Ferdinand Posted January 26, 2020 Share Posted January 26, 2020 Yes, I know that Building Regs are not properly implemented. I am ignoring that for this thought experiment. However, given that EPC100 is by definition zero-carbon on a running basis, and that the approx EPC of a Building Regs house is EPC 80-85, what does the difference actually represent? Ferdinand Link to comment Share on other sites More sharing options...
nod Posted January 26, 2020 Share Posted January 26, 2020 Miles away Most people don’t care about energy rating when purchasing a new house Our Daughter is purchasing her second home with her partner I receive messages every evening About bedroom sizes amount of parking Size of garden PRICE Not a thing about solar gain Energy efficiency While both are professionals If I asked either about Sap reports I don’t think they would know what one is Let alone care I would rate her and her partner as pretty typical home buyers Unfortunately any changes or improvements will have to be forced on builders - Sellers By central government 1 Link to comment Share on other sites More sharing options...
SteamyTea Posted January 26, 2020 Share Posted January 26, 2020 (edited) 27 minutes ago, Ferdinand said: However, given that EPC100 is by definition zero-carbon Is it zero carbon, or energy negative. Say you use gas or wood heating and produce 1tonne of carbon dioxide a year, you would have to give away at least that amount of carbon free energy to offset it. And there is still a tonne emitted. I am not sure how it works to be honest. Edited January 26, 2020 by SteamyTea Link to comment Share on other sites More sharing options...
Ed Davies Posted January 26, 2020 Share Posted January 26, 2020 (edited) 55 minutes ago, SteamyTea said: And there is still a tonne emitted. Exactly. If you burn fossil fuels [¹] at all you're not zero carbon unless you're actually sequestering carbon in some way. I don't know anybody who is sequestering much carbon. [¹] including using electricity from the grid as it now is. PS, a net-zero carbon emissions house can easily cause higher emissions than one that's net positive. Edited January 26, 2020 by Ed Davies Link to comment Share on other sites More sharing options...
SteamyTea Posted January 26, 2020 Share Posted January 26, 2020 32 minutes ago, Ed Davies said: unless you're actually sequestering carbon in some way. I don't know anybody who is sequestering much And that is fraught with problems as it has to be a totally new scheme that was not going to happen anyway. And at about 2.5 kg/m2, a lot of ex industrial land is needed. Link to comment Share on other sites More sharing options...
A_L Posted January 26, 2020 Share Posted January 26, 2020 1 hour ago, SteamyTea said: Is it zero carbon, or energy negative. Neither, EPC100 (or SAP100) means zero energy cost The Environmental Impact Rating (or EI rating) measures net carbon emissions and EI100 is net zero. 1 Link to comment Share on other sites More sharing options...
Ferdinand Posted January 26, 2020 Author Share Posted January 26, 2020 yes. Defined in Section 13 of this document I thInk. https://www.bre.co.uk/filelibrary/SAP/2012/SAP-2012_9-92.pdf So where does that leave my original question? I am dreaming about a Private Members Bill That mandates an EI number of 100 for all new dwellings out of the blue. Link to comment Share on other sites More sharing options...
Ferdinand Posted February 1, 2020 Author Share Posted February 1, 2020 (edited) On 26/01/2020 at 17:38, Ed Davies said: Exactly. If you burn fossil fuels [¹] at all you're not zero carbon unless you're actually sequestering carbon in some way. I don't know anybody who is sequestering much carbon. [¹] including using electricity from the grid as it now is. PS, a net-zero carbon emissions house can easily cause higher emissions than one that's net positive. We used to have a 2 acre garden with a woodland in it :-), in which we planted an orchard amongst other things. I guess in toto we put in 30-40 trees, and the field went to scrub over a number of years. That would be sequestering something, but no idea how much. I am sure there is someone on BH who is planting trees by the thousand. Edited February 1, 2020 by Ferdinand Link to comment Share on other sites More sharing options...
tonyshouse Posted February 1, 2020 Share Posted February 1, 2020 Zero energy is not possible, sorry, zero carbon is ill defined and now they talk about net zero carbon whatever that means i like Passive Haus, Minergie, reducing energy use building regs are in a mess Link to comment Share on other sites More sharing options...
SoldierDog Posted February 1, 2020 Share Posted February 1, 2020 The 'Future Homes Standard' is currently under consultation see https://www.gov.uk/government/consultations/the-future-homes-standard-changes-to-part-l-and-part-f-of-the-building-regulations-for-new-dwellings although a lot of people dont think it goes far enough, see https://www.leti.london/part-l for one of the many well thought responses. Link to comment Share on other sites More sharing options...
joth Posted February 2, 2020 Share Posted February 2, 2020 9 hours ago, SoldierDog said: The 'Future Homes Standard' is currently under consultation see https://www.gov.uk/government/consultations/the-future-homes-standard-changes-to-part-l-and-part-f-of-the-building-regulations-for-new-dwellings although a lot of people dont think it goes far enough, see https://www.leti.london/part-l for one of the many well thought responses. That's quite a read. The plan for zero carbon is to remove building fabric metrics and just estimate primary energy use. It's a "Fabric last" approach; build it cheap then cover it in solar panels until the CO2 metric passes. Link to comment Share on other sites More sharing options...
Ian Posted February 2, 2020 Share Posted February 2, 2020 (edited) In 2016 I built a small holiday home in Wales to minimum building regs. The EPC is C71 and the EI is B81. It is timber frame construction with timber weatherboarding. The area weighted average U value for walls roof & floor is 0.15 and windows are 0.8 (3G). No renewables and it’s heated by bulk LPG. We’ve been using the building for 3 years now and the average annual LPG usage for all hot water, heating & cooking has been 475 litres at an annual cost (excluding standing charge) of £155. To put that figure into context our annual Council Tax Bill is £1,870. Edited February 2, 2020 by Ian 1 Link to comment Share on other sites More sharing options...
Gone West Posted February 2, 2020 Share Posted February 2, 2020 They don't need to keep changing the regulations, Part L isn't too bad. If they improved airtightness to 1.0ach and mandated MVHR it would be ok. The problem lies in the quality of the construction and the inspection process. 2 Link to comment Share on other sites More sharing options...
ProDave Posted February 2, 2020 Share Posted February 2, 2020 1 hour ago, Ian said: We’ve been using the building for 3 years now and the average annual LPG usage for all hot water, heating & cooking has been 475 litres at an annual cost (excluding standing charge) of £155. To put that figure into context our annual Council Tax Bill is £1,870. That is a long standing gripe of mine. This is a term you won't hear anyone else use but when our house is complete and properly banded I will be in "council tax poverty" meaning 10% of my income goes to pay the council tax. They use the same thing "fuel poverty" when the 10% applies to your heating cost, so why do they think it is okay to be in council tax poverty with no option to do anything about it it? Link to comment Share on other sites More sharing options...
Ed Davies Posted February 2, 2020 Share Posted February 2, 2020 15 hours ago, Ferdinand said: I guess in toto we put in 30-40 trees, and the field went to scrub over a number of years. That would be sequestering something, but no idea how much. Fair enough. But it's not sustainable in that once the carbon sequestered in those trees is “used up” you won't have space for more unless you can find something to do with the wood which keeps it out of the cycle longer term. Link to comment Share on other sites More sharing options...
Ferdinand Posted February 2, 2020 Author Share Posted February 2, 2020 (edited) 7 minutes ago, Ed Davies said: Fair enough. But it's not sustainable in that once the carbon sequestered in those trees is “used up” you won't have space for more unless you can find something to do with the wood which keeps it out of the cycle longer term. That is quite an interesting insight. One thing we noticed there was an ancient (=probably 18C) yew tree which had drifts of needles underneath to a depth of several feet .. which must have been there for the best part of half a century. And amazing quality composts type soil beneath that which must have been the previous generations of needles. The further point about sequestration being an interim for 50-100 years to blunt the peak is an important one. Long life big trees which will grow for 200-300 years can perhaps go a long way to that on their own .. eg beeches, sweet chestnuts, turkey oaks etc. (The garden had been laid out by the mid-Victorians and not really changed. There was even a marked ‘turning for coaches’ circle around a particular weeping ash tree). F Edited February 2, 2020 by Ferdinand Link to comment Share on other sites More sharing options...
Ferdinand Posted February 2, 2020 Author Share Posted February 2, 2020 Incidentally, does anyone have a number for how much carbon is sequestered by a house insulated with cellulose for the next century? Link to comment Share on other sites More sharing options...
Jeremy Harris Posted February 2, 2020 Share Posted February 2, 2020 16 minutes ago, Ferdinand said: Incidentally, does anyone have a number for how much carbon is sequestered by a house insulated with cellulose for the next century? Cellulose is about 44% carbon by weight, so for a wall blown with cellulose at a typical density of around 56kg/m³ , built to the same sort of spec as ours, then each m² of wall (ignoring the timber for now) has around 17kg of carbon. Our roof has a bit more (again ignoring the timber), about 22kg/m². Our total wall area is about 347m² and the roof area is around 128m², so that gives a total amount of carbon just from the cellulose insulation of ~8,715kg. The timber frame will be ~50% carbon and at a guess is roughly around another 5 tonnes of carbon. So the total amount of sequestered carbon is probably somewhere around 13 to 14 tonnes. Link to comment Share on other sites More sharing options...
Ferdinand Posted February 2, 2020 Author Share Posted February 2, 2020 (edited) 12 minutes ago, Jeremy Harris said: Cellulose is about 44% carbon by weight, so for a wall blown with cellulose at a typical density of around 56kg/m³ , built to the same sort of spec as ours, then each m² of wall (ignoring the timber for now) has around 17kg of carbon. Our roof has a bit more (again ignoring the timber), about 22kg/m². Our total wall area is about 347m² and the roof area is around 128m², so that gives a total amount of carbon just from the cellulose insulation of ~8,715kg. The timber frame will be ~50% carbon and at a guess is roughly around another 5 tonnes of carbon. So the total amount of sequestered carbon is probably somewhere around 13 to 14 tonnes. So at the current UK CO2 emissions equivalent that is very very roughly 2 person years of carbon emissions. I am not sure of the conversion factors from carbon to CO2 conversion which presumably involves a doo dah diddle with molecular and atomic masses, three assumptions, and 4 fiddle factors. Also ignoring variations in claims about CO2 per capita emissions and calling it 5-10 tonnes per person per annum ish. F Edited February 2, 2020 by Ferdinand Link to comment Share on other sites More sharing options...
SteamyTea Posted February 2, 2020 Share Posted February 2, 2020 4 minutes ago, Ferdinand said: am not sure of the conversion factors from carbon to CO2 conversion which presumably involves a doo dah diddle with molecular and atomic masses. 16 over 44, that takes in the masses. Link to comment Share on other sites More sharing options...
Ed Davies Posted February 2, 2020 Share Posted February 2, 2020 (edited) 12 to 44 ~= 3.67. 1 mole of carbon has a mass of roughly [¹] of 12 grams and 1 mole of oxygen 16 g so 1 mole of CO₂ has a mass of 12 + 2×16 = 44 g which contains 12 g of carbon so 3.67 tonnes of carbon dioxide emissions is 1 tonne of carbon. It's not quite as widespread as kW vs kWh confusion but still pretty common to see people confusing tonnes of carbon vs tonnes of carbon dioxide. Most often, what people call a number of tonnes for “carbon emissions” is actually a mass of carbon dioxide. [¹] ignoring the minor isotopes. The standard atomic weight of carbon is 12.0096 and that of oxygen is 15.99903 g/mol. Edited February 2, 2020 by Ed Davies Link to comment Share on other sites More sharing options...
SteamyTea Posted February 2, 2020 Share Posted February 2, 2020 20 minutes ago, SteamyTea said: 16 over 44, that takes in the masses Whoops, yes, 12 overs 44 Fat fingers and gungy eyes today. Link to comment Share on other sites More sharing options...
Jeremy Harris Posted February 2, 2020 Share Posted February 2, 2020 We effectively "sequester" about 0.9 tonnes of CO2 per year, by generating zero carbon power that's exported to the grid, and used by the house in place of power supplied by the grid. That's about 0.245 tonnes of carbon per year. I've not worked out the impact of my car yet; need to get a feel for the proportion of energy it uses that will come from self-generated, zero carbon, energy. Car energy use is interesting, especially at this time of the year when the weather's a bit cool. This is the data from my ~10 mile trip to the supermarket yesterday: This data wasn't taken from the car directly, it was retrieved from Tesla's server, and is just a tiny bit of the telemetry between the car and Tesla that is running all the time the car is online. For the power fanatics, the peak power used on that trip was 134 kW (~179hp), the minimum power was ~ -41 kW (~ -55hp) and the average power for the trip was 6.75 kW (~ 9hp). Link to comment Share on other sites More sharing options...
SteamyTea Posted February 2, 2020 Share Posted February 2, 2020 4 minutes ago, Jeremy Harris said: it was retrieved from Tesla's server Don't they put axis labels on. Link to comment Share on other sites More sharing options...
Jeremy Harris Posted February 2, 2020 Share Posted February 2, 2020 4 minutes ago, SteamyTea said: Don't they put axis labels on. The data's been plotted with Grafana running on a Raspberry Pi, and there are axis labels if you look closely. The legend's at the bottom, and the left Y axis is speed, power and SoC, the X axis is time and the right Y axis is range remaining in miles. Link to comment Share on other sites More sharing options...
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