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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Hi All – Furnaces vs heat pumps.
“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.
Hmmm – isn’t this an apples vs oranges comparison
In South Africa hospitals we have moved away from furnaces and have been using reverse-cycle heat pumps for heating for a number of years.
Come Summer we reverse the cycle and get a measure of cooling.
cheers edi
On a nice evening in the summer i can turn off the a/c and open the windows. Turning off the heat from Oct to March is not an option
Would I be heaping scorn on this study, if I sat well Duh?
There might be a reason populations are high at the equator and lower as we approach the poles.
Here at 62 degrees North, we use fuel nonstop Oct to June, get a respite July and August and then the furnace starts cycling again in September.
Those milder winters 2004-2007 were wonderful for reducing our fuel bill, these next ones will probably reintroduce fuel poverty here in Canada.
Dipping the eco-lunatics in water, then setting them outside at -30C might wake them up in a hurry.
I hate to say this, DUH? Like those of us living up in Canada didn’t know how hard it is to heat a building? How short the summers?
Try this simple mental exercize: turn the energy off to a cold city in the winter or to a hot city in the summer. Which would have the most damage and fatalities?
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.
Minnesotans For Global Warming have got a point then.
Hi edi,
In Virginia, we did much the same. Past a certain point, though, unless the heat pumps have radically improved in efficiency, they’re just not effective for the job. In southern Virginia they worked but were marginal. In Minnesota… not an option.
It centers around the Human body temperature of about 98 degrees F.
Was this considered a breakthrough study?
He he……
Typical fossil fuel furnaces are at least 80% thermodynamically efficient vs. heat pumps less than 80% and add the losses of power generation and this study may not be accurate. I haven’t read the study so maybe all this was taken into consideration but I doubt it. There is a large difference with tolerance to cols compared to heat and that makes more sense.
Barry S.
Among “Other factors not taken into account” the authors neglect building codes. We here in the Northern Climes insulate up the kazoo – well, maybe not there – but you’ll understand what I mean.
Methinks this would have a large impact.
Another factor – you can dress for the cold – a warm sweater and you turn the thermostat down. Tthere’s a certain limit to (un) dressing for the heat!
edi malinaric says:
March 28, 2013 at 10:09 am
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I think you have to consider the extreme ranges in temperature that the author is using. I’m not sure how effective heat pumps are in places like Minneapolis; at the very least they would probably need to be supplemented in the coldest months.
When one has had the pleasure of living in the mild climate of the South African highveld, the extreme high and low temps experienced in some cities in the US can be quite a shock.
The older I got the more I hoped “global warming” was going to bring my current NE Ohio home closer to Johannesburg’s short winters and long summers, but alas, it was not to be.
Air to air heat pumps don’t work in Minnesota, too cold. They can be used in fall and spring, but in the sub-zero dead of winter, they just don’t deliver the BTU’s needed and actually USE more energy than they produce in heat.
You need much more expensive and difficult (if not impossible in urban areas) ground source heat pumps.
Living in colder climates in the US is more energy demanding than living in warmer climates.
Wow! This is news?? Didn’t need a study for this. And I would say it is even less expensive than what he calculated (to cool) and live comfortably in Florida, than what he calculated (to heat) and live comfortably in the upper mid-west, if you build a house right.
Having lived in both areas for extended periods, it is structurally a lot easier (less expensive) to keep a house around 22C in Florida than a comparable house at 22C in the upper Mid-West. Yes, for the obvious reason that the average air temp. in FL is year-round closer to 22C than in the U-MW, but there are other reasons. The first reason being the ground temp. in FL averages 22C and in the UM-W 13C. The second reason being no matter where you are in FL there is a massive body of water relatively close (max 75 miles) helping to regulate the temp. to within a comfortable range. For about half the year I neither have to heat nor cool my house here in N. Tampa – of course now with “global cooling” (it was 2C here this morning!!) I’ll be heating more often. But not to worry, I built it right and if E power gets to expensive, I’ll put in solar like the Doc did.
Not sure why he had to make a model.
The electric and gas utilities have data.
We need a big time research effort to discover what everyone who ever paid an electric bill already knew – that it takes a lot more energy to warm a house to 72 degrees from an ambient temp of 30 degrees than to cool a house to 72 from an ambient of 92 degrees.
Seriously, this needed research? I could have told them that without having to do any research. All I would have had to do is show them my energy bills for the last 12 months (I live in SE Wisconsin). my peak winter bills are 2-3 times higher than my peak summer bills.
We live in the US midsouth at about Lat. 34.8 and heat with air to air heatpump. Works very well from about 5C and up (most of the time here) but much below that it needs help – in our case, propane. Cannot see it working well as far north as Minneapolis.
He could have saved himself an awful lot of work had he just talked to ASHRAE ( American Society of heating and refrigeration engineers) who have had data like this for more than 50yrs.
If this study really uses 18C (64.4F) as the reference temperature for heating and cooling degree days, then it is really biased toward additional cooling costs. Nobody in their right minds cools to 18C and almost everyone heats past 18C. It would be much more reasonable to use 23C if you have to use a single temperature. I believe most serious calculations of this use 20C for heating degree days and 25C for cooling degree days.
The US National Institute of Standards and Technology (NIST) recently changed the reference temperature for taking key measurements from 20C to 23C because they found it was too uncomfortable for scientists to work all the time in 20C. The example in the press release of a day with 23C mean temperature having 5 CDDs is ridiculous, in my opinion. How many of us would turn on the air conditioner on such a day, even if it momentarily got up to 27C in the afternoon?
Miami may be the warmest city as per an average temperature over a year. But it never gets really hot or really cold. Dallas or New Orleans would have been a better reference point.
“Not included in the analysis were…”
Also not included apparently is the one thing would have started with … the actual energy consumption.
+1 to vboring
Mike.
So the libs in MN are causing global warming. Sue them!!!
““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.”
But then cooling is invariably via electricity, whilst heating can be from the primary fuel.
If via gas, and as a point-of-application source, then the in use efficiency can be >90%.
This is one of those “duh” moments……warm climates???
80 degrees is not warm for us……that’s just comfortable…..and we’re 80 most of the year
Next maybe he can produce a study saying that ice ages are more dangerous to humans then minor global warming.