zone systems - multiple dampers and thermostats

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rmcfall

Feeling the Heat
Nov 28, 2005
308
As I have posted before, I am in the process of having a new furnace installed. What I am wondering is whether a zone system with multiple dampers and thermostats would be a good thing to install? It seems that with a woodstove burning 24/7, that a zone system would be a good way to supplement areas of the house that the woodstove has difficulty heating. Has anyone tried this?
 
here is just one thing to keep in mind -
There will be a lag beteen heating in the room with the woodstove and the rest of the house. If you don't have a sufficiently intelligent control system, you may turn on the furnace for a different zone, only to find that after a few minutes the woodstove heat has mgrated there (and the furnace heat migrated in the room with the stove) making those areas much hotter than you would like.

So if you do zones, make sure they are in pretty well isolated thermally - ie. one zone is far enough from the other that the zone with the woodstove won't have much effect on the zone(s) without.
 
That is one way to separate the heating load. There are other ways a boiler and hydro air units that work off the boiler
Then there is using two smaller hot air furnaces each controling one zone. Makes for shoter duct runs and tend to be a more effecient way of distrobution. If you went boiler hydro air, there is newer high velosity 3" ducts that can fit in places normal ducts can't these systems tend to be very effecient. More important is blowing up most of the current duct work and start with a design placement that actually moves air. Not just placements because it is cheaper or more convienent to do it that way. High low feeds and returns cost more but effeciency wise, will provide even distrobution and end up costing less over a period of time
 
there is newer high velosity 3" ducts that can fit in places normal ducts can't these systems tend to be very effecient. More important is blowing up most of the current duct work and start with a design placement that actually moves air. Not just placements because it is cheaper or more convienent to do it that way. High low feeds and returns cost more but effeciency wise, will provide even distrobution and end up costing less over a period of time

I've seen this mentioned a couple times. The SDHV system isn't exactly new. Back in the early 70's in Connecticut, I worked a little with the designer of this system, Calvin McCracken. He had his entire house set up with small ducts. My dad knew about it too, but it wasn't too widely used at the time. Cal's got to be pretty old now, if still alive, but I'm sure he'd be happy to see it becoming more popular.

http://www.contractingbusiness.com/25/IssueList/Article/False/12698/IssueList

http://www.modularcenter.com/unico/about.shtml
 
After reading a bit on SDHV systems at the link, I am not sure the accounting is all correct. True, the heat loss through the ducts will be less, but any gas will cool when rapidly expanded, which is what you will be doing when you send air through a small duct at a high velocity. Ever felt those compressed air cans after blowing them for a few seconds? Without any formal analysis, if I were to guess, a system like this would be more suited to cooling than heating.
 
I added another link for heating. The only version I saw was heating only. It worked pretty well from what I experienced, but I didn't ask about efficiencies at the time. Cal also designed the water pumping system that I was maintaining for the small community.
 
Some drawbacks to high velosity smal diameter ducts. Currently the most available system is only found in hydro air systems, not a furnace version. Secondly higher velosities are much noisier. One hears the rushing air. They tend to be more expensive than conventional systems. Early on they were limited to hard pipe installations. now cheaper flexible duct work. Flexible duct work is cheaper material and labor cost but corrugations (Friction) and improper installations poor routing plague their practical installations.

IT cost more for hard pipe ducting, I believe the additional cost is worth the increase effeciency
 
So in terms of zone systems and woodheat, it sounds like it might be better to put in the zone systems after it is real clear what areas of the house won't be heated by the woodstove... We haven't moved into the house yet, so unfortunately we don't have this information yet. The house, however, is a ranch with a relatively open family, dining, and kichen areas, with the bedrooms being remote. I believe three zones would make sense--1 for the main living areas (where the woodstove is), 1 for the bedrooms, and 1 for the basement. Has anyone tried this before?

Anyone know any sites that discuss/sell these zone kits?
 
It would be my advice that you should consider two possibilities. Usually hot air with zone dampers works ok for two zones. You want 3
By the time the extra duct work is involved and the lengths of runs,you will end up witha modern version of what you are trying to advoid now. Treat the wood stove area as a normal zone. If the wood stove opperation supplies the heat, the thermostat will not activate your furnace for that zone. You might find, one furnace and zone damper for two parts of the home, and smaller separate furnace for the other part. The way you are going about it you will not need a ceiling in the basement it will be covered by duct work Remember the area you are heating requires also a return duct system. There is a lot more involved than a electronic zone damper.
My suggestion is to obtain bids and specs of the purposed installations and post them and let the forum member post commenents
 
we have a ranch style house. woodstove on one side bedrooms one the other. the bedrooms usualy stay about 69 to 71 degrees. so stove did the job. now we have 16 month old twins and when it is time for a nap we shut the door to their bedroom but because there is not good insulation in the walls the room cools off in a matter of about 30 minutes. so i broke up the heating system so that both bedrooms and bath are one zone and main house is the other. the thermostat being in the master bedroom. that worked well. but. and there is always a but to a solved problem. if the stove is crankin and we shut the bedroom doors the rest of the house gets pretty warm.

so yes, zones work well for that situ. if the doors are open the temp for the most part is good, the stove heats the house but if it is below zero outside the thermostat is set and if it starts to get cold the gas will kick in for a little help.
 
We have a large ranch with three zones: Kitchen, entrance hall, and laundry are one zone, dining room, office, and great room are one zone, and bedrooms are another zone. The system works very well. All the rooms are heated well with the fireplace except the bedrooms. We just keep the blower running constantly to the bedroom zone and it helps keep it warmer, but the furnace still needs to kick in. It's nice because we can just blow heat into the bedrooms. The system is smart, so if you have the fan blower going in all zones to help circulate air and the heat kicks on in one zone it closes the other zones so no heat goes into them. When the heat goes off it opens those zones up again.
 
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