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

Robert Haverlock replied to Hal Skinner's discussion How much heat energy is lost through the floor of a house?
"I feel like I'm preaching to the choir! So here it goes. In recent years, Building America and…"
1 hour ago
Maria Lacey replied to Linda Wigington's discussion Low-cost electricity monitoring: Accuracy & Applications in the group 1000 Home Challenge
"Steve, Thank you for posting the description of your installation process and photos of the final…"
3 hours ago
Everblue's blog post was featured

RESNET Combustion Safety Deadline is Near

An important deadline is looming for existing HERS Raters. By January 1, 2015, all existing Raters…See More
3 hours ago
Sean Lintow Sr's blog post was featured
4 hours ago
Amanda Hatherly replied to Chad Mcaulife's discussion BPI QCI Cert.
"Hello, I am the Director of one of the WAP training centers (New Mexico EnergySmart Academy) in New…"
4 hours ago
Kelly replied to Chad Mcaulife's discussion BPI QCI Cert.
"Hi Chad, I got the QCI during the pilot, but the written test hasn't changed much. The quiz…"
6 hours ago
Hal Skinner posted a discussion

Any success getting landlords to energy upgrade a single family rental unit?

Any success getting landlords to energy upgrade a single family rental unit? Multi-family dwelling…See More
6 hours ago
Steve Waclo replied to Linda Wigington's discussion Low-cost electricity monitoring: Accuracy & Applications in the group 1000 Home Challenge
"Trying again:"
7 hours ago

© 2014   Created by Lawrence Berkeley National Laboratory.

Badges  |  Report an Issue  |  Terms of Service