Chacham Ovadia Yosef, in Halichot Olam (vol. 7, starting on p. 221), codifies the ruling of Rabbi Yehuda Ha'chasid (Germany, 1150-1217), in his famous Tzava'a (Last Will & Testament), that one should not move his oven or stove to use its space for some other purpose. Once a person has an oven or stove in a given location in his home, he should not move away the appliance and put some other appliance or piece of furniture in that space. Chacham Ovadia also mentions another ruling from Rabbi Yehuda Ha'chasid's Tzava'a, namely, that if one renovates his house he should not completely seal a window or door. If he wants to make a window or door part of the wall, he should leave at least a small hole so that it is not sealed entirely.
Two pages later, Chacham Ovadia brings the ruling of the Ben Ish Chai (Rabbi Yosef Chayim of Baghdad, 1833-1909), based on a Midrash, that one should never extinguish a candle or match by blowing it out. One should ensure to employ some other means to extinguish a flame, such as exposing it to the wind, rubbing it into the ground, or placing it in water. This law becomes particularly relevant at birthday parties, where it is customary to place candles in the cake and have the child blow out the candles. This practice is improper. It should also be mentioned that Rabbi Avraham Blumenkrantz, in one of his Pesach digests, documents that the entire concept of "birthday candles" has its origins in ancient pagan customs, and therefore it should be avoided altogether.
Summary: One should not reposition the oven or stove in his home to use the space for something else. A window or door should not be sealed completely; at least a small hole should be left unsealed. One should never extinguish a candle or match by blowing it out with his mouth; some other means of extinguishing should be used.
