Frequently Asked Heating & Air Questions
All manufactures recommend you change filters monthly. However, if you have a thick filter you may not need to change it as often.
NO. they create to much restriction to the air flow and may damage your system, If you want better filtration purchase the pleated filters.
There is no clear cut answer here. It depends on how old your unit is and how efficient it is. Units produced from about 1985 on are probably going to work just fine to below zero weather conditions. Trane does not recommend turning their units off anytime. By my calculations, they still produce more heat than they consume in electricity to well below zero.