+ Reply to Thread
Results 1 to 10 of 10
  1. #1
    Join Date
    Feb 2012
    Posts
    3

    Default uneven heating and cooling

    Hello my problem is I have an old two story home buiult in 1905. It stays comfortable on main floor but the second floor is always 15 to 20 degrees hotter or colder than the main floor. I've been told that I need a variable speed blower on my furnace and a cold air return to the second floor. I only have one cold air return and it is in the dining room.

  2. #2
    Join Date
    Jun 2007
    Location
    Keyport, NJ
    Posts
    36

    Default Re: uneven heating and cooling

    Is it hotter in the summer and cooler in the winter? Do you only have one thermostat?

  3. #3
    Join Date
    Feb 2012
    Posts
    3

    Default Re: uneven heating and cooling

    yes it is hooter in the summer and cooler in the winter. we only have one thermostat.

  4. #4
    Join Date
    Jul 2009
    Location
    Northeast
    Posts
    661

    Default Re: uneven heating and cooling

    You should have a return on the second floor, that would be a place to start. Then try to balance your system using the dampers that are in the takeoffs on your main supply trunk. Less to the floor that's comfortable will force more to the one that's not. How's your insulation? If all that doesn't work then you may have to look into having your system zoned, then you need two stats not until. Another question is is it sized right?? The right BTU's and the correct sizing of the ductwork. Also, are you getting any air from the supplies upstairs.

  5. #5
    Join Date
    May 2011
    Posts
    251

    Default Re: uneven heating and cooling

    The good news is that you don;t have issues with heat rising in winter is seems, so the house must be reasonably air tight. The bad news is that you need more airflow upstairs. You'll need to add balancing dampers to the start of the branches if you have access to the ductwork.

    Otherwise, adding a return upstairs will help a little, but you might need to install better quality supply registers. They aren't cheap, but a higher quality register will have a lot less restriction and will flow more air.

    The second issue is that like the system in most homes, it's likely oversized. Short cycling will make temperature difference worse. You're better off undersized than oversized in most cases. Because a undersized system will simply fall behind a couple degrees for just a few hours a year. IT'st suprising how little heat you actually need.

    I have a 3200sqft 1925 wood frame home in SE Iowa. Attic is well insulated and I have good storm windows and it's fairly tight in terms of air leaks. I only need a total of 75k BTU's to heat my home when it's -2F outside. A smaller 2400sqft early 1900 home with solid stone walls for example might only need a 45k BTU furnace with it's thermal mass. It effectively raises the design temp.


    So, if you ready for a new system, or when you are, get it sized correctly using a proper load calculation. For now, change out the registers and make sure they are all open and in the warmest room downstairs, add a damper at the start of the branch or partly close the register.
    1925 Two-Story Stucco Beaux Arts Neoclassical

  6. #6
    Join Date
    Nov 2011
    Posts
    51

    Default Re: uneven heating and cooling

    It's difficult to balance hot air systems. I have a similar issue. I have a Coleman gas fired furnace, and the blower can't seem to deliver air pressure to some of the distant rooms. A variable speed blower seems like a good idea.

  7. #7
    Join Date
    Jul 2009
    Location
    Northeast
    Posts
    661

    Default Re: uneven heating and cooling

    Quote Originally Posted by bconvers9622 View Post
    It's difficult to balance hot air systems. I have a similar issue. I have a Coleman gas fired furnace, and the blower can't seem to deliver air pressure to some of the distant rooms. A variable speed blower seems like a good idea.

    A variable speed blower will not help, balance the system , it's simple

  8. #8
    Join Date
    Jul 2009
    Location
    Northeast
    Posts
    661

    Default Re: uneven heating and cooling

    Quote Originally Posted by motoguy128 View Post
    The good news is that you don;t have issues with heat rising in winter is seems, so the house must be reasonably air tight. The bad news is that you need more airflow upstairs. You'll need to add balancing dampers to the start of the branches if you have access to the ductwork.

    Otherwise, adding a return upstairs will help a little, but you might need to install better quality supply registers. They aren't cheap, but a higher quality register will have a lot less restriction and will flow more air.

    The second issue is that like the system in most homes, it's likely oversized. Short cycling will make temperature difference worse. You're better off undersized than oversized in most cases. Because a undersized system will simply fall behind a couple degrees for just a few hours a year. IT'st suprising how little heat you actually need.

    I have a 3200sqft 1925 wood frame home in SE Iowa. Attic is well insulated and I have good storm windows and it's fairly tight in terms of air leaks. I only need a total of 75k BTU's to heat my home when it's -2F outside. A smaller 2400sqft early 1900 home with solid stone walls for example might only need a 45k BTU furnace with it's thermal mass. It effectively raises the design temp.


    So, if you ready for a new system, or when you are, get it sized correctly using a proper load calculation. For now, change out the registers and make sure they are all open and in the warmest room downstairs, add a damper at the start of the branch or partly close the register.
    Dampers should be in the supply takeoffs, there made that way

  9. #9
    Join Date
    May 2011
    Posts
    251

    Default Re: uneven heating and cooling

    Quote Originally Posted by Sten View Post
    Dampers should be in the supply takeoffs, there made that way
    Yes... of course... if you have access to the ductwork. Thats the best solution. IF not you can do some balancing at the registers, and can also balance a system by doing the opposite and reducing air flow restriction using better quality damper. Typical dampers are cheap stamped steel and don't have very good throw and are noisy at even moderate velocties. Better registers cost 5-8X more, but can flow much higher velocities, can easily mix air in even a large room with excellent flow. and flow much more air at the same static pressure. You can easily double airflow by using a slightly larger boot and grill size and good quality register.

    The PO's in my house installed massively oversized furnaces. When I moved in some rooms were 5-7F warmer than other rooms. Now they are all within 1F and the noise at the registers has been nearly silenced. Based on my calculation, it has 120% more combined heating capacity than it needs and about 80% more cooling capacity.


    Again, I was just giving an alternative to opening up walls.
    1925 Two-Story Stucco Beaux Arts Neoclassical

  10. #10
    Join Date
    Nov 2011
    Posts
    51

    Default Re: uneven heating and cooling

    Quote Originally Posted by Sten View Post
    A variable speed blower will not help, balance the system , it's simple
    It's true, in some cases, however I found that in my system the humidifier caused somewhat of an obstacle the way it was installed. (going to re-install it....the installer just about closed up the plenum). However the variable speed blower was a great temporary fix for me.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •