HVAC for House Question

[Kilgore Trout]

So, I am looking to replace my 24 year old furnace and HVAC. I have a two zone system. I had four reputable companies come out to give estimates and I have narrowed it down to two based on reputation, price, and equipment. Price is virtually identical (+/- $300). The system in the basement controls 70% of the house (basement, first floor, one upstairs room) while the one in the attic controls most of the upstairs. Hence, I am looking for a better system in the basement than in the attic.

Bid 1: Basement: American Standard Gold 80v 115k BTU furnace (two stage gas valve, variable speed blower) paired with an 4-ton American Standard Silver 16 SEER A/C (single stage compressor). Also includes 4 inch media filter cabinet. Attic: American Standard Gold 80v 70k BUT paired with an American Standard Silver 14 SEER A/C (single stage). No 4 inch cabinet (they claim they can't fit them). I have used this company for a bunch of years. They replaced the A/C in my old house and proactively fixed multiple things under warranty (cap, leaking blower motor). Comes with a basic programable thermostat. System comes with 10 year parts, 5 years labor warranty.

Bid 2: Basement: Carrier Infinity 110k BTU furnace (two stage gas valve, variable speed blower) paired with a Carrier Infinity 4-ton 19 SEER A/C (multi-stage compressor). Includes 4 inch media filter cabinet. Attic: Carrier Comfort series 70k BTU furnace (single stage all around) paired to a 2.5 ton Carrier Comfort series 14 SEER A/C. This includes a 4 inch media filter cabinet. Also comes with a fancier thermostat (carrier infinity series) for both systems. 2 year's labor, 10 year parts warranty, though I bet I could get them to match the 5 from the other company. Haven't used them before, but they have a good reputation and they sent an actual installer to do the quote, which I kind of liked.

So - any thoughts? Bid 2 seems like the better equipment, but I don't have any personal experience with them. I am also somewhat partial to American Standard, but I don't have any experience with Carrier.

 

[Bert_]

Sounds like you have two separate systems rather than one with two zones.

 

[Kilgore Trout]

You are indeed correct. Two separate systems. When I bought the house they described it as two "zones" but they are actual two systems. No dampers or anything fancy like that.

 

[naturalgas]

You are indeed correct. Two separate systems. When I bought the house they described it as two "zones" but they are actual two systems. No dampers or anything fancy like that.

I was a service tech for 36 years for the local utility co. and for furnaces we sold Bryant/Carrier. After 15 years or so we dropped Bryant and went to American Standard. Carrier had way too many retrofit kits in different models to repair shoddy engineering. American Standard/ Trane makes a solid unit as far as I’m concerned. Personally I wouldn’t by a Carrier product after all those years of repairing any and all makes.


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[karoc]

I guess in writing the second bid seems better but that's just to pump it up. Seer rating between the two won't mount to hill beans, yahoo for your 4" filter cabinet for down stairs I guess. But who wants climb attic to change a filter, and hold on to your wallet when it comes time to purchase another filter. Which those bad boys when they stop up, just about no air gets through them. I also like Bryant equipment which is what I had in my house but that was yrs ago which I didn't want none of the bells and whistles. I never care for Carrier, we didn't sell them but they were always little more money than Bryant but just different color.
If it was me I would go with company that you been using, stick with what works. They will move you up on their priority list, companys do appreciate good customers. Yea I also was an installer, service, salesman, working for small company who puts inferences on being honest. Ahh those were days, young mans job

 

[yeldogt]

Did anybody do an actual load on the building ? 6.5 is a lot of cooling. Did you see if the state has any energy programs ... what;s the rebates. Natural gas -- is that why no heat pump?

Carrier and Bryant are the same ..... I have been using Carrier for years and have had zero problems. If the Carrier unit they are recommending is the 5 speed unit .. that's the ticket in my mind. I have used them in the last three projects .... the oldest is 6 years now. It was new in 2015.

The modern multi speed equipment is so good --- very quiet and the infinity controls are fantastic.

Report back on the model carrier ....

The 4" filters are nice -- that's what I use ... good protection for the equipment. I buy them in packs of 4 honeywell

 

[Kilgore Trout]

It is indeed a lot of cooling, but it is a big house, particularly since the basement also has heating/cooling. All the contractors came up with the same load, though the house is also apparently between sizes (i.e. a 3.5 ish in the basement would be ideal).

The basement carrier is a 24VNA9, which is the five speed compressor. The attic system would just be the basic carrier comfort furnace and hvac.

Thanks!

 

[Git]

What I do in a situation like that is to first get several bids and let them educated you on which equipment they think is best. Then YOU decide on which equipment you want and follow up with them, but this time you specify what equipment you want so they are all bidding on the same thing

 

[yeldogt]

I asked above . What about state energy programs ? Rebates available ... etc. Some states have a lot available -- often you much get the heatpump.

Natural gas?

The 5 speed is a fantastic unit ... how many heating days do you have?

The 5 speed will run to 25 percent and ramps up from there ..... good bang for the buck. I'm suprised the cost is close ---- the carrier is a much better system and teh controls are much better.

How does the current system work .... when it running on a really hot day does it shut off. How about the second floor --- is the attic insulated or is the unit up there in the heat. Any noise ..... Understanding how the current units functions helps you pick the new.

Modern system with multi staging allow the units to match what is needed -- the are silent ... no loud on and off. The long runs is the summer eliminate any humidity ... basically you leave them on and they run at low speed most of the time (the 5 speed)

 

[Kilgore Trout]

Attic is well insulated. Probably 18-24 inches of blown insulation. Current system cools the house. It turns off on really hot days, but not due to overload or anything like that. They are relatively loud, but I have simply gotten used to the old ones. Heat is on from mid November through April (though some April days don't need any heat).

In terms of rebates, the carrier price includes the rebates (about $1300), there are none on the American Standard. Local utility company isn't offering anything except $50 for a smart thermostat.

Both furnaces are nat gas.

 

[yeldogt]

So the insulation is in the floor ? The unit is up in the heat of the uninsulated attic.

On design days ..... that's the coldest day and the hottest day with the system set to what ever temp you want. It's usually 72 on the load program ... the systems should never shut off. In other words if you run the AC on the hottest day and it turns off .... it's oversized. Same with the heat .... on a day where it's 5 degrees out or whatever the coldest day is the unit should be running all day.

systems should not be loud .. if they are the ducts are too small for the equipment. Has anybody listened to them and explained why ? This is why I asked about the load ... almost all systems are oversized with too small duct work. When I design my AC in PA .... with spray foam I'm way over 1ksf per ton.

I ask about the heat because with a high enough heat load it may be worth upgrading the lower furnace to the one that modulates more to better use the controls built into the infinity system.

Does the one upstairs room have a return for the lower system ?

System in an attic w/ floor insulation are as you may assume not very efficient and it's very important for them to be sealed very well -- they can easily be wasting 1/3 capacity.

 

[Kilgore Trout]

Ok, so I misread your question on noise. The vents are not loud at all, just the A/C compressors themselves (and the furnace if you are standing right next to it, which I never am).

100% agreed that attic installs are not my favorite. But it is what I have and I don't plan to rip out a bunch of walls to change the duct work. So, it will certainly be inefficient, but the ductwork up there is pretty well sealed (and insulated).

In both bids, the basement furnace would have a VSM and two stage heat, so I think I have that covered.

 

[todd_fuller]

I can't give much comparison, but I do have two comments to offer on the Carrier bid:

1. For the Carrier Infinity unit, there are two variable speed compressors. There's an older version that I think they refer to as 'Greenspeed'. From reading the HVAC forums, this is a problematic design and fails way more often than competitors. They have a new 5-speed compressor from Toshiba (if my memory serves) that's quite reliable.

2. There are some combinations that allow heat pump use. My installer initially didn't actually know about this but there are AHRI specs for this and the heat pump isn't a big upcharge, like $1000-1500.

3. For the attic system, you don't need their thermostat. I'd get an Ecobee or something better. For all variable-speed systems out there, they all have proprietary communication so no third party thermostats. You can use the VS w/ non-communicating thermostat but you lose the variable speed thing, you can set ramp times, etc but it's not what you're paying for when you do VS. The Carrier Infinity thermostat is OK... I would never pay what they charge for it if there were alternatives.

I have this, AHRI# 204295840, installed for ~$13.5k here in Austin. They had to redo the plenum too (builder **** work) so price was higher.

 

[danski0224]

I can just about guarantee you that your existing 24 year old residential ductwork is not sized properly in order to actually get "16+ SEER" out of a forced air system.

Good luck.

 

[yeldogt]

I can't give much comparison, but I do have two comments to offer on the Carrier bid:

1. For the Carrier Infinity unit, there are two variable speed compressors. There's an older version that I think they refer to as 'Greenspeed'. From reading the HVAC forums, this is a problematic design and fails way more often than competitors. They have a new 5-speed compressor from Toshiba (if my memory serves) that's quite reliable.

2. There are some combinations that allow heat pump use. My installer initially didn't actually know about this but there are AHRI specs for this and the heat pump isn't a big upcharge, like $1000-1500.

3. For the attic system, you don't need their thermostat. I'd get an Ecobee or something better. For all variable-speed systems out there, they all have proprietary communication so no third party thermostats. You can use the VS w/ non-communicating thermostat but you lose the variable speed thing, you can set ramp times, etc but it's not what you're paying for when you do VS. The Carrier Infinity thermostat is OK... I would never pay what they charge for it if there were alternatives.

I have this, AHRI# 204295840, installed for ~$13.5k here in Austin. They had to redo the plenum too (builder **** work) so price was higher.

The original Greenspeed was a Scroll compressor I think from around 2012 ..... they pulled it and it was introduced again around 2014. My memory was the speed control being the problem ..... not really the compressor .... my memory is foggy. Anyway -- when I was looking bak in late 2014 they had just introduced the Toshiba 5 speed as well. It is a rotary compressor .... Toshiba is the big player in Rotary and they make the better units in all the Mini-splits. Mitsubishi for example.

I guess the VS control for the compressors must be expensive as the 5 speed was less money vs the reintroduced Greenspeed that was still a Scroll. The full VS Greenspeed did have slightly better specifications --- mostly in HP mode. The 5 speed was still very good --- down to 2 degrees F w/ full output. I went and looked at both running as my installer had done a few of each -- the 5 speed was quiet. The Greenspeed still had that odd high pitched sound from the control. Not like before ... but -- I wanted silent and the 5 speed fit what I wanted and it makes no noise.

My understanding is both of the units have proven to be reliable -- my 1st installer had done hundreds and hundreds of the 5 speed and many many of the Greenspeed the last I asked a couple years ago. With only a few problems --- he told me when things fail they fail quickly and it's never the compressor on the 5 speed.

Carrier now has a full VS Rotary -- so they must have developed a control for it. I have no idea if it's the same compressor as in a minisplit -- I don't see why it's not. What is the difference ? The five speed could be the same compressor with a set control output for the speeds -- who knows?

Anyway the full VS Rotary is now the top ... above the Greenspeed scroll. I still went with the same 5 speed again.

If you do a proper load on the building this will give you the various needed outputs at different outside temps. What you do is take the average temps you have in the area and plug that into the load .... this will give you the output the house will need most of the time. That's how you match it up. In my case the 3rd speed of the 5 speed is perfect in both AC and HP . I still have two lower and two higher to balance it out.

Another thing to factor is the extreme. We may have a 100 degree max -- but do you design a whole system around a temp that you may only see one day in 4 years? No -- IMO. On the hottest day of the year you will be running the system -- more than likely it will have been running for days .... if the temp in the house gets up a couple degrees at 3pm what difference will it make... None. I have also found that a proper system running and taking humidity out of the air will be just as comfortable at 75 as 70. Oversizing is a big mistake.

 

[Kilgore Trout]

So I ended up going with the American Standard equipment. The guy upgraded the thermostats to two Nest thermostats, threw in the second 4 inch filter cabinet, and knocked about a grand off the price. Everything gets installed about 10 days from now. I'll report back how it goes.

 

[yeldogt]

Not what I would have done -- but, your money and house.

Check into the Nest and the two stage operation of the furnace -- I will warn you ... the Nest can cause problems. It's overthinking and not equipment specific. Most pros hate them for the problems they cause. Same with Ecobee

 

[Git]

Not what I would have done -- but, your money and house.

Check into the Nest and the two stage operation of the furnace -- I will warn you ... the Nest can cause problems. It's overthinking and not equipment specific. Most pros hate them for the problems they cause. Same with Ecobee

I have an Ecobee thermostat. I don't understand what problem it could cause. Keep in mind, the Ecobee is not a 'learning' thermostat....

 

[Kilgore Trout]

I hear you on the nest, but that was actually the installers recommendation. That was over the American Standard thermostat, so they must know how to install them! They were going to go with a basic Aprilaire thermostat, but my wife hated the looks of it. So I asked for a suggestion and gave them a list of about 10 that passed my wife's looks test so that they would know the kind of thing that would work. They picked nest - I was suprised. I have nest smoke alarms (only company I could find where it didn't go off everytime my wife used the shower - believe I tried a bunch of others first) and they have always been really great.

In the end, I went with the company that I have worked with for the last 8 years. They have never let me down before and proactively replaced several parts (i.e. capacitors) under warranty even when they hadn't yet broken. So, we shall see if they can do a good job again. I'll let you know how it turns out.

 

[PoorUB]

Keep in mind if an ugly thermostat is an issue, with many thermostats you can use a remote sensor, and mount the thermostat anywhere in the house. If you want it handy, put the thermostat in a convenient closet and the sensor in a reasonable place to sense temp. I have mounted thermostats on the wall in the mechanical room and a sensor where the thermostat used to be. If you have a WiFi thermostat it really opens up where to put the stat as you can just pick up your phone and adjust the heat or AC.

 

[American Locomotive]

I will say that the system seems grossly oversized unless your house is pushing 4,000-5,000+ sq ft. Nearly 200,000k BTU worth of heating and 6.5 tons of cooling is a lot. On the very hottest day your AC should just about run continuously, and on the very coldest day your furnace should run just about continuously.

Our 1800sq ft. 1700s farm house with uninsulated exterior plaster walls and many original hand-made single-pane windows heats adequately with an 85,000 btu furnace.

 

[PoorUB]

I am curious to the total square feet too! That is a lot of heat and cooling for a home.

 

[Kilgore Trout]

You hit the nail on the head - a bit over 4000sq ft with tall ceilings throughout.

 

[PoorUB]

4,000 square feet? The 6-1/2 tons doesn't sound crazy, but the furnace sizes seem large to me. On the 4 ton I would put in the smallest furnace that will support that sized AC, same with the 2-1/2 ton.

I sized a system for a new home. The contractor thought I was crazy but he put in 4 ton of cooling and 80,000 BTU furnace, 3,500 square foot home in North Dakota. I told the contractor I would take the unit back and help him install a larger furnace if it didn't heat the home. Home owner is happy with the system even in the -35F weather we had last winter.

 

[danski0224]

The 6-1/2 tons doesn't sound crazy, but the furnace sizes seem large to me. On the 4 ton I would put in the smallest furnace that will support that sized AC, same with the 2-1/2 ton.

Sometimes an AHRI match will force an odd size furnace due to the blower capacity or coil size.

 

[PoorUB]

It also depends on what the manufacturer builds. In my case I could get a 80,000 BTU with a 4 ton blower. Some manufacturers you will need to go to 100,000 BTU to get a 4 ton blower.

 

[Kilgore Trout]

All,

Just thought I would update this in case others are in a similar position. I ended up with the American Standard System. The Nest thermostats works just fine. I can run the fan separately timed or otherwise to circulate air and the two stage heating is controlled by the furnace board. The energy savings are substantial. I have saved between 35 and 40% each month compared to last year (and it has been HOT this year). Makes me think that the old system was exceedingly inefficient. We will see if I get any savings on the heat.

The system is also much quieter than the old system - both the blower and the compressor. So far so good!

 

[yeldogt]

All,

Just thought I would update this in case others are in a similar position. I ended up with the American Standard System. The Nest thermostats works just fine. I can run the fan separately timed or otherwise to circulate air and the two stage heating is controlled by the furnace board. The energy savings are substantial. I have saved between 35 and 40% each month compared to last year (and it has been HOT this year). Makes me think that the old system was exceedingly inefficient. We will see if I get any savings on the heat.

The system is also much quieter than the old system - both the blower and the compressor. So far so good!

Whatever you did was going to be an improvement .... unless you pick the cheapest equipment the sound levels will be lower. Modern furnace/ air handlers don't just click on -- they ramp up. Same with multi speed condensers. I would not have predicted as high a savings -- my guess given the age you may have been in the 10 seer range. Something must have been up with the old stuff

My new house is a converted church with over 4000sf of space in the main building --- 3ton Carrier 5 speed keeping it cool on those almost 100 degree days in June on stage 4 --- it hit stage 5 at 2pm for a bit. The boiler for the radiant heat is a net of bout 60k for the whole building --- this property is north of you in PA

Your need for multi stage heat depends on where you are in VA ... with the infinity system you can have full modulation controlled by the thermostat. The board using mostly a timer and this can be messed up with the full learning of the nest. The eco doe snot "learn" like the nest ... but the occupancy sensor can affect the memory in the furnace board.