Home HVAC Replacement

 Last week when the temperature went above 80 degrees, I decided to turn on the AC for the first time in 2026. I noticed that the furnace fan was running continuously, The AC unit was struggling to keep the temp at 80, which is what I had it set to. It also didn't feel like much cold air was coming out of the floor vents. I first thought that the compressor wasn't coming on. This happened once back in 2019. I replaced the anti-short cycle compressor protection relay and got it working again. The part only cost $7 back then. Now, Amazon has it listed for $25! 

I didn't think that was the problem this time. After running for 8 hours, I noticed that there was frost on the refrigerant return line. This is caused by either restricted airflow over the indoor coils or low refrigerant. It is difficult to see the coils that are sitting above my furnace. I took a peek behind one of the side panels but couldn't see much of the coils. I have to assume that low refrigerant is the main issue.

The furnace/AC system was put in when the home was built. That would make the system 33 years old because the home was built in 1993. Back then, the refrigerant used was R22. The EPA banned all production and importation of new R-22 on January 1, 2020. An existing R-22 air conditioner is not illegal but servicing them is significantly more expensive due to supply limits. So, I would be wasting hundreds of dollars to rule out low refrigerant. Plus, if the refrigerant is low, there is most likely a slow leak somewhere. That combined with the age of the equipment, makes it overdue for replacement.

The current furnace is a Rheem Criterion Model# RGDG-075AUER (75,000 BTU) with 80% AFUE efficiency. The AC is a Nordyne Intertherm 10 SEER Model# S1BA/S1QA-024K (36,000 BTU?) 2 Ton with R-22 refrigerant. There are many replacement options. The ones with more features and higher efficiency cost the most. In order to get a rebate from the utility company, the system must have an Energy Star rating and have at least 90% or greater efficiency and have a SEER2 rating of 14 or higher. A 95% AFUE Energy Star gas furnace, and 13-16 SEER2 central air conditioning unit, plus installation, can range from $7,000 to $15,000+ depending on home size and ductwork.

I'm hoping that most of the existing ductwork can be used. Upgrading from a standard 80% AFUE furnace to a 95% high-efficiency model usually requires running new PVC venting and drain lines, which can add $800 to $2,500 in labor costs. Rebates can cover between $350 and $650 depending on model#. My budget is $8000, but I'm usually off by 50%. I only need a basic system that meets the rebate requirements. Lower price options like the Lennox Merit Series or Carrier Comfort Series would be an improvement over what I have now. The Rheem Classic Plus Series is affordable, but I was only able to find Rheem at HomeDepot. I would rather work with a local HVAC company. Oh, the joys of home ownership!