I just had an upflow XV80 installed, right side return. Looking through the installer manual and the user manual it show a filter should be installed between the blower and the return. There is no filter installed. I do have two air returns that currently have 1 inch throw away filters. Should this sytem have had the filter that came with the furnace installed, or is it okay to simply continue to use the monthly throw away filters? I would think it would be cheaper to have had the actual filter that came with the furnace installed, since it is reusable. Can anyone provide guidance? AC folks said the setup is fine.... again, based on the manuals I have.... I have my doubts. Also, the airflow at the return grates is pretty loud with thie filters installed. I did remove one for about 5 seconds and noticed the noise is drastically lessened - again, suggests the filter should ahve been installed.
Thanks for your time.