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: 111

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.

Home Energy Pros

Home Energy Pros was founded by the developers of Home Energy Saver Pro (sponsored by the U.S. Department of Energy,) and brought to you in partnership with Home Energy magazine.

Latest Activity

Casey Gesell joined Diane Chojnowski's group
Thumbnail

News & Announcements

Share your news and announcements with the community in this group.See More
18 seconds ago
Tom White's video was featured

Raising the Bar within the Weatherization and Home Performance Industry

The Weatherization Assistance Program (WAP) was created in 1976 to assist low-income families who lacked resources to invest in energy efficiency. This video not only shines a light on the existing success of the WAP, but it also takes a look at its…
21 minutes ago
Profile IconBarry Martin and David Snell joined Home Energy Pros
57 minutes ago
Shawna Henderson posted a blog post

Sales funnels are funny shaped things

One challenge seems to be at the forefront of a lot of the discussions I'm having with colleagues…See More
1 hour ago
Nate Adams joined Allison A. Bailes III's group
Thumbnail

HVAC

HVAC design, Manuals J, S, T, & D, Duct leakage, Air flow, ENERGY STAR new home requirements,…See More
1 hour ago
Nate Adams joined Evan Mills's group
Thumbnail

Home Energy Ratings

Calculating them; visualizing them; explaining them; selling them .... there is a lot to discuss…See More
1 hour ago
Nate Adams joined Michael Stuart's group
Thumbnail

INFRARED THERMOGRAPHY USERS

This group is dedicated to knowledge sharing and discussion of infrared thermography for building…See More
1 hour ago
Nate Adams joined James Sayers's group
Thumbnail

Marketing Energy Efficiency

Sharing ideas, tools and examples of promoting energy efficiency to consumersSee More
1 hour ago

© 2015   Created by Lawrence Berkeley National Laboratory.

Badges  |  Report an Issue  |  Terms of Service