Duct Sealing: Aeroseal- Smoke and Mirrors or effective?

[neophytes serendipity]

How would Aeroseal benefit a home with ductwork that leaks, but is too small before it is sealed up?

[talbot3]

What pressure are the leak rates measure at?

[cherokee180c]

25 Pa

[energy_rater_La]

nice that you came and posted ShortCircut. Thanks.

Ted, in another forum/thread you made a statement about duct sealing
not being worthwhile, because of low energy costs rendering duct leakage
esoteric. based on your climate and ducts being within the bldg envelope.

Has this thinking changed based on your client's experience?
Was the duct leakage amount verified before or after by anyone
other than the aeroseal company?

[cherokee180c]

Obviously that question was for TED, but don't think that just because some of the leakage is into the envelope that you don't gain efficiencies from reducing that leakage as well. My basement, and especially my utility room is now several degrees warmer. That energy was going to cool an area that was already over cooled, so it was all wasted energy. As you can see in the "2nd Story not cooling" thread, proper balance and airflow where you need it can result in savings of over 30%. I will be re-measuring my HVAC usage in a few days when my replacement MTU comes in for my TED energy meter. I expect about a 15% savings from the increased air-conditioned air flow and reduced amount of humidity and heat from air infiltration into the return system, not to mention the building envelope. My Audit company comes back shortly to rerun the overall home leakage blower door test as well to confirm overall leakage improvement.

[energy_rater_La]

you don't have to sell me on the benefits of duct sealing
and proven results.
that you are testing before and after is a good thing.
sharing the audit info is appreciated also.

[cherokee180c]

I figured that by your user name, I just wanted to get that info out there. I am as excited as anyone to actually quantify the actual best estimate of Aeroseal impact through my TED meter measurements when it is back online later this week.

[Short Circuit]

The theory that ductwork leakage is not important is BUNK. Plain and simple. If I have a 4-ton system, and I'm leaking 1-ton via small leaks all around the supply side and return side, then I really have a 3-ton system. Further, that now 3-ton system has to overcome the introduced temperatures which those leakage areas introduce whether in heating or cooling modes. Increased dust from return leakage and increased humidity also results from all these leakage areas...

Why is it BUNK? Because no envelope is perfectly sealed. When I moved into my 40 year old rancher ~ 6 months ago, I had an energy audit performed. The IR pictures told quite a story - my high-hats were leaking like there was no tomorrow and the basement sill plates were too. I literally had visual proof that air was coming into my home and sweeping across my ceilings behind my walls. So, if I'm leaking 1-ton of conditioned air, it simply DOES NOT stay in the home; it escapes outside and it's 1-ton I just lost in efficiency. 25% of my capability and 25% of my utility bills are going out my envelope.

AEROSEALING allows me to keep that 1-ton within the walls where I want to keep it. Attic sealing stopped the leakages thru my high-hats and, the theory goes, will indirectly halt the "chimney effect" of my basement being so leaky with air coming thru the basement and being sucked out of my attic. We shall see this upcoming winter if the basement is "warmer".

I'll be cutting my cooling and heating load 50%. That directly goes to the bottom-line of equipment pricing when I get quotes. AEROSEAL paid for itself as it was 25% of that 50% savings I've produced by doing AEROSEAL + attic Seal & super-insulating.

[mchild]

Attic sealing stopped the leakages thru my high-hats and, the theory goes, will indirectly halt the "chimney effect" of my basement being so leaky with air coming thru the basement and being sucked out of my attic. We shall see this upcoming winter if the basement is "warmer".

I have an 1800s farm house with an open air crawl space under the oldest part of the home. The second story had high-hats and pull down stairs which allowed air to flow from the crawl up through the attic at gale force rates. With the open air crawl and the easy movement of air to the attic I had unbelievable stack (chimney) effect. We used to keep a rolled up throw rug at the bottom of the door that went into the hand dug cellar in which the open air crawl was part of. We did that because of the high velocity air movement under the door during the winter when the stack effect was working so well.

After foaming the attic we no longer keep the rug at the base of the door. While the floors over that crawl are still cool to almost cold, by stopping the air from moving from the crawl, up through the house, and out of the attic we have seen a huge improvement in comfort and in our energy bills. We have also downsized our HVAC equipment (heating capacity has been reduced by about 60% and cooling capacity by 40%).

[cherokee180c]

Long term, there is no doubt in the cost effectiveness, but short term I was assuming a conservative 6 year payback, since my house is pretty effiecient already. I figured a 15% reduction in A/C and heating costs. My last 2 months bills in the hottest part of summer were under $200 each after fixing my A/C balance issues. The MD and BGE credits actually make it a no brainer.

[tedkidd]

nice that you came and posted ShortCircut. Thanks.

Ted, in another forum/thread you made a statement about duct sealing
not being worthwhile, because of low energy costs rendering duct leakage
esoteric. based on your climate and ducts being within the bldg envelope.

Has this thinking changed based on your client's experience?
Was the duct leakage amount verified before or after by anyone
other than the aeroseal company?

ERLA, I'm wrong at least once a day, and when that stops being true it's because I'm probably dead.

I'm not sure what thread you refer to, but I've been posting here for 3 years and my learning curve has been and continues to be very steep.

YES, My friend ShortCircuit's experience and continuous feedback has changed my perspective on duct leakage. Ductwork may be within the envelope, but leakage creates pressure imbalances that magnify exfiltration and infiltration in wall cavities and conditioned spaces. It prevents Heating and Cooling from going where you want and need it to go to maintain even comfort. Furthermore, this leakage impacts comfort and control, which are primary drivers of thermostat fiddling, which seems to be another culprit behind high bills.

The problem as I now see it is the cost of diagnosing and cost benefit analysis required to SELL duct sealing is a significant impediment. People want to know what it will save them at THEIR home, not the average home.

Let's use some hypothetical multiples...

If the diagnostics to determine the energy savings is 1x, and the aeroseal is 3x, the diagnostics add another 1/3 to the price of simply jumping in and doing the work.

So you see the catch 22.

I suspect everyone would benefit from this service, particularly at equipment replacement. But are you willing to take the leap of faith and spend 3x?

Or do you want to go the 1x route, which means 4x total cost? I've yet to find anyone willing to pay the 1x for duct diagnostics.

And most people are choking on the fact that equipment replacement is even happening. There is a huge educational process involved with major land mines at every turn, as short circuit will attest. We have a huge amount of time invested together counterbalancing all the bad information he was being fed. He may now be better equipped to consult on this work than anyone in his geographic location. Which lead to:

How do you build information demand without supply? How do you build information supply without demand?


Yes, I still see hugely subsidized energy cost as a barrier to people embracing comprehensive energy retrofits. Most people want to do one thing at a time, unfortunately if equipment doesn't come LAST the sizing issue takes you down a dead end.

[Shophound]

Here is my Aeroseal results:

Return Leakage = 350 CFM. Reduced to 92 CFM (Wall Cavity)
Supply Leakage = 250 CFM. Reduced to 60 CFM.

Unfortunately my TED meter is only reading from 1 phase of my electric right now, so I can't verify savings yet. We had some really bad thunder storms an I think a surge may have killed something in my MTU unit. The basement is much warmer now though, so you can really tell the leakage has been reduced. I also have much better flow in my Master Bedroom.

I'm curious...if you were to open up the lower floor return fully, would your significant temperature difference between first and second floor rematerialize, now that you've had this Aeroseal process done. Would you mind conducting a brief test to see what difference, if any, this would make? Thanks.

As it is, have you noticed it is now even easier to keep temperatures more even between floors post Aeroseal?

[cherokee180c]

I am literally only 3 days post sealing right now, with very little time really spent back in the house to quantify real results. I can say the following with certainty, but need to measure to prove:

1. The temperature difference between the 1st floor and basement is almost totally gone. It is imperceptible now, so probably within 1 degree. This is with all basement registers closed, which is the same as the before duct sealing case.
2. I think you can safely conclude that the basement was 4 degrees cooler before, solely due to the leakage from all the HVAC supply side ductwork leakage, that has now been eliminated.
3. The utility room is now only slightly cooler than the basement. It is hard to even notice the difference, so maybe 1 degree. This space was supercooled before with all the leakage.
4. I have much more airflow from all registers upstairs.

Funny but true story is I purchased another three Activents for upstairs for winter use (ie close when it gets too warm upstairs) since I didn't want to move the downstairs Activents. Anyway as luck would have it, they arrived on Friday when they were sealing my ducts. I rushed to hook them up in my master bedroom. The next morning my wife commented that is was a lot cooler in the bedroom overnight, which I thought as well. I then discovered to my surprise that in my haste, I had the controls backward so both master bedroom vents were actually shut all night. So it appears that just the increased airflow in my master bathroom and walk in closet as well as the rest of the upstairs was enough to at least create that perception.