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Sap ratings


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I’m just doing the SAP for our next build 

I e been quite specific about u values of windows and doors Insulation etc   and heat pump sizing 

Just looking at today’s planning approvals 

The Saps look quite generic with little detail with terms like Insulation conforming  to build standards 

Sap rating 77 C 

Our previous traditional build achieved 88 B

Without ASHP MVRH or PV 

 

77 sounds low 

I wonder if I’m including unnecessary detail 

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Our "as designed" SAP was I think 89B  I thought that was poor and worse than I hoped for.

 

BUT they got the roof insulation detail wrong (the roof is better insulated than they calculated) and they based the SAP on 4.5 ACH

 

I hope the as built SAP will be better.

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The SAP rating is based on energy cost. Going all electric with a heat pump will increase the energy costs though offset to some degree by the efficiency of the heat pump. No one really cares about the SAP ratings, important hurdle is getting Building Reg compliance which is made easier with a heat pump

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45 minutes ago, ADLIan said:

No one really cares about the SAP ratings

 

Landlords in England are regulated on it, and it is an offence to rent out a below-required property - subject to certain exceptions etc. It is likely to be D by 2025, and C by 2030. I think Scotland and Wales followed. This was basically a LiBDem initiative from about 2010, pushed by Ed Davey.

 

AIUI Scottish Gov have followed, and are trying to apply an improvement-ratchet to Owner Occupied properties, with an aim of "All C by 2045" or similar. How are they doing?

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I'd be careful about comparing it too much with a previous build - costs and carbon factors have changed. Assuming the sap represents your wall and roof bud up the things that might make a difference are:

-the assumed air permeability.

-inclusion of stuff like pv panels.

 

As an example, our design sap was 77c with pretty good levels of insulation, triple glazing, but we are all electric dhw and heating which penalised us.

 

As built sap 93A due to inclusion of more pv and an air test with a better value than originally assumed.

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Our as built SAP has just come in at 94/95A.  ASHP and 4.2 PV, and based on 3.0 ACH.  I think they assumed radiators upstairs (UFH downstairs), but we were (nervously) going to do without wet heating upstairs and have electric UFH in bathrooms and wiring for infrared panels elsewhere in case we needed them.  No doubt that would've given us a very poor score, as my understanding is electric heating panels are still badly penalised by SAP2012.  I believe  SAP10.1 is still to be adopted despite being in the pipeline for ages, but is much "kinder" and more forward looking.

Edited by Becca
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19 hours ago, Becca said:

Our as built SAP has just come in at 94/95A.  ASHP and 4.2 PV, and based on 3.0 ACH.  I think they assumed radiators upstairs (UFH downstairs), but we were (nervously) going to do without wet heating upstairs and have electric UFH in bathrooms and wiring for infrared panels elsewhere in case we needed them.  No doubt that would've given us a very poor score, as my understanding is electric heating panels are still badly penalised by SAP2012.  I believe  SAP10.1 is still to be adopted despite being in the pipeline for ages, but is much "kinder" and more forward looking.

 

Should've been AS DESIGNED SAP, not as built. ?. If I'm this absent minded already, what hope for the build! ?

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20 hours ago, Becca said:

Our as built SAP has just come in at 94/95A.  ASHP and 4.2 PV, and based on 3.0 ACH.  I think they assumed radiators upstairs (UFH downstairs), but we were (nervously) going to do without wet heating upstairs and have electric UFH in bathrooms and wiring for infrared panels elsewhere in case we needed them.  No doubt that would've given us a very poor score, as my understanding is electric heating panels are still badly penalised by SAP2012.  I believe  SAP10.1 is still to be adopted despite being in the pipeline for ages, but is much "kinder" and more forward looking.

In 2017 our as built SAP came in as an A95 without any PV and we had electric heating. We did have high insulation and air tightness values. We used electric towel rails in the bathrooms and an EASHP as backup heat in the MVHR.

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