riceart77

Mid-efficiency furnaces are still commonplace in the US, and they don't have sealed combustion systems - they get combustion air from the indoor space, but they vent 100% of combustion products out. High-efficiency furnaces in the US made in the past 30 years or so use sealed combustion with intake and outtake to the outside. (North American high efficiency furnaces older than about 30 years were not necessarily sealed).

But yes, the GP is full of shit. Maybe they have some other non-induced vented gas burning appliance (ie a hot water heater or gas hob), or their measurement equipment is faulty.

> My experience (sample of one) is that they don't.

There is something very very wrong with your equipment (or you're measuring something else not having anything to do with the heating equipment - more likely). A high efficiency furnace has a sealed combustion chamber, the entire thing runs in a circuit vented to the outside - combustion air comes from the outside and it is vented to the outside. If it is not airtight sealed from the indoors, it is broken. Even a mid-efficiency furnace with a non-sealed system will vent 100% of the flue gas outside.

> Natural gas combustion is at best _mostly_ exhausted.

Bullshit for any modern equipment (ie installed in the last 50 years).

> So, yeah, it’s not wasteful to vent your computer exhaust outside in the winter, but no one’s doing that.

Uh, come again? If I am using my computer anyway - why would I exhaust the waste heat outside if I have to heat the indoors anyway? That is wasteful.

> your eyes just slide over them and you don’t notice.

Nah.

There have been minisplits in the US for years, they are just not very common. Moreover they have been commonplace in Asia for decades now. They are noticeable. I personally think they look like ass. They are huge and you are blind if you don't notice them. There is a reason why ducted or recessed models are available internationally for luxury homes. It has nothing to do with Americans.

> Current file systems do not allow this where a file can have a block somewhere in its interior that is just a partial block.

Because it would be costly for uncertain benefit?