Hurrah! We’ve just received formal agreement that Porter’s meets the Passiv Haus – Passive House – standard.
So now we’re passive house ID5042. And the PH organisation across the country is holding Open Days, on Friday 11th to Sunday 13th November. So you can go to see Passive Houses near you. And we’re opening Porter’s on all three afternoons. Go to https://passivehouse-international.org/index.php?page_id=474 , click “Come and have a look!” which will open the list of buildings – several hundred. More detail on each if you click it. And there are flyers to download (small and large).
Dr Roderick Williams has been working on our behalf with WARM, which is one of the few UK based Passivhaus Certifiers working on behalf of the Passivhaus Institut, Germany, to achieve this certification. It would have been easier and almost certainly quicker to have done this as the house was being built. But we were under considerable financial pressure at the time and the additional expenditure did not seem a good idea then.
BUT – we’re not a zero-carbon house – not quite, so we’ll have to relinquish this claim. While it’s certainly true that we get all our heat and hot water from sunlight and wood, when you look at the electricity power balance from the records of the last three years, it isn’t really possible to say that we generate more electricity than we use. And if the electricity we use from the mains isn’t all from a carbon free source, then we’re not zero-carbon.
Could we become so? Ignoring, for the moment, the argument about taking our electricity from an all-renewable source supplier, such as Ecotricity, or from a nuclear source supplier such as EDF, then the answer is, almost certainly, no. The PV panels, limited to 4kWp without special permission, simply don’t generate enough electricity over the course of a year to achieve this.
The figures show that although we generate more electricity in a year than we draw from the mains supply, it isn’t possible to show that we generate more than we use. So we’re not self sufficient in electricity. We’d probably need a PV system twice the size to achieve this.
With the present PV system, to achieve a balance, I think we’d need to use less than 4,000kWh/a. And as the Klargester package sewage system uses about 1kWh a day, as does the MVHR, that’s over 700kWh/a used already. It wouldn’t be comfortable – not enough cooking- too many cold meals!