Picking up the pieces after a botched install - Page 2
Page 2 of 3 FirstFirst 123 LastLast
Results 14 to 26 of 30
  1. #14
    Join Date
    May 2009
    Posts
    196
    Quote Originally Posted by neophytes serendipity View Post
    So, at best, you have 70k btu of heat available somewhere around 60* F... and less as it gets colder. Just guessing here, but you *might* have 18k btu of HP available at 10*F if the rest of your system is perfect (and it isn't)... so, 18k btu + 34k btu= 52k btu.
    According the manufacturer's performance data, the HP is good for 16k @ 10. 50k total system output @ 10. My point is that 63k is definitely not there @ 10--which is partly why I'm trying to figure out what to do next.

    60k BTU at 1600 SF with a winter design of 10* F? Do you leave the door open or something?
    22k of losses through 330sq ft of glass area, most of it single pane, most of it on the upper level.


    @Shophound: Infiltration was measured at about 0.5ach / 100cfm. I've done some improvements since then, however, and the current figure will be lower.

  2. #15
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    67,579
    What load calc program was used to calc the heat loss.
    Contractor locator map

    How-to-apply-for-Professional

    How many times must one fix something before it is fixed?

  3. #16
    Join Date
    Sep 2008
    Posts
    5
    Cold Feet,

    When it's 40 F outside, is the temp of your lower level the same as the upper level.

    sg

  4. #17
    Join Date
    May 2009
    Posts
    196
    Quote Originally Posted by clarke View Post
    When it's 40 F outside, is the temp of your lower level the same as the upper level.
    No. Upstairs will be at the thermostat set point; downstairs will be 7-10 degrees colder.

    This has been attributed to the lower level ductwork rather than the unit sizing.

  5. #18
    Join Date
    Sep 2008
    Posts
    5
    Cold Feet,

    When it's 10F outside is your heat pump running 100% and is your 10KW of heat on 100%.

    sg

  6. #19
    Join Date
    May 2009
    Posts
    196
    Quote Originally Posted by clarke View Post
    When it's 10F outside is your heat pump running 100% and is your 10KW of heat on 100%.
    To be honest I haven't looked at system status data at 10F but I get high stage heat from both the HP and heat strips at other times.


    If I go for a separate system for the lower level, is there an overwhelming reason to go for one option (elec baseboards, minisplit heat pump, dedicated split system, hydronic) over the other given the climate and the small heat loss of the floor? I'd like to separately zone all five major rooms if possible.

  7. #20
    Join Date
    Dec 2005
    Location
    Mechanicsburg PA
    Posts
    215
    1. Close the 2nd floor registers to force the heated air where it's needed.
    2. Replace the single pane windows.

    Unless the ductwork to the 1st floor is grossly undersized this should work.
    Arizona dreaming....

  8. #21
    Join Date
    Sep 2008
    Posts
    5
    Quote Originally Posted by Cold Feet View Post
    To be honest I haven't looked at system status data at 10F but I get high stage heat from both the HP and heat strips at other times.


    If I go for a separate system for the lower level, is there an overwhelming reason to go for one option (elec baseboards, minisplit heat pump, dedicated split system, hydronic) over the other given the climate and the small heat loss of the floor? I'd like to separately zone all five major rooms if possible.
    Cold Feet,

    I'm having difficulty with the 60MBTUH heat loss of your 25 year old 1600 sq. ft. home and the size of the heat pumps that are being recommended. Beware heat pump systems with those capacities will generate 10+ air changes per hour and it will be uncomfortable living conditions.
    Your system does not function properly at 40F. At that temperature you have more then enough capacity. You should balance the distribution system to deliver more air to the lower level. This will lessen the heat input to the upper level and allow the system to run long enough to heat the lower level. One way to do this is to throttle the dampers in the upper level registers. I don't recommend this because it changes the fan static pressure. A well installed duct system should include damper regulators at each take off to each register and balancing should be accomplished using these dampers.
    Better yet install one of the many zone control systems available. My personal favorite is the system manufactured by ARZEL TECHNOLOGIES.


    Good luck with your project
    sg

  9. #22
    Join Date
    May 2009
    Posts
    196
    jjou812 and clarke:

    Downstairs is ducted with a very short 8x12 metallic feeder leading into two 8" round metallic ducts. Upstairs is fed off a 9x20 metallic trunk. The only balancing control I have is through the register louvers. The upstairs (old) duct work doesn't have dampers and the installer refused to install dampers on the new (basement) ducts. Closing all the vents upstairs makes no difference--I tried it last heating season.


    I'd like to replace the windows, but the price tag to replace all of them is between ten and one hundred times the cost of having the ducts fixed or installing a separate heating system for the lower level. I don't have the spare funds right now.


    I'm fairly confident I did the loss calculation right but I'll post the measurements for one room if anyone is volunteering to check my work for systemic screwups.

  10. #23
    Join Date
    Jun 2005
    Location
    Near Chicago, IL
    Posts
    3,317
    Quote Originally Posted by Cold Feet View Post
    jjou812 and clarke:

    I'd like to replace the windows, but the price tag to replace all of them is between ten and one hundred times the cost of having the ducts fixed or installing a separate heating system for the lower level. I don't have the spare funds right now.


    I'm fairly confident I did the loss calculation right but I'll post the measurements for one room if anyone is volunteering to check my work for systemic screwups.
    FYI: Check out the window selections in HVAC-Calc.

    It only takes a couple of keystrokes. Watch the loss/gain numbers.

    Hint: Single pane windows with storms perform pretty darn well.

  11. #24
    Join Date
    Mar 2008
    Location
    Long Beach, CA
    Posts
    3,267
    Quote Originally Posted by Cold Feet View Post
    No. Upstairs will be at the thermostat set point; downstairs will be 7-10 degrees colder.

    This has been attributed to the lower level ductwork rather than the unit sizing.
    Coldfeet,
    As we all know, heat rises. Do you have an open floor plan that allows the heated downstairs supply air to immediately ascend upstairs? If so, an increase of volume to the downstairs will make little improvement. The bottom of my stairway is always cold because there is no ceiling to hold the heat down. I know of other houses that are always cold downstairs because of very open floor plans and high ceilings.

    Also, where is your return air register? Is it in the ceiling at the top of the stairway? IMO, if it is mounted high in the house it is causing part of the problem. Not only is the heated air rising to the upstairs, but it is being sucked out and reheated. All you’re left with is the cold strata of air on the first floor which is minimally affected by the heater.

    Few HVAC pros agree with this theory. They either do not want to understand airflow and air density or they want to continue installing heater returns on ceiling because it is an easier install.

    So, I agree that your problem is probably ducting, but not necessarily the supply ducting.


    Quote Originally Posted by jjou812 View Post
    1.

    2. Replace the single pane windows.
    Window replacement is a large part of my business. Unless your windows are very drafty, it is my opinion that window replacement will have little affect on heater performance. What dual pane windows do best is help retain heat, which in turn will help save on unit cycling. If the heater doesn’t heat the house, the windows can’t hold it in.

    Brian

  12. #25
    Join Date
    May 2009
    Posts
    196
    Quote Originally Posted by Brian GC View Post
    Do you have an open floor plan that allows the heated downstairs supply air to immediately ascend upstairs?
    It's a hybrid plan. The upstairs level is open plan and is connected to the downstairs hall via an open stairway. The downstairs hallway leads to five rooms, each of which has well-fitting doors that are almost always closed.

    The hallway is chilly (~66 degrees) but 61 is not unheard of in the larger rooms--despite the fact that they're isolated from convecting with the rest of the house.

    Also, where is your return air register? Is it in the ceiling at the top of the stairway?
    I've got five spread between the two levels. Upstairs is served by a single 24x4 (duct size) return at the top of the stairway. The basement has four 12x4 returns--one in the hall, one each in three of the rooms. All returns in the house are mounted at floor level.

    I did some smoke tests last heating season. There's no rise up the stairway. At tread height, air goes downward into the basement. From about 2' above tread height to at least 6' above the level of the main floor, there is no air movement. Light a scented candle here and the smell will linger for 24 hours or more, even with the air handler fan running continuously.

    As for the basement rooms, the only air movement other than infilitration and via the supply & return registers is under the doors. This air is cold , and in two rooms, flows into the rooms from the hall. There's no hot air escaping above the doors.

    Given what I've seen with smoke tests I don't think I'm losing heat upstairs.

  13. #26
    Join Date
    Sep 2008
    Posts
    5
    Quote Originally Posted by Cold Feet View Post
    jjou812 and clarke:

    Downstairs is ducted with a very short 8x12 metallic feeder leading into two 8" round metallic ducts. Upstairs is fed off a 9x20 metallic trunk. The only balancing control I have is through the register louvers. The upstairs (old) duct work doesn't have dampers and the installer refused to install dampers on the new (basement) ducts. Closing all the vents upstairs makes no difference--I tried it last heating season.


    I'd like to replace the windows, but the price tag to replace all of them is between ten and one hundred times the cost of having the ducts fixed or installing a separate heating system for the lower level. I don't have the spare funds right now.


    I'm fairly confident I did the loss calculation right but I'll post the measurements for one room if anyone is volunteering to check my work for systemic screwups.
    Cold Feet,

    Installing storm windows would be beneficial. U value of a wood framed single pane clear glazed window is U .9 with storm U .55 significant improvement. Your distribution is another issue. You state that when you close all the registers in the upper level nothing changes. When you do this does the air flow to the lower level increase. You can get an idea with just a piece of toilet tissue. Use the tissue as a vane type air measuring instrument and note how far the air displaces the vane with the registers in the upper level open and closed. If your air flow doesn't increase. This can happen because of ( a loose fitted damper at the register and you did not change the flow by closing the damper again use the tissue, excessive duct leakage, your lower level trunk line is tapped into the plenum creating excessive static pressure at the tap or a combination of any of these and more.
    Your description of the distribution in your home suggest a simple zoning installation which would balance your system.

    sg

Page 2 of 3 FirstFirst 123 LastLast

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
Comfortech Show Promo Image

Related Forums

Plumbing Talks | Contractor Magazine
Forums | Electrical Construction & Maintenance (EC&M) Magazine
Comfortech365 Virtual Event