Complete systems including furnace, AC, Evap coil or just air handlers and AC/HP condenser?

post Mdl numbers.

IMO

Complete HVAC system: natural gas for heat, electric for AC (Installed in 2001). 1st floor outside AC 3.5 ton Lennox HS26-042-2P, basement 4 ton Lennox air handler CB31 MV-51-1P. 2nd floor outside AC 3 ton Lennox HS26-036-2P, attic 3 ton air handler CB31 MV-41-1P. Heat is Navien boiler NHB-150 (NG), (replaced in 2019) since hydronic radiant floor system in basement under the kitchen floor. Heat generation is adequate, as well as cooling on 1st floor, but 2nd floor AC is problem. Runs constantly and on hot days, doesn’t get to 71 degrees until midnight. Can’t deal with cooling & only getting to 77-78 degrees during the day, so evaluating options.

What size is upstairs living area? How are your building qualities, ie windows, attic insulation?...have you had an HVAC service on upstairs system recently?...what is your Thermostat setting? Any idea of your Delta split number?...

TD

Recent home appraisal has upstairs at 1929 SF & downstairs at 1914 SF. Windows are good. Attic insulation could be improved. Was looking at spray foam, but $8000, so thinking better use of $ to replace the system. Can add blown air insulation for $3200, so that is still under consideration. Just replaced attic condenser fan motor in may. Get AC service maintenance annually. I have Nest thermostats on both floors. Usually set at 72. No idea what delta split number is. That’s a good question for my contractor when he provides proposal. Thanks for your input!

Delta Split number is the difference between supply temperature and return temperature...acceptable range is 15-20 degrees... I am just wondering what your upstairs supply temp is....a 3 Ton condenser should be adequate if working correctly....

TD

I will definitely ask contractor about delta split number. I don’t think I have a way to determine that myself. Good to know a 3 ton should be sufficient. I’m thinking perhaps we don’t have adequate returns. Was not happy with the contractor who did the conversion from 1 zone to 2 back in 2001. Perhaps there was skimping on the number of returns. Old 1 zone system had returns in each of 4 bedrooms & hallway for total of 5 returns. New 2 zone system has returns in primary bedroom, bedroom over garage area & hall for total of 3 returns. I trusted the contractor & didn’t know right questions to ask, so that is why I’m trying to educate myself before signing any contract for replacement equipment.

You don't have a thermometer (cooking) in the house?

Yes, sorry I am remedial. So do I put the thermometer at an air vent to get the supply temp & then is room temp the return temp?

No, go buy a cheap digital thermometer at a big box store. Take your readings from a supply register and a return register.

TD

Ok. Will do. Thank you

Depending on your budget, Coleman's can be more expensive but they perform excellently. Carrier is a safe, all-around good choice as well. Talking to contractors and getting quotes is the best way to narrow down a tight decision like this.

Twintech Heating & Cooling

https://twintechheating.ca/

Delta split for 2nd floor problem AC was 10.3. Supply register was 66.2 and return register was 76.5. For 1st floor where AC is acceptable, supply register was 59.8 and return was 73, delta split at 13.2. Both AC systems were serviced in May. 2nd floor condenser fan motor was replaced, but no other service issues.

Your upstairs Delta split is not good. . You can see that the supply temp is poor. The question is why and needs to be determined. The obvious reason that should be checked is the refrigerant charge.

TD

Yes, I immediately knew the upstairs Delta split was poor. Cooling has never been optimal, even when the unit was newer, which has made me regret putting the air handler in the attic. Will have refrigerant checked, but also need to assess number of returns & if venting is adequate. Thank you for your input.

Just a general comment, a well-installed inexpensive unit (regardless of brand) will perform better than a poorly installed expensive unit (regardless of brand). I would hazard a guess that 80% to 90% of installs are poor! And, unfortunately, google reviews and other online reviews by homeowners aren't very helpful (unless the system just failed to work immediately after installation). HVAC contractor selection is a crap shoot and the odds of finding a good one aren't high!

Brands are pretty much similar so I wouldn't lose any sleep over choosing one over another.