The best replacement for insulation is radiant barrier.

The best alternatives to insulation are rated as following:
★★★★★  radiant barrier
★★★★  rolled insulation
★★★★  fiberglass
★★★  new windows
★★  isolation
★★  fiberglass insulation
★★  cellulose
★★  insulation
★★  thermal mass
★  wiring first
★  spray foam
★  batting
★  batts
★  foam
★  no insulation
★  roll
★  attic fan
★  insurance
★  rolled
★  cellulose for attic
★  rolls
★  batt insulation
★  blown insulation
★  regular insulation
  batt
  r19
  cellulose insulation
  styrofoam
  foam insulation
  roll insulation
  unfaced
  solar hot water
  r30
  pink insulation
  unfaced insulation
  closed cell
  blown in insulation
  fibreglass
  ceiling insulation

Your alternative for insulation is not listed? Suggest!
Speaking about insulation, one probably shouldn't forget about vapor barrier.

Other search terms related to insulation and their ratings are:
★★★★★ vapor barrier
★ drywall
★ radiant heat barrier
★ cavity wall
heating
radiant barrier
built in vapor barrier
soffit vents
attic
polystyrene
sheathing
knob and tube wiring
plasterboard
You have in mind a companion for insulation and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of insulation in all years. Click on graph for more.
insulation
radiant barrier
rolled insulation