> I don't see the point of building tight, if you're going to have massive holes in the building, through which you force tons of air (which you should). Would

> I don't see the point of building tight, if you're going to have massive holes in the building, through which you force tons of air (which you should). Would you call a jar airtight if you never close the lid? I'm not quite sure why you're taking thing so literally about combining the two actions. I would call a jar airtight because the glass cannot be penetrated by air, nor can the lid and band. You can then ventilate the airtight (proverbial) jar on your own terms: using filters and such to control the quality of the air that goes in/out. The build tight is about the building enclosure; the ventilate right is about exchange stale/dirty interior air with cleaner exterior air in a controlled fashion. A fully sealed building with zero ventilation would be horrible for people due to increased chemicals from people just breathing (CO2) or cooking. It is absolutely necessary to ventilate a building, but it can be done so to also reduce the incoming undesirable elements in the exterior air. > Ventilating forces out all that hot or cool air that you paid for, so you have to heat or cool the replacement air. Ventilating using HRV/ERVs takes the conditioned air and transfers some of its properties (temperature, moisture) to the incoming air to temper it. The incoming air is/can be also filtered to removed things like pollen, dust, wildfire smoke, etc. > It's basically greed or ideology over health. There are entire industry standards (ASHRAE 62.1 and 62.2) on the topic of good indoor air quality (IAQ) to make sure that 'just enough' stale air is removed (e.g., to reduce CO2 counts) while not 'over-ventilating' (increasing costs), and it is a topic of active academic research (especially post-COVID): * https://www.youtube.com/playlist?list=PLsc2-5fAgMq4bj2P8fMgQjzJmx8p1mCMd https://www.youtube.com/playlist?list=PLsc2-5fAgMq4bj2P8fMgQ... By not having a tight building envelope treated air can leak out, and untreated air can leak in, and depending on the size of the leaks (holes) you can even get bugs/creatures entering. The whole point of buildings is to separate environments: inside versus outside. Leaking building compromise that separation reducing the control you have. And if you do not want to separate your interior and exterior environment live in a tent or under a tarp: plenty of ventilation, very little air-tightness.