Highest SAP rating?

[Anonymous]

I'm currently advising on an ultra energy efficient “true” zero carbon new home to built in the SW of England. The provisional SAP rating is A136. My client is interested in discovering if anyone has actually built a house with a higher SAP rating than this? Any information/views gratefully received. Thanks David Strong

[Tom Foster]

Interesting – anything more on this?

[Anonymous]

The preliminary SAP Rating has been checked a couple of time and all looks ok -the reason for the very high rating is an ultra low energy demand resulting from very low U values, low air permeability (less than 1.5 m3/h.m2 @50Pa) + MVHR + air source heat pump + 50kW of PV on the roofs of adjacent stables and redundant farm buildings.

[Tom Foster]

Is that bad actually? If it allows good SAP for a merely medium-insulation building, it's substituting capital expenditure on hi-tech for same on average-tech insulation and airtightness, for same result as far as carbon, energy demand etc.

Yes, having installed energy generation equipment, it's then depriving the nation of that energy product, by 'squandering' it. There might be questions about uncounted eco-footprint resulting from hi-tech, compared to lots of EPS and sticky tape. What else makes the SAP trade-off wrong? It's against 'fabric-first' ideology, but what really is the objection?

I sometimes think this kind of thing is OK as long as the energy product is so lo-grade that it can't possibly be seen as tradeable energy commodity – can't be used anywhere except very close to where it's generated (or captured). That is, lo-grade heat. The building itself captures its residual heat demand from the sun. That seems OK as long as it's coming in through windows, but not OK if it's done via solar collectors on the roof.

[Tom Foster]

You mean because the energy generated, which is supposed to cancel the heating demand, all comes in the summer/daytime and is largely fed-back into the grid for paltry payment – leaving the winter/night heating demand to be expensively bought from the grid?

Yes, come to think, it's as clear as that – which makes that 'trading' aspect of mainstay SAP completely irrelevant to reducing occupants' fuel bills (indeed systematically misleading) – therefore irrelevant also to 'fighting fuel poverty'.

I wonder whether the politicians appreciate the latter effect of SAP? Someone needs to publicly trip a politician or two up, when they're boasting about what they're doing to reduce fuel poverty. That might bring a change in this anomaly.

[Anonymous]

Right, I know about the 'self-certification' style of building control. What I don't know are the penalties for abusing it. Either what the penalty is or how it is enforced. Somebody or somebodies presumably has a right to bring action in the case that building control has failed. Who is that somebody?

[Author]

Posts