Zoning Basement HVAC
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Zoning Basement HVAC
This summer I finished renovating a basement in a 2-story house. The basement was kind of finished when I bought the house but in a really crappy way with just one supply register and no return so I tore it all and and started over. The house was also really leaky then and I blew cellulose into the walls and attic.
When I finished the basement I did 2" of xps foam against the foundation walls then a 2x4 stud wall with fiberglass. I kept the non-heated non-insulated slab. The basement has a hall and 2 rooms, each with a supply and return. At the end of the hall is a bathroom with just a supply, but also a heated floor with thermostat. For soundproofing reasons I used exterior grade doors and insulated all the interior walls too.
As you may have guessed the basement gets over-heated and over-cooled. If you just close the supplies the air can get kind of stale. There is also decent room to room variation within the basement because the individual spaces are so well sealed. I'd like to add zone dampers and thermostats (I've always known I may need this so I already have thermostat cables in the walls or access). I have a single speed fan and a non-modulating furnace which was powerful enough before I insulated the house, so I don't see this being done as two or three equal zones. I have an idea for how I want the system to work:
Summer:
Keep damper open during a standard circulate cycle.
If cooling is needed open damper during the next primary cooling call until the need is satisfied.
If heating is needed open the damper and run the system fan.
Winter:
Keep damper open during a standard circulate cycle.
If heating is needed open damper during the next primary heating call until the need is satisfied.
If cooling is needed open the damper and run the system fan.
So I kind of want to make the basement rooms slaves to the primary system. They can't actually make heating or cooling calls, but I do want them to be able to run the fan. Is this a good idea? Does any controller exist that can do this or do I need to build something?
Thanks!
When I finished the basement I did 2" of xps foam against the foundation walls then a 2x4 stud wall with fiberglass. I kept the non-heated non-insulated slab. The basement has a hall and 2 rooms, each with a supply and return. At the end of the hall is a bathroom with just a supply, but also a heated floor with thermostat. For soundproofing reasons I used exterior grade doors and insulated all the interior walls too.
As you may have guessed the basement gets over-heated and over-cooled. If you just close the supplies the air can get kind of stale. There is also decent room to room variation within the basement because the individual spaces are so well sealed. I'd like to add zone dampers and thermostats (I've always known I may need this so I already have thermostat cables in the walls or access). I have a single speed fan and a non-modulating furnace which was powerful enough before I insulated the house, so I don't see this being done as two or three equal zones. I have an idea for how I want the system to work:
Summer:
Keep damper open during a standard circulate cycle.
If cooling is needed open damper during the next primary cooling call until the need is satisfied.
If heating is needed open the damper and run the system fan.
Winter:
Keep damper open during a standard circulate cycle.
If heating is needed open damper during the next primary heating call until the need is satisfied.
If cooling is needed open the damper and run the system fan.
So I kind of want to make the basement rooms slaves to the primary system. They can't actually make heating or cooling calls, but I do want them to be able to run the fan. Is this a good idea? Does any controller exist that can do this or do I need to build something?
Thanks!
#3
What you are talking about is expensive and somewhat un-reliable. There are several aftermarket zoning systems but they are not always trouble free.
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I'm doing the work myself so it won't be too expensive. A few hundred dollars for thermostats and 6" duct dampers. I just don't know much about the zone controllers and if they'll do what I want.
I'm an electrical engineer I could build the zone controller myself (the logic is fairly simple). I'd just rather buy something off the shelf.
I'm an electrical engineer I could build the zone controller myself (the logic is fairly simple). I'd just rather buy something off the shelf.