The interval depends upon your living conditions. If you have pets or burn candles you should change more often. Run cheap filters and change frequently. Lower utility bills and your system will last longer!
I had to get Freon recently and it made think, why is there not a “check engine light” or app or something that would have alerted me before it got bad. Your test will be helpful.
Thank you for your information. This is less scary than other videos have made this sound. What is the date to find a new system to use the new refrigerant? Better yet, how do I find a reliable contractor like you in my area, northern virginia near dulles airport? someone that won't give me bs, but honest truth?
