Most apartment buildings with HVAC have shared air intake and shared exhaust vents. So if my neighbor is running his A/C then he is actively exhausting hot air from his place which travels through the exhaust vents, some of it gets exhausted out the building and some of it gets recirculated. But the exhaust vents are shared, so if I’m not running my A/C then some of his hot air can end up in my place. In practice, is this a measurable effect?
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The excess heat from apartments is transported to the evaporators on the roof. Your apartment’s unit has nothing to do with it.
If your neighbors, especially the one below you, are running their AC it should help **reduce** the heat coming into your apartment.
If they’re keeping their place colder than you then heat is flowing out of the walls into your neighbors places, and you’re only gaining heat from the exterior face.
As u/tdscanuck says, the AC hat exchange is normally on the roof, none of the heat from their units should affect you at all.
I’m a little confused by your question, since if you have shared HVAC then, by definition, your neighbor does have “his A/C”…there’s just the building’s AC.
An apartment-HVAC should have a great big condenser on the roof (possibly in the alley out back) where the AC is dumping heat. If your neighbor has selected a colder temperature than you then he’s getting more cool air from the central AC but the heat rejection is happening at the AC condenser outside the building. Other than the fact that we’re all sharing the same atmosphere, none of “his hot air” should be coming back into your apartment.
If you have a shared HVAC that means you do not control the temp settings on your AC. You may be able to open or close your vents, but whomever has the controls of the AC will determine what temp it is set for and both of your apartments will adjust to that temp. All of the heat exchange is done at the condensing unit on the roof or outside the building on the ground or a landing. None of it is “vented” out of the building so there is no way for hot air to get into your room from the AC running.
Most apartments in the US do NOT have shared ductwork, specifically so fire/smoke/odors don’t get transferred.
Short answer to your question: no.
Longer answer to your question: no, because you’re misunderstanding how your apartment’s HVAC system works.
Most apartment buildings will have a central means of introducing outdoor (“ventilation”) air to each apartment suite. It’s usually a single ventilation air handler that pressurizes a supply ductwork system. Air will not “leak” from one suite to the other through the ductwork: it’s positively pressurized, air can’t go backward through a supply grille in one unit into the ductwork and transfer into another suite. Sometimes this air is introduced to your central corridors instead of to each suite, but it just means the corridor is pressurized and won’t allow air to “leak” from one apartment to the corridor and back into another apartment. The principle is the same.
They sometimes have a central means of exhausting air, which will consist of one or more fans in an array that (usually) draws air out of your bathrooms and/or kitchen. This will exhaust odours from your space, but it can’t result in air being transferred from one suite to another. The fan(s) will be near the end of the duct run, at or near the termination out the building, so that the entire ductwork system upstream of it is negatively pressurized. It’s always “sucking” air from all apartment suites, so air cannot go through an exhaust grille into the ductwork from one suite and go backward out a grille in another suite. It’s physically not possible.
Usually in my experience in newer apartment buildings you will have entirely separate exhaust fans for your bathrooms and kitchen, not connected to adjacent suites at all.
Your heating and cooling may be accomplished by a variety of means. For heating you may have a central boiler plant somewhere in the building that supplies heating water or steam through a pipe system to each individual suite, which feeds an in-floor pipe circuit, baseboards, radiant panels or fan coil of some sort. Your cooling may be from a central system with a chiller, dry cooler, or some other device that rejects heat to the atmosphere, from which chilled water is pumped to each individual suite for use in in-floor cooling, panels, a fan coil, etc. Your suite will have its own thermostatic controls, completely separate from other suites.
You may also have something like a split-system heat pump, with an “indoor” unit in your suite and an “outdoor” unit somewhere outside that will pump heat from the outside in when it’s cold, and from the inside out when it’s hot. Each suite will have its own indoor unit, but several indoor units may be ganged together to work with one outdoor unit. This will have essentially no effect on the controllability of your suite, it will still be entirely separate on your end.
Generally your ventilation/exhaust system will operate entirely independently of the heating and cooling, while heating and cooling will be interconnected such that you aren’t running both the heat and the cooling at the same time (it’s a huge waste of energy).
Source: I’m a licenced professional engineer who designs building HVAC systems for a living.
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