Installing a radiant heat floor system (see Figure 12-6) is almost surely not a do-it-yourself project, but it merits elaboration because it's such a complete and effective way to use solar energy water heating. A snaking closed loop of plastic tubing runs beneath your floor. When hot water flows through the tubing, the heat radiates upward through the floor and into the room.
You can use solar heated water to literally heat your home off-grid. Radiant heat, without solar, costs much less than forced-air heating for efficiency reasons. But when you supplement your radiant heat system with a solar water heater, you can drive your heating costs down to nearly nothing. Of course, sunshine isn't very reliable, particularly on the coldest nights when you most need heat, so you can't use solar heating exclusively; it can only be a supplement. But it can be very effective.
You can use any type of water heating system with a radiant floor system, but the capacity of hot water that you use goes up dramatically with a radiant heat floor system. So the attraction of a solar system also goes up dramatically, because you get much cheaper hot water per gallon.
At the very least, radiant heating reduces your carbon footprint. When you combine it with solar, the pollution savings can be impressive.
The engineering is complex, and the installation is clearly not for the faint of heart. There are technical problems, of course, but the systems have been in use for a long, long time. New technologies are making these the system of choice for a lot of homes.
Here's why: With conventional forced-air systems, hot air comes in through the vents and immediately rises to the ceiling. That's not where you want it, so you need to either pump in more heat than you really need (inefficiency) or use overhead fans to move the air back down (inefficiency). Moving air makes you feel colder, and you get stuck listening to blower noise as a big machine goes on and off all night. Furthermore, heated air dries out very fast, so your lips dry up, and your skin gets tight.
With radiant floors, the heat starts at ground level and rises naturally, which is much more efficient. There's no blower noise, wind chill is nonexistent, and you don't have to mess with HVAC filters. The big benefit is that the heat is in the room — the floor and furniture — not just the air. You can adjust your thermostat to a lower temperature in a radiant house and achieve the same comfort level because the floor and furniture are where the heat is. Where you set the thermostat is a question of comfort, not numerical temperature.
The floor of your house gets nice and warm. You can use hardwood floors or tile and slate, and the floor never feels cold. You can go barefoot in the middle of winter, and you don't end up hopping around looking for your slippers.
If you're planning on a room addition to your house, consider using a radiant floor in that room. Your existing HVAC system likely won't have enough capacity to heat an additional room. Adding a solar water heater to your house and using your domestic heater to heat the radiant floor in the addition works wonders, and it's much cheaper than adding another small HVAC system.
You can also cool your house with radiant flooring. It doesn't work quite as well as heating, but if you have solar panels, you can use these at night to cool the water that's already in the closed loop of the radiant floor system. The reason the collectors will cool is simply because they have so much area, and the heat will escape into the cool, nighttime air. This is especially true if a breeze is blowing.
A geothermal system in conjunction with radiant heat is also an excellent way to go. Geothermal is a system of wells drilled into the ground; water is run through the wells, and the inherent warmth of the earth's interior is used in a heat exchanger. In general, geothermal systems work best in climates that are both very hot in the summer and cold in the winter.
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Global warming is a huge problem which will significantly affect every country in the world. Many people all over the world are trying to do whatever they can to help combat the effects of global warming. One of the ways that people can fight global warming is to reduce their dependence on non-renewable energy sources like oil and petroleum based products.