Residential central air conditioning is rated by a Seasonal Energy Efficiency Ratio or SEER system. Since 2006, units sold in the US must have a SEER of at least 13. Air conditioning systems marked with an Energy Star meet strict US government energy-efficiency guidelines. Additional costs:
Earthworm. An earthworm is one of the animals that are classified in the Annelida phylum. Like many other animals, the earthworm has a closed circulatory system. A closed circulatory system means that the blood is confined to blood vessels and its blood recirculates so it gets maximum use. The worm uses its bodies suface area to absorb oxygen from the soil instead for using lungs or gills.
Butterfly Valve BVHS. The butterfly valve BVHS with safety closing function is used with the actuator IC 40 in systems where it is important that in the event of a main voltage failure, the valve closes preventing air streaming into the furnace without being under control.