You could argue we should all be worried about surplus heat, all the time.
I heard an interesting argument about the efficiency of air conditioning the other day. It pointed out that, while removing heat from a room is of course not 100% efficient, it is merely shifting heat from one place to another (plus some waste).
Whereas heating is ALL "waste". So more waste heat should be generated from, and more energy used in, heating vs air conditioning.
We definitely have a bias to accept that the New Englander is virtuous in heating his or her home in the winter, but the Arizonan is wasteful in cooling their "inhospitable" house in the summer.
> while removing heat from a room is of course not 100% efficient, it is merely shifting heat from one place to another (plus some waste).
> Whereas heating is ALL "waste".
> So more waste heat should be generated from, and more energy used in, heating vs air conditioning.
This is a logical mistake. It doesn't matter whether you think the heat produced in heating is metaphysically "wasted" or not; the energy used in heating vs air conditioning is a function of the temperature differential you want to maintain. Air conditioning means you're doing work to keep a certain volume of space at an artificially low temperature, and heating means you're doing work to keep a volume of space at an artificially high temperature. The amount of energy you use in order to achieve that goal depends on the amount of work you need to do, not on whether you're doing the work in order to lower or raise the temperature.
Both result in "waste" heat (eg, added entropy) but in the case of combustion or resistive heating (covered above in the thread), the entire purpose is to generate waste heat. Whereas in air conditioning (or, as mentioned, heat pumps), the waste heat is only a side effect.
Both processes involve doing work by consuming energy. In one case, the work is moving heat, and in the other case, the work is producing heat. The term "waste" is pretty meaningless in this context; what you really have is the question "how much energy does this process consume?" The answer to that question won't change depending on how you label the products.
You have yet to advance an argument that a space heater produces more heat than an air conditioner does! In general, that is the case, but that's an artifact of the temperature range that people find comfortable (combined with the temperature range of climates where people live). It has absolutely nothing to do with whether their machines are in a state of metaphysical grace.
Imagine that people enjoy a temperature between 60 and 70 degrees Fahrenheit, and some people live in a wintery area where the outside environment is -20 degrees, while others live in a sweltering area where the outside environment is 105 degrees. The Arizonan chilling his house down to 70 is maintaining a temperature differential of 35 degrees between the house and the outdoors. The Michigander heating his house to 60 is maintaining a differential of 80 degrees. That much larger differential means much more work needs to be done to maintain it, and the Michigander will consume more energy and produce more heat in the process of keeping his house comfortable.
If the climates were the same and the human temperature target were 10 to 20 degrees, then the Arizonan would be trying to chill his house by 85 degrees, while the Michigander would be heating his by a modest 30. The Arizonan's air conditioner would still be producing "useful work" in the form of moved heat, and "waste heat" in the form of emitted heat, and the amount of emitted heat would be large because a very large amount of work is being done. The Michigander's heater would still be producing "useful work" in the form of emitted heat (or as you call it, "waste heat"), and the amount of emitted heat would be low, compared to the air conditioner, because the Michigander is willing to stay much closer to the environmental temperature than the Arizonan is.
Yet again, labeling the heat "waste" has no implications for how much of it there is.
If we're talking about electrical heating, this is only true for resistive heating, which is indeed all "waste heat". But many air conditioners can run in "reverse cycle" [0], where you're transferring outside heat back in, and is much more efficient, apparently 50% cheaper to run in electricity costs.
When you run one of these systems, your New Englander and Arizonan are virtuous to the degree of the difference between inside and outside temperatures. ;)
There's even now some combined cycle AC systems which use the extracted heat to generate your hot water [1], sadly not yet available/cost-effective for small residential installations, but they're only off by a factor of 2 now (8kW is the smallest system I've seen, my central air is 4kW).
I actually just replaced a 20-year-old AC system that had a link to the hot water system. Installers just removed the water heater link entirely. Said that the extra resistance and energy involved in the exchange cost more than just venting the heat in modern systems with high SEER ratings. No idea if that's accurate; just what I heard.
Sorry, I meant both resistive AND combustion (eg, "gas"). Now, obviously, natural gas is far cheaper than electric for heat in most of the US at least, but it's all 'generated' heat, with all of the waste heat and CO2 emissions that entails.
Heating need not be 'all waste'. An air (or ground) source heat pump heats a room, counterintuitively, by pumping heat from the colder air outside. It uses less energy than the amount it releases into the room.
I don't know that I've encountered a space heater based on a heat pump, but in my mind...
"air conditioner" - a machine which keeps one or more rooms in a house cool, powered by a heat pump.
"heater" - a machine which keeps one or more rooms in a house warm, usually not powered by a heat pump.
"refrigerator" - a machine which keeps its own interior cool, powered by a heat pump.
"freezer" - a machine which keeps its own interior below freezing, powered by a heat pump and usually attached to a refrigerator.
All of which is to say, a heat pump is a machine that moves heat. It's named after its effect. But "heaters", "refrigerators", and "air conditioners" are named after their purpose, not their mechanics, and include heat pumps--if they do--incidentally, as the mechanism by which they achieve their purpose. If somebody came up with a refrigerator that still kept your food cold but didn't use a heat pump, I wouldn't hesitate to call it a "refrigerator".
I heard an interesting argument about the efficiency of air conditioning the other day. It pointed out that, while removing heat from a room is of course not 100% efficient, it is merely shifting heat from one place to another (plus some waste).
Whereas heating is ALL "waste". So more waste heat should be generated from, and more energy used in, heating vs air conditioning.
We definitely have a bias to accept that the New Englander is virtuous in heating his or her home in the winter, but the Arizonan is wasteful in cooling their "inhospitable" house in the summer.
Maybe we should rethink this.