coconutsaregood

Super efficient windows you have there. Are you using Perspex of something? That range is half of those made with coated mineral glass and inert gas cavities.

Thanks Mike for the research on this matter. The current crisis should afford me time to browse those papers. Just noting your assertion on one of the several group of pollutants: VOC. A failure to limit this problem alone implies the chosen ventilation system is not complying with the current bldg regs. Car exhaust fumes (filter required for intake air) is not a requirement for bldg regs but NO² generated inside is one (gas or wood fumes).

Hello David, thanks for the reply and I am sorry I kind of ignored your response initially because I simply wanted the sum. I'm a little rusty on bldg regs these days and need to catch up, I still think in 1980s standards. The only constructive criticism I would add to your statement above is that "sick building syndrome" was a big topic in the past and the experts (CIBSE) state typical ventilation rates, for a dwelling, of one whole air change per hour to ensure the pollutants (including the ones less easy to sense and detect including perhaps: COVID 19) are diluted. So seeing fresh air rates, on this enthusiastic forum, of less than one I do find alarming. Yes you can live with it, but are they healthy? Building Regulations' minimum of around 0.43 air changes per hour, demonstrates the thinking has changed in recent decades but that is average. As we know you still need intermittent blast of fresh air for kitchens & utility rooms from a health requirement and WCs from the "wife" demands. These intermittent demand raise the average minimum. Your argument with the guys on here will go on I see, as you try to overturn the converts with what we in the industry call Life Cycle Costs of the different solutions to air control in buildings. One aspect I can add is that Green buildings are seldom a good investment in terms of investment appraisal, so the selling point of Green tends to be the benefits that are subjective or emotional. I have the opinion that unless fossil fuels incur carbon tariffs (methane is way too cheap and competitive) Green will always struggle in investment terms and will continue until we run out of gas/oil and for now it will be up to wonderful Greta & others to persuade us all to change. The main point is you cannot take one function of a building in isolation, you have add it all together and look at the whole answer in terms of costs over the life or the term you are going to need the building. The value (the later is what you are all arguing about) of these things will increase as more people get educated or informed but the infamous estate agent is a barrier to progress on that front. thanks for reading and forget the cost argument it never works.

sorry, got you now: 92 x 0.3 = 27.6 ta

forgive me if this has already been mentioned but how do you arrive at your flow rate of fresh air in litres per second please?

QSs do not generally have the finer inside knowledge to give accurate estimates on single private house projects that are worth less than around £400k. They can provide a document (bill of quantities) that can accompany the specification to get tenders that are on a "level playing field" even before the drawings are finished. But the fee is difficult to justify on low value contracts.