And the most frugal is the latter.
Okay, I'll explain.
Passive solar power is usually used to produce heat for various applications, and indeed, heat can do a lot of things besides just heat your house. Unfortunately, most passive solar "systems" are expensive to obtain and install and it takes someone very handy to build their own system.
But of course, there's another way. It may not produce the dramatic results that a system does, and it may not be visible so that others can see how cool you are, but you may save just as much money with even more efficiency. Affordable passive solar power comes in many ways rather than one, and some of the ways might even be frowned upon by your neighbors. If you're ready to be a rebel with a cause (that of saving your bank balance), read on.
Passive solar powered ice tea maker
Fill a gallon glass jar or pitcher about half full of water, add three heaping tablespoons of loose tea or four to six teabags and set it on a slab of stone or dark cloth in a sunny location for several hours. That's all there is to it. If the tea is too strong, add water. Add sugar if desired. You'll save money hand over fist if you've been buying tea premade from the grocery store.
Passive solar powered water heater
This is a very affordable way to heat water. Put it into well washed milk jugs or other clear or semi clear containers and put them in a sunny place. In a few hours, you'll have water hot enough to wash dishes or wash your hair (or take a bath if you've put out enough containers). If you need convincing, just test the temperature of the water from a garden hose that's been in the sun all afternoon.
Passive solar powered clothes dryer
This was invented many years ago. In the traditional manner, two T-posts are set in the ground, usually about 20 feet apart, and wire or plastic line is strung from one to the other. You pin wet laundry to the line with clothespins and wait for it to dry. It works best when the sun is shining, of course and a breeze will hurry the result. The sun dries, kills pathogens with its ultraviolet rays and, given enough time, will whiten whites and remove stains.
Do you use the sun in these ways? It will save you money.
There are more ideas coming up, but share yours, please. Why not use passive solar power for all it's worth?