Well, a cranked up 15 watt tube amp can rattle the windows too.
As I see it, your options are:
1. A really low wattage EL84 Class A tube amp - 3 watts or so. Still loud, and they don't have the punch or headroom of a bigger amp, but you can crank them.
2. An attenuator (Weber MASS, Ultimate Attenuator, Hotplate)... lots of "big amp guys" use them. Some of them (Hotplate) mess with your tone if you turn them down too far, but it's better IMO than not being able to get your power tube distortion. And at some point the speakers don't get enough power to keep them happy, but that issue applies to any lower-volume solution.
3. An amp with a master volume, but then, again, you're not getting the most out of the power tubes.
4. An isolation speaker cab - might not be practical for your situation, but it will let you play the amp LOUD.
5. A dummy load/power amplifier "re-amp" setup.
I use scenario #5 with my Hiwatt 100 and it sounds great. Very little difference between the re-amp and going straight in to the cab. But you do have extra gear to lug around.
For your situation, I would recommend trying the Weber MASS. I've heard very good things about them - they don't trash your tone as much. The Ultimate Attenuator might be better, but it's really a dummy load/re-amplifier in a box (and much more expensive).
My $0.03
Mike