Unused rooms....Should I close the vents or leave them open

Reply

  #1  
Old 05-15-14, 03:49 AM
Member
Thread Starter
Join Date: May 2014
Location: usa
Posts: 11
Received 0 Votes on 0 Posts
Unused rooms....Should I close the vents or leave them open

I have a two story house. I do not use the upstairs at all. There are 4 rooms up there.. Should i close the room vents? Close the vents and doors?? Close the doors and open the vents?? Should I open the vents. Open them just a little bit???............ If I ask 10 HVAC guys, 5 will say open / 5 will say close???. Any thoughts out there??
 
Sponsored Links
  #2  
Old 05-15-14, 11:10 PM
Member
Join Date: Mar 2006
Location: Wet side of Washington state.
Posts: 18,482
Received 25 Votes on 19 Posts
I don't think any competent HVAC tech will tell you to close the registers in four rooms unless your house has twenty or more rooms total. The furnace needs to have a minimum airflow through it to keep the heat exchanger from overheating or the cooling coil from freezing. Closing off too many registers WILL upset the airflow significantly UNLESS you have a "dump" zone in the house that opens a damper when the airflow drops too low. This problem may be somewhat alleviated if you have an ECM (variable speed) motor which will have a tendency to increase the speed to overcome the added resistance in the discharge ducts.
 
  #3  
Old 05-16-14, 04:48 AM
HVAC RETIRED's Avatar
Member
Join Date: May 2008
Location: Wisconsin USA
Posts: 715
Received 0 Votes on 0 Posts
Should have dampers installed at the branch-take-offs which you could adjust during the heating season so the temp-rise does not go above the furnace rating usually 60 or 70F temp-rise MAX.

Do not block-off Return areas as that can buildup excessive pressure in a room that is forced outside.

A lot depends on the duct & diffuser sized capacity going to the first floor area; of course the heating & cooling will no-doubt be considerably oversized for only one floor area.

If the cooling coil is going to be under-loaded installing a TXV refrigerant metering device plus a suction line accumulator will help prevent liquid refrigerant from slugging the compressor...
 

Last edited by HVAC RETIRED; 05-16-14 at 04:52 AM. Reason: adding needed info
  #4  
Old 05-16-14, 05:11 AM
Member
Join Date: Jun 2012
Posts: 896
Received 2 Votes on 2 Posts
Where's the thermostat located? If it's on the 2nd floor, you've got to leave the system as is.
If it's on the first floor, you may be able to throttle back the 2nd floor registers a bit. Don't close them, just reduce the air flow maybe 50%? Then you'll have to monitor the system for a few days. Things to look or feel for would be an increase in humidity downstairs do to short cycling or as others have said, a possible freeze up. If the system performs ok, you should notice the temp increase on the 2nd floor while maintaining a comfortable level on the 1st.
 
Reply

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Thread Tools
Search this Thread
Display Modes
 
Ask a Question
Question Title:
Description:
Your question will be posted in: