中央与专门的回报辩论具有明显的赢家。但是首先，让我解释术语。强制性空气加热和冷却系统的供应管道将调节空气吹入房屋的房间。这对大多数人来说都是显而易见的部分。但是那个空气必须来自某个地方。在加热和冷却设备的另一侧是管道系统的返回侧。它返回空气再次得到调节。

设计系统返回侧的一种方法是使用中央回报。该设计可能具有单个返回通风孔，或者可能具有多个返回通风孔。无论哪种情况，回报都将在房屋的公共区域中。例如，在我家中为卧室提供服务的系统在走廊上有中央回报。

设计返回空气的另一种方法是专用回报。也就是说，每间卧室都有自己的回流通风口，将空气送回系统以进行加热或冷却。在每个卧室里有专门回报的房屋仍然在公共区域有更多的回报通风孔。

的the two types, one has significant advantages. Can you guess which one it is?

中央回报的不良说唱

The central return is common on most older houses. It’s also common in “starter homes” and other less expensive houses. Because of that, some people think of a house that doesn’t have dedicated returns as being cheap or out-of-date. We occasionally haveHVAC设计clients who tell us they want dedicated returns because they don’t want the house to seem cheap.

Another knock on the central return is noise. I can empathize with that sentiment because I used to live in a condo with a noisy central return. It was right below the TV in the living room, and we’d have to turn up the volume whenever the system started running.

中央回报的最终缺点是它会导致房屋中的气流问题和压力失衡。当您将条件空气放入关闭的卧室时，就会出现此问题，并且没有办法让空气回到中央回报率。卧室将增加正压。中央回报率附近的区域将产生负压。失衡会减少气流，增加空气泄漏，甚至可能导致燃烧设备的背景。最后一个可能是危险的，因为它可以将一氧化碳放在房屋中。

但是，当您考虑中央与专门的回报辩论时，这里有什么真正的问题？

Why a central return is better

获得中央回报的原因之一是您最终会减少管道。返回侧的较短管道可能意味着对气流的阻力较小。当然可以进行低电阻的专用回报，但是中央回报通常更容易。

Central returns also can mean less energy loss if the ducts are in unconditioned space. Even though return air is not as cool or as warm as the conditioned air in the supply ducts, it still can be a lot cooler or warmer than the air in an unconditioned attic, crawl space, or basement. That means conductive heat gain or loss. Of course, you不应该将管道放在无条件的空间中根本没有，但是许多房屋确实有这个问题。

Another type of loss that happens in the return ducts is through leakage. Yes, ducts should be airtight with no leakage. But the shorter your return duct system, the fewer connections there will be to seal. Also, leakage on the return side will suck in air from the surrounding space, which can causeindoor air quality problems。

And speaking of indoor air quality, central returns are a great way to be able to usehigh-efficiency filters(MERV-13 typically). Theproblem with trying to use high-MERV filters是对气流的阻力太高了。Increasing the filter areais the solution here. When it comes to central vs. dedicated return vents, the central return makes that easier.

Instead of putting the filter(s) at the air handler, you put it (them) at the return vents. The photo above shows one of the filter grilles in my house, and I’ve sized them to have a lot of filter area relative to the airflow rate. Yes, you can do that with dedicated returns, too, but then you have more filters and probably different sizes as well. We like to size all our filter grilles the same so the homeowner can buy all the same size filters.

如何获得良好的中央回报

中央回报的不良说唱是导管设计不良的结果。解决设计问题也可以解决感知问题，因此让我们看看您需要做什么。基本上有两件事要注意。

Fixing the noise problem is easy. Noisy return vents are mainly the result of the blower being too close to the return grille. The solution is to put some distance and a couple of turns between the grille and the blower. Another way to reduce the noise is to size the system properly. Oversized systems have bigger blowers, and bigger blowers are noisier. Even better, use a small-capacity, variable-speed system (minisplit），比传统系统更安静。

空气阻力的问题的解决方案,heating and cooling losses, and pressure imbalances is to provide return-air pathways. That’s all a dedicated return does anyway. But you don’t need to have an opening in each bedroom connected to a duct that carries air all the way back to the system. You just need to have a way to get the air from the closed bedroom back out to the hallway.

提供回流通路的一种方法是使用卧室门周围的缝隙。We usually talk about this return-air pathway as a door undercut, but air can move around the sides and top of the door, too. Interior doors aren’t weatherstripped and usually don’t fit tightly in the frame, so air can get through all four sides. This method won’t work with all bedrooms, though. The amount of supply air put into the bedroom has to be fairly low.

我们在设计中经常使用的另一个返回空气道路是跳线导管。上图显示了加利福尼亚的Mike Macfarland的一张。该管道是在两根靴子之间拉紧的一小段弯曲，刚性肘部旋转了空气。当卧室门关闭时，这种跳线可提供返回空气路径。另外，套头衫上的格栅与专用返回时的格栅没有区别，因为那些想在每间卧室里看到回程的人。

Transfer grilles are another type of return-air pathway. It’s a grille through a wall or door. Sometimes it’s a straight shot through one grille and out the other. Another way is to put a grille on each side of the wall but offset them vertically. That can provide more privacy than the straight-through type. The photo above shows one of the完美的余额回流通路I installed at the condo I used to live in, and it worked great.

One thing that’s critical to do with a central return and a filter grille is to make sure the ducts are airtight. If you put the filter at the grille and have any leakage in the return duct, that duct makes it to the blower, coil, and heat exchanger. You don’t want that.

The clear winner

在中央与专门的回报辩论中，我说明显的赢家是中央回报。在某些人中，它的不良说唱不是真正的缺陷的结果。这是因为设计差。遵循本文的指导，您可以获得安静的中央回报，从而减少能源损失，并为您提供更好的室内空气质量。是的，如果您需要，我们将为您提供专用的回报，我们将使它们运行良好。但是我希望您现在看到中央回报的好处。

_________________________________________________________________________

Allison A. Bailes III，博士是一个speaker，作家，建筑科学顾问和佐治亚州迪凯特的能源先锋队的创始人。他拥有物理学博士学位，并写Energy Vanguard Blog。他也有a book on building sciencecoming out in the fall of 2022. You can follow him on Twitter at@energyvanguard。