Why do ethers generally have lower boiling points than alcohols with similar molecular weights?

Ethers generally have lower boiling points than alcohols of similar molecular weights because they lack the ability to form intermolecular hydrogen bonds with one another.2

In alcohols, the presence of a strongly polarized O—H bond allows molecules to attract each other through hydrogen bonding, which significantly increases the energy required to transition from a liquid to a gas. In contrast, ether molecules do not contain a hydroxyl group and therefore lack this polarized O—H bond. While ethers possess nonbonding electron pairs on their oxygen atoms that allow them to form hydrogen bonds with other substances (such as alcohols or water), they cannot engage in this type of bonding with other ether molecules.12

Consequently, the boiling points of ethers are much closer to those of alkanes with similar molecular weights, as both classes of compounds lack the strong intermolecular association provided by hydrogen bonding.2