Grand designs passivhaus premium

[Mart]

He has a fairy extensive website now

Just for clarification, is anyone allowed to use that site to help find fabulous woodland creatures, or is it a site that's exclusively for the use of said paranormals?

Asking for a friend?

Mart if you are hoping to find creatures such as shown below on the website, I think you may be a bit disappointed!

That's a shame ................. <cough> is probably what my friend will say.

[AGT]

The joys of typing on a phone

[Mart]

The joys of typing on a phone

Hope you didn't mind my joking. I'm the last person who can throw stones as I make dozens of mistakes in my posts (ever since getting long covid), and even after proof-reading, have to go in and edit them when posted, as I miss many more.

But sometimes, a small error can lead to a fabulous difference/digression ...... at least in my weird, and childish mind.

Or just the way the english language allows for ambiguity - for our site, here's a US news headline from over 20yrs ago - 'Man charged in battery case.'

[Moxi]

'Man charged in battery case.'

Moxi

[AGT]

The joys of typing on a phone

Hope you didn't mind my joking. I'm the last person who can throw stones as I make dozens of mistakes in my posts (ever since getting long covid), and even after proof-reading, have to go in and edit them when posted, as I miss many more.

But sometimes, a small error can lead to a fabulous difference/digression ...... at least in my weird, and childish mind.

Or just the way the english language allows for ambiguity - for our site, here's a US news headline from over 20yrs ago - 'Man charged in battery case.'

No, crack on, all taken in a fun positive way!

[AE-NMidlands]

'Man charged in battery case.'
Moxi

and
"Police have apprehended 2 boys stealing fireworks and batteries...
They let one off but charged the other."
(groan!)

[Mart]

Did anyone watch it?. Loved the spray seal for cracks but was revolted by the size of the place. A £1,500 catflap and a £20,000 skylight?

Also, how can a roof that vast be generating only 270 kWh per day (maybe it was the 1st March). Does the average home really only use 8kWh power per day and how can they be limited to only 2.5 x that in export?

Answers on a postcard please.

Finally, £1.25M and only 1/2 finished.

Impressed with the spec though, self generate 4X your consumption.

Hi Joe. Finally got round to watching it (Wifey was away, and would not have been happy if I'd 'cheated' on her).

Glad you mentioned the cat flap, as I'd forgotten you'd said it, and it's been playing on my mind since watching.

So, lots of questions, and if I seem to be knocking the idea of Passivhaus, or energy efficiency/conservation, I'm honestly not, just wondering where the point may be reached at directing investment better?

So the cat flap stood out, as a great example. I totally get the need for it, to meet the standard, but £1k+ invested in PV, or a wind farm, would shirley generate more energy, than that lost by a more basic catflap? And multiplied by a heatpump COP, even lower generation in the heating months would probably equate.

It just seems to me, that perhaps the advances in energy generation (and storage) may now be creating a conflict, albeit it a fun and good natured conflict, with energy savings. Just considering my PV, roughly equal to 240Wp per 'normal' panel, we could now generate 3,000kWh's pa more with panels pushing 400Wp this decade. Our annual gas consumption (pre A2A units) was 8,000kWh's, so in net terms and via a HP that would roughly equate*. But our 1930's semi could never economically be improved to Passivhaus levels, I assume?

I'm extremely torn on these thoughts as they seem wrong, but just pondering out loud, that perhaps as energy saving returns diminish, there may be a point where making more energy is better? I use the word better, as cheaper might imply I'm obsessing over the money, but I'm not, I'm pondering what gives the best net result. Perhaps 1,000kWh pa from extra PV, is better than the savings from a specialised catflap?

Speaking of, I hope the outer door is partially ventilated, as there's nothing a cat likes more than a sneaky space to hide in. So I can imagine Tiddles curling up inside the unit, between doors?

*Not trying to cheat, this would only be a net equivalent (of extra export to extra consumption), and I'm playing extremely fast and loose, as the gen would be summer weighted. Plus our house PV being E/W exaggerates the issue, but perhaps a Ripple like wind farm investment is another example.




Other thoughts hopefully less controversial, why did they get so concerned about the roof PV possibly being 2% short of the 4x energy multiplier they needed? Do I assume the energy generation has to be on the house for the standard, and they couldn't just plonk some PV panels on a ground mount. Plus, whilst I thought the black wooden cladding was very nice, perhaps a few black panels wall mounted, would have got them to the required annual production?

Again, apologies to anyone with or aiming for Passivhaus, I'm honsetly not knocking the idea, just wondering how things may have changed now, as technology improves, so what gives the best bang for your buck, as you chase those harder and harder last savings.

Hope this is fun, and of course the great thing, is that both energy saving, and energy generation, plus heatpumps and batts, are all improving, so it's all good news.

[Ken]

That sounds like "cost benefit analysis"

Surely if one did that one would build something 1/2 the size etc in the first place. Then i think after near normal insulation and energy sources then keep pilling on the RE +batts+ little green grid until A=B. If i had to pay that much for a cat flap there would only be one outcome.

But this is "mine is bigger than years" terriotory and think of those who have millions pound super yachts which they only ever go on a few weeks a year. A lot of people are into this on a different scale with cars,clothes,shoes,phones etc. otherwise what stuff would the Chinese make.

[Stig]

I also got around to watching it last night. As far as Passivhaus goes I'm also a bit torn: I love the idea that there's independent checking on build quality as it sounds like that's exactly what the UK building industry needs (I'm sure they'd hate it!) but I'm also wondering if all the extra cost (in time, money and embedded carbon) is justified as energy is decarbonised. (I know very little about Passivhaus so maybe a build gets marked down for, e.g., using loads of phenolic insulation)
I'd suggest there should be two cost-benefit calculations done when starting such a project, one for money spent now vs. money saved on running costs and another for carbon 'spent' now vs. carbon saved during the life of the building.

I think everyone, including the client, agreed that it should have been more like half the size!

[Stinsy]

I think that every house should have decent insulation and airtightness. However at the same time it should be normal to put 6kWp on the roof of a 3-bed semi, and normal for the same house to have 14.4kWh of batteries.

Technology has moved on. Passivhaus is centred around super-expensive, ultra-thick insulation and very-difficult-to-achieve air-tightness that just aren't worthwhile IMO. Particularly when you can build a house with 20-30W/m² heating demand for half the price!

I know a guy with a Passivhaus. He fitted an ultra-expensive 2-story, full height, gable-end window. I told him he'd need aircon for summer but he moaned on about how the sun angles meant it'd be cool in summer and warm in winter. Anyway as I predicted it is unbearable in summer and he's spent a fortune on special coatings on the windows (that obviously reflect the precious winter-sun too) and ugly-as-hell blinds. So don't mistake "Passivhause" for "well designed"! Just because the magical spreadsheet says your design is good, doesn't mean it is!