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: 112

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.  Home Energy Pros is sponsored by the Better Buildings Residential Network.

Latest Activity

Malcolm McKelvie replied to Alan Gindt's discussion Minneapolis Blower Door System for sale in the group Energy Auditing Equipment for Sale, Trade or to Purchase
"yes I would pay the delivery fee!"
12 hours ago
Alan Gindt replied to Alan Gindt's discussion Minneapolis Blower Door System for sale in the group Energy Auditing Equipment for Sale, Trade or to Purchase
"Malcolm, If you want to pay delivery from USA we can talk. Otherwise no thanks."
13 hours ago
Malcolm McKelvie replied to Alan Gindt's discussion Minneapolis Blower Door System for sale in the group Energy Auditing Equipment for Sale, Trade or to Purchase
"How old is it? I assume it is in good working order? I'm interested in it but the price needs…"
14 hours ago
William H Nickerson replied to Kim Tanner's discussion Fantastic innovation
"So that's where you use those True Flow plates....."
18 hours ago
Colin Genge updated an event
Thumbnail

Passive House Testing Webinar with Kevin Brennan of the Passive House Academy at Online

September 29, 2015 from 1pm to 2pm
Tests needed to qualify as a passive houseWhy we’re seeing an increase in PH buildingsBest…See More
yesterday
Colin Genge updated an event
Thumbnail

DM32 Smart Gauge 101 Webinar at Online

September 22, 2015 from 1pm to 2pm
Webinar Learning Objectives:Gauge settings and operationCalculate results in the gaugeUpdate the…See More
yesterday
Colin Genge updated an event
Thumbnail

Blower Door 101 Webinar at Online

September 15, 2015 from 1pm to 2pm
See how easy it is to do your first test. Learn tips to perform your first duct test in only twenty…See More
yesterday
Colin Genge updated an event
Thumbnail

Zone Pressure Diagnostics (ZPD) with Bill Eckman of NME$A Webinar at Online

September 10, 2015 from 1pm to 2pm
Benefits and limitations of Zonal Pressure Diagnostics (ZPD).Best practices for accurate…See More
yesterday

© 2015   Created by Lawrence Berkeley National Laboratory.

Badges  |  Report an Issue  |  Terms of Service