Where to start with HVAC?

[pete_c]

In the older 2 story home in the midwest had 2 zones of HVAC with two smaller furnances / AC units and the home was ~ 2000 SF. 
 
The 2nd floor AC unit running by itself would keep the whole house cool typically. 
 
In current homes 3000 + SF have one HVAC unit and it works fine for the two story home.
 
Proper ductwork and an efficient HVAC and tight home will typically provide even heating and cooling throughout a home.
 
Here and due to WAF during the summer and winter the home temperature remains at 68-70 F 24/7 365 days a year.
 
A few years back due to a few gotchas; one related to HVAC engineering; cancelled a home build. 

 

[wkearney99]

Proper ductwork and an efficient HVAC and tight home will typically provide even heating and cooling throughout a home.

 
This being the key.  And it's hard to get there without compromises.  
 
Large enough ducting to allow for longer runs introduces noise and loss, as do any turns.  
 
We ran into that problem given the placement of the system; which was a factor driven by the geothermal units.  I raised the HVAC ducting question with the architect very early-on in the process.  His understanding of it ended up being 'less than ideal'.  As a result we had to add an air-handler for the 1st floor instead of a larger unit for it and the basement.  Not too big of a deal but my alternative would have been larger ducting intruding in the ceiling space (perpendicular joists) and the likelihood of unwanted noise due to the longer runs needed.
 
Were we to do it again I'd have picked a different place for the system and factored that into the floorplan of the levels above it.  Ah well.

 

[tritium6]

There's little point in having more than one thermostat per zone.  Because a zone is only going to act as an individual element.  More than one thermostat won't 'do anything'.  More often than not adding a thermostat to a zone overrides whatever other one might have already been present.  We did that for our setup.  There's now a remote thermostat in a better location to allow for more balanced temperature overall.  The thermostat specifically recognizes the added one as an override and ignores the in-built one.
 
If you want more fine-grained temperature control then you usually need additional zones.  These need not be additional climate units but typically just in-line dampers branching off the main duct trunk.  We have a unit in the basement that has two such trunks; one for the home theater and the other for the rest of the basement.  Either unit can 'call for' conditioning and the air handler will come on and open only the damper leading toward that zone.  There's typically a zone control unit in-between the thermostats and the climate unit.  But the ductwork needs to be engineered to work properly.  As in, there needs to be a return from within each zone; not just one main return.  
 
Again, climate management within the house DOES NOT BENEFIT from people laying hands on the controls for it.  Being able to "control it" manually is NOT a smart way to look at it.  Sometimes it's helpful to NOT have controls readily accessible, if just for behavior modification...

 
I was thinking more along the lines of whether we can have fewer than one thermostat per zone. Are there multi-zone thermostats? Possibly using remote temperature sensors?

Anyone have experience with Lutron temperature control? Does it integrate into the RadioRa2 software?

 

[wkearney99]

Some thermostats also support a remote controller.  We've got one on our Honeywell setup.  
 
https://www.forwardthinking.honeywell.com/products/wireless/portable_comfort_control/pcc_feature.html
 
It's capable of remotely controlling all four of the zones remotely.  That and they all show up within the app on our touchscreen devices (ios and android).  
 
Truth is we don't make use of it, nor the apps, for anything other than temporary hold changes.  As in, for a party or something.  This is important to follow, as making manual changes often results in VERY inefficient operation.
 
The nice thing is the thermostats themselves allow for making the hold changes just until the next timed event, or until released.  But for the more semi-permanent holds it's more useful to use the vacation feature as that allows for setting the far-end resumption time and temp also.
 
There are thermostats that support attaching a remote temperature sensor to them.  Some wired, some wireless.  
 
Let's step back and ask, what sort of control scenarios are you envisioning?  

 

[tritium6]

Some thermostats also support a remote controller.  We've got one on our Honeywell setup.  
 
https://www.forwardthinking.honeywell.com/products/wireless/portable_comfort_control/pcc_feature.html
 
It's capable of remotely controlling all four of the zones remotely.  That and they all show up within the app on our touchscreen devices (ios and android).  
 
Truth is we don't make use of it, nor the apps, for anything other than temporary hold changes.  As in, for a party or something.  This is important to follow, as making manual changes often results in VERY inefficient operation.
 
The nice thing is the thermostats themselves allow for making the hold changes just until the next timed event, or until released.  But for the more semi-permanent holds it's more useful to use the vacation feature as that allows for setting the far-end resumption time and temp also.
 
There are thermostats that support attaching a remote temperature sensor to them.  Some wired, some wireless.  
 
Let's step back and ask, what sort of control scenarios are you envisioning?  

 
1) I'm concerned that if I have 5 zones, my builder will put 5 ugly thermostat boxes on the wall. I'm guessing there is a way to avoid this using remote temperature sensors.
 
2) If possible, I would like to integrate my HVAC into an automation system. So far I'm planning on RadioRa2 and Elk M1, so HVAC would be a nice addition. My plan is to have physical controls which operate without additional software, and I can add software control later. I've played with CQC previously and I'm a professional software developer, so I'd like the ability to write custom software to interact with the HVAC system. I know the Nest will achieve this with their REST API, and I'm guessing Lutron will too since RadioRa2 plays nice with 3rd party software.
 
My control scenarios are 1) primarily controlled via scheduling. 2) method for manual override, either physical or app based. 3) If possible, 3rd party integration so I can integrate via CQC or custom code.
 
Thanks a bunch, you all are really helping me crystalize my requirements.

 

[tritium6]

Ok, so you're *very* confident in how the HVAC contractor engineered the setup to take into account the renovation?  
 
Too late and wrong just means more money and hassles later, instead of at the present.
 
We've got an AC line running up from the basement geothermal unit up to the attic air handler.  It's inside spray-foamed insulation in an exterior wall.  I was unsure about the routing of the line but let them set it up that way.  Last winter that line would tick-tick-tick inside the wall, but only when the heat was running.  But not always and not during the hotter months when used for AC.  So now I'm waiting until winter returns to repeat the symptoms.  If it does that again I'll have to pull apart of ton of drywall and abandon a lot of copper tubing to re-run it down along a basement ceiling bulkhead and up in through an interior closet.  So trust me, it's FAR better to cause delays DURING construction than after...

 
No, I'm not confident in his work. I lack the skills to judge an HVAC system. I know we have multiple zones on each system, but only 1 return upstairs and 1 return downstairs. What should I be looking for to judge?

 

[wkearney99]

There's lots of options for the thermostats.  They don't all have to be 'ugly' but they do need to be positioned properly.
 
Start by asking which thermostats your contractor intends to install, and why.  
 
I wouldn't necessarily have chosen the ones we've got but the HVAC contractor offered some compelling explanations as to why they'd be a good fit for our setup.  I added the Redlink internet gateway and remote sensors myself.
 
We've also got RA2 lighting and are quite pleased with it.  I was cautioned against the Lutron thermostats by several different integrators (including the HVAC contractor that installed the system).  Seems there have been some rough spots with them.  Now, things may have improved since then but I wasn't prepared to be a guinea pig.  Likewise since we have geothermal we were cautioned against the Nest device as it's logic had proven problematic for such systems.  Again, things have the potential to improve over time, but it wasn't right at that time.
 
As for integrating, honestly, I've yet to see much need for it.  Yes, it might be possible to really fine tune the operation of the HVAC system based on much more interactive scheduling.  I might be able to tweak a percentage or two efficiency out of it if I did things like tie it into detecting when we come and go.  But it's not just when we LEAVE that's involved, it's also when we come back.  This is important in that it does no good to reduce the HVAC operation if the period isn't long enough.  The recovery time for the system to bring the zones back up to the desired temp has to be taken into account.  So for a short trip that's less than the recovery time it might end up wasting more energy to allow the temp to change and then have it struggled to bring it back (as opposed to it just 'coasting' along).  That's a gross over-simplification, of course, but it summarizes my point that automation integration may or may not be effective.
 
A well designed (and scheduled) HVAC system should be largely invisible.  It took us about a month into each seasonal change to arrive at our desired schedules.  But once we got that sorted we've really never needed to control it otherwise.  Save for parties or setting vacation start/stop timestamps.

 

[drvnbysound]

I've been working on a home that's roughly 4,000 sq ft, which has (3) separate air handlers, and (3) separate compressors. Basically 3 individual systems under a single roof. One is for the main portions of the home (living areas, kitchen, dining, breakfast, additional bedrooms), another is for the master suite, and the third is for the guest suite. Each zone/system has it's own thermostat.

 

[wkearney99]

No, I'm not confident in his work. I lack the skills to judge an HVAC system. I know we have multiple zones on each system, but only 1 return upstairs and 1 return downstairs. What should I be looking for to judge?

 
Ok, so think about this.  When you have a zone then the air has to circulate from the source (furnace or AC coils) and get sent to that space.  The air has to circulate back to the system via a return.  This means that whatever conditioned air was pushed into a zone has to likewise get pulled back from that zone.  Otherwise it'll have to travel through some other zone, at which point it would likely cause the temp to change in that other zone.  Which would sort of make it pointless to have the zones separated, wouldn't it?    
 
If you have zones set up to allow for different conditions then they need to likewise have the ability for their return air to be handled separately.  
 
We have only one setup with two zones (the other two have their own systems and returns).  The 2-zone setup handles the whole basement and the home theater.  The theater is setup on it's own zone due to the fact that the number of people and equipment in the space might result in much different temperature needs than the rest of the finished space.  As in, lots of people in there during the summer, along with the equipment, might require a lot of cooling.  Having it separate would keep the rest of the basement from becoming an icebox.  The same is true during winter, except that the enclosed theater would likely NOT need the added heat, but the rest would.  
 
So it comes back around to how are your zones laid out and how is it you envision the spaces being used?  And is the system set up to fulfill those needs efficiently?

 

[tritium6]

I've been working on a home that's roughly 4,000 sq ft, which has (3) separate air handlers, and (3) separate compressors. Basically 3 individual systems under a single roof. One is for the main portions of the home (living areas, kitchen, dining, breakfast, additional bedrooms), another is for the master suite, and the third is for the guest suite. Each zone/system has it's own thermostat.

 
So you have 3 systems, each system is 1 zone, so you have 3 thermostats?

 

[tritium6]

There's lots of options for the thermostats.  They don't all have to be 'ugly' but they do need to be positioned properly.
 
Start by asking which thermostats your contractor intends to install, and why.  
 
I wouldn't necessarily have chosen the ones we've got but the HVAC contractor offered some compelling explanations as to why they'd be a good fit for our setup.  I added the Redlink internet gateway and remote sensors myself.
 
We've also got RA2 lighting and are quite pleased with it.  I was cautioned against the Lutron thermostats by several different integrators (including the HVAC contractor that installed the system).  Seems there have been some rough spots with them.  Now, things may have improved since then but I wasn't prepared to be a guinea pig.  Likewise since we have geothermal we were cautioned against the Nest device as it's logic had proven problematic for such systems.  Again, things have the potential to improve over time, but it wasn't right at that time.
 
As for integrating, honestly, I've yet to see much need for it.  Yes, it might be possible to really fine tune the operation of the HVAC system based on much more interactive scheduling.  I might be able to tweak a percentage or two efficiency out of it if I did things like tie it into detecting when we come and go.  But it's not just when we LEAVE that's involved, it's also when we come back.  This is important in that it does no good to reduce the HVAC operation if the period isn't long enough.  The recovery time for the system to bring the zones back up to the desired temp has to be taken into account.  So for a short trip that's less than the recovery time it might end up wasting more energy to allow the temp to change and then have it struggled to bring it back (as opposed to it just 'coasting' along).  That's a gross over-simplification, of course, but it summarizes my point that automation integration may or may not be effective.
 
A well designed (and scheduled) HVAC system should be largely invisible.  It took us about a month into each seasonal change to arrive at our desired schedules.  But once we got that sorted we've really never needed to control it otherwise.  Save for parties or setting vacation start/stop timestamps.

 
I've never seen a thermostat that wasn't ugly. I'm paying extra for a centralized RadioRa system to get all those switches off the wall. Then we're gonna turn around and stick this big ol thermostat on the wall... doesn't make much sense. Got any examples of non-ugly thermostats?The builder was probably planning to supply the cheapest thermostat he can find.

 

[wkearney99]

I've been working on a home that's roughly 4,000 sq ft, which has (3) separate air handlers, and (3) separate compressors. Basically 3 individual systems under a single roof. One is for the main portions of the home (living areas, kitchen, dining, breakfast, additional bedrooms), another is for the master suite, and the third is for the guest suite. Each zone/system has it's own thermostat.

 
Ours is a bit larger but we didn't treat the bedrooms separately.  It's been effective enough to balance the system at the registers to arrive at a suitable temperature across the whole floor.  I could see where some folks might want to condition the bedrooms separately.
 
The nice part is with geothermal we end up with NO NOISE outside the house due to compressors.  That and no wasted space for them.  And for the size of our systems they'd have been BEASTS.
 
Granted, it wasn't as inexpensive as traditional HVAC but current federal and state tax credits greatly offset the difference.  Upside is between them and the MUCH greater amount of insulation our HVAC costs are just about the same as our old house that was ~60% smaller.

 

[wkearney99]

I've never seen a thermostat that wasn't ugly. I'm paying extra for a centralized RadioRa system to get all those switches off the wall. Then we're gonna turn around and stick this big ol thermostat on the wall... doesn't make much sense. Got any examples of non-ugly thermostats?The builder was probably planning to supply the cheapest thermostat he can find.

 
I wasn't going to go there... but I've never seen much appeal with centralized switching.  Sure, you "can" do a lot with keypads but the end result tends to rate a very low WAF.  That and they're very confusing to guests, kids and cleaning personnel.  But hey, that's just my perspective.

To me a lot of this is covered by the notion of "ugly vs invisible over time".  Hell, it's fair to say that applies to a LOT in life.  But when it comes to switches and other controls (audio, lighting, HVAC, etc) I think it's more important to consider usability than just appearance.  
 
Here's an example, for the master bedroom my wife absolutely HATES anything with an indicator light that's anything more than a bare pinprick of light.  So the control panel for the alarm got swapped around to the adjacent master closet wall.  Thankfully the RA2 keypad backlighting is programmable. That and she really does not like using a keypad button for main lighting.  Here, the WAF was critical.
 
Another example is thermostat backlighting, viewing angle and indicators.  The Honeywell units have a red light that's part of the lower case.  It only comes on when a condition exists (like a filter needing a change).  This, to me, is much smarter than just some small part of the LCD that would've flagged it.  That and it's backlight and touchscreen are coupled such that tapping on the screen to 'wake it up' doesn't trigger controls.  I can press on it in the dark with that being interpreted as a control.  This was useful mainly during the seasonal changes and I wanted to compare the outside temp with the inside temp and setback value.
 
The point here is, for me, functionality is a LOT more important than aesthetics for a thermostat.  But then the Vision Pro units are reasonably decent looking: 
http://www.forwardthinking.honeywell.com/products/thermostats/thermostat_products.html
 
One naive notion that comes to mind is thinking just because it has a display then it ought to be usable for more.  As it turns out the points where you'd place a thermostat are often NOT the places you'd want to use a screen.  So don't worry that it doesn't do more, or that it might not have the flashiest looking LCD screen.
 
Me, I love gadgets.  But I've learned to appreciate usability (and marital harmony) a lot more.

 

[pete_c]

I know we have multiple zones on each system, but only 1 return upstairs and 1 return downstairs. What should I be looking for to judge?

 
Here in the Midwest 2 story home (80's) that was zoned between floors the 2nd floor had only one large return in the 2nd floor hallway.  The 2nd floor air handler was in a closet in the hallway bathroom and supply went octopus like into the attic and went ducted out to the ceilings of the bedrooms.  There were two air supplies in each bedroom and none in the hallway.  The single return did cause uneven heating and cooling unless you left the bedroom doors open which was a design flaw.  The main floor air handler was in the basement and did have returns and supplies to all of the rooms on the main floor of the home.  I did leave the air handler fan on 24/7 (well I do that today too) and never really paid attention to the noise of the air handler in the basement or 2nd floor hallway closet.  Both of the air handlers were behind a couple of doors and the house was relatively quiet.
 
Another home (thinking it was around 7K (don't remember anymore) sf built in the 70's we initially had two zones (one per floor) and we added a 3rd zone in the kitchen / laundry room area.  All of the handlers were configured with multiple room returns.
 
Here too as wkearney99, the thermostat settings and nice looking thermostat is never touched.  The Leviton HAI Omnitouch consoles have access to the thermostat and mostly looked at only for temperatures around the house.  I utilize the Leviton HAI remote combo temperature / humidity sensors and I do like to look that the house is evenly cooling or heating.   That said the Omnistat2 has many features on it plus it can be managed by the Leviton HAI OPII panel locally or remote (via cell phone).

 

[tritium6]

Here in the Midwest 2 story home (80's) that was zoned between floors the 2nd floor had only one large return in the 2nd floor hallway.  The 2nd floor air handler was in a closet in the hallway bathroom and supply went octopus like into the attic and went ducted out to the ceilings of the bedrooms.  There were two air supplies in each bedroom and none in the hallway.  The single return did cause uneven heating and cooling unless you left the bedroom doors open which was a design flaw.  The main floor air handler was in the basement and did have returns and supplies to all of the rooms on the main floor of the home.  I did leave the air handler fan on 24/7 (well I do that today too) and never really paid attention to the noise of the air handler in the basement or 2nd floor hallway closet.  Both of the air handlers were behind a couple of doors and the house was relatively quiet.
 
Another home (thinking it was around 7K (don't remember anymore) sf built in the 70's we initially had two zones (one per floor) and we added a 3rd zone in the kitchen / laundry room area.  All of the handlers were configured with multiple room returns.
 
Here too as wkearney99, the thermostat settings and nice looking thermostat is never touched.  The Leviton HAI Omnitouch consoles have access to the thermostat and mostly looked at only for temperatures around the house.  I utilize the Leviton HAI remote combo temperature / humidity sensors and I do like to look that the house is evenly cooling or heating.   That said the Omnistat2 has many features on it plus it can be managed by the Leviton HAI OPII panel locally or remote (via cell phone).

 
The Leviton system seems to be getting toward what I was looking for. So I put the sensor
 
http://store.leviton.com/Omnistat-Remote-Indoor-Sensor-23A00-2/dp/B009RQSD8Y#.U_zgU4CwJQ0
 
in the walls and connect it via cat5 (overkill, I know) back to the thermostat
 
http://store.leviton.com/Omnistat2-Multistage-Humidity-Control-Thermostat/dp/B00CUF2DYE?field_availability=-1&field_browse=6059159011&id=Omnistat2+Multistage+Humidity+Control+Thermostat&ie=UTF8&refinementHistory=brandtextbin%2Csubjectbin%2Ccolor_map%2Cprice%2Csize_name&searchNodeID=6059159011&searchPage=1&searchRank=salesrank&searchSize=12#.U_zfVICwJQ0
 
which can live in my wiring closet. I will need one thermostat in the closet per zone, and at least one remote temperature sensor per zone. The thermostat contains a local temperature sensor, I presume, which can be disabled in place of the remote sensor. Did I get that all correct?