How to Paint a Rusty Air Conditioner

Rusting metal can be a problem for air conditioning units and other appliances, and it is important to remove the rust before it has a chance to spread.
Removing rust from an air conditioner requires special tools.
It is important to remove all the rust to keep it from growing, rather than simply painting over the area. There are an assortment of tools that can be used to remove the rust, and an appropriate type of paint and primer is necessary to keep it from coming back. .

Step 1

Remove the rust off the air conditioner. You can do this with a chisel or a screwdriver, an air compressor, a sandblaster, a wire brush or chemicals that convert rust into nonreactive compounds.

Step 2

Scrape the surface with a metal brush, wash with detergent, then rinse and dry it.

Step 3

Paint the air conditioner with a rust-inhibiting primer and two coats of exterior paint to prevent it from rusting again. Apply the primer with a brush rather than spraying it on as this will get the paint deeper and inhibit rust from recurring.

Things You Will Need

  • Chisel
  • Screwdriver
  • Air compressor
  • Sandblaster
  • Rust conversion chemicals
  • Metal Brush
  • Cleaning detergent
  • Rust-inhibiting primer
  • Outdoor paint


  • Wear eye protection.


  • Painting over the rust will not remove it.