Home HVAC Advice Needed

Joined
Aug 30, 2004
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28,639
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CA
I have a 2-story, 2300-sq ft tract home in Northern CA. Temps reach 100F in the summer and 35-40F in the winter, humidity is not an issue. The single-zone HVAC system is original (1997) and is in need of replacement due to refrigerant leakage. The house also has the original R-19(??) insulation. After soliciting bids from three different contractors, I am soliciting feedback on the equipment and ductwork improvements that were proposed.

1) The south-facing upstairs rooms get very warm during the summer months. All three contractors stated the ductwork to the upstairs is undersized and the return is located in a poor location (stairwell area). Supposedly, correcting both issues is not financially feasible. Two contractors said to leave it alone unless I want to add a separate HVAC system for the second floor. Another contractor suggested adding an "air scoop" to divert more flow to the upstairs rooms, which would presumably improve cooling during the summer months. This would be accompanied by a motorized "dampener door" to reduce flow during the winter months. Does this sound like a viable solution?

2) All three contractors recommended a single-stage A/C unit and an 80% efficiency furnace for reliability. Two contractors also suggested a single-stage furnace for reliability. However, one contractor suggested pairing the single-stage A/C unit with a two-stage furnace for improved comfort during the winter months. Supposedly the two-stage furnace can run at a reduced output level (when appropriate), which would help maintain a more constant temperature. Does this make sense? Also, from a reliability standpoint, are two-stage furnaces still significantly more reliable than a variable furnace?

Thank you.
 
Joined
Jan 22, 2011
Messages
7,880
If you been happy with the past performance of your present system as far as even temperature distribution through out the house, I don't see any reason for drastic changes. I agree with the suggestions offered in the first sentence of # 2, unless you like the idea of large circuit boards in your furnace. The problem with high efficiency is complexity and high initial and repair costs. Often when the warranty runs up, much of the energy savings of high efficiency components get offset by high repair costs. You would be amazed how good efficient windows would help with those warmer southern facing bedrooms. It is better to prevent the heat buildup than trying to attack it. I like simpicity.
 
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Joined
Jul 16, 2020
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487
I've had a two stage Carrier Infinity system for 17 and can 100% say two stage is worth it. I'm in PA so the two stage AC is great for humidity. I think the recommendation for single stage AC and a two stage furnace would be a good option.
 

FZ1

Joined
Feb 7, 2008
Messages
5,915
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Texas
I have a 2-story, 2300-sq ft tract home in Northern CA. Temps reach 100F in the summer and 35-40F in the winter, humidity is not an issue. The single-zone HVAC system is original (1997) and is in need of replacement due to refrigerant leakage. The house also has the original R-19(??) insulation. After soliciting bids from three different contractors, I am soliciting feedback on the equipment and ductwork improvements that were proposed.

1) The south-facing upstairs rooms get very warm during the summer months. All three contractors stated the ductwork to the upstairs is undersized and the return is located in a poor location (stairwell area). Supposedly, correcting both issues is not financially feasible. Two contractors said to leave it alone unless I want to add a separate HVAC system for the second floor. Another contractor suggested adding an "air scoop" to divert more flow to the upstairs rooms, which would presumably improve cooling during the summer months. This would be accompanied by a motorized "dampener door" to reduce flow during the winter months. Does this sound like a viable solution?

2) All three contractors recommended a single-stage A/C unit and an 80% efficiency furnace for reliability. Two contractors also suggested a single-stage furnace for reliability. However, one contractor suggested pairing the single-stage A/C unit with a two-stage furnace for improved comfort during the winter months. Supposedly the two-stage furnace can run at a reduced output level (when appropriate), which would help maintain a more constant temperature. Does this make sense? Also, from a reliability standpoint, are two-stage furnaces still significantly more reliable than a variable furnace?

Thank you.
Don't let 'em sell you stuff you don't need. The system has worked ok since 1997, right? Furnaces last forever down here in the warm Southwest. Find out where the freon is leaking and repair or replace that part only. You need additional insulation in the attic. Insulation is your best investment: Insulation works in all seasons. You also need to see that the roof is properly vented both on fresh air entry under the soffits and on exit from the top of the roof. Hope this helps.
 
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Joined
May 7, 2004
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Nokesville, VA
. Another contractor suggested adding an "air scoop" to divert more flow to the upstairs rooms, which would presumably improve cooling during the summer months. This would be accompanied by a motorized "dampener door" to reduce flow during the winter months. Does this sound like a viable solution?

Most houses with two stories have dampers to control airflow to the 1st and 2nd floors. They aren't usually motorized and have to be adjusted manually. I'd be surprised if a house built in 1997 didn't have these dampers, although the one in my dad's house for the 1st floor was drywalled over when the original builder finished the basement (knuckle draggers at work, there).

If your house has these, make sure the damper for the 2nd floor is fully open and start closing the damper for the 1st floor. In some houses there may be two dampers for the 1st floor, one for the left side of the house and one for the right.

You'd hope that one of the contractors that looked at your system would have pointed these out if they exist, but it's not a profession known for honesty....
 
Joined
Mar 8, 2012
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1,925
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MO
If not a second system for upstairs then dampers as skyactiv mentioned would be my choice. Don’t get too fancy with the furnace in your location. A single system without dampers will never make the upstairs comfortable without freezing you out on the ground floor.
 
Joined
Sep 24, 2005
Messages
958
Location
Indiana
I've had a two stage Carrier Infinity system for 17 and can 100% say two stage is worth it. I'm in PA so the two stage AC is great for humidity. I think the recommendation for single stage AC and a two stage furnace would be a good option.
I believe this guy is correct.

I'm looking into a system replacement currently. For my money the 2-stage is a must for the reason that the majority of the time it will run at low and be significantly quieter. Current single stage furnace replaced a 2-stage and I regretted it immediately.

Whether to replace or not is a hairy proposition indeed. One factor not addressed in the video is that nobody wants to lose heat during a cold stretch and not have the luxury of waiting around on multiple quotes. Heck, my 15 year-old furnace, 33 year-old condensing unit & 60 year-old evaporator coil are working satisfactorily so I can wait on estimates - one was given on visit and I'm still waiting on the second one after a couple of weeks. I'm a fix it if you can guy but with energy prices skyrocketing, prices for new systems rising it plays a factor too.
 
Joined
Apr 11, 2003
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Cincinnati
Don't let 'em sell you stuff you don't need. The system has worked ok since 1997, right? Furnaces last forever down here in the warm Southwest. Find out where the freon is leaking and repair or replace that part only. You need additional insulation in the attic. Insulation is your best investment: Insulation works in all seasons. You also need to see that the roof is properly vented both on fresh air entry under the soffits and on exit from the top of the roof. Hope this helps.

Pay attention to the above, please.

You can install “the world’s best HVAC system” but it won’t perform like it unless you address the insulation and ventilation variables in the heating/cooling equation.
 
Joined
Jul 17, 2020
Messages
68
Location
AZ
Recommend a 2-stage heat pump system with Ecobee thermostat.

Installed a Trane last fall and could not be happier. The system is very quiet and no big temperature fluctuations.

With the Ecobee, use one with remote sensors. We run sensors in bedrooms and family room.

These sensors detect when a room is in use, and the thermostat adjusts accordingly.
 
Joined
May 5, 2013
Messages
783
Location
Peace valley, Missouri
Two story houses need 2 cooling systems a separate one for the second floor. Installed a two ton air handler in attic ceiling grills and return filter grill in hall ceiling. Lines and wiring run in flue chase. Contractor is more important the the brand of equipment. Call your utility company see if they offer a energy audit that includes a blower door test ( tells how tight the house is).
 
Joined
Oct 20, 2018
Messages
371
Location
D-FW, Texas
I just had a 5 ton Amana single stage A/c and 80% furnace installed. The consistent feedback I get from those in the industry is more complex = higher cost = lower long term reliability/ higher maintenance $$. That and don’t expect to get more than 15 yrs out of today’s units regardless of brand. My old unit was 20 yrs old Carrier / R22 that needed a recharge every yr. Last year I was quoted $200/lb for R22 or $100 for the R458A replacement.

I would look at the run time per year and cost of nat gas to see if going to more efficient makes sense.
 
Joined
May 30, 2010
Messages
15,659
Location
North Carolina
I have a 2-story, 2300-sq ft tract home in Northern CA. Temps reach 100F in the summer and 35-40F in the winter, humidity is not an issue. The single-zone HVAC system is original (1997) and is in need of replacement due to refrigerant leakage. The house also has the original R-19(??) insulation. After soliciting bids from three different contractors, I am soliciting feedback on the equipment and ductwork improvements that were proposed.

1) The south-facing upstairs rooms get very warm during the summer months. All three contractors stated the ductwork to the upstairs is undersized and the return is located in a poor location (stairwell area). Supposedly, correcting both issues is not financially feasible. Two contractors said to leave it alone unless I want to add a separate HVAC system for the second floor. Another contractor suggested adding an "air scoop" to divert more flow to the upstairs rooms, which would presumably improve cooling during the summer months. This would be accompanied by a motorized "dampener door" to reduce flow during the winter months. Does this sound like a viable solution?

2) All three contractors recommended a single-stage A/C unit and an 80% efficiency furnace for reliability. Two contractors also suggested a single-stage furnace for reliability. However, one contractor suggested pairing the single-stage A/C unit with a two-stage furnace for improved comfort during the winter months. Supposedly the two-stage furnace can run at a reduced output level (when appropriate), which would help maintain a more constant temperature. Does this make sense? Also, from a reliability standpoint, are two-stage furnaces still significantly more reliable than a variable furnace?

Thank you.
Almost same setup here, 2300sf 2 story 4 ton single zone system( more humidity here). I had it replaced with a 4 ton system and zoned dampers, rerouted ductwork, so that air can be sent up stairs, downstairs or both. Thermostats ( wireless) upstairs and downstairs. I am very pleased. There is more airflow ( more airflow sound) when only one floor is running, i.e. all 4 tons of air only going down stairs or upstairs.

I think my setup is what @skyactiv posted above.
 

JTK

Joined
Aug 14, 2003
Messages
14,908
Location
Buffalo, NY
I dunno brother.

First it was your illuminated house #, the smashed gutter corner, now the HVAC.

It's time for a new Casa De Critic.
 

The Critic

Thread starter
Joined
Aug 30, 2004
Messages
28,639
Location
CA
I dunno brother.

First it was your illuminated house #, the smashed gutter corner, now the HVAC.

It's time for a new Casa De Critic.
You might be correct. Homeowners insurance went up 50% last year due to the wildfire exposure (its only a matter of time before it burns down), all of the windows are due for replacement, needs new flooring, one bathroom remodel and now this.
 
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