Controlling Airflow in Existing Dwellings

The new concept of "controlling airflow" is discussed with a Savings-to-Investment Ratio (SIR) calculated. Controlling airflow includes 1) air sealing to red...

Views: 114

Comment

You need to be a member of Home Energy Pros to add comments!

Join Home Energy Pros

Comment by Rick Karg on June 26, 2014 at 9:04am

David, I am the guy who put together and narrated the video.I am sorry you missed the section in the video about increased heating load resulting from ventilation, which was 6.4 therms (slide 9). I did mention the increased cooling load, but did not include it in the SIR calculation because of the location; Portland, Maine, where cooling is a minor issue. If you use this analysis in a heating/cooling climate, both the heating and cooling load increases from ventilation should be included in the SIR equation numerator. The RED Calc Free Advanced Infiltration tool reports both heating and cooling loads.

Regarding maintenance, you are correct, I did not include any maintenance costs. If these were included they would be subtracted from the numerator as a recurring annual cost and would lower the SIR value. I ignored these costs because we don't have a good idea of what they are. Of course, there will be some homeowner work involved, such as cleaning the ventilation fan blades, etc. We hope to get a better idea of maintenance costs for ventilation systems within the next five years or so.

It is best practice to add ventilation to each room using ductwork, as you suggest, but it is not required by the ASHRAE 62.2 standard. I assumed a high quality exhaust fan installed in a centrally located bathroom would provide local and whole-building ventilation (this complies with ASHRAE 62.2). If the ventilation system is more complex, the cost of installation would increase. This would, of course, impact the SIR value. A ventilation system that distributes fresh air evenly throughout a home is preferred. However, it is common that this best-practice solution will not fit into the project budget, especially for the folks working within the low-income weatherization program.

Comment by David Eakin on June 26, 2014 at 8:20am

You did not add the (other) expected yearly running costs for the ventilation unit (additional air conditioning costs for heat/coll/dehumidify, any replacement parts/service, etc.) in the initial SIR computation; you only talk to the fan electrical costs. Also note: if the structure does not already have duct work (a very common occurrence in older buildings) the additional ventilation duct work costs make this proposal very costly, and assuming a single exhaust fan will provide adequate ventilation to each individual occupied room - especially with closed doors - without dedicated duct work is problematic regardless of what the ASHRAE prescriptions preach. It is the reason why paired supplies/returns are the best way to deliver conditioned air to each occupied room vs. central supplies/returns.

Videos

  • Add Videos
  • View All

Twitter

Latest Activity

Profile IconMichael Sumpter and Bill Gartner joined Home Energy Pros
10 hours ago
Malcolm Jackson joined allen p tanner's group
Thumbnail

Energy Auditing Equipment for Sale, Trade or to Purchase

Discuss the pros and cons of the equipment you are interested in prior to purchase. Post equipment…See More
13 hours ago
Amber Vignieri liked tedkidd's discussion What if more efficient homes were actually worth more?
16 hours ago
Amber Vignieri posted a blog post
17 hours ago
Eric Kjelshus replied to Rob Madden, Solar Home Broker's discussion Indoor Air Quality Monitors and Meters
"I have been using air advice for 5 yr or so - I end up with a report in 35 min I can e-mail or show…"
19 hours ago
Profile IconShane Matteson, Jay Cooper and Mike Harris joined Home Energy Pros
yesterday
Kim Burnett commented on Diane Chojnowski's group Home Energy Pros on Twitter
"Good morning, would you please add me. Thank you. Kim Burnett A+ Abundant Energy Experts"
yesterday
Kim Burnett joined Diane Chojnowski's group
Thumbnail

Home Energy Pros on Twitter

We've created a twitter list of members of Home Energy Pros who tweet about home performance and…See More
yesterday

© 2016   Created by Lawrence Berkeley National Laboratory.   Powered by

Badges  |  Report an Issue  |  Terms of Service