HVAC Frustration. Need Advice

[rsw686]

Since you are going with HAI I would look at the Carrier Infinity systems. HAI has serial integration with the Infinity thermostat so you don't loose the advanced functionality.
 
http://www.homeauto.com/newsandevents/pressreleases/content/20100824CarrierInfinityBryantEvolution.asp

 

[apostolakisl]

Thanks for the offer Work2Play.  I probably will need three zones.  If I was a bit younger, I might consider this as a DIY project, but the more I'm learning, its pretty involved. Doesn't look like a project for the faint-at-heart.  The cost I'm getting for just the zoning is $4500 - $5500 which should give you some idea of what's involved. 
 
Overall the direction that I'm seeing in HVAC systems is a bit disturbing.  As their systems get more complex, they are using this fact to make it HARDER to hook their systems to other systems.  Their systems are becoming more proprietary than ever because they want to force you to buy ALL their equipment and more.  If your Trane, for example, and you make all your communications proprietary, they can force others to have to license systems that connect to it, and they can force consumers to not only buy their system, but buy their high-end systems if you want to communicate with it. If you want to control it remotely,  great, buy our $800 interface and it will work great with OUR iPhone app.   

 
 
$4500 to $5500 is absurd.  The hardware involved includes 3 dampers, 3 thermostats, a transformer, and a zone control board.  The honeywell board costs about $300, the dampers are about $30 or so each, and the thermostats will cost whatever you choose, I suppose that could be $200 ea (but I bet the price didn't include the thermostats since you were specing out your own special ones).  If you have flex duct and all the runs more or less home run back to the unit, it is just a matter of disconnecting them all from the main plenum, splitting it up into 3 sub plenums, and running ducts with dampers between the main box and the sub boxes.   You'll have a couple hundred dollar in duct board, collars, "pooky", and flex duct.
 
And you only need a pressure relief valve if your unit is a single stage and there isn't enough outflow on a single zone to accommodate the unit.  I have one on my unit at the office, but it doesn't open, so it was a waste, but the inspector wanted it.
 
I have the Carrier infinity at home, and the serial thermostats are nice and all, but I wouldn't say they are worth paying extra for.  They are great for initial check out on the unit and trouble shooting certain problems.  Otherwise it is just like, hey look at the cfm's my unit is making right now. . . wooohooo what would i do if I didn't know that. . . yeah, the same thing you would do not knowing that.

 

[tmbrown97]

I was quoted about 2500 to go from 2 zones to 4 - that would've required a bypass most likely; decided to wait instead until I replace the unit sometime in the near future.

 

[apostolakisl]

I was quoted about 2500 to go from 2 zones to 4 - that would've required a bypass most likely; decided to wait instead until I replace the unit sometime in the near future.

 
 
I would suggest not splitting a single unit into 4 zones if indeed it isn't capable of running in a low enough stage to avoid the bypass relief.  You will find that when only one zone is calling, those pressure levels will result in an hvac experience that is less than ideal.  In other words, the air will be howling through the ducts and be drafty.  Unless you set your relief valve to a relatively low pressure, but that is not efficient.  Feeding cold air back into the evaporator is a waste of electricity.

 

[ano]

Being in Phoenix, where AC is used 8 months a year, all the systems being proposed were at a minimum 2 speed fans, if not variable speed fans.  My home office is the furthest room from the unit, and is a Southern facing room, so I'm not worried about too much breeze, especially when it is 120 out.
 
One company told me their system eliminated the relief valve by not ever fully closing the dampers. If that is really true or not, who knows.  One other guy recommended against a zoned system, but I think with the layout of my house, being in Phoenix, it is a requirement.  With our current builder special system, when its 83 in our kitchen where the thermostat is near the HVAC, and 115 outside, it can be 86+ in our family room on one side of the kitchen, and 93+ on the Southern most bedroom (my office) on the other side.  You guys in cold environments have it lucky because when it is cold, it is uniformaly cold in all directions.  Not true in the heat. The sun beating down on a room can really heat it up a room MORE than what the 115 heat would suggest. So my office, where i spend the day, is in the Southern most room the furthest from the air handler. Without zoning, it wouldn't have a chance in ..., oh you get the idea.

 

[signal15]

That RCS zone controller at Smarthome looks interesting.  I have a single stage furnace without a variable speed fan.  I currently have a single thermostat running the forced air system, so a single zone for the whole house.  My master bedroom is far from the furnace and doesn't get good airflow compared to the rest of the house.  It could be a balancing issue as the guy I had out to balance it did a terrible job (I wasn't home to watch him).
 
I leave my fan run all the time to keep the whole house at a more consistent temp, and it keeps the dust down since the air is constantly being filtered.  My concern is that if I set up this zoning thing so my bedroom is on it's own zone (it's about 750sq ft), that leaving the fan on is going to cause all of the warm or cool air to be sucked out of the room through the returns and the thing will just start heating or cooling again shortly after it turns off.  How would this be dealt with?  Would I have to set my fan back to auto?

 

[rsw686]

I have the Carrier infinity at home, and the serial thermostats are nice and all, but I wouldn't say they are worth paying extra for.  They are great for initial check out on the unit and trouble shooting certain problems.  Otherwise it is just like, hey look at the cfm's my unit is making right now. . . wooohooo what would i do if I didn't know that. . . yeah, the same thing you would do not knowing that.

 
For a basic application I would agree with you. ano was asking about 4 zones and the Carrier Infinity system will support up to 8 zones. Since it is purpose built to control their HVAC unit I'm assuming there is a benefit with multiple zones in the efficiency and controlling of the variable speed fan and stages of cooling.

 

[apostolakisl]

Being in Phoenix, where AC is used 8 months a year, all the systems being proposed were at a minimum 2 speed fans, if not variable speed fans.  My home office is the furthest room from the unit, and is a Southern facing room, so I'm not worried about too much breeze, especially when it is 120 out.
 
One company told me their system eliminated the relief valve by not ever fully closing the dampers. If that is really true or not, who knows.  One other guy recommended against a zoned system, but I think with the layout of my house, being in Phoenix, it is a requirement.  With our current builder special system, when its 83 in our kitchen where the thermostat is near the HVAC, and 115 outside, it can be 86+ in our family room on one side of the kitchen, and 93+ on the Southern most bedroom (my office) on the other side.  You guys in cold environments have it lucky because when it is cold, it is uniformaly cold in all directions.  Not true in the heat. The sun beating down on a room can really heat it up a room MORE than what the 115 heat would suggest. So my office, where i spend the day, is in the Southern most room the furthest from the air handler. Without zoning, it wouldn't have a chance in ..., oh you get the idea.

 
I too live where it is hot, maybe not 115, but 105 isn't unusual.
 
You may think there is no such thing as too much breeze, but trust me, there is.  What you'll get is a roller coaster of being too cold, too hot, too cold, etc.  When the unit is on, high velocity 55 degree air will blow on you, then click, it is off.  It is far more comfortable to have long cycle times with just enough air to cool the room.  If it turns out that you need continuous blasting away to just maintain normal temp, then you need more vents and/or better insulation.  High velocity air will also produce wind chill effect, so two people in the same room just feet apart may find the room comfort to be very different.
 
Eliminating the relief valve by leaving the other dampers open a little may be fine or it may overcool those areas.  It depends on just how balanced your system is without zones.  In a situation where one zone is calling a lot more than the others, you will freeze out parts of your house.  Like if you are having a party with lots of people in the living room, your bedrooms will start to get freezing cold.  If indeed that SW office you have is way out of proportion to other rooms in your house, then it may be a daily event that the other side of your house freezes in the afternoon.  Simply put, you are only partially zoning the system if you don't fully close dampers.  And this may work just fine if your demand from different parts of the home isn't hugely different.

 

[apostolakisl]

That RCS zone controller at Smarthome looks interesting.  I have a single stage furnace without a variable speed fan.  I currently have a single thermostat running the forced air system, so a single zone for the whole house.  My master bedroom is far from the furnace and doesn't get good airflow compared to the rest of the house.  It could be a balancing issue as the guy I had out to balance it did a terrible job (I wasn't home to watch him).
 
I leave my fan run all the time to keep the whole house at a more consistent temp, and it keeps the dust down since the air is constantly being filtered.  My concern is that if I set up this zoning thing so my bedroom is on it's own zone (it's about 750sq ft), that leaving the fan on is going to cause all of the warm or cool air to be sucked out of the room through the returns and the thing will just start heating or cooling again shortly after it turns off.  How would this be dealt with?  Would I have to set my fan back to auto?

 
Leaving your fan running 24/7 is largely incompatible with zoning a system.  Zoning a system only opens the dampers to the zones that are calling, so if you want continuous circulation to all rooms, then all dampers must be open, and thus you are not zoned.  If you had the system close dampers just while the heating/cooling elements are on, then flip everything open at all other times, you will undo what the zoning just finished accomplishing. .. controlling the temp different in different parts of the house, as it mixes the air all back together again.

 

[ano]

So three companies have now come with estimates.  What they all have in common is they all like Trane and universally have bad things to say about Honeywell zoned systems.  They are not really satisfied with that air bypass valve, and they claim they are not reliable.  This is them talking, not me. 
 
Two of the three recommended Trane systems with Trane's zone controller. They all talked highly on the Trane zone controller, even the third one who put together a non-Trane system.  Anyway, I think the main touchscreen Wi-Fi Trane thermostat goes in the middle. One company had just sensors in the other zones, the other had full thermostats.  With both you can access them from an iPhone app. or the Internet, but my HAI system won't be able to control it. 
 
The third company did a fair bit of research, and created a system that HAI can control.  A Carrier Infinity has an option for an interface box which can connect to the Omni Pro II with a serial port.  This would have three touchscreen thermostats and the Omni can fully control and monitor it.  The zone control would be from Carrier.  
 
All are in the 17 - 20 SEER range, 4 ton, variable speed fans, and dual-speed compressors.  One Trane system actually uses two compressors, depending on the demand.  Most have 10 year warranties on parts, including zone parts, one has a 10 year warranty parts and labor.
 
The zoning added anywhere from $3800 to $5500 to the cost for three zones.  The other parts of the system are in the $10K range, give or take.  All will use existing air ducts.

 

[apostolakisl]

So three companies have now come with estimates.  What they all have in common is they all like Trane and universally have bad things to say about Honeywell zoned systems.  They are not really satisfied with that air bypass valve, and they claim they are not reliable.  This is them talking, not me. 
 
Two of the three recommended Trane systems with Trane's zone controller. They all talked highly on the Trane zone controller, even the third one who put together a non-Trane system.  Anyway, I think the main touchscreen Wi-Fi Trane thermostat goes in the middle. One company had just sensors in the other zones, the other had full thermostats.  With both you can access them from an iPhone app. or the Internet, but my HAI system won't be able to control it. 
 
The third company did a fair bit of research, and created a system that HAI can control.  A Carrier Infinity has an option for an interface box which can connect to the Omni Pro II with a serial port.  This would have three touchscreen thermostats and the Omni can fully control and monitor it.  The zone control would be from Carrier.  
 
All are in the 17 - 20 SEER range, 4 ton, variable speed fans, and dual-speed compressors.  One Trane system actually uses two compressors, depending on the demand.  Most have 10 year warranties on parts, including zone parts, one has a 10 year warranty parts and labor.
 
The zoning added anywhere from $3800 to $5500 to the cost for three zones.  The other parts of the system are in the $10K range, give or take.  All will use existing air ducts.

 
I don't know how many tons you are needing, but have you considered 2 or 3 separate units rather than zoning.  No matter how fancy your zoning, you get better independent control with separate units, and you still get heating/cooling if a unit goes down, which they all do at times.
 
Not sure why they are laying the bypass valve on Honeywell.  Bypass relief isn't a product of the control board, it is a product of too many CFM's for the available outflow ducting.  If you are splitting a system up into zones that are too small for the unit on its lowest setting, a relief valve is needed.

 

[ano]

None of the systems I had proposed to me have any type of bypass relief valve.  That is really what is at the heart of this whole problem/solution.  These systems have variable speed fans, intelligent thermostats, and a dual speed compressor, so they don't need any type of relief valve.  If they know only one damper is open, they just run the fan very low and run the compressor at 50%.  Because of this, you HAVE to use their smart thermostats.  Honeywell can operate differently because of that bypass valve. 
 
As for multiple units, I already have two units in my house.  On the office/family room side I currently have a 3.5 ton unit and all the companies are proposing to step that up to 4 tons. On the opposite side of the house, I have a 3 ton unit which basically does the master bedroom and a laundry room.  It isn't very efficient, but it also generally only runs at night when my electric rates are very low. 
 
The contractors all gave me quotes for replacing the 3 ton units in addition to the other, and these quotes were in the 10K range.  Doing some quick math, this tells me a zoned system is going to be a whole lot cheaper than using two 2 ton units.  Two units as opposed to zoning would cost $5000 more, and I'm not convinced it would be really any better. Also I'm not really sure I want a total of three units for a house that is only 3000 sq. ft. 

 

[fcwilt]

The Lennox system and the WaterFurnace system I mentioned DO NOT use a bypass damper. They are both multi-stage/variable speed blower systems. The zone controller takes care of all the "smarts" so the thermostats can be "dumb".

 

[apostolakisl]

The Honeywell runs multi-stage systems, it doesn't do continuously variable systems.  As far as I know, anything with a continuous variability would run a proprietary control systems (or at least licensed).  Although I have to wonder how much better result you would get as compared to a 2 stage setup.
 
I am a bit surprised that in 3000 sf you need so many different zones.  I think you are going to have your 3000sf twice as split up as my 6000sf house.  I have about 30K into my entire Inifinity system including everything from scratch and a total of 8 tons over 3 units (2 3's and a 2), none of them zoned.  As it turns out, I probably could have gone with 6 tons.  The fancy infinity thermostats do tell me how much time they spend in high vs low, and mostly they run low speed, except for the upstairs unit.  I just pulled up my 3 ton downstairs unit, it is at 617 hours low heat, 777 hrs high heat, 5091 hrs low cool, and 353 hrs high cool since install.  And I am talking about Texas, where the temp is over 100 degrees for months on end.
 
Maybe you should inquire about better insulation and/or windows.  It might cost the same and result in better savings and better comfort.  I put in all the low e windows and spray foam.  Really good insulation is a really good way to keep your temp equal throughout.  Spray foaming the underside of your roof deck can make a huge impact.

 

[CalgaryRoofing]

Lou is likely correct. We see this all the time in our business (Roofing). Spray foam is the likely solve.
 
The secret is to get involved with the roofing contractors doing the spray to the roof deck so it is done right.
 
Roofing Calgary