I don't get it brother, you're going to have to spoon feed me this one.
No worries, and it's hard for me to figure out 'where to begin'.
Those snorkels are 4' off the ground, (at the bottom of the eves') and that is literally 'air snorkels' so that the combustion air intakes that are on the house ~1 foot off the ground don't get plugged/blocked with snow.
Thing is, we have Natural Gas furnace as well as Natural Gas hot water tank. In the kitchen, we also have a Natural Gas cooktop. Point being, all that 'natural gas' needs to be burnt, in order to create heat. Ergo, that 'combustion air' needs to be supplied. If you DON'T have a 'combustion air intake' then it will literally SUCK air in through every window, doorway, crack in the wall, gap at the bottom of walls, and foundation joints. Hence why houses are 'cold and drafty' because people block things off as much as they can. Often, they don't actually install a 'combustion air intake' (I shit you not,,,, wasn't in the Building Code for a LOT of years) so then you also have chimney's drawing air down and creating CO hazards as well.
But, not unlike the air breather in any vehicle, once you 'open that up' all the sudden you're getting performance, proper air-flow (where it's needed) and cleaner air in the home because of said airflow.
I don't know of anyone else in this city that actually has snorkels, though they are starting to sell 'manufactured ones' at the local Home Despots as well as at 'The Rona' and such.
Our furnace room is blocked off, so that is 'cold' with the outside air. But the house itself as is the basement, is SO MUCH warmer nowadays. We made those about 4 years ago, and this is also why:
I walk with a cane. I can't shovel snow "one-handed" so My Lady has to do all that. It sucks, and still bothers me to the core, but I have to live with it. We USED to keep a path clear to that intake, and it had to be shoveled a few times a week through the winter. I can't get her to do that, though she doesn't complain. So we built them snorkels (we started with 1, but figured "more is better" so we added a second one) and now the snow DOESN'T have to be shoveled all that way, all that often. This is the first time this season where the 'drift' needed to be moved, just to keep the airway 'unblocked'.
Go ahead and tell me more about 'how cold it is where you are.....' because you're talking about your drink,,, RIGHT? HA.
Hope that clarifies things for you too, brother.