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

Don Fitchett posted a blog post

Small Businesses: Diversify with Infrared Thermography Services, Save Your Business, Save the Country...

HERS should all offer Infrared Thermography Services.It is all ways great advice for small…See More
3 hours ago
Richard Beyer replied to Mike Kandel's discussion Our Homes Suck – And That's Why Our Kids Have Sinus Problems
""There are thousands of potential harmful products that can contribute to existing homes poor…"
4 hours ago
Richard Beyer replied to Mike Kandel's discussion Our Homes Suck – And That's Why Our Kids Have Sinus Problems
"Barbara, We both know a fan switch will only conserve on energy. What is Berkeley devising to clean…"
4 hours ago
Richard Beyer replied to Mike Kandel's discussion Our Homes Suck – And That's Why Our Kids Have Sinus Problems
"Ted no one can help anyone with their head stuck in the sand. All you said is MONEY is your God.…"
4 hours ago
Richard Beyer replied to Richard Beyer's discussion Spontaneous Combustion and Flash Fire regarding Spray Foam Insulation
"Hal, Thank you for laying out those facts. Fire safety is just as important of an issue as energy…"
4 hours ago
Don Fitchett commented on Diane Chojnowski's group Facebook Pages
"I just went through the 1st 2 pages of member's facebook pages liking them. While our training…"
6 hours ago
Don Fitchett joined Diane Chojnowski's group
Thumbnail

Facebook Pages

Does your company or organization have a Facebook Page?This group is for pros who have facebook…See More
6 hours ago
Mike Kandel added 3 discussions to the group Building Performance Institute (BPI)
7 hours ago
Mike Kandel posted discussions
7 hours ago
EnergyLogic Academy updated an event

RESNET Phase 2 Rater Training - Field Training at EnergyLogic Academy - Berthoud CO

September 22, 2014 to September 24, 2014
The EnergyLogic Academy will be hosting the second phase of HERS Rater Training August 4th - 7th,…See More
7 hours ago
Mike Kandel commented on David Byrnes's blog post Strategies To Keep Millennials At Their Peak Performance In A Home Performance Company
"David - I'd like to speak with you about this article. Please email me at mkandel@bpi.org."
7 hours ago
Hal Skinner replied to Richard Beyer's discussion Spontaneous Combustion and Flash Fire regarding Spray Foam Insulation
"This thread has certainly turned into what sounds like  a thread from a fire safety website…"
10 hours ago

© 2014   Created by Lawrence Berkeley National Laboratory.

Badges  |  Report an Issue  |  Terms of Service