- LED Corn Cob Bayonet Bulbs - if you don't already have them, get them to replace your incandescent bulbs. If you boondock, you can have all the light you want without draining the battery.
- Tabata Mats - Much nicer on the feet and easy enough to hose off or replace
- Bathroom Fan - Original was obnoxiously loud. Replaced with a Noctua computer fan. Even if it fails, it's 15 USD and moves lots more air.
- Bathroom Vanity LED Bulbs - definite upgrade over the old, dim incandescent bulbs
- Reflectix Insulation inside the closets and cupboards - pain the butt but totally worth doing
- Hard styrofoam insulation under the sofa and kitchen cabinets. Lifting the ducts off the cold metal floor makes a world of difference.
- Upgrading the cheesy mattress that comes with the RV (ok this one might not count but OMG what a difference) with a bed in a box - better mattress means more between me and the fresh water tank. No one who's ever slept on an unheated water bed would put that tank under the bed without heating it.
- and the mattress warmer. When we have shore power, its really nice to climb into an already warm bed.
I thought I'd start a thread about inexpensive upgrades that others might have done and share the ones we've done that we especially like.