My aunt passed away in 2013. We inherited half her store/home. In 2007, she had the place remodeled, and bought a near top of the line 96% efficiency furnace & central AC, with triple filtration, germicidal lamp, etc. The building is 1420 square feet. It is a 100+ year old brick miner’s home that was expanded & made into a grocery store in 1922. In the 1930’s it was added onto again, with indoor plumbing and a bakery/kitchen. In the 1940’s it was added onto yet again, and once more in the 1950’s, when it became a music store. So this is a poorly insulated, cobbled together mess, but it is comfortable as can be. Our highest bill was $280 for everything – water, gas & electric. This was in a very cold February when we had squatters in the building trying to run the bills up, just for spite. The unit is quiet and efficient. Even with the big single pane store front windows, the area between the supply vents is warm & comfortable. There is a little bit of cold spotting by the display windows, but this Lennox system makes the old building really livable. The AC is nice too. It does not “hard start” and it cools the place off great. We are in Colorado Springs, so the climate is rather moderate for winter and mild to moderate for summer. Maybe a few days of below 0, and sometimes it will stay below freezing for 30 days or more, but no -30, & rarely ever +100. I really wish I could take this system with me when I sell the place. I am a skilled tradesman, so I know the installation is not perfect, and the building is poorly insulated & poorly sealed, but this furnace is still wonderful. Filters are pricey, at $30 each, but they last a while too. I have not priced the second filter, yet. Don’t care, it’s worth whatever it costs. My home is in Phoenix, Arizona. We have an American Standard brand (not name) gas pack AC/Furnace rooftop unit there. It’s okay too, but I wish really we had the Lennox AC & Furnace. In August, our bill was $108 for everything. I set it at 75 degrees. We set it at 73-75 in winter, as we are used to the Arizona heat. Even with some sob tenant and a bastard executor of the estate trying to kite the bills and skim the utilities off the estate, the bills were not too bad. The executor put the utilities into the name of the estate, cranked the furnace up to 80 degrees and put the baseboard heater on in the garage set for 90 degrees, and it only ran up a $280 bill. The tenants were roasting coffee in summer and the roaster & the AC unit would not run at the same time, so this system has been abused by a couple of a–holes who knew they did not need to repair or replace it.