So, firstly 88% of homes were built pre-2000[1] and the regulations that resulted in these improvements came into force in 2010. Assuming the regulations instan

So, firstly 88% of homes were built pre-2000[1] and the regulations that resulted in these improvements came into force in 2010. Assuming the regulations instantly had the desired impact (unlikely) we're discussing around 6% of UK houses. Those built earlier (on average) achieve significantly worse than 10m3/hr/m2 air permeability of the building envelope[2]. So the vast majority of UK homes have more ventilation than a Passivhaus building, and for the purposes of the initial discussion I think this is enough to demonstrate the inadequacy of this level of ventilation for the stated purpose, else Covid spread wouldn't be a problem in the UK within the home. It appears that for new builds latest research[3] shows an average of around 4m3/hr/m2, which is better than I expected, however the research suggests this is in part due to temporary measures by builders to achieve higher ratings than they would otherwise, and this is born out by the distribution of ratings achieved with an unlikely precipitous drop at precisely 5m3/hr/m2. However, for houses built to this standard some form of additional ventilation is a requirement of Part F[4]. It is possible to build a house with as low as 3m3/hr/m2 and provide no additional ventilation, but it must have been designed to > 5m3/hr/m2 so this should not be common. For social housing we can assume a single bedroom home will be around 40m2 with 2.6m between floors, and the required ventilation rate is 13l/s, or 47m3/hr/m2. This is around 0.45ACH. In fact the legal minimum rate per m2 is 1.08m3/hr, so for a typical home with 2.6m between floors this works out to 0.42ACH. So any house built to modern standards and used correctly should achieve the Passivhaus level of ventilation, unless it has tall ceilings. Certainly any UK home built with continuous mechanical ventilation is pretty comparable to Passivhaus standards for airflow. > People don’t open trickle vents, they turn down the extract fan timer because of fan noise People can also turn off the MVHR in a Passivhaus. I'm not sure what purpose it serves to compare correct use of a Passivhaus to incorrect use of this small fraction of UK homes. [1]https://www.statista.com/statistics/292252/age-of-housing-dwellings-in-england-uk-by-tenuree/ https://www.statista.com/statistics/292252/age-of-housing-dw... [2]https://www.researchgate.net/profile/Dominic-Miles-Shenton/publication/267304548_AIRTIGHTNESS_OF_UK_DWELLINGS_SOME_RECENT_MEASUREMENTS_AIRTIGHTNESS_OF_UK_DWELLINGS_SOME_RECENT_MEASUREMENTS/links/561f71bf08aecade1ace3adc/AIRTIGHTNESS-OF-UK-DWELLINGS-SOME-RECENT-MEASUREMENTS-AIRTIGHTNESS-OF-UK-DWELLINGS-SOME-RECENT-MEASUREMENTS.pdf https://www.researchgate.net/profile/Dominic-Miles-Shenton/p... [3]https://discovery.ucl.ac.uk/id/eprint/1573697/1/1-s2.0-S0378778817322612-main.pdf https://discovery.ucl.ac.uk/id/eprint/1573697/1/1-s2.0-S0378... [4]https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/468871/ADF_LOCKED.pdf https://assets.publishing.service.gov.uk/government/uploads/...