No heat In farthest rooms


Old 08-09-15, 09:25 PM
Thread Starter
Join Date: Oct 2014
Location: USA
Posts: 6
Received 0 Votes on 0 Posts
No heat In farthest rooms

Have a Carrier furnace Model 58STX070, two-story house.
- Furnace in the garage, two bedrooms, toilet
- Bedroom, living room, kitchen, dining.

The further the space from the furnace, the little the air
comes in. The registers at the other end of the house, does
not only have very low air flow, but the heat is so limited.
Sure the law of physics would prevail here and I expect such
to happen. However, the heat is so low it's like the register
does not exist.

The bedroom upstairs, right above the heater gets so warm,
even after closing both register grills, the room is still hotter
than any other space in the house. I would think with the two
grills closed, more heat would be flowing into the fathest
registers for more heat. Yes, I know the the further the grill
the less heat comes out from it. But theses furthest areas
are not warm but still cold.

Just moved into this house in November 2014 and got the HVAC
system completely cleaned. The furthest rooms feels like they
don't have registers. There must be something I can do to
help get in some heat otherwise, why have registers there just
for 'show'? Any sugestions?

Any idea will be much appreciated.
Sponsored Links
Old 08-10-15, 06:04 AM
Group Moderator
Join Date: Mar 2003
Location: NC, USA
Posts: 21,238
Received 265 Votes on 240 Posts
Do you have access to the ducts either from a crawl space, attic or basement? I would first inspect to make sure they are connected. The duct can become disconnected so you may be blowing your heated air into the attic.

Also inspect to make sure that no ducts are collapsed or crushed. This is especially possible with flexible. I have seen them collapse or pinch shut when there are not enough hangers to support the duct. In attics and crawl spaces people crawling around can crush or squeeze them which also kills air flow.

That's the cheap & easy to check. If the ducts check out OK then you have to consider if the ducts are improperly sized or installed wrong.
Old 08-10-15, 07:27 AM
Norm201's Avatar
Join Date: Sep 2013
Location: United States
Posts: 7,604
Received 91 Votes on 83 Posts
PJ forgot to mention that your duct should have dampers that can be adjusted to limit flow to the rooms that are closest to the furnace and allow much more heated air to flow to longer runs. These dampers are located near the furnace in the duct work. The handle will be in line with the duct if fully open and perpendicular to the flow of air when closed. You need to balance the flow of heated air to each area of the house (damper might be in any position from fully closed to fully open). This is usually done by the furnace installers, but by trial and error you can achieve the results you need. It is not the same as the room registers being closed or open. This is not a cure all but will provide the means to address the issue in a better way. Insulating the long runs of duct work can help. Booster fans can also be used but they use energy.
Old 08-18-15, 08:06 PM
user 10's Avatar
Join Date: Mar 2004
Location: NA
Posts: 1,999
Received 35 Votes on 30 Posts
Many problems can cause this, including but not limited to undersized trunk lines.

Yes, try adjusting dampers.

Also check your air filter type - many filters on the market are very restrictive to airflow, especially if you have a larger furnace/ac.

Do you have a copy of the service invoice? Does it mention anything about temperature rise?
Old 08-19-15, 06:46 AM
Join Date: Jan 2011
Location: USA
Posts: 4,491
Received 31 Votes on 27 Posts
A few other things, leaking ducts, lack of a return air vent or dirty filter in one.

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:
Your question will be posted in: