As mentioned before, the products of complete combustion of alcohols and hydrocarbons (strictly speaking alcohols are hydrocarbons also) are water, CO and other carbon molecules.

As I mentioned in another post, the soda can or cat food can stove can bring a quart of water to boil within 6 min. on 2 or 3 tbsp of denatured alcohol and only costs pennies to make. For just purifying water or soup or water for dehydrated meals they work great. for longer buring times go for something store-bought. If you're trapped inside and don't want to open a window you should have a fire place in your house.

Having a battery powered CO/ smoke detector is a must if you plan on doing this. You can't smell or taste CO but you will feel the headache and dizzyiness. Consult your CO detector packaging for appropriate placement in your house.