Home energy audit scheduled - Page 2

strider3700 · 03-22-11, 02:53 PM

up here we get the same thing. Subsidized first visit with a free follow up and you need both and show the improvements to qualify for the tax credit.

RobertSmalls · 03-22-11, 06:21 PM

Quote:

Originally Posted by Daox

Of course, despite my work, sealing is still the biggest deal. With the blower door test and pressure set to 50 pascals, the flow rate was 2180 cfm. He thinks that with his suggestions I can easily knock that in half.

How many air changes per hour does that work out to?

Daox · 03-22-11, 06:49 PM

Well, house is roughly 1650 sq/ft. Volume is split between 8 and 10 foot ceilings, so we'll say 8.5 for guestimates. Cubic volume looks to be 14,000ft^3. So, 2180 * 60 = 130,800 cfh. 130,800 / 14,000 = 9.34. Looks to be about 9.34 air changes an hour. However, that is at -50 pascals. To compare, with all the exhaust fans running (two bath vents & kitchen stove vent), furnace running, and dryer on the house only dropped to -8.5 pascals. So, its pretty leaky. But, I don't know if 9.34 air changes an hour is accurate number unless all air change tests are done @ 50 pascals.

RobertSmalls · 03-22-11, 08:25 PM

Here's a couple of articles that give context to your ACH50 numbers:

We have passed the preliminary blower door test. - Passive House DC
Acing the Blower Door Test with Miranda Homes | Earth Advantage Institute

Daox · 03-23-11, 12:07 PM

Interesting read. Considering an energy star house has to only meet 7 ACH, 9 doesn't sound so bad... Still, a lot of room for improvement though.

Daox · 02-16-12, 10:51 AM

I just scheduled my follow up test for mid March. I'm really not ready for it yet (will have to scramble to do a few things), but apparently I have to do it before a year has passed since the first test to qualify for the tax credit. I was under the impression I could just call them back whenever and use the tax credit for that year, but apparently that is not the case.

Anyway, I've done a bunch of air sealing mainly on the 2nd floor and hope to do more sealing before the auditor comes. I know my basement is horribly leaky, so I'm thinking of attempting to seal the basement door and any holes between the floors with caulk and expanding foam. Unfortunately my furnace doesn't have a dedicated intake, so it must still use inside air, so sealing the basement up isn't the best option right now.

Daox · 03-15-12, 12:37 PM

Well, I had the audit done this morning. The results were pretty disappointing.

CFM for the 1st test at 50 pascals was 2180 CFM. This calculates out to roughly 9.3 ACH (air changes per hour). The new number I got today was 2010. This calculates out to 8.6 ACH. So, not even quite a 10% reduction.

However, the auditor did say I did a good job with what I had done. Besides sealing up the basement rim joist area, all the other leakage is mainly coming from BETWEEN the floors or between the 2nd floor ceiling and the attic along the angled areas of my roof (very similar to a 1.5 story).

So, I'll probably start with the basement. The current plan would be rigid foam that is kept in place with 1 part foam (great stuff). I've avoided doing this mainly because its going to be a big pain in the butt. My basement walls are roughly 2 feet thick and getting in the cavities that deep not only to foam but also just to clean them out is not going to be fun. The other two sides (joists running parallel to the wall) are also going to be tricky due to space restrictions as well.

After the basement, I'm going to have to start cutting into things to seal them up. At that point I'm not sure if it would be better to just work from the outside and add rigid foam. I'll check that out more once I get that far.

For those who don't know what ACH is good/bad here is a general chart from Higgy's energy audit, and passive house requires .6 ACH or less!

TimJFowler · 03-15-12, 12:44 PM

Quote:

Originally Posted by Daox

Well, I had the audit done this morning. The results were pretty disappointing.

CFM for the 1st test at 50 pascals was 2180 CFM. This calculates out to roughly 9.3 ACH (air changes per hour). The new number I got today was 2010. This calculates out to 8.6 ACH. So, not even quite a 10% reduction.

However, the auditor did say I did a good job with what I had done. Besides sealing up the basement rim joist area, all the other leakage is mainly coming from BETWEEN the floors or between the 2nd floor ceiling and the attic along the angled areas of my roof (very similar to a 1.5 story).

It's still progress - not as much as you want - but progress! It sounds like you've picked much of the low-hanging fruit and the next improvements will require more effort.

I'm in a similar situation and need to do some ROI calcs to figure out which project to do next.

Good Luck,
Tim

03-22-11, 06:49 PM	#13
Daox Administrator Join Date: Aug 2008 Location: Germantown, WI Posts: 5,525 Thanks: 1,162 Thanked 374 Times in 305 Posts	Well, house is roughly 1650 sq/ft. Volume is split between 8 and 10 foot ceilings, so we'll say 8.5 for guestimates. Cubic volume looks to be 14,000ft^3. So, 2180 * 60 = 130,800 cfh. 130,800 / 14,000 = 9.34. Looks to be about 9.34 air changes an hour. However, that is at -50 pascals. To compare, with all the exhaust fans running (two bath vents & kitchen stove vent), furnace running, and dryer on the house only dropped to -8.5 pascals. So, its pretty leaky. But, I don't know if 9.34 air changes an hour is accurate number unless all air change tests are done @ 50 pascals. __________________ Current project - To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. & To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. Last edited by Daox; 03-15-12 at 11:35 AM.. Reason: correct CFM numbers

03-23-11, 12:07 PM	#15
Daox Administrator Join Date: Aug 2008 Location: Germantown, WI Posts: 5,525 Thanks: 1,162 Thanked 374 Times in 305 Posts	Interesting read. Considering an energy star house has to only meet 7 ACH, 9 doesn't sound so bad... Still, a lot of room for improvement though. __________________ Current project - To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. & To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

02-16-12, 10:51 AM	#16
Daox Administrator Join Date: Aug 2008 Location: Germantown, WI Posts: 5,525 Thanks: 1,162 Thanked 374 Times in 305 Posts	I just scheduled my follow up test for mid March. I'm really not ready for it yet (will have to scramble to do a few things), but apparently I have to do it before a year has passed since the first test to qualify for the tax credit. I was under the impression I could just call them back whenever and use the tax credit for that year, but apparently that is not the case. Anyway, I've done a bunch of air sealing mainly on the 2nd floor and hope to do more sealing before the auditor comes. I know my basement is horribly leaky, so I'm thinking of attempting to seal the basement door and any holes between the floors with caulk and expanding foam. Unfortunately my furnace doesn't have a dedicated intake, so it must still use inside air, so sealing the basement up isn't the best option right now. __________________ Current project - To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. & To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

03-15-12, 12:37 PM	#17
Daox Administrator Join Date: Aug 2008 Location: Germantown, WI Posts: 5,525 Thanks: 1,162 Thanked 374 Times in 305 Posts	Well, I had the audit done this morning. The results were pretty disappointing. CFM for the 1st test at 50 pascals was 2180 CFM. This calculates out to roughly 9.3 ACH (air changes per hour). The new number I got today was 2010. This calculates out to 8.6 ACH. So, not even quite a 10% reduction. However, the auditor did say I did a good job with what I had done. Besides sealing up the basement rim joist area, all the other leakage is mainly coming from BETWEEN the floors or between the 2nd floor ceiling and the attic along the angled areas of my roof (very similar to a 1.5 story). So, I'll probably start with the basement. The current plan would be rigid foam that is kept in place with 1 part foam (great stuff). I've avoided doing this mainly because its going to be a big pain in the butt. My basement walls are roughly 2 feet thick and getting in the cavities that deep not only to foam but also just to clean them out is not going to be fun. The other two sides (joists running parallel to the wall) are also going to be tricky due to space restrictions as well. After the basement, I'm going to have to start cutting into things to seal them up. At that point I'm not sure if it would be better to just work from the outside and add rigid foam. I'll check that out more once I get that far. For those who don't know what ACH is good/bad here is a general chart from Higgy's energy audit, and passive house requires .6 ACH or less! Attached Thumbnails __________________ Current project - To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. & To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

03-22-11, 02:53 PM	#11
strider3700 Master EcoRenovator Join Date: Dec 2008 Location: Vancouver Island BC Posts: 745 Thanks: 23 Thanked 37 Times in 30 Posts	up here we get the same thing. Subsidized first visit with a free follow up and you need both and show the improvements to qualify for the tax credit.

03-22-11, 08:25 PM	#14
RobertSmalls Journeyman EcoRenovator Join Date: May 2009 Location: Buffalo, NY Posts: 344 Thanks: 3 Thanked 17 Times in 15 Posts	Here's a couple of articles that give context to your ACH50 numbers: We have passed the preliminary blower door test. - Passive House DC Acing the Blower Door Test with Miranda Homes \| Earth Advantage Institute