SAP10, 0.233kgCO2e/kWh for electricity

[Dreadnaught]

This tweet seems significant, but I am not entirely sure how. I guess it will enable houses heated entirely using electricity, which is what I plan for my near passive house, to more easily comply with the SAP requirements. I wonder if it will also feed through to PHPP and the calculations of primary energy demand.

 

 

So after much delay SAP10 is out for review from BRE (it was originally going to be called SAP2016). The carbon factors are updated (thankfully), along with many other positive changes. […]
The SAP10 grid elec carbon factor is set at 0.233kgCO2e/kWh (down from 0.519) & mains gas is set at 0.210 (= 0.233 with a 90% boiler). This reflects the huge decarbonisation of the grid over the past few years.

https://twitter.com/NigelBanks_ilke/status/1031797729121460225 

 

Edited August 22, 2018 by Dreadnaught

[Visti]

That is awesome news for us as we're going full electric!

[ADLIan]

@Visti Not sure what stage you are at with Building Regs but SAP10 will not be used in foreseeable future. Most likely will be introduced in next update of Part L - sometime in 2020?

[Guest Alphonsox]

We're fully electric but stuck on SAP2009, I wonder if this could be retrospective ?

[ADLIan]

For Building Reg compliance no. You have to comply with Regs and associated SAP version in force at time of application.

[ProDave]

So does that mean as an all electric house (heating by ASHP) that if my as built SAP is done with SAP10 it will get a better EPC rating than the design SAP done with SAP2012? (everything else being the same?)

[pdf27]

I think it looks like the cost penalty of electric heating is coming down a bit too:

I think heat pumps at <35°C are assumed to be 230% efficient, with a fuel price of 16.55 p/kWh (standing charge should be paid for anyway) = 7.19 p/kWh of heat

Assuming a top of the line (90%) gas boiler with a fuel price of 3.94 p/kWh = 4.38 p/kWh of heat plus a standing charge of £87

 

Break even is at 2676 kWh/year of heating - 25 kWh/m²/year for a typical 100m² house. Hot water demand will shift this a bit, but I think it means the predicted fuel costs will be much the same for both options too.

 

Full document is available at https://bregroup.com/sap/sap10/ BTW.

[ADLIan]

@ProDave

SAP energy rating is based on energy costs and these are normally increased (inflation?) in new versions of SAP so your SAP/EPC will probably remain the same. The big difference is reducing the carbon intensity of electricity (fewer coal fired power stations) so should make Building Reg compliance of all electric houses easier.

[Dreadnaught]

12 hours ago, pdf27 said:

Break even is at 2676 kWh/year of heating - 25 kWh/m²/year for a typical 100m² house. Hot water demand will shift this a bit, but I think it means the predicted fuel costs will be much the same for both options too.

 

 

Yes. And that disregards the capital and installation costs, and maintenance charge, of a gas boiler, which makes the decision even easier for a new build like mine. I am even thinking of going for electric-resistance heating only removing even the costs associated with an heat pump.

[pdf27]

If it was just a cost thing then electric resistance makes some sense - same for very small houses or ones you're thinking of letting out. If it was somewhere I was going to live I'd want a heat pump though - mostly for summer cooling. Getting a decent rating on fuel cost might be quite hard though, and that might put developers off.

[Dreadnaught]

@pdf27 Yes, I agree about summer cooling. Something I am thinking about. Am considering a low cost (sub £1000) air-to-air heat pump (otherwise known as an air conditioner) just for summer cooling. My approach is however still a work in progress so I might change my mind.

[epsilonGreedy]

On 22/08/2018 at 18:34, ADLIan said:

For Building Reg compliance no. You have to comply with Regs and associated SAP version in force at time of application.

 

 

I just want to confirm something, is the "time of application" the submission date when technical diagrams are sent to building control for approval typically a couple of weeks before the foundation dig?

[Jeremy Harris]

7 minutes ago, epsilonGreedy said:

 

I just want to confirm something, is the "time of application" the submission date when technical diagrams are sent to building control for approval typically a couple of weeks before the foundation dig?

 

The regulations that apply are those in force on the date that you submit for building regs approval, and cannot be changed if the rules subsequently change, unless by agreement.

 

As an example, we were originally required to meet Code for Sustainable Homes Level 4, but that was scrapped just before we started the build, so I applied to have the CfSh requirement lifted (only because I didn't want to build the stipulated bike shed) and this was agreed. 

[Ed Davies]

2 hours ago, JSHarris said:

As an example, we were originally required to meet Code for Sustainable Homes Level 4,

 

That would have been a planning requirement, rather than building control, wouldn't it?

[Jeremy Harris]

Just now, Ed Davies said:

 

That would have been a planning requirement, rather than building control, wouldn't it?

 

Yes it was, but the points awarded for the performance elements were supposed to have been checked by BC for compliance with the CfSH criteria, so there was a crossover between planning and building control, in effect (planning stipulated it, but building control were required to verify performance-related aspects).