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  1. #1
    Join Date
    Jun 2011
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    SW Ohio
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    224

    Energy Audit/Manual J done... feedback on results?

    OK, so I was able to take advantage of a program that the city has going on to do Home Energy Audits on homes to help save energy. The company came out and did the audit along with a blower door test. My biggest problems we air leakage coming from my pull down stair case, whole house attic fan and some air leaks near the rim joist on my house. The blower door test results were: 0.64 ACH at -50 Pascal with the house drawing 3652 CFM. They had the total sqf of the house being 2308 (1500 1st floor). They said I should be down near 0.40 ACH.

    When I called them to ask questions about the audit I asked if they did a manual “J” as well and they said yes. Looking over the report it looks as if a 2.5Ton unit is what it calls for but when the guy came to do the audit he didn’t measure any windows/doors and said he had the sqf of the house already. I showed him a drawing I had done that has all the room dimensions as well as window and door and he took a photo of it with his camera. So, I’m not sure looking over the report if you can tell if they used my info or just did a quick whole house manual J.

    I did this to find out what leaks if any my house had so I can fix them and to find out what size HVAC should be used. Currently the house (ranch 1500sqf 1st floor) has a 16yr old Bryant 90PlusI 80KBTU with a 3Ton AC. The AC unit leaks but not bad that we have to charge it once a year. They gave me quotes for both a Bryant Hybrid HP and Water Furnace GEO system. I was surprised that the HP was only $3K less than the Geo once all the tax/rebate stuff was off. Still, the HP quote was close to $4K more than quotes I had last year when we first moved into the house. I also wanted a quote to just replace the AC but I did not get that and after seeing the prices for the other stuff I’m sure it would be too much.

    Can anyone give me any feedback on my blower door results and what you make of the manual J report?



    Last edited by rk05; 09-14-2011 at 07:41 AM. Reason: Forgot links to report!

  2. #2
    Join Date
    Aug 2011
    Location
    Kingston, Ontario
    Posts
    207
    I have recently had our home audited including blower door test and was confused about the infiltration rates quoted.

    You say that your house measured 0.64 ACH at 50 Pa. Well ours for similar sized house was 8.42! Why? I suspect that your 50pa figures may have been converted to ENIR - the natural infiltration rate.

    This link explains this and gives some typical figures:
    http://www.pct.edu/wtc/docs/articles...Door-FINAL.pdf

    I would be interested to hear from the pros to confirm this.

    BTW - I have been working on reducing our ACH - found many ceiling openings around light fixtures and ceiling registers. Also large opening where brick fireplace passes through ceiling in attic. (Maybe some openings where fireplace support comes through floor too, but haven't crawled in our low crawl space to find out -yet). Our leakage area was quoted as 230 sq.in. My rough estimate of openings found is 150sq.in. Sealing attic ducts may increase that further. It's worth starting to look!

  3. #3
    Join Date
    Jun 2011
    Location
    SW Ohio
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    I guess I'm curious to know how high my leakage is to other homes and how much this is going to effect my HVAC performance once it is tightened up?

    The leaks in the basement along the rim joist are going to have to wait until I get a bathroom remodeled. I have a drop ceiling but don't want to tear apart the basement yet. I would rather do a whole remodel at the same time of the basement.

    Was also wondering how the manual j results would change with the leaks being taken care of? If we got the ACH down to 0.40 could that lower the AC down to 2.0Ton unit?

  4. #4
    Join Date
    Dec 2010
    Location
    Down by the river
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    1,628
    whoe did the manual J? did they measure your current insulation R-values? he may have left some things off the reports that they show you, but I see no load summary from window loss and gain etc. It apears to have been a minimal attempt at the load calc.

    you also state 1500ft 1st floor, I hope you do not have 1 system for 2 floors because it's not on this load calc.
    It's hard to stop a Trane. but I have made one helluva living keeping them going.

  5. #5
    Join Date
    Jun 2011
    Location
    SW Ohio
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    The same company that did the energy audit did the manual J, they do HVAC work and home energy type work.

    Its a ranch house with only one system. The guy that did the energy audit took my house dimension info from me (actually took a picture with his camera) but also said before I gave that to him that he has all the info needed for the manual J to be done. That's why I'm wondering if they did a quick one using just the size of the house.

  6. #6
    Join Date
    Dec 2010
    Location
    Down by the river
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    Quote Originally Posted by rk05 View Post
    The same company that did the energy audit did the manual J, they do HVAC work and home energy type work.

    Its a ranch house with only one system. The guy that did the energy audit took my house dimension info from me (actually took a picture with his camera) but also said before I gave that to him that he has all the info needed for the manual J to be done. That's why I'm wondering if they did a quick one using just the size of the house.
    2 types of load calc. 1- block load and 2- room by room, both are going to need window,door and insulation info. Block load is aceptable to make sure tonnage is right, room by room is needed for airflow calculations.

    the load calculation he has done is basically for a normally sealed home. He is not showing you what the leaks you have add, help or hurt your calculations, through infiltration.
    It's hard to stop a Trane. but I have made one helluva living keeping them going.

  7. #7
    Join Date
    Dec 2010
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    Down by the river
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    This load calc you show say's it was done in 2005
    It's hard to stop a Trane. but I have made one helluva living keeping them going.

  8. #8
    Join Date
    Jun 2011
    Location
    SW Ohio
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    Quote Originally Posted by Southern Mech View Post
    This load calc you show say's it was done in 2005
    I saw that too but the correct date is down at the bottom of the page. I don't know if that was a generic entry they used?

  9. #9
    Join Date
    Jun 2011
    Location
    SW Ohio
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    Teddkidd, Udarrel, PSTU or anyone else familure with Energy Audits or Manual J's can you tell me anything from the numbers I have posted? Not sure if the ACH is normal, High ect and what can be said about the results from my manual J. Does it appear to be a quick run through or did they just not give me all the info ect.

    Thanks

  10. #10
    Join Date
    May 2004
    Location
    south louisiana
    Posts
    3,139
    unless orientation, size of overhangs,
    degree of shading, window type and size were
    taken your numbers are off.

    a picture of a house has never given me
    the info I need to do an energy rating.
    I need to draw the house or have a set of plans.

    specific inputs are needed to audit a specific house.
    insulation levels & areas minimally or not insulated.
    duct location, insulation and leakage values.


    for your size house the target leakage in cfm would
    be close to sq ft. more than this is still leaky,
    tighter would need fresh air.
    its hard to get existing homes tight enough to
    require fresh air.

    when you hire someone to audit, do the work and retest
    do you really think that the audit is unbiased?
    if you have to grade your own work..would you fail yourself?

    just things to think about.

    hopefully more infiltration locations were shown to you than
    just the ones you listed.

    best of luck
    The cure of the part should not be attempted without the cure of the whole. ~Plato

  11. #11
    Join Date
    Jun 2011
    Location
    SW Ohio
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    energy_rater_La, they had all that info because I told the guy who did the audit to take it. At first he said that he had all the info needed for the guy back at their shop to do the J but when I mentioned window sizes, door sizes orientation of the house that’s when he asked to see the drawing I had made.

    So your saying I should be somewhere around 2300CFM as a target leakage for my house then? Is the amount of leakage hurting my AC system allot. I know if it were tighter I would be more efficient but is my current ACH that bad?

    The only other leaks pointed out were two pocket doors we have leaking from the attic down into the main floor.

  12. #12
    Join Date
    May 2004
    Location
    south louisiana
    Posts
    3,139
    sorry I missed that...thought he has just taken a pic of the house.
    not gotten your information.

    target from my experience is roughly equal to sq ft.
    not tight enough to need fresh air, not loose enough to
    be heating & cooling great outdoors.
    the happy medium..
    this will put you around the .40 ach they mention.
    at .64 you can do a lot of sealing without worry
    of making the house too tight.

    the leakage at the attic access brings attic temps into the house.
    costs you more to heat and cool.
    things like attic tents that fit over staircases & hatches
    are stapled and caulked and provide an air seal and insulating
    value work well. http://www.attictent.com/
    I've tested quite a few of these, as long as they are caulked in place
    they seal well. just wish they had more R-value.

    foam for the rim joist.
    find the pocket doors in the attic and you will be able to
    see into the wall area above the door. it is only the door casing
    that is providing any type of seal. closing up this thermal bypass
    will help.

    did they test the ducts & return air for leakage?
    you could have a good amount of duct leakage,
    this is very common.

    best of luck
    The cure of the part should not be attempted without the cure of the whole. ~Plato

  13. #13
    Join Date
    Jun 2011
    Location
    SW Ohio
    Posts
    224
    I'm going to build a "box" using insulation board to cover both the whole house fan and the stair case into the attic. I also plan on getting some of the reflective insulation and using that along with magnets to cover the house fan from the inside of the main living space.

    No they did not do that but I wish they would have. All of my ducts are in the conditioned space of the house. As others on the forum have talked about, the company that did the audit does HVAC work primarly and sent out a sales guy after the audit with quotes for a new HVAC system.

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