[kburkhal66]

We have a Lennox 80UHG furnace which is original to the home (1997). It is only 80% efficient and the thermostat is consistently 3 degrees below actual (partly due to location).

This is not our forever home so hate to drop a ton of money into a replacement furnace/AC. Is it possible to upgrade components for better efficiency? I talked to an HVAC guy a year ago who stated my controller was to old to upgrade the thermostat to a NEST of similar type unit.

The overall airflow in the house stinks. The upstairs master is always warm while the other bedrooms are always cold (opposite in the summer). The master is directly above the furnace (2 stories above) which means logically it is likely to better flow. However, there is a huge discrepancy to the other bedrooms. Do I need to consider a secondary blower unit?

I wanted to ask here before getting a sales job from any number of HVAC companies.

 

[roughneck]

Residential equipment isn’t intended to be rebuilt or upgraded.
The temperature issue you describe is a duct issue, not an equipment problem.
New thermostat or not you still would have a 23 year old furnace that is likely towards the end of its life.
The Nest is a terrible thermostat.

 

[user_12345a]

Going from 80% to 95%+ doesn't save all that much.

High gas usage is caused by high heat loss most of the time.

You can use any thermostat but I would not go for a nest.

The only real upgrade that can be done is replacing the blower motor with a more efficient type and it's not worth it - costs hundreds of dollars.

 

[kburkhal66]

Thanks for the feedback. I guessed the furnace could not be upgraded w/o replacement or else more people would be doing it. It was still worth asking.

At this point, it sounds like I just stay the course on the current unit until it dies and then replace. If it doesn't die, then I may take a slight hit on resale but not likely worth the cost of a new HVAC system.

On a side note, the duct work looks like it was installed conveniently (contractor) rather than efficiently (HVAC specialist). Not much I can do about that now.

 

[user_12345a]

At that age, the heat exchanger should be inspected every year.

On the 80%'er they can pull the blower and have full access.

 

[kburkhal66]

I have had it inspected on a regular basis and I recall talking about the blower unit. I did have a capacitor go bad and they wanted to charge me $250 (it was a weekend). I went down the street to the Repair Clinic and got one for $7.

 

[Old Thomas]

If I bought your house I would consider the furnace to be at the end of its useful life and I would offer a commensurate price. If you plan to be there for a few more years, consider a new basic low cost furnace. The cost is not huge, utility bills and reliability are more favorable, and you can use it as a feature when you sell.