Hot water heating consumes up to 37% of home energy used (depending on who you read) and an obvious way to cut that down is to install a solar hot water system, but what if your site is not satisfactory or you don’t have the money? Even if you have solar, another energy source like gas or electricity is required for cool and cloudy weather, and one of the things that bugs me is the water we waste while waiting for the water to run hot, both water and energy are wasted if you have a number of small jobs requiring hot water. This caused me to think about things based on other projects that I have completed and been able to share with you, thanks to the miracle of Grass Roots.
I used to do some work in China and I know that in some parts of the country it is not possible to provide hot water on tap, so the residents by hot water from a vendor and then keep it hot in a thermos or series of thermos flasks. So the thought naturally came to me, why couldn’t we use a solar oven such as the one I wrote about in GR 167 to heat the water then store it in the same way?
For this Christmas I got a Thermos Airpot, which is a pump action insulated jug that allows you to pump out hot water as you need it and by taking the 2 litre billy from the polystyrene insulated hay box, filling it with water and heating it in the solar oven –there you have it - free storable hot water! I am going to get a number of the standard type thermos flasks so that as you heat the water, you can store it. The 2 litre billy takes about 3 hours to come to the boil( Jan/Feb in Sydney) so you heat and store a number of thermoses in a day and they are efficient enough to keep the water hot enough overnight for a solar coffee or tea the next morning.
If you didn’t have the thermos but could make a haybox insulated cooker, you could use that to keep the water hot overnight, and I have done that too, but you can’t beat a thermos of hot water in the kitchen for convenience (convenience = the system gets used). OK, the system does not produce enough water to bath your kids, have a shower or put a load of clothes through, but it does produce enough for hot drinks, washing the dishes or wash your hands (when diluted with cold water of course!). These are the sort of jobs where only a small amount of water is used on a regular basis and you need to run it for a while before it runs hot.
With a bit of work and perhaps some already existing gear you too can have solar hot water and do your bit for self sufficiency and the environment – every little bit helps.
