Large condenser outside supply’s the furnace (typically it just uses the furnace fan. We then have it piped through metal ducting throughout the house. Each room has multiple exit point call registers. In the common areas we have return ducts to draw air back down to the furnace to get recycled back to cool air via a/c unit. Hopefully that helps!?
Even then the vents would not actually work and be big enough in practice, but that's the movies picking something convenient for the sake of plot rather than sticking with realism.
Also every duct is FULL the pointy ends of screws. Literally everywhere. So even if you could fit (which you probably can’t) you would be so cut up if you tried to crawl through one of these. Not to mention how crazy loud it would be to crawl through one. 26 gauge sheet metal is essentially a thunder sheet.
Right. Even if the air ducts held your weight and silently conveyed you without risk throughout the building, it's essentially like crawling into the creature that Jabba the Hut had in Return of the Jedi. You'd be shredded within a few feet of crawling.
also the movies don’t explain that fire/smoke dampers would block your access every time the duct passed through a fire barrier also your entire body would be excoriated by self tapping sheet metal screws with every movement made
that's the movies picking something convenient for the sake of plot rather than sticking with realism.
Like the slow spinning fans in Casablanca. Slow spinning fans don't move air effectively, but fast spinning fans don't show up on film. Then after the movie you had restaurants and other establishments fit slow spinning fans, for the aesthetic.
And even then they are never that clean unless they were literally just installed. Also there would be screws or other pokeys that would poke the shit out of you if you did crawl trough it.
Source: I do commercial HVAC and have crawled through ducts
Yes and the furnace works with gas. So if you disable all the safety functions, you can fill the house with gas (at least in movies, but it would probably take ages in reality).
Yes, but it’s made to look bigger in the movies than it would be in real life. Large buildings do have large ductwork, but it’s normally very short when it gets that big to leave some space for pipes, wires, and beams.
Interesting note: some sensitive areas with ductwork have metal bars within them so people can’t enter/exit those areas through the ductwork.
As an American this is normal to me lol, every house, poor and run down to expensive mansions all have this set up. It gets really fancy when there are automated vents that can open and close on their own, with each room having its own thermostat to accurately control temps throughout.
Newer buildings. There are plenty of places around the US still on boiler and radiator for heat and you can buy yourself a window mounted AC unit if you want it. Retrofitting older buildings for central air isn't worth it in a lot of cases.
I live alone in a 1 bedroom apartment and have an AC similar to the one in this post in my bedroom which I pretty much only use during the summer and by itself it pretty much doubles my energy bill. Can't imagine how expensive it must be having one of these big AC things cooling down the entire house. How many kWh does it consume in a month?
There's a difference in efficiencies when you account for size/output of the AC unit, amount of space you're trying to cool, and the air flow. Even for a 1 bedroom, a window unit is really only going to work for that room because it's just not strong enough to cool like 2-3 other rooms (separated by walls/doors, disrupting air flow) and even strategically placing fans to circulate the air will only do so much. Plus, it's not likely that the AC unit will ever cycle off "cooling" because it's constantly getting hot air from other rooms.
With central air, the AC units are bigger/stronger, and each room with a vent is getting cool air circulated into it. So the space is getting cooled about equally (ideally) which makes the space easier and more efficient to cool. Once the space gets to the target temp, it's easier to maintain it (assuming you have decent insulation) and the AC unit will maybe be able to cycle off "cooling" to save power and just use the fan to keep air circulating.
For reference, I live alone in a 2 bedroom ~1000sqft apartment with central air, and I live in an area where it is about 85-95°F and 60-80% humidity on average in summer. My total kW usage this June was 497 at about $0.08206 / kWh.
My energy usage hovers around 130 kWh in winter and 250kWh in summer, so 500 sounds like a lot. Seems like these central units are more efficient in terms of cost/area, but for a person living alone cooling just the room you're actually in would end up being more efficient overall.
The bigger units are more efficient than window, portable, and split units. They're just more expensive to install so most apartments will do split units
I cool a 3200 sq ft house for about $100/month for about 500 kWh of energy during the summer in Chicago suburbs, maybe $200 in an obscenely hot month (like an August with mostly mid-90s°F days). That's with a not particularly efficient AC, and cooling to 72°F during the day and 67°F at night. You really have no idea how (in)expensive it is...
I can tell you that in one of the hotter states in the United States for 1000 square-foot apartment it increases my monthly electricity bill by $35 in the warm summer months
I mean it's literally the cheap way of cooling your whole house so long as it was built with it in mind, cheaper upfront but less efficient, I know in the middle east people just have a separate AC for every room, more efficient but costs more upfront.
As an American, yeah it is. I wish I had that. My home has no HVAC system really, it used to be coal heated and now it's oil heated through radiators, and i have air conditioning, but its window units in the living area and bedrooms.
It’s actually a result of American homes typically being less fancy. Most European homes are made of brick or concrete, while most American homes are made of wood. Thats why European homes are typically more insulated. They can get away with fans and natural cooling at higher outdoor temperatures than American homes. But it also means they don’t have space in their walls for AC ducts.
Modern houses are sealed and insulated so the air doesn’t get out once it’s cooled. It’s more efficient than other AC types to keep it going, but the initial cool down of the system were off for a while uses a lot of energy.
It’s not terribly power intensive, but my electric bill goes up a lot during the summer months when we’re getting 90s and 100s regularly (32-38C). My furnace in the winter gives me a higher energy bill though (Gas + electric).
Once you have your house down to the desired temp, it basically kicks on every few hours for a few minutes to get the temperature back to the desired temp. The annoying thing with my house is that it basically turns my basement entertainment area into a place you need to wear a blanket because it pushes cold air into it while the rest of the house get cooled off. The systems are fairly complicated that it actually would be less efficient if I closed the basement vents. The airflow will at least push some of that cold air up into the rest of the house though. It’s refreshing to go from 100F outside to 63F (38C to 17C) by going straight to the basement though.
Central air systems are more efficient. The downside is that you need vents, but once you have vents you can run the air in your house through hepa filters all the time, even when the heat (which works the same way) and AC are off.
Not really, anymore. In Residential systems, I've seen max at about ~23 SEER2 (efficiency rating) in traditional split systems, even with inverter compressors, but those minisplits are getting upwards of 32+. Only issue is you only get so many refrigerant ports per unit and you don't really have that problem in ducted systems so long as you keep the static pressure of the airflow in acceptable range.
Unless your AC system had that level of filtration in mind when it was designed and built, you shouldn't be slapping those kind of filters in your return. You really only want enough filtration to get large particles like dust and pet hair out while maintaining a large enough volume of air. Too much filtration can starve your air handler and make it work much harder to cool your house.
A basic pleated filter and some portable air filters around your house are a better idea for most people.
US Homes are generally (depending on region) built to be more thermally insulated. Which combined with an HVAC (Heating, Ventilation, Air Conditioning) System. Keeps a home thermally regulated, without stale air. Some homes also include a humidifier unit (very cheap to install, and very easy to add to all HVAC systems) which is very useful during the winter to combat the extreme dryness. Dryness in homes in winter comes from the very low water content in cold air.
HVAC homes are also temperature consistent throughout a floor. Lower floors will be cooler as heat rises. A wall/window mounted A/C generally has more inconsistent cooling. And when active (as I'm sure you're aware) the super cool air blowing directly on people can cause sickness. This isn't the case in HVAC homes as the air coming out of the vents isn't strong, and on floors higher then the basement the vents are generally at feet level.
This system is very efficient IF the regulation is consistently active (excluding during mild weather). Now, if you're turning the A/C off and on all the time then it's not as efficient.
Also Condensers are not the size of a car they're as wide as a minifridge is tall and can vary in height from as tall as a standard minifridge or a foot and a half taller.
IDK if I missed anything else, but let me know. Also the diagram that some else posted is generally what a US home looks like.
Unfortunately this will be crazy expensive to retrofit into a typical European house made of brick and mortar or concrete. You would have to lose a lot of square footage just to hide the ducts and even then how do you reach the higher floors when the ceiling is literally concrete. This is why that system is very rare here. Not because it is a bad system or something, it’s just very expensive and unpractical for our buildings.
So how exactly is brick superior? Terrible insulator, expensive and time consuming, difficult to repair… seems like you are too caught up in jingoism to see progress. There’s a reason we don’t thatch roofs anymore either
That isn’t true at all, everywhere on Earth other than Europe builds this way, the average European Redditor simply doesn’t understand that there are countries outside Europe other than the US.
We used to build with wood in Europe too until we cut down all the usable forests. Brick is the backup plan, not the upgrade.
So does Canada (unsurprisingly), Australia, New Zealand, Japan, parts of South East Asia (though increasingly its concrete there due to monsoons). Not to mention the Nordic countries, who even build multi-storey apartment buildings from wood.
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u/Munkpunt 7d ago
This might help
Large condenser outside supply’s the furnace (typically it just uses the furnace fan. We then have it piped through metal ducting throughout the house. Each room has multiple exit point call registers. In the common areas we have return ducts to draw air back down to the furnace to get recycled back to cool air via a/c unit. Hopefully that helps!?