From the Institute of Physics , comes this piece of research that suggests all the summer energy we use on air conditioning in warm climates doesn’t compare to the energy used to keep warm in cold climates.
Cold cities less sustainable than warm cities, research suggests
Living in colder climates in the US is more energy demanding than living in warmer climates.
This is according to Dr Michael Sivak at the University of Michigan, who has published new research today, 28 March, in IOP Publishing’s journal Environmental Research Letters.
Dr Sivak has calculated that climate control in the coldest large metropolitan area in the country – Minneapolis – is about three-and-a-half times more energy demanding than in the warmest large metropolitan area – Miami.
Dr Sivak calculated this difference in energy demand using three parameters: the number of heating or cooling degree days in each area; the efficiencies of heating and cooling appliances; and the efficiencies of power-generating plants.
Not included in the analysis were the energy used to extract fuels from the ground, the losses during energy transmission, and energy costs.
“It has been taken for a fact that living in the warm regions of the US is less sustainable than living in the cold regions, based partly on the perceived energy needs for climate control; however, the present findings suggest a re-examination of the relative sustainability of living in warm versus cold climates.”
Heating degree days (HDDs) and cooling degree days (CDDs) are climatological measures that are designed to reflect the demand for energy needed to heat or cool a building. They are calculated by comparing the mean daily outdoor temperature with 18°C.
A day with a mean temperature of 10°C would have 8 HDDs and no CDDs, as the temperature is 8°C below 18°C. Analogously, a day with a mean temperature of 23°C would have 5 CDDs and no HDDs.
Based on a previous study, Dr Sivak showed that Minneapolis has 4376 heating degree days a year compared to 2423 cooling degree days in Miami.
In the study, Dr Sivak used a single measure for the efficiency of heating and cooling appliances, as most are currently rated using different measures so they cannot be directly compared. His calculations showed that a typical air conditioner is about four times more energy efficient than a typical furnace.
“In simple terms, it takes less energy to cool a room down by one degree than it does to heat it up by one degree,” said Dr Sivak.
Grouping together climatology, the efficiency of heating and cooling appliances, and the efficiency of power-generating plants, Dr Sivak showed that Minneapolis was substantially more energy demanding than Miami.
“In the US, the energy consumption for air conditioning is of general concern but the required energy to heat is often taken for granted. Focus should also be turned to the opposite end of the scale – living in cold climates such as in Minneapolis, Milwaukee, Rochester, Buffalo and Chicago is more energy demanding, and therefore less sustainable from this point of view, than living in warm climates such as in Miami, Phoenix, Tampa, Orlando and Las Vegas,” Dr Sivak concluded.
From Thursday 28 March, this paper can be downloaded from http://iopscience.iop.org/1748-9326/8/1/014050/article
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Observe the climate cycles… slow to warm, fast to cool.
It’s easier to cool. Pretty obvious really. Any location on the planet spends more time nett “cooling” (tending to lose heat to space) than nett warming (tending to gain heat from the sun). Clouds, latent heat and enthalpy make it less simple in reality, but the essence of the drive remains unchanged.
Let’s not forget the billions of BTUs expended for the plowing, blowing, moving and salting of frozen precipitation so we can get to work to make the money to pay the heating bill for the house
we bought when we moved up north without thinking things through.
Cold cities use more energy than hot cities.
Here in the UK we had always known that to be the case in spite of the claims of the Eco fraternity. Right now heating is costing us a bomb with nearly 20% of our bill now going to combat global warming, climate change or whatever label they want to use to switch sell a totally failed product from a shady set of dealers with no integrity whatever.
The optimum global temperature is few degrees C more than the current, because then large northern land areas in Canada, USA, and Russia (Siberia) will be better. Warming in the tropics will be handled by the growth of vegetation.
Silly question? How about just directly comparing the total per capita energy usage in Minneapolis and Miami? That doesn’t get directly at heating/cooling costs, but from a carbon standpoint it’s a more interesting and relevant number anyways that takes all regionally related affects into account. I guess that’s not actually “research” because the findings are too easy to get at, aren’t in any way controversial or arguable, and don’t alllow the “researcher” to manipulate the data.
Just a quick comment on heat pumps. Heat pumps are rated at 40 F. Below that, their efficiency drops off rapidly. By 25F or so they are mostly useless.
Minneapolis in the winter is a lot colder than that. The last time I was there (in January) the overnight low was -22F.
Cold kills. Warmer is better.
Wow. Never let facts ruin good research fundings!!!
So, you can go to the DOE website and look up the per capita heating usage in Minnesota and Florida…
here: http://apps1.eere.energy.gov/states/residential.cfm/state=MN
and here: http://apps1.eere.energy.gov/states/residential.cfm/state=FL
According to that website, which I’ll consider reasonably authoritative, Minnesota residents use a combination of 25MMBtu natural gas and 4100 kWh electricity to heat there homes, per capita. Florida residents us a combination of 0.8MMBtu natural gas and 6400 kWh electricity to heat their homes, per capita. At that point you have to make some assumptions, but assuming that at least the conversion processes (CO2 produced per kWh and per MMBtu only, all other efficiencies are already accounted for) are essentially identical for both locations, and I approximated 800 g/kWh CO2 and 53000g/MMBtu CO2 then the total ACTUAL per capita heating CO2 production is about 4.6Mg CO2 per capita in Minnesota and 5.1Mg CO2 per capita in Florida.
So, at least according to my calculations based on the US DOE numbers the professor is wrong in both magnitude and sign on who uses more energy for “climate control” on the heating side alone. I think it has to go without being said that Floridians use more energy cooling their homes than Minnesotans, so that only makes his analysis worse.
So, I see that most people here are saying, “well, duh?” to the study findings. But I get the opposite results. Can anyone see what mistake I’ve made in my “study”?
How would have thought that a species whose origins where eastern Africa would have found warm climates easy to live in , and hence requiring less energy, then cold ones . Next they will be telling us the reason why human have sweat glands and are not covered in fur.
H/T to Curt and Glenn for good contributions.
There re different kinds of heat pumps. One will work well down to -25 C. The ones cited have a working fluid for warmer climates.
The cost of the energy needed has not really been discussed. Natural gas, used to heat Waterloo, is really cheap per MJ and electricity is not. So the calculation is a bit more complicated than as presented. I note also the point about the energy needed to create the infrastructure to provide gas and electricity.
The obvious (to me) solution is to combine heat pumps and gas so when it costs less to move heat, you do, and when it costs more, or your need more efficiency, you burn gas. You are allowed think and act sensibly!
Joe Public says:
March 28, 2013 at 12:06 pm
But then cooling is invariably via electricity, whilst heating can be from the primary fuel.
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cooling need not be from electricity. the evaporation of water provides low cost cooling. properly done it is almost free.
there is no equivalent low cost process to provide heating. no matter how much insulation you install in a house, it will not warm the house. you need to add energy which costs $$.
Patrick B says:
March 28, 2013 at 7:56 pm
Miss my house in Hawaii – no furnace, no air conditioner, no heat pump, perfectly comfortable year round.
============
still waiting for global warming to kick in so the Great White North will be the new Hawaii.
“In simple terms, it takes less energy to cool a room down by one degree than it does to heat it up by one degree,” said Dr Sivak.
I would disagree.
At best the amount of energy needed to either raise or lower a control volume of air 1 degree F will be the same.
Now, if you want to remove water while cooling the CV 1 degree – that would take additional energy.
Well, if you live in a colder clime like Canada:
A/C = decadent summer comfort
Heat = winter survival (continuation of eating and breathing)
The two are not on the same page at all. GK
knr: “[Who] would have thought that a species whose origins [were] eastern Africa would have found warm climates easy to live in, and hence requiring less energy, [than] cold ones . Next they will be telling us the reason why human[s] have sweat glands and are not covered in fur.”
Exactly. That’s why all those other animals on the African Savannah have sweat glands and no fur – like lions, tigers, apes, monkeys, antelopes… oh, wait…
Other than humans there is really only one class of animal that has both sweat glands and no (or little) fur: sea mammals.
This pivots around a specious concept of “sustainable”. It is just utter madness to be so concerned about sustainability, when it has nothing at all to do with the cost of energy to have human comfort. The earth is awash in sources of hydrocarbons that can be converted to use as fuels for burning one way or the other. Moreover, we still have a thousand years of energy supply in the form of thorium buried in the Nevada desert that nobody is seriously developing. And then there is LENR.
What are the people who are so fixated on “sustainability” going to say when LENR devicees become a commercial reality. I can assure you that they will find some reason to object to greatly reduced costs of energy. The only sustainable issue the sustainability crowd cares about is their ability to whine, worry, fret and lobby to reduce human liberty and prosperity.
G. Karst says:
March 29, 2013 at 9:01 am
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Does that calc include the energy required to warm the propane so it can vaporize and be in a useful vapor state?
As an architect dealing with such stuff on a regular basis, I can tell you this study is only worth burning the paper it printed on and then only in cold cities. There are too many variables to draw such sweeping conclusions from such partial data ( sound familiar?). Northern cities suffer because they are generally older when energy didn’t make a difference. Good design takes into account local conditions that can vary even within a single property. It not even worth comparing similar buildings in different cities. Construction techniques should and do vary. I would also note the following:
1. No one designs for the same temperature in winter and summer.
2. Heating and cooling loads vary from place to place with seasonal and even daily characteristics.
3. Building use, people, equipment and lighting, all work to help heating and against cooling.
So it seems that waste heat from incandescent light bulbs and appliances is a net positive for most of the year.
I love the warm glow and slight warmth that they provide during winter. In the long days of summer there is less waste heat due to extra daylight.
I have been stocking up on the 100 and 75 watt bulbs for a few years. I think my comfort is worth more than the energy savings.
That must be why I am using 200 kw or less a month in my home in the Bahamas. No heating, no a/c, though I do have ceiling fans. If I was in Canada over the winter I would be using over 1,000 kw a month. Life is more energy efficient when you are living in a warm climate.
I meant to say that I think my comfort is worth more than the “perceived” energy savings.
Our single most expensive hydro [electricity] bill occurs in summer due to electricity costs for a/c. Went over $400 for one bill. In winter, our natural gas bill is higher than in summer, as furnace is gas.
As for sustainability, I second the sentiment of theBuckWheat. People assume they know what is meant by “sustainability,” but I think he’s right – it’s the ability to have something to whinge & whine about.
Hi HappyCrow and Peter in Ohio – my apologies – you’re absolutely right – short thinking at this end.
Not much heat to be extracted from air at -20C air.
And to think that I spent some time in Winterpeg when the daytime temp hovered around -21C and dropped below -30C at night.
cheers edi
Does the study acknowledge that heating for buildings also comes from appliances not used primarily for heating, and from other sources? Buildings trap heat from appliances used primarily for a non-heating use, such as refrigerators, computers, and lighting. Buildings also trap heat from people and from sunlight coming in windows.