HVAC design, Manuals J, S, T, & D, Duct leakage, Air flow, ENERGY STAR new home requirements, and more. Since heating & cooling are such a big part of home energy use, understanding HVAC is critical.

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  • Does anyone have experience doing ACCA Manual S with Water Furnace equipment?  As far as I can tell they do not provide enough data to properly perform the Manual S. 

  • I bet a lot here in this group can identify this refrigeration system. :)


  • http://homeenergypros.lbl.gov/group/radiant-control-coatings-and-th...

    We have been applying a radiant control coating to interior and exterior ac units and ducts for over 30 years withv great resuls.

    I started a classroom for Radiantt Control Coatings a few years back.


  • For ES 3.0 you have to verify the contractor is certified.  If he is certified he knows he has to take that measurement.  I would discuss the requirement with him and find out why he doesn't want you drilling in the cabinet.  I know you do not want to hit a piece of the coil.  The recommended practice is to use the same holes the certified HVAC companies tech used for rater measurements.

    My next step is who hired you and is paying you.  They can decide not to go ES 3.0 - talk to the contractor - or depending on the paper work, refuse to pay him until he properly completes the process.  I hope it doesn't go that far.

  • I just go through the filter.  if it is not metal or electronic.  Leave the filter in place and poke a hole with your probe in a corner.  If you want to know the pressure drop across the filter place the probe just under the filter and compare to the number above the filter.

  • I want to test static pressure for Energy Star version 3 in a split heat pump with the air handler in an interior closet so it does not have any return air duct the filter is in the slot at the bottom of the air handler. The inspection form requires 2 inputs a supply side static pressure (I took it in the riser plenum attached to the Air handler.) and a return side static pressure that is supposed to be between the filter (slid in the bottom of the Air handler) and the blower fan. The contractor says he doesn't think he needs to take the return side static pressure because there are not any return air ducts but he will not allow me to drill a hole in the cabinet between the filter slot and the blower. What do you suggest I do to get an accurate number?

    Thank you in advance for any help you can offer.

  • You  havent given  enough information to make an educated guess.  How dusty was the house before?  Is it in all rooms or just a few.  is it dust or fibers from the cloth materials in the home.  If you can sweep your hand across a surface and the materiall rolls up it is fibers and is probably not coming from the duct work

    Take a camera and shoot some pictures down the duct or runs and that will show you if something is in the duct system as well.  What type and efficency  filter is the homowner using?  You might check the returns and see if there are any openings to the outside of the envelope . 

    when you gave "more air" how did you do that?

  • Good morning,

       I have a client that complained that certain rooms were either cold or hot. She had 45% leakage. We gave her more air, tightened the ducts and now she called and said that the home is now getting very dusty. What is the cause and what to do next. It has gone through the summer with the air blowing thru it, I would think the the dust in the ducts are already blown out

    hanks for your reply

  • When will the ICC Codes prevent the installation of air handlers and ductwork in unconditioned attics. This practice is the biggest obstacle to achieveing the best results when retrofitting.
  • I went out to get the mail this morning and saw my neighbor's roof.  The attached image shows what I am thinking is ice, frost on the roof.  It is obviously circular around the flue from the furnace. The flue from the DHW is separate and not in the image.  It was frosty this morning and overcast. At 8:30 most roofs have frost. By the time I noticed this and took the shot, the frost on the other roofs is gone.

    Is this excessive condensation from moisture in the flue gases and does that mean the furnace has a problem?


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