Joeboy wrote: ↑Fri Nov 10, 2023 3:59 am
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.