The quickest way for people who know about air-conditioners and don't know about heat pumps is to consider what would happen if you put your air-conditioner the wrong way around in the wall. Instead of lovely cold air coming in and waste hot air going outside, the waste hot air would be heating the house and the cold air would be going outside.
There is no such division of things into air-conditioners and heat-pumps. Air conditioners ARE heat pumps.
In some parts of the world dual-direction heat-pumps are (or rather were) called 'Reverse-Cycle Air Conditioners' meaning they they could be switched from cool-inside/warm-outside to warm-inside/cool-outside.
Another thing to learn is the difference between temperature and heat. It's very similar to the difference between voltage and kilowatt-hours.
And 'cold' or 'freezing' are just labels. A litre of water at 70 degrees C will give the same amount of heat going to 40 degrees C as a litre of water going from 40 degrees C to 10 degrees C.
Similarly 100 cubic metres of 'freezing' air at zero degrees C going to -10 degrees C can give as much heat as 100 cubic metres of air going from 30 degrees C to 20 degrees C.
That 'freezing' air at 0 degrees C is actually at 273 degrees Kelvin. It has A LOT of heat in it.
It’s the same principle, but in the US I expect a “heat pump” to run well in both directions where an “air conditioner” might not have a reversing valve at all, or won’t really defrost the outside coils in cold weather.
Strange article. It seems to imply that air-conditioners and heat-pumps are two different animals. But all air-conditioners are just heat-pumps. They just work one-way only. For a few extra bucks, the so-called 'heat-pump' merely has the capability to direct the hot and cold air-flows in the opposite direction.
(In other words, if you took that window-installed air-conditioner and reinstalled it to face the other way in autumn, it would blow the cold air outside in Winter and the hot-air inside.)
In some countries (Australia), heat pumps are often called Reverse-Cycle Air Conditioners. Some newish (last 25 years or so) houses have no other form of heating.
In other words, reverse the cycle, and instead of the air-conditioner pushing cold air into the room and warm air outside, it will push warm air into the room and cold air outside.
This video is a great explainer on heat pumps [1]. The TL;DR is that they are essentially nothing more than air conditioners that run in the opposite direction. Plus, a heat pump and an air conditioner can be combined into a single system.
This. Heat pumps are just AC run backwards, and it doesn't take much to make an AC able to run in both directions. The only thing is if you need a lot more heating than you need cooling you may need a larger system. But because they're new a different, as well as in demand, you get price gouging on installation compared to an AC in a lot of places.
Compared to a traditional air conditioning unit, the reversing valve is the major difference. Your standard AC can only move heat from indoors to outdoors. A heat pump can do the reverse to warm your space. My basement heat pump is rated to provide heat even when it’s -20F outside.
However there are air heat pumps which differ from the AC ran in reverse only in how the heat is distributed around the house. For example with warm water in the pipes not just blowing warm air around.
Wow, I'd never considered that aspect of a heat pump before. But it makes sense -- a heat pump is (conceptually) just a backwards air conditioner, after all; it stands to reason that it'd make the room colder while it's operating.
Nope, it’s all about the temperature differential. Using a heat pump like an air conditioner is the same efficiency either direction. Usually when you’re talking about heat it’s going from (say) 20F to 70F, with AC it’s more like 90F to 70F. With heat you might even need to do like 0F to 65. AC max might be 115 to 75 which is still substantially less.
Is a heat pump any different from regular air conditioning in that regard?
I'm from an area of the country where you run the AC 8 months out of the year so this question is weird to me unless somehow a heat pump (reverse AC) is different than an AC pump running normally.
Yes, the only real difference between an air conditioner and a heat pump is that air conditioning only works one way, whereas a heat pump has some valves and solenoids and whatnot that allow it to switch directions.
It's kind of bonkers that we so frequently install air conditioners but not the tiny bit of extra parts to make it into a proper heat pump. I hope this will change in the near future.
It's kind of confusing terminology. I'll stick with how these terms are used by industry/laymen - heat pump also has a scientific definition that's more broad than how it's normally used.
There's a process called a "vapor compression cycle" which essentially works by moving energy from a cold area to a hot area (which makes the cold area colder and the hot area hotter).
Air conditioning is when you put the cold side of a vapor compression cycle in a building to keep it cool.
The term "heat pump" most typically refers to a device where the hot side of the vapor compression cycle is put in a building to keep it warm.
However, many heat pumps have an air conditioning mode, where the hot and cold sides of the vapor compression cycle switch places depending on the season. So air conditioner refers only to cooling, while heat pump may refer to heating along or a device which can both heat and cool.
Air conditioners are heat pumps. They move thermal energy from the inside to the outside to cool a space.
In this context, a heat pump refers to the same type of system, but in reverse. Instead of moving thermal energy from inside to outside, you're moving that energy from outside to inside. This can work even when it's cold out, because cold outside air still has a lot of thermal energy that can be moved.
The main benefits of heat pumps for heating are twofold:
1) It's significantly more efficient then electric resistive heat, because heat isn't being generated, simply moved around.
2) Heat pump systems can be configured to work to both heat and cool a space. There are very few changes needed to make this happen, meaning that if you need AC, you might as well get a heat pump to do both jobs.
There is no such division of things into air-conditioners and heat-pumps. Air conditioners ARE heat pumps.
In some parts of the world dual-direction heat-pumps are (or rather were) called 'Reverse-Cycle Air Conditioners' meaning they they could be switched from cool-inside/warm-outside to warm-inside/cool-outside.
Another thing to learn is the difference between temperature and heat. It's very similar to the difference between voltage and kilowatt-hours.
And 'cold' or 'freezing' are just labels. A litre of water at 70 degrees C will give the same amount of heat going to 40 degrees C as a litre of water going from 40 degrees C to 10 degrees C.
Similarly 100 cubic metres of 'freezing' air at zero degrees C going to -10 degrees C can give as much heat as 100 cubic metres of air going from 30 degrees C to 20 degrees C.
That 'freezing' air at 0 degrees C is actually at 273 degrees Kelvin. It has A LOT of heat in it.
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