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Documentation > Greenhouse effect > Acting individually > An example of emission calculation : how much carbon equivalent at Jancovici and co?

How much greenhouse gases at home ?

Published in a little different form in "La Revue Durable" november 2002 - last translation september 2003

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Since I try to convince whoever I run across that it is indispensable to calculate how much greenhouse gases any activity generates, it was about time I did it for my own house ! This page shows an example of the various contributions of my family to the world emissions, with some commentaries that I hope will prove useful to identify action possibilities.

These figures have been obtained with the default values included in the method "carbon inventory" that I contributed to set up for the french environmenent agency (ADEME). The idea is of course not to show how virtuous (or haw bad !) I am, but just to show where are the main emission sources for an "ordinary man", and, therefore, where are the reduction potentials.


Energy used at home

I live in a natural house that has a central heating running on natural gas. Natural gas is a fosssil fuel (not renewable), even if it has the lowest carbon content of all hydrocarbons (and therefore the fuel that frees the least CO2 for a given quantity of energy). My invoices from mid-2001 tio mid-2002 show a annual consumption (for 2001) of 32.000 kWh, which means, since natural gas frees about 225 grams of CO2 per kWh, my boiler emits 7,2 tonnes of CO2 per year, which corresponds to a little bit less than 2 tonnes carbon equivalent per year.

The same gas provides the hot water for the showers (neverending when the ladies are locked in the bathroom), and feeds the stove to cook the frog legs (because we french eat frog legs at every breakfast, everybody knows that !), so that the emissions linked to hot water and cooking are included in the above figure.

We also consume electricity, for an annual total of 4.800 kWh. The production of this electricity has generated 400 kg of CO2, or 111 kg of carbon equivalent. Elsewhere in Europe, the same electricity consumption would have generated much higher emissions, most of the european electricity being made out of fossil fuels (mostly coal and gas, a little heavy fuel oil).


Kg CO2 emitted for 4.800 kWh

% extra compared to France


































2 544


United Kingdom












It is easy to see that in some european countries (Germany for example) our electricity consumption would have lead to emissions representing half those of heating, as in France they "only" represent 20% of heating.


Have we already "done something" that lead to a decrease of our emissions ?

We changed the fuel oil boiler - that was there when we bought the house - for a natural gas boiler with a regulation that lowers the temperature at night (for the same comfort, we saved 2,3 tonnes of CO2, or 600 kg carbon equivalent),

We installed double glazing on every window (probable saving of 5 to 8% of the total, that is 100 to 150 kg carbon equivalent),

And most of all...we got the sweaters out of the drawers ! The inside temperature is 18 to 19 °C during the day, and 15 °C at night (it is perfectly bearable, and actually much more comfortable for a good night's rest).


What action possibilities still remain ?

install a solar heating, at least for sanitary water (we could save up to 200 kg carbon equivalent, roughly, for sanitary hot water ; 1 tonne carbon equivalent for a solar heating of the house, that requires to install a heating floor in each room).

If we lived in the country: install a wood fueled boiler: we could save almost all the emissions linked to heating (so that is a lot),

insulate better the house (likely saving of 10% to 20%, but it would require a lot of work),

lower the inner temperature a little more (likely saving of 10% to 20%),

and at last....move house for a smaller one !


What could we do, on the opposite, to increase our emissions ?

change the boiler for a fuel oil or a coal one,

ask EDF (the french electricity provider) to give up nuclear power plants, or, if it becomes possible to purchase our electricity from another company that has gas or coal fired plants, change our supplier (I could then multiply the corresponding emissions by up to 10 !),

increase the temperature and live half naked all year round,

extend the house: this would lead to emissions for the manufacturing of the materials, then lead to additionnal emissions because of an increased energy spending for the heating,

intall the air con (in a country that produces its electricity with coal or gas - Germany, USA, Greece, Denmark..., this is probably a very good way to significantly increase the emissions)..


Energy for work

The adults of our household consist of a man and a wife (so boring classical...). My wife is said to be "at home", and therefore does not occupy an office during the day, and I work at home, which means that I also save the emissions otherwise linked to the heating and the maintenance of an office. Indeed, anyone who works outside his home induces an energy spending for the heating of the place where he(she) stands during office hours, and the hot water if applicable, and these emissions account, of course, in the national total per person.

The corresponding emissions, for me, are already included in the gas and electricity invoices for my home. The fact of working at home (though said "at home", my wife probably works more than I do...) corresponds to a saving of 1,8 tonne of CO2 (0,5 tonne carbon equivalent) per concerned adult. The reference data for this statement comes from a study I did on telework.

What action possibilities still remain ?

nothing much....

What could we do, on the opposite, to increase our emissions ?

I could take an office outside

My wife could take a job "outside"


Energy for public services

Attending school being mandatory until 16 (and often prolongated a little over that age), my kids go to school. This place is heated, is packed up with teachers that come to wrok by car, etc. By other ways, I pay taxes (and I don't consider that I pay too much of them, because I am definitely pleased to benefit from the corresponding services), and therefore "consume" various public services (army, justice, waste collection, school, health insurance, etc).

I don't know what share of the emissions of public services I should be charged, but I definitely "own" a little fraction of these. I would not be suprised to discover that a couple of hundred kg of CO2 "hide" behind this public service consumption.

What action possibilities still remain ?

difficult to say !

What could we do, on the opposite, to increase our emissions ?

put our kids in boarding school: it is then necessary to build a dormitory, heat it in the winter, etc, and if we don't move house at the same time for a smaller one, the global emissions increase,

and for the rest, I don't know much...



We have a car, that covers 12.000 km/year for "long" drives (typically going on holidays, as everybody knows that being on holidays is an important occupation in France !), and, for a minor fraction (let's say 2.000 km/year), some driving around. This car needs roughly 10 litres per 100 km on highways (where we do most of our driving) and I will take twice that amount as a rough estimate for driving around (it is probably a bit too much, but that compensates for the emissions linked to the manufacturing of the car and to road construction). If I include the emissions linked to refineries, this petrol consumption leads to about 4 tonnes of CO2 per year, that is 1.100 kg carbon equivalent.

Have we already "done something" that lead to a decrease of our emissions ?

We have chosen a place with a good public transportation system (I never drive during the year for professionnal visits, and that limitates also the need to drive the teenagers around),

We benefit from the fact that I am a home worker (probable saving of a couple hundred kg carbon equivalent compared to the situation where I would have to drive 20 km every day to go to work), and it is exceptionnal that I travel for my work with something else than a train or a metro (I don't fly any more: if it is too far, I use Internet !),

We also benefit from the fact.....that my wife is at home ! It might seem totaally politically incorrect to state this, but it is a fact that not "going to work" saves the necessity of a second car (all our neighbours where both husband and wife have a job have two cars) and saves the corresponding kilometers: that is not nothing !

When moving around (market, supermarket, takling kids to school...) we try to walk or cycle as often as possible (but my wife and I have sometimes different conceptions of what "as often as possible" should mean !).

We try - and for 8 years we have managed to stick to it nous y parvenons - not to board a plane for holidays (a return trip Paris-New York represents, per passenger, almost 4 tonnes of CO2 equivalent, or one tonne carbon equivalent).


What action possibilities still remain ?

totally drop the car when moving around, what will often mean a longuer trip, but :

when ingestigating, it is amazing to discover the number of places that are served by public transportation (mostly buses).

one should not mix up lengthening of the trip and lost of time : in the public transportation, I use my time to read, work.... all things that I could not do while driving.

go on holidays by train !


What could we do, on the opposite, to increase our emissions ?

easy: by a second car, if possible a Hummer or a Porshe (anyway nothing more efficient than 30 litres/100 km or 8 miles to the US gallon), take planes every other day (as some notorious ecologists willingly do, by the way !), move house and live far from everything....



Any food production generates greenhouse gases emissions:

cereals, fruits and vegetables generally require fertilizers (agrochesmistry is very energy intensive), mechanical force (tractors) therefore gasoline, transportation from the field to the shop, therefore more gasoline, etc.

meat production requires an intensive plant production: several kg of cereals are necessary to produce a kg or pork or poultry, but up to 50 kg to produce a kg of beef.

fishing requires diesel for the boat, than for the transportation of the fish...

any "processed food" (does not only designates peanut butter and frozen pizzas, but also noodles, milk, orange juice, biscuits, chocolate, yogurt....) generates, on top of this, emissions for freezing (if applicable), cooking and/or heating, producing all the packaging, and transporting the finished or semi-finished goods - and the employees of the companies - around, that can represent a significant fraction of the initial "carbon content" of the food processed.

I had the possibility to estimate emissions linked to a kg of food (as part of my job), and if I apply these values to what I think are our annual consumption, I get the table below:

Food items

kg consumed per year by the whole household

grams carbon equivalent per kg of food

total kg carbon equivalent
Bread, noodles and rice




Fruits and vegetables




























Cheese (real cheese !)




Cheese ("hard cheese", like gruyere)


























Actually, I should probably add 10% to account for olive oil, biscuits and chocolate...

Eveything is included in these figures, though: our kids do not eat much at the school restaurant and we don't go to the restaurant every day, therefore emissions that would be linked to the preparation of food "outside home" are marginal in the total.

Have we already "done something" that lead to a decrease of our emissions ?

We eat meat just once a day (but a notorious franch autor of recipe books says it's much enough !) and mostly pork and poultry.

Most fruits and vegetables we eat are in season (no strawberries, tomatoes or eggplants in winter...), because otherwise they must be imported from the other side of the planet, or grown in a greenhouse heated with fuel oil, or we would buy them frozen, and all these situations are synonymous of increased emissions (I confess a little exception one in a while, but it is not a habit !),

We buy all we can to local producers (fruit, vegetables, poultry...) in the open market, what avoids long distance transportation (no green beans from Kenya or kiwis from New Zealand coming by plane, or even spanish strawberries coming by truck ; the only noticeable exception is related to oranges in winter),

all fresh products (fruits, vegetables, meat, bread...) come from local shops or the open market, that consume less transportation per selling unit than large supermarkets and don't require that we go by car (in addition, the least we go to the supermarket, especially with kids, and the least we buy "junk food", and therefore we save money that we can invest in "superior food" bought at the open market): the supermarket is only used for "basic grocery" (noodles, oil, coffee, etc), les produits d'entretien and dairy products such as yogurts (that it is hard to buy in the open market in "large" quantities, that is anything over 10 pieces).

We almost never buy frozen foods, nor we have a freezer at home (we just have the freezing compartment of our fridge, that can hold a couple of remains of previous meals). Freezing food and keeping it frozen indices significant emissions, especially in countries with electricity produced out of coal or gas, and in addition for any processed food it is necessary to manufacture a packaging that will be thrown away and that represents significant emissions),

What action possibilities still remain ?

Becoming.....vegetarian (possible saving of 0 to 2,5 tonnes of CO2 equivalent per person, or 0 to 0,7 tonne carbon equivalent, depending on the fact than we would still eat fish (and shrimp, which is probably one of the most "carbon-intensive" sea products there is), or no animal product at all.

Eating organic is generally a good thing to do, but a little calculation is necessary in order to determine what is the exact benefit:

avoiding nitrogenous fertilizers suppresses the N2O emissions of cultures and the CO2 émissions of chemical industries to manufacture these fertilizers, per unit produced we cut these emissions by half,

but as less fertilizers are used, the outputs per hectare are lower (the outputs we get now are not "sustainable" at all, because they are allowed by abundant fossil fuels), while the path followed by the tractor does not depend on the cultivated surface and not on the output of the culture. Hence the "amount of mechanical energy" by unit produced increases, but not to the point of offsetting the effect previously mentionned.

And at last it is of course necessary that the organic product does not come by plane from 10.000 miles away (what I saw several times): the remedy is then worse than the disease !


What could we do, on the opposite, to increase our emissions ?

eat a 500 g steack every day (just this would make our emissions soar by several tons carbon equivalent !),

eat every other meal a processed meal bought "ready made" in a supermarket. Incidentaly, many people explain to me that it is more "economical" to buy food in the supermarket compared to the open market or small stores. On a broad basis, this is obviously false: if this type of distribution allowed everyone to make neverending savings, the economy would go into perpetual recession ! Even if the unit cost of each product decreases (and comparing is not always meaningful: it is not the same chicken that is purchased directly from a farmer in the open market and in a supermarket), the global amount paid when leaving the supermarket always increases. It's just that the basket is filled up with "accessory" items that can't be found in the open market but that have a debatable utility: non eddible product bought while "passing by" in the supermarket, but without which we would probably live equally happy, junk food of all kind, etc. It should also be noticed that ready made plates are much more expensive per kg that the same ones done at home (with better products): the price per kg of potatoes already peeled and pre-cooked includes the salaries of people that peeled the potatoes, the cost of manufacturing the plastic packaging, and the transporation costs between the field and the potato-peeling plant. If the price is the same, it's that the product is not !


Manufactured products

Most our purchases are about:

replacing household appliances, but the emissions linked to their manufacturing are secondary compared to the emissions linked to their use,

a computer every 2 or 3 years for my work (by obligation more than by pleasure) with a corresponding emission estimated at 100 kg carbon equivalent per computer (I never had the occasion to make the calculations).

some clothes, CDs, toys for Xmas...... My experience is that compared to emissions induced by heating and transportation, the quantities are secondary if we buy little quantities of manufactured products (and I don't buy a new pair of trousers every day !). Let's say we will add 15% on the total to take these spendings into account, maintenance of the home included.


Even if we try not to throw away too much (a good start being not buying products with a lot of packaging...), we obviously have things in our wastebin. Though I did not weight it precisely, I estimate that it contains about 20 kg of waste per week, and, if its composition is "standard", that leads to an emission of roughly 400 kg carbon equivalent (see details).



When we go on holidays, we rent places to sleep. These places, be they a house in the country or a sailsboat, it was necessary to build them, then it is necessary to heat them in the winter, and that also leads to emissions. If we do a little prorata temporis, the emissions of this item are estimated around 20% dof the heating item above, that is 400 kg carbon equivalent overall.


If we except a couple of diverse contributions I'm thinking of (freshwater adduction, that needs energy ; wastewater treatment, that also requires some ; recurrent spending for services such as insurance premiums or telephone bills, because the employees of these companies have heated offices ! ; or occasionnal such as the plumber) or that I'm not thinking of, my household generates the following emissions:


Annual emissions in kg carbon equivalent
Heating/hot water


Energy for work


Transportation (all purposes)




Leisure (transp. excluded)




Total before manufactured products


Buying manufactured products

700 (1)

Total (année de référence 2001/2002)


(1) this corresponds roughly to 500 kg per year.

As we are 6 in the house, it is easy to deduct that we all emit about one tonne carbon equivalent per year.

This represents roughly half of an average French's emission (all greenhouse gases included). This apparent modesty owns a little to every item mentionned above under the questions "Have we already "done something" that lead to a decrease of our emissions ?", but also to the fact that emissions are generally not adjusted when the size of the family decreases. For example, if we keep the same house once all the kids are gone, we will mechanically increase the emissions per capita for the heating of the house, and the same way of thinking can be applied to the family car.

Still every member of Janco & co is emitting twice too much if we want to stabilize CO2 in the atmosphere: getting there will not be trivial, and refusing the easy collective actions to lower the emissions (such as nuclear energy) will increase the difficulty of achieving that goal with only energy savings (that are wishable anyway) and renewable energy.


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