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Comment by hyeonwho4 | Hacker News Reader

This is called an FCU (fan coil unit) and is common in Asia. It consists of a high efficiency central chiller run by building management, and pipes to bring coolant to each unit. Then in each unit there is a heat exchange coil with a fan to blow the room air through the coil. Hence fan coil unit.

The advantages of this system are that the only sound in the unit is the fan, and air is not circulated between units. The disadvantage is that building management can turn off A/C centrally if they want to save money.

For some reason Americans are slow to pick up HVAC innovations that are common elsewhere: heat pumps, split-system air conditioners, FCU, etc. I guess it is because energy is cheap to them and they don't mind noise.

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> For some reason Americans are slow to pick up HVAC innovations that are common elsewhere

Few want to spend the money to convert older buildings. That includes homeowners, building owners, and condo/co-op boards.

Someone a few weeks ago posted a long essay about how much heat pumps make sense from an investment and environmental standpoint. It glossed over the fact that most American middle income households, when presented with the choice of dropping $25,000 on a heat pump/mini split or sticking with window mounted ACs and that cost a fraction in terms of up front costs, will go for the cheaper option ... or spend the money on some other home improvement or accessory like a car.

Not saying it's right, but that's the way it is.

But why would this be any different in America than the rest of the world? What you've written seems to me like a universal.

It's more expensive in America - larger houses requiring larger units and more ductwork/labor, and probably the manufacturers pricing for the world's richest market.

One of the big questions that I haven't seen a compelling answer for re: heat pumps in the US is why heat pumps are so expensive compared to AC exchanges. The amount of equipment differences between an AC and a heat pump are largely a valve to reverse refrigerant flow and the small bit of electronics to control said valve. Yet heat pump units in the US are significantly more expensive for effectively the same COP and operating efficiency ranges as their cooling-only brethren.

We do have ductless AC in the US. It's technically a bit different but accomplishes the same thing using the same principles.

Of course, most of those systems are made by Japanese companies like Mitsubishi...

How does ventilation (the V in HVAC) work for FCUs? If the pipes only bring coolant to each unit where does fresh air come from? Conventional HVAC systems have Heat Recovery Ventilation so what's the equivalent here?

I don't know. I don't think that most Asian apartments have central fresh air. Usually the unit owners open windows regularly.

But opening the windows would negate most of the benefits of the higher efficiency of the FCU, would it not?

Heat pumps (for heating) and split air conditioners are fairly common in the US.

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