Heat recovery ventilation is an available technology and it’s not practical in the winter to sit in a house with the windows wide open, even with the heating on full so no-one will actually do it.
Part L1A of UK building regulations stipulate an air permeability of no more than 10m3/hr/m2 of building envelope at 50pa of pressure. My home has approximately a 1:1 ratio of building envelope to volume, though this will vary a great deal. But for such a home this works out to 10ACH at 50pa. There are various studies on how to convert these measurements to natural ventilation rates, but the conversion rate is around 10-30, with the typical house being adjusted by a factor of 20, i.e. 0.5ACH, however this can be as high as 1ACH.
Some homes will be constructed to higher standards, but will not likely achieve less than half this rating.
This also ignores the presence of trickle vents inside windows in homes without mechanical ventilation, and that the majority of homes in the UK were built to lower standards - typical values for homes built prior to 2010 are 15-20m3/hr/m2.
Therefore, 0.5-1ACH is a pretty standard background ventilation rate for homes in the UK. Your typical Passivhaus home with 0.4ACH from mechanical ventilation has less ventilation than a typical home, not more.
Only very large homes built to strict modern standards and with a high interior volume to building envelope ratio could possibly have 3-4x less ventilation.
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-dw...
[2]https://www.researchgate.net/profile/Dominic-Miles-Shenton/p...
[3]https://discovery.ucl.ac.uk/id/eprint/1573697/1/1-s2.0-S0378...
[4]https://assets.publishing.service.gov.uk/government/uploads/...