Not enough storage

I have zero storage in my home.

I can tell the house was built by a man. There are tons of sheds and a whole room in my house that was definitely a man cave. The kitchen is small and I have no storage though. I have a pantry in the kitchen that is jammed packed. The bathroom linen closet has much more than towels in it. What stinks is that I have a large hallway closet that would be ideal for storage. The problem is that I have a water heater and indoor HVAC unit in there. Those two units take up the entire space. The HVAC sits on a little wood platform up in the air. I was initially excited about shoving stuff under the platform. My husband informed me that I don’t want to block airflow, so that area is a no go. I have tried to be creative with how I store. My vacuum mounts on the side of the wall. I put my dust pan on top of the water heater. My bucket and mop can fit in between the HVAC and water heater. I really want to add cleaning products in there. I could easily slip a shelf overhead, but it wouldn’t be all that easy to reach. I also don’t want to block both machines too badly. What if I need a HVAC repair or a water heater service appointment? I don’t want to empty the closet every time that happens. I want the worker to be able to access the machine easily.