Hey! it's a game of hydrogen bonding. Ether is characterized by an oxygen atom bonded to two ally or aryl group. These lack the hydroxyl group of alcohol. withought the strongly polarized O-H bond ,these can't engage in hydrogen bonding with each other,hence they have much lower boiling point than do alcohol with similar molar weight. Hydrogen bonding is a type of intetmolecular forces, meaning it describes how certain molecules are attached to each other. The hydroxyl group (O-H) of an alcohol is special in that it acts like a mini magnet. The oxygen atom has a slightly negative charge, while hydrogen atom has a slightly positive charge -like poles of a magnet. This means that partially negative oxygen atom of an alcohol can temporarily bind to partially positive hydrogen atom of another alcohol. Thus, the presence of hydroxyl group makes alcohol stickier than ether that are of same length. That's why it takes more heat to boil alcohol than ether. thank you.

Because in ethers, intermolecular hydrogen bonds are not present.