Solar panels and green roofs
It's at this time of the year especially that I get a real buzz from the solar array on top of my house, and from the green roof planting that thrives in the cool shade beneath. From Spring to Autumn it's a real pleasure to go home and see how much heat has been harvested from the free energy of the sun. Normally from Spring to Autumn the domestic hot water for both the main house and the rented flat is virtually free. Indeed at present too much energy is produced and the plan one day is to use the 11metre long pool in the garden as a solar dump for all the excess solar energy.
Solar energy is in my view a very worthwhile long term investment and a positive step in reducing carbon emissions.