Similar to other poncho-like garments in Latin America, a ruana is basically a very thick, soft and sleeveless square or rectangular blanket with an opening in the center for the head to go through with a slit down the front to the hem. A ruana may or may not come with a hood to cover the head.
The International Association of Fire Chiefs recommend a carbon monoxide detector on every floor of your home, including the basement. A detector should be located within 10 feet of each bedroom door and there should be one near or over any attached garage. Each detector should be replaced every five to six years.
This means that the most important place is near your bedrooms. I recommend that you have a carbon monoxide detector within 15 feet of each bedroom door, 10 feet is even better if you can afford more detectors. If two bedroom doors are 30 feet apart or less, then place one in the middle. If however they are more than 30 feet apart you will need more than one detector.