Lennox G43UF Air Filter

It is suggested the your furnace filter is exchanged for a new one every 90 days or so for optimal air quality through the ducts. The size of the HVAC air filter optional choice because it is based on the declared size of your air handler. Air Filters are made in lots of types and sizes, depending on your choice for how clean you want the air and air handler size requirements.

What are the indications that my primary air filter is not well?

Check eBay to see if your air filter is in stock!
If you are going to be buying or purchasing a replacement air filter for your Lennox G43UF, do your due diligence and make sure of the model number as well as make a visual comparison so that you are positive that the correct replacement air filter is being ordered. There is no need to install the replacement part alone. Hire a pro locally to pay to install it for you.
Feel free to download your manual for help.
Check eBay for your air filter!