I currently have a Lennox G12Q3(or O3)-82-4 natural gas furnace rated at 82,000 BTUH. It's about 20-years old. It works OK and my only complaint is the odd "hamper filter" it uses. The filter is a loose piece of filter material I wrap around a piece of what looks like garden fence. My daughter has allergies and It would be nice to be able to use a better filter. Can I retrofit this unit to take a new filter? Also, would it be cost effective for me to replace the whole thing with a more efficient new furnace since gas prices will be high this winter?
depending on return ducts you may be able to have filter rack installed or there may be room inside furnace. if heating bills are high jumping up to 94% furnace may be good idea. would not do it just for an 80% if still working.
It's called a hammock filter and more efficient media is available. When properly installed (DO NOT trim the edges!), it does a fairly decent job.
20 years is the life expectancy of a typical furnace, so replacing it isn't a bad idea. (even if efficiency wasn't a factor)
I also have a G12 installed about 1975 or so. The hammock style filter is a little bit of a pain, but works just fine
if you are planning on staying in your home, upgrading would be a good idea at this point.
you will not only have a more efficient system, but the accessories such as high efficiency filtration, humidification, de-humidification, two (or better yet, modulating) staged heat will make a world of difference in the comfort level of your home.
get some recommendations from friends, family or co-workers that have had a good experience with different contractors in your area. then get a few bids.