We just rented a house (8 yrs old, 2200 sf, 2 story, 2 zone) in the Dallas metro area and went over this afternoon to do some cleaning and check everything over. I had seen that the air returns were very dirty and there was a large buildup of dust on the edges of the ceiling fans. I expected the filters to be super dirty and wanted to get them changed ASAP. To my surprise there was no filter in either location and I'd bet my bottom dollar that there has never been a filter installed (too much caulk, etc. around the edges where the filter should fit in). I'm used to seeing a metal frame where the filter goes and that isn't even present.

I'm sure the owners will call someone in (they've been very good on having other needed repairs done) but I'd like to be able to explain to them simply and clearly what effect this has had on their system and on the electricity bills up to now and the importance of bringing in a professional and not a handy-man which they've done for the other work.

English is their 2nd language and it's definitely can take some time to make sure everything is clear. I'm not very knowledgable in the area but I'm sure all the dust and dirt getting sucked in is affecting the life-span and effeciency of the system. Any information would be appreciated. Thanks!