My refrigerator started running constantly last summer, and the electric bill jumped with it. The culprit was a sagging door gasket that let cold air pour out all day. Replacing the seal myself cost thirty dollars and an afternoon, versus a service call that would have run ten times that.

How to test the seal

Close the fridge door on a dollar bill, then tug it out. If it slides out easily, that section of gasket is not sealing. Do this around the whole door. The dollar bill test tells you exactly where the leak is. A worn gasket also looks flat, cracked, or has a gap you can see when the door is closed.

Order the right gasket

Write down the fridge brand and model number, usually on a sticker inside the door or on the side wall. Search for the model plus the word gasket or door seal. Match the model exactly, since gaskets are shaped for specific doors. Most come with a small strip of screws or a magnetic core that holds them in place.

Removal and install

Unplug the fridge first. On most models the gasket is held by screws behind the door panel or snaps into a groove. Work it loose gently, starting at a corner. Clean the groove with warm soapy water and dry it. Then seat the new gasket, starting at a top corner and working around. Make sure the magnetic strip faces the fridge, not the room. Tighten the screws hand tight, not cranked, then plug it back in.

What to do if it still leaks

If the door does not close snugly after a new gasket, the door hinges may have shifted. Tightening the hinge screws or adjusting the hinge height often closes the last gap. Check the gasket again with the dollar bill test around the full perimeter.

My fridge runs quieter and the bill dropped back to normal within a month. A leaking gasket makes the compressor work overtime, so replacing a worn seal pays for itself fast and keeps your food colder with less wasted energy.