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PH premium
PH plus
PH classic
PH Energy Conservation building
figures on the left are your heat demand. figures on the right is the remainder of your primary energy demand (which includes DHW demand, aux electricity and domestic electricity)
PH Classic 15kwh/m2a heat demand/ 115kwh/m2a is the remainder (120 total including 15 heat demand)
So take a 200m2 house x 15kwh/m2a = 3000kwh/a
to produce a kwh using oil or gas costs about 10cents per kwh. so thats 300€ per year for heating (£247/a)
your DHW demand could be up to 30kwh/m2a.
What's the “+RES 60” and “+RES 120” bit?
In essence as far as I can see, these add in consideration of on-site PV/wind/methane generation etc as contribution to electrical/cooking/water heating demand. In 'PH Classic' you were free to do these as an alternative to (minimised) grid supply, i.e. good idea but outside the PH calc.
Still no integrated consideration, though, of solar gain as contribution to space heating, except for that kind of solar gain that comes in thro windows and (if a bit of storage is desired) falls on heavy floors/walls.
The latter is a primitive way of harnessing solar gain, which carries with it danger of summer overheating, and therefore must be limited in its scale and therefore in its contribution to space heating. Better ways to do it are quite capable of capturing enough, indeed surplus heat right thro Dec/Jan, without risk of summer overheating.
Still, neither Classic PH nor the two new grades take this possibility on board - you're free to provide 'back up heating system' in this way, i.e. good idea but outside the PH calc.
But that 'outside the PH calc' attitude closes the door on the possibility that a building-integrated solar capture/storage delivery design could produce surplus heat right thro Dec/Jan, allowing the stringency of insulation/airtighness standards to be relaxed by a calculated degree - and still fall squarely within high PH targets.
Part of the appeal of PH for me was that it's either a PH or it isn't (ignoring EnerPHit). Now there are Fifty Shades of Passive it seems to me that there will be even more opportunities for bogus claims to PH achievement...
I'm reminded of the A+++++ rated appliances etc. Why not just make an A harder to achieve each year/cycle?
But, yes, adding complexity to the rating system doesn't help - you might was well just quote the kWh/(m²·a), etc, figures, e.g., Passive House 15/120, PH 15/90/60, etc.
15 + 115 = 130 but the primary energy limit is 120.
Also I don't understand the statement 'the new “Passive House Plus” label confirms that about as much energy is produced as is consumed' in the press release as compared to 15/90 + RES 60. 60 is not about as much as 90 let alone about as much as 15+90.
Does anybody have a reference to an actual source document? That's quite deliberate I believe. "Fabric first" and all that. Building an 'inadequate' fabric and then adding high-tech (=high embodied energy) renewables energy gear to substitute for the lack of insulation is not what PHI is about, AFAIK. When there's enough as-built evidence of reduced resource usage through an alternative strategy, I expect they may reconsider. Yes, it is quite clearly a signpost labelled 'start of the slippery slope'. I hope the label stuck to it reading 'Danger' is read by enough people.
In fact PHI has nicely drawn a line in the sand and refused those bloomin' Americans who want an 'easier' PH standard 'to suit the American market'.
But apart from facts, back in the land of marketing, the slippery slope is all about brand dilution.
The point is, now your average lay customer asks for a PassivHaus and the first response is "which type?" Then they have to sit through an explanation of all the models in the range.
Although the standard may or may not have changed, the 'menu' of PH types begins to grow in the same way you can't just get a 'coffee' in most coffee shops. It has to be something like 'frothy macchiato with a hint of lemongrass'*
*can you tell I'm a tea drinker..?!
Most people I know just want to know how much extra it will cost (a separate argument) - having different types just makes that comparison even harder.
Responding to that in terms of cost should just be a simple "Base Build plus X, Y and Z percent ", firmed up later with an appropriate LZC assessment for renewable options and a review of non heating demand and non regulated electricity consumption.
Different criteria, but akin to say BREEAM assessments targeting Good, Very Good or Excellent - it's possible to say within a matter of minutes what the cost burden as an addition to base build will be - type of thing that cost consultants live for.
Going back to the PH renewables, then it doesn't really matter if it's all gained from one technology, or a basket of technologies - cost per kW might vary, but cost per kWh isn't that different
Regards
Barney
So taking standard PHPP limit we have 120/2.7 = 44.44 (lets call it 45) is energy used without the multiplier
So 60kwh/m2/a from PV would more than cover this load. However the primary demand is calculated based on treated floor area, but the RES is based on ground area.
In my case it would be 116m2 TFA vs 81m2 ground area so
116 x 45 gives 5220kwh/a
and
81 x 60 gives 4860kwh/a
Not quiet net-zero but getting there. Take the new requirement of 90Kwh/m2/a and factor it down to 90/2.7 = 33.33 (34)
116 x 34 = 3944kwh/a
and now we are a net exporter.
Now I might be way off with this but that's the only way it makes sense to me. My calcs could be off so please check :-)
They usually use 15kWh/m2.annum for hot water, 20kWh/m2.annum for heating and 20kWh/m2.annum for electricity so 55kWh/m2.annum.
Sufficient Solar Thermal heating reduces the heating to 1kWh/m2.annum and the hot water figure to 1kWh/m2.annum, so for a 160m2 house a 4kWhP PV array is usually sufficient to get it to zero.
If I was launching a new Passive House standard I'd add an extra page to the PHPP calculation called Solar Heating and it would show how many m2 of solar is required to get a house to zero.
The biggest cost in Passive Houses is still all the gadgets and machines, like ducted HRV, Heat pumps, stoves, solar hot water etc,.
It appears that the definition of passivhaus classic is different to the classic definition of passivhaus, and that seems like a catastrophic marketing mistake to me, so I hope I've misunderstood.
But the whole scheme appears to be predicated on the definition of something called PER and the definition of PER is noticeable by its absence or by any references to its definition. It does seem though that fundamental to the definition is the concept of an entire electricity generation and distribution system based completely on renewable energy. This begs the question of whether they consider nuclear renewable or not. And they repeat the (IMHO) canard that we must build houses now assuming this to be true because the houses' current boilers will still be in place when the transition is complete. There's nowhere in the world yet that actually meets the starting condition for the definition to be usable. Pigs might fly decades earlier!
The whole thing still looks like an (IMHO) ill-advised jump into a political minefield; not an area that science-based enterprises are best qualified for.
Are there any published documents that actually get to the bottom of the PHI proposals, or is it still all a discussion taking part in smoke-filled rooms?
It's pretty clear to me that there isn't a single measure of 'greenness' that everybody can agree on, but even if there is, we haven't discovered what it is yet.