Cold cities use more energy than warm cities

Air conditioner row (Photo credit: ToddMorris)

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

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edi malinaric
March 28, 2013 10:09 am

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

March 28, 2013 10:10 am

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

john robertson
March 28, 2013 10:23 am

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.

March 28, 2013 10:24 am

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?

March 28, 2013 10:26 am

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?

March 28, 2013 10:27 am

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.

March 28, 2013 10:30 am

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.

March 28, 2013 10:30 am

It centers around the Human body temperature of about 98 degrees F.
Was this considered a breakthrough study?
He he……

Barry Strayer
March 28, 2013 10:32 am

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.

Tom Norkunas
March 28, 2013 10:35 am

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!

Peter in Ohio
March 28, 2013 10:42 am

edi malinaric says:
March 28, 2013 at 10:09 am
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.

March 28, 2013 10:52 am

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.

Milwaukee Bob
March 28, 2013 10:59 am

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.

March 28, 2013 11:03 am

Not sure why he had to make a model.
The electric and gas utilities have data.

March 28, 2013 11:04 am

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.

March 28, 2013 11:10 am

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.

D Caldwell
March 28, 2013 11:14 am

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.

March 28, 2013 11:15 am

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.

March 28, 2013 11:16 am

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?

Curious George
March 28, 2013 11:27 am

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.

March 28, 2013 11:34 am

“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

March 28, 2013 11:58 am

So the libs in MN are causing global warming. Sue them!!!

Joe Public
March 28, 2013 12:06 pm

““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%.

March 28, 2013 12:09 pm

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

March 28, 2013 12:13 pm

Next maybe he can produce a study saying that ice ages are more dangerous to humans then minor global warming.

Jason H.
March 28, 2013 12:19 pm

These researchers could have saved a lot of resources, had they just interviewed people who pay an electric bill.

March 28, 2013 12:31 pm

Barry Strayer says:
March 28, 2013 at 10:32 am
“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’m afraid you are not understanding how heat pumps and air conditioners work. They can use one unit of electrical energy (work) to transfer multiple units of thermal energy from the cold side to the warm side. A typical modern air conditioner has a “coefficient of performance” of over 3. That is, for one unit of electrical enegry, it removes over 3 units of thermal energy from the zone being cooled, and adds these 3+ units, plus the waste heat from the electrical energy used, to the warm outside.
When used as a heat pump, it’s even better, because the waste heat from the electrical energy is added to the zone being heated. So the one unit of electrical energy removes 3+ units of thermal energy from the cold ambient and adds 4+ to the zone being warmed.
Now, if the electrical energy has come from burning fuels, there is plenty of waste heat generated at the power plant. But fossil-fueled electrical generation averages about 40% thermal efficiency these days (with a range of about 35% to 55%), so you can still come out well ahead of a furnace of 60 to 80% efficiency in delivering heat to the zone (with most losses in the heat exchanger).

Jim Clarke
March 28, 2013 12:32 pm

Dr. Sivak…also know as Prof. Obvious…
Next up: New computer model reveals that, due to rotation of the Earth, sun appears to rise in the east and set in the west for majority of global population! Some exceptions exist for those at high latitudes.

March 28, 2013 1:38 pm

Now I understand why we decided to sell our home in central Oregon and move to the Palm Springs area. I just thought it was because we were tired of cold winters and enjoyed warm winters. Golfing in the sun is much more fun than golfing in the snow.

Jeff Mohr
March 28, 2013 1:59 pm

I wonder if he thought to include the cost of electric lighting? In the hot climate, lighting adds to the heat load to be air conditioned, while in the cold climate it helps heat the place. It would be best to use actual usage data.

March 28, 2013 2:15 pm

I’m really skeptical. Comparing existing inefficient heating to efficient cooling doesn’t mean cooling is greener, only that it is more efficient at the current moment. There also may be differences in insulation. As others have pointed out, some have heat-pumps.
I live in a high-rise. My electric bills in the summer are twice what they are in the winter. I don’t use ANYTHING to heat in winter – either it is because the surrounding apartments leak enough, or my southern exposure means I have solar warming. And I’m at 42 degrees north in Michigan.
There might be one point. If you don’t keep the heat on, pipes freeze and burst. You only need to cool a house when you are there, and you are likely to be out during the hottest part of the day. Perhaps a 24/7 place like a hospital would be a better comparison.

March 28, 2013 2:19 pm

Strange choice of Miami. I’d like to see the results using Phoenix.

D.J. Hawkins
March 28, 2013 2:21 pm

@Barry Strayer says:
March 28, 2013 at 10:32 am
I think the study assumes that all energy is supplied by electricity, although only a loon with nothing better to do with his money would use purely resistive electric heat in Minnesota. In most parts of the US peak electric usage is in the summer, not winter. You are far more likely to run into electric infrastructure limitations in Miami in the summer than Minneapolis in any season. You are more likely going to be able to build another gas pipeline to heat homes in Minneapolis that a 350KV powerline to cool homes in Miami.

March 28, 2013 2:31 pm

So a warmer world would require less fossil fuel to sustain us in comfort? Would that be a negative feedback of some sort? Or is this laying the groundwork to justify moving Minneapolis to Florida in order to save the environment?
There’s so many things wrong with the analysis that the fact they came up with the correct conclusion is actually a surprise.
Imagine if they’d been bright enough to compare fuel efficiency of cars and trucks as part of their study.

Jeff in Calgary
March 28, 2013 2:31 pm

This study probably underestimates the issue. Most people do not turn on the AC at 19°C. Most people tend to turn it on only at about 24° or 25°C. So Miami would acutaly be quite a bit lower than he had determined.

Philip Bradley
March 28, 2013 3:07 pm

Curt says:
March 28, 2013 at 11:16 am
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.

Also humidity has a large effect on what temperature feels comfortable in the heat. Summers here in Perth are hot and dry, and I run my aircon at 26C to 28C. Some years ago I lived in the humid tropics and would run the aircon at 21C/22C.
Then there is a secondary effect from humidity. Low humidity hot climates have large diurnal ranges. An adequately insulated house has sufficient thermal inertia that night time cooling keeps the house at a tolerable temperature during the hot afternoon hours.
A comparison between Minnesota, Miami and Palm Springs would have been more informative. And as noted above, they should have used actual data on what temperatures people turn heating and aircon on.
They would have found what I already know, people use least energy in warm to hot dry climates.

March 28, 2013 3:23 pm

That’s hardly surprising. Having lived in North Queensland and spent a bit of time in Canada it’s clear. Heating in Canada is way way more expensive than air conditioning in Queensland

March 28, 2013 4:03 pm

Why are people being paid to carryout this type of research? Talk about speaking the bloody obvious. All you need do is compare the fuel bill for a house in winter vs summer.

Leo Danze
March 28, 2013 4:16 pm

Humans evolved in warmth and so are closer to discomfort in cool temps than warm. Easy.

March 28, 2013 4:56 pm

A high-tech proof of what anyone could have seen intuitively by looking at a map of pre-industrial Earth by population density. The largest cities and highest population densities were always in the lower latitudes. Higher latitude cities took over when coal became common and people could afford to live there without dying in droves every winter.
Incidentally, lower latitude cities didn’t start to make their come-back until the invention of air conditioning. We’re still only a few decades into that transition but air conditioning’s impact on the heating/cooling day calculation is a non-trivial component to the migration of US businesses.

March 28, 2013 5:25 pm

Much of California, except the coastal areas , Nevada, Arizona and much of the south west can be effectively cooled with evaporative coolers, and indeed are. I have a large portable one in my 2000 sq ft shop in California and it lowers the temperature therein by about 20 degrees and adds some needed humidity for about 50 bucks a month. They are not as comfortable as air conditioners but the are a great alternative.

Joe Shaw
March 28, 2013 5:56 pm

I agree with previous commenters that the paper would be more useful / credible if the author had 1) made an attempt to validate the estimates against actual energy consumption data (e.g., monthly variation in electricity and natural gas variation) for the two locations, and 2) looked at additional locations with different climates. I also think the heating / cooling degree day methodology is incomplete since it ignores insolation. I did the ACCA Manual J residential heat lost and heat gain calculations for a planned home addition last year and found that for my location (Northen VA) about 25% of my sensible heat gain was due to solar heating through windows, skylights and glass doors. I expect that this faction is likely substantially higher in areas like Miami and Phoenix, and for commercial buildings with a lot of glass.
The paper would also be improved by citing original source data rather than a paywalled paper for the heating and cooling degree day data – it is available from NCDC at:
There is a large discrepancy between the degree day values used by the author (e.g, Minneapolis, MN, 4376 HDDs / 2433 CDD, Miami, FL h3 HDD / 2423 CDD), and the NCDC data (e.g., Minneapolis 7876 HDD / 699 CDD for station 103 Minneapolis Intl Airport, Miami 149 HDD / 4361 CDD for station 65 Miami Intl Airport). This discrepancy may be explained in the paywalled paper.

Joe Shaw
March 28, 2013 6:06 pm

On further reflection the difference in degree days is almost certainly due to conversion between F (from NCDC) and C (used by the author). Do’oh.

March 28, 2013 6:12 pm

In my opinion, there are several theoretical flaws in the argument put forward by the good doctor as well as some practical ones. I am responsible for a large factory in the outer suburbs of Minneapolis and spend a lot of time studying energy usage. When your heating and cooling bills go into the six figures in the summer time, you spend some studying them.
First, the theoretical problem with Dr. Spengler’s argument is the Carnot Cycle states as matter of thermodynamic law that it takes more energy to cool than to heat as you must change the entropy of the system. The inherent energy to overcome chaos will always mean heating is easier as cooling as hot objects are more chaotic than cold ones. I know it is hard to keep with modern physics and this work is only a 190 years old, so they might be tad behind on their reading.
Another issue is that warmer climates have much higher water content in their air than does a colder climate. Therefore, it is not only air that is being heated or cooled but water as well. When you cool, you always see water draining off of the coils. This means that we are losing energy to the heat of condensation (the energy required to transition from a gas to a solid) as the water vapor must give up that energy up the cooling coils. This energy contributes nothing to temperature change – only to phase change. The Carnot cycle also means that the cooling coil uses even more energy than the heat of condensation because by its nature, refrigeration is imperfect.
When we heat up here, we use large, pulsed gas fired furnaces – whether in our homes or in our buildings. We do not burn the gas in turbine, then covert it electrical energy and then transmit it over miles of cable to final be used as a heating element or to run a heat pump. Meaning, we have no transmission loss of the gas energy – it is efficiently and directly converted into heat.
Minnesota winter frequently has a dew point below zero – our average dew point for the whole month of January is 9°F. Meaning we have very little water to heat or cool in the air. Contrary to the good doctor, it takes far less energy to heat a cubic foot of dry air one degree than it does to cool a cubic foot of wet air one degree.
As a practical matter, the energy usage of our factory is pretty straight forward; the number of kilowatt hours we use in a day is solely proportional to the product of the temperature above 72° times the dew point. My regression fit against my metered electrical usage is 81% on this single term. I know in July I will use 180,00 kWh more than in May. The temperature is not that different (73°F vs 58°F), but the air is much drier (67° dew point vs 44°). Neglecting water vapor is a major practical flaw.

March 28, 2013 6:35 pm

Go figure!

Michael Tremblay
March 28, 2013 6:38 pm

While I don’t disagree with Dr Sivak’s conclusions I certainly find fault with his methodology. Why is he calculating theoretical energy usage based on the assumed efficiencies of the appliances involved when he can get hard data from the power suppliers and calculate a far more accurate amount of energy used on HDDs and CDDs?
The information on how he has calculated his findings will result in approximations leaving his conclusions open to much more debate (and skepticism) than if he used the actual data for energy consumption in those cities.

March 28, 2013 6:51 pm

“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”
Who took it for a fact?

Patrick B
March 28, 2013 7:56 pm

Miss my house in Hawaii – no furnace, no air conditioner, no heat pump, perfectly comfortable year round.

Tom Norkunas
March 28, 2013 8:14 pm

D.J. Hawkins says:
March 28, 2013 at 2:21 pm
My primary source of heat is resistive electric, electric storage heat. The REA turns the heat on at night (cheap low demand), heatings bricks in an insulated cabinet, and the heat gets withdrawn during the day when the thermostat demands. This ,except for generation and transmission loss, is nearly 100% efficient. Much less expensive than propane or fuel oil. This works for me down to -40C.
Fall and spring I have a air source heat pump ofr heat,which then cools me when it’s 35C. This is cycled by the REA (again,for lower rates).
Location is rural Northwest Wisconsin.

March 28, 2013 8:18 pm

A warm Earth is more hospitable than a cold Earth.
Only enemies of humanity would want you to believe otherwise.

March 28, 2013 8:47 pm

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.

Mike Wryley
March 28, 2013 9:05 pm

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.

David Cage
March 29, 2013 12:43 am

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.

Cherry Pick
March 29, 2013 2:21 am

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.

March 29, 2013 3:20 am

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.

Paul Schauble
March 29, 2013 4:04 am

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.

March 29, 2013 5:41 am

Cold kills. Warmer is better.

March 29, 2013 5:50 am

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…
and here:
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”?

March 29, 2013 6:19 am

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.

Crispin in Waterloo but really in Yogyakarta
March 29, 2013 6:20 am

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!

March 29, 2013 6:31 am

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.
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 $$.

March 29, 2013 6:54 am

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.

Box of Rocks
March 29, 2013 7:57 am

“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.

G. Karst
March 29, 2013 9:01 am

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

March 29, 2013 9:10 am

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.

March 29, 2013 9:23 am

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.

Box of Rocks
March 29, 2013 9:28 am

G. Karst says:
March 29, 2013 at 9:01 am

Does that calc include the energy required to warm the propane so it can vaporize and be in a useful vapor state?

March 29, 2013 11:25 am

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.

March 29, 2013 11:59 am

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.

March 29, 2013 12:00 pm

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.

March 29, 2013 12:01 pm

I meant to say that I think my comfort is worth more than the “perceived” energy savings.

March 29, 2013 7:22 pm

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.

edi malinaric
March 30, 2013 6:06 am

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

March 31, 2013 10:03 am

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.

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