What happens if its cloudy or rainy for several days in a row?
Your solar electric system would produce less electricity, but you wouldn’t notice the difference inside your home. Grid-tied solar systems never “run out” of electricity. Although solar panels only produce their maximum output in full, unobstructed sunlight, they will still produce power on cloudy or rainy days – albeit much less than normal. During these times, you end up buying more power from the utility company to make up the “deficit.” When we design systems we take into account weather variables and can accurately estimate monthly and annual solar electricity production.
Your solar thermal system will capture heat on the sunny days, and even on seemingly cloudy days. This energy is stored in the tank, and is often enough to bridge the gap for fully overcast days. If your solar tank is “emptied” of all its usable heat, your regular appliance takes over, and you don’t notice any difference inside your home.
