If there is no need to turn the locos then a wye or a simple turnout will do. There have been plenty of prototype houses that the stalls come from turnouts and locos were turned on a wye track or balloon.
Personally, I like the wye turnout, if you can arrange it.
This is an old Model Power kit that I detailed inside. The wye turnout is a short Peco.
Most of the turnouts on your layout will be common lefts or rights. If you have a chance to use a more interesting design somewhere, go ahead. It will add visual interest. On the other hand, if you have a particularly fussy engine that wants to use this engine house, you may want to give it a straight-through path. A wye turnout, and particularly a tight one like this, gives you a short S-curve as you snake into the engine house. It’s fine for short engines, but longer steamers in particular will have issues, even if the trackwork itself is perfect.
I am using Atlas snap switch turnout, which I think is between the #4 and #6 in turnout size with a Pikestuff 2 bay engine house and it works great… and seeing the photo above the WYE, it looks great as well. The straight piece of the turn out goes into my left bay of the engine house where I park one GP38 in the house and my other is out front of it to set up a MU if I want… The turned out track into the right bay is where I park my Dash 9. Having the straight line into one bay does make hooking up easier.
This is how I got one track to go to two into the engine house. The engine house in question is a Walther’s backwoods engine house / car barn. I removed the center support from the doors to make the two doors into one then split the single track with a simple #5 Bachmann right hand turnout.
This is the best picture I can find of my engine facility:
I used 2 rh switches since I have a third service track next to the building. Mine is all set on a curve which would make a wye unusable. But it really is dependent on your track configuration as it approaches the engine house.