Friday, December 27, 2013

DIY low flow toilet and save energy

During winter time the outside of our toilet water tank was condensing when taking a shower. It dripped on the floor and was annoying.
Our  DIY low flow toilet with the lid removed

Now I have solved this with some empty beer cans. By placing five of them, filled with some small rocks and mostly water, they now displace about 2.5 liter of water in the water tank. When flushing less cold water enters the tank, and it also gets some stored heat from the beer cans, so the outside surface of the water tank now never gets so cold that condensing starts.

Two more good things happen at the same time: Less water is used and less heat is stolen from the warm air in the room.

Two displacement cans on one side, three on the other makes a low flow toilet
Heating one liter of water one degree C takes 0,00116 kWh. In this case each flush uses 2,5 liter less water and the water will over time heat from 8 C to the room temperature of 22 C.  Not every flush will make the water heat to 22C before flushing again, but let us assume this in sum happens a total of five times pr day. Then the reduced heat taken from the room for a year will be 0,00116 kWh/lC x 2,5l x ( 22-8 C) x 5 x 365 = 74 kWh. With a long heating season this might be as much as 50kWh saved on heating.