Announcement Announcement Module
Collapse
No announcement yet.
How to check airflow from heat ducts? Page Title Module
Move Remove Collapse
X
Conversation Detail Module
Collapse
  • Filter
  • Time
  • Show
Clear All
new posts

  • How to check airflow from heat ducts?

    How can a homeowner check the amount of airflow out of the heating ducts without a specialized instrument? My master bedroom is about 3 degrees colder than the rest of the house and I'm thinking I need to reduce the amount of output in the rest of the house in order to provide more airflow to the master bedroom.

  • #2
    Re: How to check airflow from heat ducts?

    have you tried adjusting the heat registers in the other rooms?

    this will push more warm air into your mbr.

    also, check the register in the mbr.? it might be partially closed.

    Vince

    Comment


    • #3
      Re: How to check airflow from heat ducts?

      I have not adjusted any of the dampers yet. The register in the MBR is fully open as well as the damper.

      My thought is to check the volume of air flowing out of the registers and then adjust the dampers so the flow is equal.

      Comment


      • #4
        Re: How to check airflow from heat ducts?

        The only reliable way to do this is through the use of a flow hood there are way to many variables in ductwork design and construction...

        The easier way is to simply use trial and error start by choking down the registers in the less used area of your home forcing more air into the areas you want

        If you want to make a fun project out of it you can purchase a ductalator and a few books ( ACCA Manual D and J) and verify proper system design and function...

        Okie

        Comment


        • #5
          Re: How to check airflow from heat ducts?

          Here's a low tech way. Tape a piece of toilet paper to a dowel and note how high it blows up into the air if held a specific distance from the register. Have fun explaining what you are doing to your wife.
          sigpic

          Comment


          • #6
            Re: How to check airflow from heat ducts?

            I dont think you are going to gain 3 degrees in your mbr without seriously choking the system down.

            Is this 3 degree difference being measured just before the furnace turns on, or just before it turns off? If you have a 3 degree difference when the furnace is at the end of its heating cycle, I would suggest adding another supply register. Or its possible that you could have too much or too little return.

            If the 3 degrees is measured just before the furnace starts its heating cycle, you could try running the furnace blower constantly to help even out the temps, but it sounds more like an air infiltration issue.

            Andy

            Comment


            • #7
              Re: How to check airflow from heat ducts?

              KHE

              I have the same kind of problem in my house. The master bedroom is farthest from the air handler - furnace. To help solve this, I partly blocked air flow from registers in warmer rooms. In the master bedroom only for testing I removed the register and return grill. This has helped things. I found that by replacing the register with a better and less restrictive type where I can have a wide angle and downward air sweep that helped. I also installed a new return grill with farther spaced slats to reduce restriction and noise.

              Just for a day or two you might try removing the register and return grills. (watch the return duct that things don't get sucked into it.) As for choking down the system, try a little blocking off air flow from the supply registers in warm rooms, but please don't get carried away. The furnace needs to run at close to the design total air flow.

              If you have a smallish oscillating (sweeps left - right) pedestal fan try placing it high up (near ceiling) in the room in a spot known to be warm, run it on low speed and aim it downward and toward a known cold spot in the room.

              Comment


              • #8
                Re: How to check airflow from heat ducts?

                "Have fun explaining what you are doing to your wife."

                Tell her you are recycling toilet paper.
                ---------------
                Light is faster than sound. That's why some people seem really bright until you hear them speak.
                ---------------
                “If I had my life to live over again, I'd be a plumber.” - Albert Einstein
                ---------
                "Its a table saw.... Do you know where your fingers are?"
                ---------
                sigpic http://www.helmetstohardhats.com/

                Comment


                • #9
                  Re: How to check airflow from heat ducts?

                  Draft Gauge


                  #460 Flow Meter


                  Dwyer




                  Been using this device for years to determine FPM's on newly installed gas water heaters.
                  Northern Kentucky Plumbers Twitter Feed | Plumbing Videos

                  Comment


                  • #10
                    Re: How to check airflow from heat ducts?

                    if you have a damper on the duct work use that not the registers or you will hear the air coming out of it .
                    Charlie

                    My seek the peek fundraiser page
                    http://observatory.mountwashington.o...nal&fr_id=1040


                    http://www.mountwashington.org/weather/conditions.php

                    new work pictures 12/09
                    http://public.fotki.com/hvachawk/

                    Comment


                    • #11
                      Re: How to check airflow from heat ducts?

                      you can actually make a fairly acurate meter using a dc booster fan and a multi meter.
                      sigpic

                      Comment


                      • #12
                        Re: How to check airflow from heat ducts?

                        Thanks for the replies. The furnace is in the center of the basement and the supply trunk lines go in two directions. I've partially closed off the dampers in the rooms closest to the thermostat and it seems to have improved. The temp difference is down to 2 degrees now. I'll continue to work at balancing it over the next few days.

                        Comment


                        • #13
                          Re: How to check airflow from heat ducts?

                          Any chance your MBR is above the garage?
                          If so open up the ceiling in the garage.
                          I have seen many homes where the builder drapes in a sheet of poly, dumps a open pipe into the space to attempt to heat the cavity
                          and then try to stuff 6" of insulation into the 3.5" remaining space.
                          The feeders to the MBR vents travel through this cool space and perhaps also up one of the garage walls loosing much of the heat.

                          Comment


                          • #14
                            Re: How to check airflow from heat ducts?

                            Originally posted by Ruudacguy View Post
                            I dont think you are going to gain 3 degrees in your mbr without seriously choking the system down.

                            Is this 3 degree difference being measured just before the furnace turns on, or just before it turns off? If you have a 3 degree difference when the furnace is at the end of its heating cycle, I would suggest adding another supply register. Or its possible that you could have too much or too little return.

                            If the 3 degrees is measured just before the furnace starts its heating cycle, you could try running the furnace blower constantly to help even out the temps, but it sounds more like an air infiltration issue.

                            Andy
                            This and WBROOKS seem to offer the best advice. Maybe your MBR needs more airflow. How many outside walls does this room have? Do you have large windows or french doors, etc.?
                            How about room volume such as high ceilings or as suggested is this room over an unheated space such as a garage? As always do the little things such as caulking, seals, insulation. How did you measure the temp difference?

                            First impressions, without any of the above questions answered or seeing the home, you need an addition supply line into the room, but that is just a guess.

                            I really didn't answer you exact question, but maybe you got some help.
                            thepapabear<BR>When a bureaucrat has a hammer, everything begins to look like a nail.

                            Comment


                            • #15
                              Re: How to check airflow from heat ducts?

                              Try leaving your bedroom open and see if that makes a difference. If it does, trim about a half to three quarters of an inch off the bottom of your bedroom door.

                              Comment

                              Working...
                              X