Every bedroom HVAC zoning?

My house has 2 HVAC systems, one for upstairs, the other for downstairs. Most of the downstairs is open, so zoning it probably won't be helpful. Each room upstairs has varing usage, heating and cooling properties and climate control needs. I am thinking of zoning the upstairs unit into 5 zones. I'll tie it into my home automation controller so that I can heat and cool based on room usage.

Most of the information I'm seeing talks about zoning upstair and downstairs or upto 4 zones. Is zoning each bedroom not commonly done because it is cost prohibitive or because of some other reason? I'll have to add a bypass damper with temperature sensor to the upstairs HVAC system. Other than that, are there any other recommendations? If anyone else has already done this, what controller and thermostats did you use?
 

ver0776

Active Member
I would (don't listen to me though) focus on getting the temperature recorded in the different rooms. (look a www.bwired.nl) Once you know the temperature differences, it will help decide on zoning and possible reduce the individual zones you need to control. Maybe a couple of the rooms are occupied about the same times and the temps are similiar and you can save a zone and use a 4-zone system then.

Even in a 4-zone system, I would like to know the temps in every room possible, even if I don't have independant control of said rooms.

Sorry, not trying to answer you question as much as promo the 1-Wire temp monitoring setups... HVAC is still in my future too.

Vaughn
 
Thanks for the link. Holy cow! There are enthusiasts and then there are fanatics. I don't know whether to make that a goal or stop now. Very nice indeed.

I've done some temperature measurements in my upstair rooms. There are temperature differences of up to 20 degrees F (due to one of the rooms being a home theater). The bedrooms and office can be 5-10 degrees off. It is because of this big gap and the times of room usage that I've been considering zoning each bedroom.
 

dublin00

Member
Black Magic said:
Most of the information I'm seeing talks about zoning upstair and downstairs or upto 4 zones. Is zoning each bedroom not commonly done because it is cost prohibitive or because of some other reason? I'll have to add a bypass damper with temperature sensor to the upstairs HVAC system. Other than that, are there any other recommendations? If anyone else has already done this, what controller and thermostats did you use?
I have a similar situation myself. My house is shaped like a U with one room that sticks out from one leg of the U like an apostrophe. Heating/Cooling the upstairs is a challenge with one leg of the U having a direct southern exposure and the other facing north. That and I have an aging mother-in-law in one upstairs bedroom that needs a constant temperature day and night.

Before you start I recommend reading up on the pitfalls of zoning HVAC. Lots of websites on the internet with useful info (some old threads here too). Also read up on the specs of your current furnace: does it have single stage or dual stage heat, a constant or variable speed blower, etc. With dual stage burners you can shutoff the second stage when only one/two zones are calling. And a true variable speed blower can eliminate the need for a bypass damper, but such furnaces are very rare in residences.

You can find lots of zone controllers that support more than 4 zones. Look at AprilAire and Jackson Systems. They both provide zone controllers that are expandable with add on boards so you can add many many more zones. I think one of the residential Jackson zone controllers even goes up to 14 zones :angry: .

I haven't installed/selected a zone controller yet, but since I have an ELK-M1 I will most likely use the AprilAire 8870 or RCS TS-40/16 RS-485 thermostats and a compatible zone controller. I prefer the AprilAire myself since it seems to be slightly cheaper per unit and it looks pretty neat on the wall, but the RCS are easier to retrofit when replacing an existing thermostat. I'm also probably going to take advantage of the zone controller install to add on an air-cleaner and humidification control to the HVAC system at the same time (parts are cheap and the ducts are being re-configured anyway...).

I'll probably install mine as soon as I find the time to finish installing my M1. Lets us know how yours works out. I'll do the same.
 

TCassio

Active Member
They make individual room dampers that are X10 controllable. Take a look at Automated oultets site, I believe they sell them.
 
I've been doing a lot of research on Multi-Zone HVACs. There are many of things to consider. Manipulating your HVAC system or scoping out a new one isn't typically done by homeowners. Doing some things will validate any warranty, doing others will drastically reduce its mean time to failure.

Chakara, those automated registers look pretty nice and from your review they seem to be very quiet. Automated registers essential accomplish the same thing as manually closing and opening the currently installed vents. This poses a few problems - static pressure build up in the duct work; wind noise from leakage at the register; automated register fighting the air pressure trying to close/open while the blower is on.

Give me some time to organize my research. I'll post my guide on this or another thread.
 

markthomas

Active Member
RCS makes a 6-zone controller that you or an HA controller can control via RS-232. Some HA controllers already have built-in support for zoned RCS systems (I'm not aware of a published list anywhere though)

And it's inexpensive compared to many solutions.
 

noshali

Active Member
markthomas said:
RCS makes a 6-zone controller that you or an HA controller can control via RS-232. Some HA controllers already have built-in support for zoned RCS systems (I'm not aware of a published list anywhere though)

And it's inexpensive compared to many solutions.
Spanky,

Is there any support for RCS zone contrllers using a serial port expander. Would be really interested in this.

regards,
 

Spanky

Senior Member
Need to do some research on the zone controllers from RCS to see if the temperature is set the same way as the thermostat temperature protocol.
 

noshali

Active Member
Spanky,

Thanks...that way I could just get a zone controller and get elk to do everything. Important stuff to note would be the status of the dampers and the temp reading from the thermostat.

I don't know if manual operation of dampers is supported. Meaning have ELK open the dampers and close them also. Let's see what you find out and then we can take it from there.


Here is the stuff from the RCS website...not clear on what they mean by mechanical data. Hopefully it is the staus of the dampers.

Remote Communications Interface
RS-232, 3 wire full duplex operation.
RS-485, 2 wire half-duplex operation.
9600 Baud
Addressable System ID 1-16
Read Temperatures, Setpoints and Modes remotely.
Set Setpoints, Modes and Fan operation (Auto/On) remotely.
Read mechanical system status.
RS-232/485 Commands:
Read Zone Temps
Read and Set Zone Setpoints
Read and Set Zone Modes
Read and Set Fan Mode
Read and Set Vent Mode
Over 20 Commands

Here is the link to the serial data communication.
http://www.resconsys.com/docs/thermostats/...50-00225-42.pdf

regards,
 

justmikie

New Member
one of the reasons that 4 zone controllers are more common, is that the more zones you create, the more probelms you create.

I'm not an HVAC guy, but after working with a few, here is a summary of our experience.

2 zones - common and works great. Just put in a bypass damper.
3 zones - bypass damper, and possbily a dump zone. A dump zone is usually an open area that has a duct from the HVAC system that is always open. When any other room calls for heat or cool, the dump zone will get it. this can either be a seldomly used room, or a larger, more open area.
4 zones - definatley use bypass and dump zone. If you have 4 separate zones without a dump zone, the amount of air being pumped out makes a lot of noise, raises the duct pressure, and causes very fast heating/cooling. this seems like a great idea, but it casues very short duty cycles for the hvac unit which is not good for the unit.

As people above have mentioned, if you have a multi-stage unit, then you can do more splitting since the unit itself can run at 2 different "speeds".
 
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