I stayed in the Larrabetzu albergue last year. Here is what I wrote:
Last night in the newly opened albergue in Larrabetzu. Run by the Bilbao Association, one of 5 they take care of. About 18 beds. The albergue is on the 2nd floor (3rd US) under the rafters. I imagine it will be very hot in summer. There are windows at ground level but not much breeze. Small kitchen area with dishes, microwave, and refrigerator, but only water source is in the bathroom. No place to wash clothes other than the bathroom. this is not at all meant as a complaint but just so you will have the info. It is a very lively town, still very much an ETA stronghold, I was told, though I'm not exactly sure what that means in the post-truce world.
I had a pleasant night there but do think it would be almost unbearably hot in high temperatures because there is no way to get a breeze.