Heating water - my shower experiences

Last October as a result of utterly adverse circumstances, I had to learn that cold showers are not lethal (I was pretty convinced before). Newly born environmentalist I was, I decided to adapt my shower behaviour to cold water on no-hair wash days (and no, I have not moved to daily hair washing ever since). Ok, perhaps, the truth is that those extra 4 minutes in bed in the morning kind of make my day...it is amazing how quick one can shower when it is not fun....
I have been living with the conviction of saving the planet ever since, but of course, it is now time to figure out what the sacrifice is worth in terms of CO2.

Energy needed for heating water is calculated as

Liters * specific heat of water (1,16 Wh/l*Kelvin)*increase of temperature in Kelvin

With warm water, I used to shower approximately 7 minutes in the morning and assume, that water was heated from 15 to 40°. My current shower doesn’t take too much, about 6 litres per minute.

Therefore

42litres * 1,16Wh/l*Kelvin*30Kelvin = 1218 Wh per showering session and 445 kWh per year.

I was very proud when I got that far and then realized that I didn’t have a clue what this meant in terms of CO2 – my shower is not heated by electricity, but how “dirty” is gas???

Research brought me that far:



Of course, I assumed that some of the energy contained in the gas is lost when converting it to heated water (about 10%). So in the end, my calculation looked

370kWh/90%*0.25kg/kWh = 122 kg of CO2 per year

Antina reloaded only showers twice per week with warm water, therefore the shower footprint goes:

Hot shower days: 37 kg of CO2
Cold shower days: 0 kg of CO2 (at least not for heating up water). Saves me 85kg of CO2 a year.
Or almost 7 trees
Or almost 60 Euros
And about 6000 litres of water because of the shorter showering times.

Supposedly, I am also having a better immune system and better skin. I cannot see this but of course strongly believe in it (and as we all know, the belief is pretty much sufficient most of the time).

I have neglected the CO2 needed to pump the water to my shower – a thinking approach to this is included in the spread sheet that will also allow you to calculate your own shower footprint – check out at

http://ecowise.se/ShowerSpreadsheet.xls