A ferrite filter on a refrigerator isn't likely to do much good...the line current is enormous and it would take a similarly enormous ferrite. But I really doubt that's the problem.
If your noise is really all "locally" generated (man made), ways to isolate the source include:
-Run your receiver by powering it from a battery (a car battery, lantern battery, whatever works) and turn OFF the power to everything in your home by pulling the mains fuses or circuit breakers. I mean, shut off EVERYTHING including clocks, timers, doorbells, everything. See if that impacts the noise. If it does *not* impact the noise at all, then the noise source isn't in your house, it's somewhere else.
-Take a portable radio receiver (battery powered, obviously! - a cheap little one will do) tuned to the "AM" broadcast band, down below the bottom or up above the top of the band where there aren't any signals. Turn up the volume to hear background static and walk around the house and the neighborhood while listening closely to see if the "noise" peaks anywhere. If it does, try to figure out where -- the proximity of the radio will tell the story. This can help find arching insulators, bad transformers, all sorts of wideband noise sources. Do NOT use an "FM" receiver, that won't work.
If all else fails, you can try stuff with your own receiver to reduce the noise. For one thing, some receivers have much better noise blankers than others. I've had HF rigs where the noise blankers are very ineffective and did practically nothing, and other rigs where the blankers were so effective they eliminated 99% of all local noise to the point where I could hear very weak signals easily. This is a huge "variable." One of the best noise blankers I've ever used is in the old Drake TR-7 transceiver: It was an "option," called model NB-7 (for "noise blanker-7") and it's very, very effective. But these only really work for man-made noise, they don't do much about real atmospheric noise (which comes from the sun, lightning, etc).
Also, external DSP noise reducing systems can be effective. The external ones work in "audio" only, not at radio frequencies, but they can make life a lot easier.
Also, noise blanking which works as an accessory in the receiving antenna line using a "sense" antenna to find a noise source and then literally pulsing off the receiver in phase with the noise pulses (MFJ sells a popular unit like this) can be helpful. You kind of "miss" a little bit of what's on the band when using one of these, because your receiver will be literally disconnected from your antenna at some pulse rate, but it's surprising: You get enough "signal" to make weak signals very workable when without the appliance, they can't be heard.
WB2WIK/6