Find where the energy goes

atmosphear commented on an entry by sort77 titled "I'm absolutely SICK today" regarding make a smaller ecological footprint:

Solar panels at the moment are very cost-inefficient and their energy efficiency is very low. It’s a good thing to consider moving into solar energy, but first I think you should find out where the energy goes in your household.

Apparently you are living in a private house. How do you heat up the house or hot water you use? If it’s with electricity, using solar panels to generate electricity and electricity into heat will end up with a devastatingly low energy efficiency.

The commercial solar panels efficiency is less than 10% (meaning over 90% electricity loss). I reckon there was also the problem of converting the direct current (DC) to alternating current (AC), which electric heaters might convert back to DC. Inverters will eat their part of the power (though it will be converted into heat). All this ends up eating roughly 95% of the solar power before you get to even use it.

Heating is mostly needed in the night time, when sun doesn’t either heat up the house or shine on solar panels. Thus there would be need for battery system, which eats again power in electric/chemical energy conversion.

Using solar thermal collectors (or more correctly speaking, since thermal collectors are usually industrial applications, solar hot water collectors) would be both cheaper and more energy efficient. It should be relatively simple to add solar heating to existing water and heating systems either as additional heat source or integrating into existing if the heating is already done with something else than electricity.