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Thread: Zoning Sanity Check
08-04-2008, 09:45 PM #1Regular Guest
- Join Date
- Aug 2008
Zoning Sanity Check
Iím looking for some guidance, a sanity check and some answers before I start interviewing HVAC contractors.
Any feedback would be appreciated:
(I apologize in advance for the long post. Hopefully, it makes for interesting reading).
After seven years I finally got the green light from the wife to have our basement finished and want to take the opportunity while the check book, walls and ceiling are open to have our first floor and second floor HVAC systems Zoned with motorized dampers and communicating thermostats.
I read the site rules. I have no plans, time or energy to do this myself. My plan is to gain as much knowledge to successfully vet through various HVAC contractors with the intent of identifying the best one and get quotes based on what I want instead of what contractors may think I need (or want to sell me).
Donít get me wrong, Iíll keep an open mind when speaking with them; I would just prefer to come from a perspective of knowing what I want and being knowledgeable about it.
I currently have two HVAC systems:
York Diamond 80 Natural Gas Furnace Model # P4HUC20N08001 A (Single stage)
York Condenser Model # H1RA048S06D
York Evaporator Coil model # G1UA048S21B
York Diamond 80 Natural Gas Furnace Model # P4HUB16N080001 A (Single Stage)
York Condenser Model # H1RA042S06D
York Evaporator Coil model # G2FD046H17A
My intent of having both of our HVAC systems Zoned is first for comfort and second for energy savings. For example, on the second floor, in order for the master bedroom temperature to be comfortorable, the childrenís rooms end up being too hot or too cold (usually resulting in high energy bills). At night, we spend most of our time in the family room located in the back of the house (first floor), yet the HVAC is blowing air into the unoccupied (front of the house) dining room, foyer, living room and office etc (resulting in a high energy bills).
The plan is to get quotes to have the basement, front half of house (first floor) and back half of house (first floor) divided into three Zones off of one HVAC system located in the basement. Another, quote to have the master bedroom suite (second floor), guest bedroom suite (second floor) and two childrenís bedrooms (second floor) divided into three Zones off of one HVAC system located in an unconditioned attic (Iím assuming the HVAC contractors will perform a manual J to ensure my basement HVAC can support the basement and first floor when zoned).
I did some research here and other places on the Web, and it appears to me that getting HVAC contractor quotes for the Honeywell EnviraZone System with VisionPro IAQ Thermostats is the way to go. Specifically, the Zone of greatest demand algorithm makes so much sense to me. If I understand it correctly, all Zone dampers are opened and the HVAC cycles on. As the smaller zones (or zones with a lesser need) have their temperature set points met, their dampers close redirecting additional conditioned air to the remaining zones until the Zone with the greatest demand is satisfied. All zone dampers are then opened again while the system purges itself and then the system cycles off. To me, this makes a lot more sense than having each zone independently make calls to repeatedly cycle on and off the HVAC when needed.
My home is located in central NJ. Both of my HVAC systems are about 7 years old. Ideally, I would like to keep them for another 3 to 5 years since they are not that old and I cannot afford to have them both replaced at this time.
I plan to instruct the contractors to price in adding a motorized damper to the existing trunk line in the basement and use that for the back of the house first floor. Then install two additional trunk lines with motorized dampers for the basement zone and front of the house first floor. For the second floor zones, I think itís best to simply have the contractorsí quote ripping out the existing flex duct and replacing it taking into account zoning.
Zone Controller and Thermostats:
Does anyone have positive of negative experiences with the Honeywell EnviraZone combined with the VisionPro IAQ Thermostats?
Does anyone foresee problems having the Honeywell EnviraZone / VisionPro equipment integrated with my existing York HVAC systems?
Am I painting myself in a corner by going with the Honeywell EnviraZone combined with the VisionPro IAQ Thermostats? In other words, if I decide in 3 to 5 years to have my HVAC system replaced with a multistage heating and cooling unit and/or variable speed ECM blower, will the Honeywell EnviraZone controller combined with the VisionPro IAQ Thermostats not be compatible?
In my attic, I have R6 black jacket Flex Duct. From what I can tell, it appears to be installed poorly. Bends are kinked in numerous places and there are no hanging straps supporting it anywhere. As long as Iím having the upstairs zoned, should I consider having a contractor price-in replacing all the Flex Duct with R8 Silver Jacket Flex duct?
Will the higher R8 Silver Jacket Flex duct provide any significant energy savings over R6 black jacket flex duct that is located in my unconditioned attic?
From what Iíve been reading, I should probably expect to hear two different approaches from different contractors regarding air handling and duct. Some contractors will suggest performing a standard manual J and D to confirm if my ducts were originally sized correctly and if they were, the contractor will simply dump excessive CFM into unoccupied areas of the home. Other contractors will perform a manual D but take into consideration zoning, then suggest upsizing (or adding) supply and return ducts in each zone in combination with a bypass damper from supply to return. Should I expect this? If so, which approach (or contractor) would be better?
I want to have the HVAC contractorsí price in sealing and insulating the basement and first floor metal duct. Is there any insulation type I should tell them I want them to stay away from? For example, is there any type of duct insulation that will result in mold in my basement? Recommendations?
I would prefer to instruct my contractor on which type of damper to include in the proposal.
Itís my understanding that the EnviraZone will support two types of dampers. Normally Open (Spring Open) / Powered Close and Modulating (MARD) Dampers. My understanding is that traditionally, Modulating Dampers provide the advantage of being able to stay in any position between fully open and fully closed. Will the EnviraZone truly modulate with MARD dampers?
If the EnviraZone will not truly modulate the MARD dampers, are there any other reasons to instruct the contractor to include them?
Any other damper type pros/cons I should consider with the Envrozone?
Same thing with the bypass damper; Itís my understanding that the EnviraZone will support a MARD damper as a bypass damper when combined with a static pressure control (SPC) device. At first thought, this seemed like a no brainer. I wonít have to worry about a tech not calibrating correctly (setting the counterweight on the arm properly) traditional barometric bypass damper. Which type bypass damper (MARD with SPC or traditional Barometric) does everyone suggest I specify the HVAC contractors quote with the EnviraZone and why?
Basement Zone and Return Air Vent:
I definitely want the contractor to price and install supply and return vents for the finished basement zone. However, when the basement zone is not calling for conditioned air, I donít think I want the basement return vent sucking in potentially musty basement air and circulating it to the two first floor zones. I was thinking of instructing the HVAC contractor to put motorized dampers on both the supply and return vents in the basement. The thought is that when the basement zone calls for conditioned air both the supply and return open simultaneously. As a result, when the basement is not calling for conditioned air, the basement return will be closed preventing basement air from circulated to the first floor zones. Is this something doable, or will the contractors look at me like Iím nuts?
Itís my understanding that the EnviraZone controller combined with the VisionPro IAQ Thermostats can also be integrated with a Heat Recovery Ventilator. Is this something we should seriously consider having added to our quote? Our house is seven years old. My wife and I both work from home and as a result (between work, sleep and family time) itís not unusual for us to be in the house 20 hours a day.
There is nothing more frustrating to me than having the Air Conditioning crank out air in the morning or evening only to find out its colder outside. If I have the HVAC contractors include an outside temperature sensor, will the EnviraZone controller combined with the VisionPro IAQ Thermostats have the artificial intelligence to shut-off the condenser and evaporator coil and simply circulate the cooler outdoor air through the house via the HRV?
Will the HRV unintentionally warm up the outside air defeating this purpose or is there some sort of automatic seasonal setting?
Are my existing York HVAC systems builder grade junk? (I have very high utility bills).
Can anyone confirm what the SEER rating is of my combined Condenser and Evaporator coils? Iím thinking they may be 10 Seer which could be contributing to my very high electric bills. However, I thought 10 Seer had already been outlawed in favor of 13 Seer before my home was built in 2001.
Thanks in advance for any feedback.
08-05-2008, 12:28 AM #2Professional Member*
- Join Date
- Jul 2000
- Northern Wisconsin
With high energy costs you should first take a long hard look at the building envelope and improvements that can be made there. Why? Because if you size a system to existing insulation values and then come in behind the install and insulate you'll end up with to large of a heating and cooling system that will have potentially serious issues and it could possibly shorten it's life.
Zoning...... the perverbial can of worms. Most existing duct systems are not properly sized to handle zoning. Some products do a better job of dealing with less than perfect conditions but it still comes down to the heating and cooling equipment. Each requires minimal air flows and trying to zone single stage equipment usually requires that major ductwork modifications need to be made.
I have no personal experience with the zoning items that you mentioned so I can't speak to that.
What will get you the best possible system in this upgrade will be all in the selection of the contractor. Choose carefully and ask for references and check each one of them out to find if the customers they've done retrofit work for in the past are happy.
You have a total of 7 1/2 tons of air conditioning now in the two systems. Your home must be fairly large.
Good luck with your project and keep an open mind.Use the biggest hammer you like, pounding a square peg into a round hole does not equal a proper fit.
08-05-2008, 11:14 AM #3
The Evirozone can be used with the MARD dampers. Usually they(those dampers) are for larger systems though.
The Evirozone will be compatible with most systems you might upgrade to.
It does require a dual fuel add on control if you go to dual fuel later.
The draw back is when you go to raise the temp in a zone, such as the basement. It wonít bring on the system right away(because of the zone with greatest demand algorytm). The blower will start. But it wil try to raise or lower the temp by mixing the air first.
It will not work as an economizer control.
It will control an ERV, or HRV.
Both ERVs, and HRVs are not usable as economizers to get free cooling. Thats not how they are designed.
Do NOT damper the basement return.
First, if it does draw return when the basement zone isnít calling. It helps to prevent stagnation in the basement.
Second, if it draws return from the basement when the basement isnít calling, its mostly because you are short on return.
Youíll be lucky to find a contractor that knows how to do a Manual J, let alone a Manual D.
They will have to use a bypass or dump zone. A bypass will work better then a dump zone.
A modulating bypass is a good idea, incase you do upgrade to a VS blower later.
Are you basement and first floor ducts going to be in an uncoditioned space?
You will most likely still need a dehumidifier for your basement zone.Contractor locator map
How many times must one fix something before it is fixed?
08-05-2008, 05:02 PM #4Regular Guest
- Join Date
- Aug 2008
08-05-2008, 05:34 PM #5Regular Guest
- Join Date
- Aug 2008
Thanks for your responce
08-05-2008, 08:22 PM #6
I would recomend a drop ceiling for the baement.
Unless you have no plumbing pipes at all in the ceiling.
The dampers won't modulate. They will open slow, so you don't get a rush of air. But you are better off with spring open power close dampers.
The Envirozone can control an ERV/HRV.
You would be better off with an ERV if you have humidity concerns.
Yes, it can slow a VS blower for better moisture removal.Contractor locator map
How many times must one fix something before it is fixed?