Revolutionary Vented Slab Passive Solar Homes
With heating bills soaring, and likely to go out of site, the revolutionary vented slab passive solar design (RVSPSD) is a must for any low mass home with a good southern exposure. The patent on the RVSPSD ran out several years ago, so now it is available to everyone! The RVSPSD is probably the most cost efficient solar design for low-mass homes such as stick-built conventional homes and straw-bale homes.
The idea in any passive solar design is to make your house itself a collector. By incorporating the vented slab passive solar design into a conventional or straw-bale home, the problem of insufficient mass is solved for a fraction of the cost of any active solar system. The RVSPSD is only likely to add two to three percent to the cost of any home. An active solar space heating system is likely to cost $12,000 - $25,000 or more. Also, the RVSPSD can be incorporated into modular homes, especially if the home has a basement.
The RVSPSD consists of cement blocks placed so that their holes line up, and then these blocks are covered with a concrete slab. Vents in the south and north sides of the house floors are integrated with the holes in the concrete blocks. Air heated by south-facing windows is circulated throughout the house and through the cement blocks under the slab by the air blower in a forced-air furnace, and through heat ducts, including some ducting under the slab. Additional benefits include slab floors that are warm and that can even be covered with wood flooring, or wall-to-wall carpeting, with little effect on the efficiency of the RVSPSD system.
In order to prevent moisture from entering the cement block heat storage system, careful attention must be paid to the foundation design. The hundreds of houses built using the RVSPSD to date have had no moisture problem, and some of them were built in the 70s. Another advantage to the RVSPSD is that by incorporating a high-quality fine-micron filter into the forced air furnace, the air inside can be made far cleaner than the air outdoors. The air must be filtered in order to prevent dust from accumulating in the blocks.
The book on the RVSPSD entitled The Passive Solar House: Using Solar Design to Heat & Cool Your Home by James Kachadorian states that the design should not be used in houses with basements. However, Kachadorian arrived at this conclusion based on his understanding that solar storage in a solar space heating system must be located in the heated space. He was not aware that active solar space heating systems frequently successfully heat a large water storage tank that is not located in the heated space. The storage tank is frequently located in the basement.
If a basement is heated living space then the cement blocks and slab heat storage system can be located in the basement floor as long as there is sufficient air circulation, and sufficient south-facing glazing.
For more details on the RVSPSD read The Passive Solar House : Using Solar Design to Heat & Cool Your Home by James Kachadorian.