairly easy wins, like reducing or removing thermal bridges, ensuring that airtightness is better than the regs require, etc.

[Mr Punter]

Building regs are being used to improve the energy efficiency standards of new buildings.  The standards for Part L, which deals with this, have become far more ambitious compared to all the other approved docs, so what worked 5 years ago will not pass now.

[PeterW]

@epsilonGreedy you’re missing a step here - that shows the difference between the 2013 regs and the new 2016 amendment that brought in TER and DER for new builds. The 2016 Fabric Elements are different again. 

 

If  you read the 2016 amendments, it does state the following :

 

 stated value represents the area-weighted average for all elements of that type. In general, to achieve the TER and the TFEE rate, a significantly better fabric performance than that set out in Table 2 is likely to be required.

 

They are basically saying in an average build at 2016 rates you would still need to be better, but to ensure no-one try’s to do something silly such as a glass box with a roof 5ft thick, they do limiting fabric factors. 

 

Its not difficult to beat the numbers - 500mm of loft insulation is cheap, air tight tape is a couple of hundred and so on. Just approach it methodically and you can soon be heading into decent scores and not having the issue of trying to find points to scrape a DER pass. 

 

Part L1A is here

 

 

[epsilonGreedy]

18 minutes ago, PeterW said:

@epsilonGreedy you’re missing a step here - that shows the difference between the 2013 regs and the new 2016 amendment that brought in TER and DER for new builds. The 2016 Fabric Elements are different again. 

 

 

Ok so in 2016 TER/DER effectively overrode the much quoted 2013 thermal standard by a massive margin. Those differences in u-value are huge, nothing like an incremental raising of targets after 5 years. Would I be correcting in thinking that TER/DER indirectly results in a mid band B or better EPC score?

 

I thought some of the 2016 era building regulation changes were scrapped at the last minute. Does anyone enforce TER/DER?

[PeterW]

1 minute ago, epsilonGreedy said:

Does anyone enforce TER/DER?

 

Yes ... your final SAP that has to show you exceed the TER for the property. 

 

Has your architect wandered off into the sunset on this..? Before you move on much more I would seriously consider getting the DER done ASAP and understand what’s the minimum you need to do to get a pass. 

[Jeremy Harris]

8 hours ago, epsilonGreedy said:

 

Ok so in 2016 TER/DER effectively overrode the much quoted 2013 thermal standard by a massive margin. Those differences in u-value are huge, nothing like an incremental raising of targets after 5 years. Would I be correcting in thinking that TER/DER indirectly results in a mid band B or better EPC score?

 

I thought some of the 2016 era building regulation changes were scrapped at the last minute. Does anyone enforce TER/DER?

 

 

My experience was that little attention was paid by building control to the design EPC, they solely focussed on examining the as-built assessment in terms of compliance with Part L1A.  The DER/TER has to be right, or you just won't get an EPC at all.

 

The regulations that you have to comply with for the as-built assessment are those that were in force on the date of your building regs submission, so if you applied for full plans approval, or submitted a building notice, before 2016 the older set of requirements apply (principally those in Part L1A in this case), and if you submitted your building regs submission after this date then you need to comply with the 2016 amendments.

 

Worth noting that Part L1A was due to be amended to ensure all new homes are "nearly zero energy" by 2019, but I believe this has been delayed still further.

[the_r_sole]

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Edited September 26, 2019 by the_r_sole

[ADLIan]

I'll post this reply here as it's the most recent but it does overlap with a couple of other threads.

 

The previous Appr Doc L1A was the 2010 version, effective Oct 2010 and included the DER/TER measure (based on CO₂ emissions). The next revision was the 2013 version, effective April 2014. This gave an average decrease in CO₂ emissions of 6% compared to 2010 but also introduced the Fabric Energy Efficiency Standard, partly to plug a loophole in the 2010 version.The 2016 revision did not contain any technical updates.

 

Not sure of the source of Table 1 above (shown in full in the other thread) but it is riddled with errors. See the original in Appr Doc L1A. These figures are not cast in stone, SAP gives a lot of design flexibility and it is possible to build a wall with 100mm cavity or U=0.28 and still get overall compliance (though not sure why anyone would build a wall with such a poor U-value!).

 

Zero carbon homes by 2016 was a Govt ambition but was kicked into the long grass a few years ago.

 

As regards the EPC Building Control only need this as part of the sign off - it is not part of the compliance paperwork, there is no pass or fail here.