Air leaks remediation and house tightness

[ggal]

Out of all the websites I visited which write about air infiltration into houses and the corrective measures to be taken to correct that situation, only 2 ( and I visited over 40) mentioned that making a house too tight can cause new problems.
If I was to find the sources of air leaks into a house I would explain that sealing ALL air leaks could be worse than leaving them in place, but if one really wants to stop all air leaks (or most of them) I would recommend an HRV or ERV be installed.

Any comments would be appreciated.

Gabe

[James H. Bushart]

Air sealing ceases when additional air sealing is not cost-effective, when the air-leakage-reduction target is reached, or when the minimum ventilation level is reached.

None of this can be determined without a blower door test.

Ideally, a house is completely air tight with all required amounts of fresh air provided through mechanical means where it can be conditioned and filtered. Rarely is this ever achieved.

[ggal]

Originally Posted by jbushart

.....
None of this can be determined without a blower door test.
......

Hello James
My point was that most of the websites I visited and who use infrared cameras, are talking about finding leaks and lack of insulation or the presence of moisture and the fact that finding the above and correcting them will save the home owner money and make the house more comfortable.
Except for 2 sites, no site mentioned that making a house too tight could make the situation worse.
Also, practically non of the infrared camera users mentioned the use of a blower door test.

Gabe

[James H. Bushart]

Originally Posted by ggal

Hello James
My point was that most of the websites I visited and who use infrared cameras, are talking about finding leaks and lack of insulation or the presence of moisture and the fact that finding the above and correcting them will save the home owner money and make the house more comfortable.
Except for 2 sites, no site mentioned that making a house too tight could make the situation worse.
Also, practically non of the infrared camera users mentioned the use of a blower door test.

Gabe

That is because an infrared camera is insufficient to address what you are referring to as "house tightness". It is like attempting to photograph the wind and use your photo to judge its speed and volume.

Lack of insulation has nothing at all to do with air leakage. Insulating an air bypass simply filters the conditioned air as it leaves the building.

[ggal]

Originally Posted by jbushart

That is because an infrared camera is insufficient to address what you are referring to as "house tightness". It is like attempting to photograph the wind and use your photo to judge its speed and volume.

Lack of insulation has nothing at all to do with air leakage. Insulating an air bypass simply filters the conditioned air as it leaves the building.

So you are OK with inspectors going into houses with their IR cameras, pointing out air leaks and moisture and suggesting that the air leaks should be eliminated without telling the home owner about the consequences of on overy tight hosuse without make-up air systems?

[ggal]

"The sealing of air leakage is very cost effective and can pay for itself in the first year from energy savings that the sealing will generate."

This is a quote from an inspector's website.

No mention of the consequences....

[James H. Bushart]

Originally Posted by ggal

"The sealing of air leakage is very cost effective and can pay for itself in the first year from energy savings that the sealing will generate."

This is a quote from an inspector's website.

No mention of the consequences....

There are no "consequences" if you do it right. A blower door test is essential. An infrared camera is an optional tool to use in addition to a blower door.

[James H. Bushart]

Originally Posted by ggal

So you are OK with inspectors going into houses with their IR cameras, pointing out air leaks and moisture and suggesting that the air leaks should be eliminated without telling the home owner about the consequences of on overy tight hosuse without make-up air systems?

No, I am not. Blower door tests are the only means of quantifying air leaks and measuring the effectiveness of sealing them. Not cameras.

[ggal]

Originally Posted by jbushart

No, I am not. Blower door tests are the only means of quantifying air leaks and measuring the effectiveness of sealing them. Not cameras.

No Offence but if your blower door test tells you that the house could be tighter (based on whatever standard for air changes per hour you use) do you start sealing different areas and you perform a blower door test after every stage to see if you achieved the desired effect?
We don't have an equivalent to BPI in Canada (unfortunately) but we have NRCAN which is somewhat similar but without the teeth .
Also, what do you use to find the actual leak locations when you use a blower test?

Thank you for your replies so far

Gabe

[Sean Fogarty]

Originally Posted by ggal

No Offence but if your blower door test tells you that the house could be tighter (based on whatever standard for air changes per hour you use) do you start sealing different areas and you perform a blower door test after every stage to see if you achieved the desired effect?
We don't have an equivalent to BPI in Canada (unfortunately) but we have NRCAN which is somewhat similar but without the teeth .

Maybe you should go with someone who does one and you will understand better.
James already answered your question. Most homes that lack the most modern building methods will be impossible to completely seal up. Even the smallest cracks will allow bypass, so unless you start from scratch you may never see this.

Also, what do you use to find the actual leak locations when you use a blower test?

I found you hands work pretty well, and once again once you do a couple you will understand better..


Gabe

Thank you for your replies so far

[ggal]

Originally Posted by sfogarty

Maybe you should go with someone who does one and you will understand better.

That would be great except that people are afraid to share thier knowledge in the immediate area surrounding them probably because they are afraid of losing business.
That is why I post here because hopefully people would not be threatened by someone far away.

Gabe

[rspermo]

Gabe,

You are correct! Many home inspectors do not totally understand the actual complexities of house air leakage. Every change to a house must be viewed in relation to what it may do to another part of the house. For example, to foam the rafters of an existing house without looking at the HVAC sizing would be a mistake. James is correct - the only way to actually quantify the home's leakage and air change per hour is to do a blower door.

[Brian A. MacNeish]

Originally Posted by ggal

Hello James
My point was that most of the websites I visited and who use infrared cameras, are talking about finding leaks and lack of insulation or the presence of moisture and the fact that finding the above and correcting them will save the home owner money and make the house more comfortable.
Except for 2 sites, no site mentioned that making a house too tight could make the situation worse.
Also, practically non of the infrared camera users mentioned the use of a blower door test.

Gabe

No house is too tight. Airtightness improves comfort and saves energy. Since 98-99% of the interior house vapour that moves into wall and celing cavities is air leakage, proper airsealing may save prevent a mould/rot situation in areas of air leakage. Once a house is airtightened, it will need supplemental mechanical ventilation, sometimes as simple as a good bath exahust fan on a timer, or possibly a timed whole house exhaust system. Here's a brochure that I worked on and updated in the 1990's:
http://www.conservens.ca/resources/p...lder-Homes.pdf

In the 1980's while running an insulation/airsealing company, we were installing good exhaust systems and instructing our customers on controlling interior moisture problems from basement dampness, not drying clothes inside/venting dryers to exterior, not storing wet firewood inside, covering aquariums, not too many plants, etc

[ggal]

Originally Posted by Brian A. MacNeish

No house is too tight.

http://www.conservens.ca/resources/p...lder-Homes.pdf

Thank you for the brochure Brian.

As for your comment that NO HOUSE IS TOO TIGHT, why else would newer houses need mechanically assited air exchangers (HRVs)?

Too tight is obviously a relative term but let's assume that an older home can be sealed to the level of a new house, wouldn't you agree that if an HRV is not added that house WILL be too tight to the point that it will be uncomfortable.

Gabe

[Roy D. Cooke, Sr]

Re: The House as a System
http://www.mitsubishielectric.ca/en/hvac/m-series/specifications.html

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