More insulation or more BTU's? - Page 4

MN Renovator · 01-01-12, 10:29 AM

Quote:

Originally Posted by stefanc

Another thing I noticed when installing the woodstove- There's no insulation (spray-foam or loose fill) behind the window trim between the rough framing and window. That's definitely going to be addressed very soon also.

I spray-foamed mine, before that they built the house filling the gap with tightly shoved furnace filter, ahem, I mean fiberglass in the gap. When I took my trim off it was a windy day and the movement of the trim was enough to disturb the dust and the air that passed through the up to 1 1/4" gap between the drywall and the window had dust blowing out of it. Nice little breeze there and I think the window trim itself stopped more infiltration than the fiberglass. Funny thing is I had an energy audit and my energy auditor suggested I shove fiberglass into the gap at the bottom trim of the carpet where the IR scan showed air was moving into the house. ...no thanks buddy, and he's Energy Star, BPI certified and I think REM too if there is a certification for the REM rating. The spray foaming of the windows was before the energy audit and I could tell right after I did it that the room was tons more comfortable and the humidity level of the house doesn't drop like a stone anymore now that its well sealed.

Make sure the rest of the cavity nearby is filled with insulation, if it is spray foam the gap with a window/door suitable spray foam.

S-F · 01-01-12, 05:11 PM

I deal with auditors on an almost daily basis and I must say that on the whole they know little more about building science than the average mildly interested home owner. They want me to do some of the most useless things. Here's a good one: I have to go back to a house to insulate the incoming water pipes. I guess that auditor wants to make sure that the pipes freeze. The odd thing is that the auditor you speak of, MN Renovator, is BPI certified. I have taken all of the courses that they offer and they are absolutely fantastic. I highly recommend them to everyone here. I know the people who developed the BPI courses and to my knowledge they haven't offered the auditor course yet. They certainly haven't offered it here in MA or I'd have taken it.

About the windows, it's mind boggling how many windows are replaced leaving the cavities for the old weights empty. Many installers just cut the rope and let the weight drop down in there. Low expansion 1 part foam is your friend here. It's not really about the R Value, since the window next to it is one of the largest sources of lost heat in the house. It's all about the air sealing. If you only have R 13 in your walls but passivehaus air tightness you'll still be doing great. Now if you top that with a whole wall R Value of 50 or so your only problem will be that there is no longer a single heat source to dry your mittens out on in the winter. We should all tear out=r interior walls out, seal with spray caulk (my new favorite product) and truss to the inside to make a 12" cavity for cellulose. Then you sell your boiler on craigslist. Or sell if for scrap. At that point it's probably worth more as scrap that as a heater.

MN Renovator · 01-01-12, 06:18 PM

My auditor didn't want me to insulate the incoming pipes, but in my house they come up through the concrete slow which is below grade so they wouldn't freeze but it would be pretty dumb anyway. I did insulate the 3 feet of pipe going into the water heater from the water softener and the other 3 foot sections that came in the 4 pack I insulated until the 3/4" copper split into separate 1/2" lines to the kitchen and bathrooms, so I insulated 9 feet of hot and 3 of the cold. Interesting that the section of copper pipe that comes UP from the water softener is actually noticeably lukewarm so there is some fluid convection going on pulling heat down but its a 4" section and I ran out of insulation.

I have original 1985 double pane windows, they are sliders and have no weights. The biggest window other than the patio door has a bad seal which my home inspector mentioned before I bought the house, the energy auditor seemed to think it didn't really matter much. I'm not sure how I'd seal it, run a thin bead of clear silicone around the seal like I planned to do around the wood seams of the window that the spiders seem to be coming through as there are always webs around the corners?

Spray caulk, I'm going to do some searching around. 12" of cellulose and that much or more ceiling would really remove the need to add heat? I'd imagine losing windows would help a bunch. I wish I was passivehaus air sealed, I don't even know if my house is that tight yet. I don't use any method of ventilation other than my bathroom fan for showers and I don't feel like its stuffy or uncomfortable and to be honest I don't know what that feels like or if I'd notice but the house smells fine. I was at just under 1500cfm50 for 2200sq ft after fixing the windows but before sealing outlets, switchplates, and the two attic hatchways which both were very leaky, I have a natural draft water heater and furnace and could feel air pouring in for those so the result is likely severely screwed by that 4 or 5 inch diameter exhaust. I should have plugged those to see the change for when I eventually end up with a sealed combustion furnace.

S-F · 01-02-12, 09:43 AM

Generally it's assumed that only the first several feet coming from the hot water heater or boiler need to be insulated. Beyond that the ROI is too far out.
By bad seal on the window do you mean that the casement is loose? If so then the only real answer is to replace the window. You might be able to get a replacement sash that would fix it though. Aside from that you can use DAP Peel N' Seal for the colder months when you don't operate the window. Personally I'd just install a replacement casement.
Spray caulk rocks but it's a pain to get because you need to be in the loop with the company that makes it. It's not for a home owner or regular contractor. I can't use it because of the restrictions. But the stuff rocks. You can get spray foam air tightness without actually having to lower yourself to using spray foam.
If you got good air sealing and your house was R 10, 20, 40, 60 (slab, basement walls, above grade walls and attic) you'd basically not need heat. You could heat your house with cooking and doing a little exercise from time to time.
A really tight house (read, less than 1.something ACH @ 50) will be unpleasant without some fresh air. You'll wake up in the morning feeling not so good. Smells will stick for a long time. The whole house will be stinky. BO, onions and so on. To calculate your ACH @ 50 number you need to find the exact cubic footage of your house. So you multiply your Sq. footage by the ceiling height and don't forget to include the space in the ceiling between floors.
About sealing outlets and so on. There was an article on GBA over the summer about energy efficiency myths and sealing outlets was one of them. Your sheathing should be air tight and that's your air boundary. The exception is if you use the ADA (airtight drywall approach). To do that you'd need to tear out all the walls and basically everything and caulk new drywall to absolutely everything it touches and caulk plastic pans behind and around all electrical boxes. Not much fun, and if you're going to do all that work you might as well just air seal the sheathing.

AC_Hacker · 01-02-12, 11:22 AM

Quote:

Originally Posted by S-F

...(read, less than 1.something ACH @ 50)...

I'm guessing that the "50" is fifty pascals pressure?

-AC_Hacker

S-F · 01-02-12, 12:32 PM

Yeah. That's the standard. # of Air Changes per Hour at 50 pascals, or the "air change fifty" number. "Taking the house to air change fifty". I'm not sure why 50 was chosen but it's the number everyone uses. There has been some talk floating around over the past year of how each blower door test should be conducted multiple times at different levels because they show different points of leakage. Even the passivehaus people use ACH @ 50 alone for their air tightness ratings (.6 ACH @ 50). .6 is absolutely what to aim for but in practice it's very, Very hard to get. There is a thread here somewhere about a house a friend of mine built here in western MA. It's a ranch with 12" walls, about R 120 in the ceiling and a 5 KW PV array. He's won a bunch of awards for it. When the LEED people did the final blower door it came out to be .9 ACH @ 50. Passivehaus standards are hard to meet and sometimes not practical. For example that house also doesn't meet passivehaus criteria because it only has R 30 under the slab, not R 45. The ROI on that extra R 15 would be about 10,000 years. The ROI on the R 30 as opposed to R 15 or 20 is probably 10,000 years for that matter. Another catch is that blower doors don't come with the ring for such low settings so no one really has them. You have to special order them. The reason is that once you get that tight it's really just a competition with yourself and the passivehaus folks over exact numbers.

MN Renovator · 01-03-12, 04:12 PM

"Generally it's assumed that only the first several feet coming from the hot water heater or boiler need to be insulated. Beyond that the ROI is too far out."

There was a sale, it was a bagged 4 pack of 3 foot sections but it worked out because I used one on the cold side and the remaining 9 feet was pretty much exactly what amount of pipe I needed to cover the main section before it splits into the 1/2" lines.

"By bad seal on the window do you mean that the casement is loose? If so then the only real answer is to replace the window. You might be able to get a replacement sash that would fix it though. Aside from that you can use DAP Peel N' Seal for the colder months when you don't operate the window. Personally I'd just install a replacement casement. "

No, the casement isn't loose, the seal between the two panes of glass is letting air into the gap between the panes. It looks like the glass needs to be washed but its really a film from the condensation that happens in the summer between the two layers of glass.

Spray caulk rocks but it's a pain to get because you need to be in the loop with the company that makes it. It's not for a home owner or regular contractor. I can't use it because of the restrictions. But the stuff rocks. You can get spray foam air tightness without actually having to lower yourself to using spray foam.

Sounds awesome!

If you got good air sealing and your house was R 10, 20, 40, 60 (slab, basement walls, above grade walls and attic) you'd basically not need heat. You could heat your house with cooking and doing a little exercise from time to time.

Sounds like my house when it is within 20 degrees of the outside temperature, more temperature than that and the sun and internal heat sources are less than what can maintain the temperature. I've gotten lucky a few times with it 25 degrees lower outside as an overnight but with good sun the next day.

"A really tight house (read, less than 1.something ACH @ 50) will be unpleasant without some fresh air. You'll wake up in the morning feeling not so good. Smells will stick for a long time. The whole house will be stinky. BO, onions and so on. To calculate your ACH @ 50 number you need to find the exact cubic footage of your house. So you multiply your Sq. footage by the ceiling height and don't forget to include the space in the ceiling between floors."

I'm at 5.1ACH50 but that is with the furnace and water heater chimney pouring tons of air into the house and before a good load of the sealing that has been done already since the energy audit.

"About sealing outlets and so on. There was an article on GBA over the summer about energy efficiency myths and sealing outlets was one of them. Your sheathing should be air tight and that's your air boundary."

The whole house is wrapped in 3/4" of XPS and the gap seemed tight but not caulked or anything when I pulled off and replaced a few chunks of rotten siding. Would I caulk that, is that where its all leaking through. My IR images make my outlets and switch plates on the ground level, attic hatches upstairs, and all kind of small gaps downstairs to be among the leakiest items in the house as far as I can tell. A thick cold streak comes from the outlets. If gasketing the exterior facing plates isn't the answer, how do I find and seal the sheating?

01-01-12, 05:11 PM	#32
S-F You Ain't Me Join Date: Nov 2009 Location: Northampton MA Posts: 662 Thanks: 6 Thanked 71 Times in 58 Posts	I deal with auditors on an almost daily basis and I must say that on the whole they know little more about building science than the average mildly interested home owner. They want me to do some of the most useless things. Here's a good one: I have to go back to a house to insulate the incoming water pipes. I guess that auditor wants to make sure that the pipes freeze. The odd thing is that the auditor you speak of, MN Renovator, is BPI certified. I have taken all of the courses that they offer and they are absolutely fantastic. I highly recommend them to everyone here. I know the people who developed the BPI courses and to my knowledge they haven't offered the auditor course yet. They certainly haven't offered it here in MA or I'd have taken it. About the windows, it's mind boggling how many windows are replaced leaving the cavities for the old weights empty. Many installers just cut the rope and let the weight drop down in there. Low expansion 1 part foam is your friend here. It's not really about the R Value, since the window next to it is one of the largest sources of lost heat in the house. It's all about the air sealing. If you only have R 13 in your walls but passivehaus air tightness you'll still be doing great. Now if you top that with a whole wall R Value of 50 or so your only problem will be that there is no longer a single heat source to dry your mittens out on in the winter. We should all tear out=r interior walls out, seal with spray caulk (my new favorite product) and truss to the inside to make a 12" cavity for cellulose. Then you sell your boiler on craigslist. Or sell if for scrap. At that point it's probably worth more as scrap that as a heater.

01-01-12, 06:18 PM	#33
MN Renovator Less usage=Cheaper bills Join Date: Nov 2010 Location: Minneapolis, MN Posts: 939 Thanks: 41 Thanked 116 Times in 90 Posts	My auditor didn't want me to insulate the incoming pipes, but in my house they come up through the concrete slow which is below grade so they wouldn't freeze but it would be pretty dumb anyway. I did insulate the 3 feet of pipe going into the water heater from the water softener and the other 3 foot sections that came in the 4 pack I insulated until the 3/4" copper split into separate 1/2" lines to the kitchen and bathrooms, so I insulated 9 feet of hot and 3 of the cold. Interesting that the section of copper pipe that comes UP from the water softener is actually noticeably lukewarm so there is some fluid convection going on pulling heat down but its a 4" section and I ran out of insulation. I have original 1985 double pane windows, they are sliders and have no weights. The biggest window other than the patio door has a bad seal which my home inspector mentioned before I bought the house, the energy auditor seemed to think it didn't really matter much. I'm not sure how I'd seal it, run a thin bead of clear silicone around the seal like I planned to do around the wood seams of the window that the spiders seem to be coming through as there are always webs around the corners? Spray caulk, I'm going to do some searching around. 12" of cellulose and that much or more ceiling would really remove the need to add heat? I'd imagine losing windows would help a bunch. I wish I was passivehaus air sealed, I don't even know if my house is that tight yet. I don't use any method of ventilation other than my bathroom fan for showers and I don't feel like its stuffy or uncomfortable and to be honest I don't know what that feels like or if I'd notice but the house smells fine. I was at just under 1500cfm50 for 2200sq ft after fixing the windows but before sealing outlets, switchplates, and the two attic hatchways which both were very leaky, I have a natural draft water heater and furnace and could feel air pouring in for those so the result is likely severely screwed by that 4 or 5 inch diameter exhaust. I should have plugged those to see the change for when I eventually end up with a sealed combustion furnace.

01-02-12, 09:43 AM	#34
S-F You Ain't Me Join Date: Nov 2009 Location: Northampton MA Posts: 662 Thanks: 6 Thanked 71 Times in 58 Posts	Generally it's assumed that only the first several feet coming from the hot water heater or boiler need to be insulated. Beyond that the ROI is too far out. By bad seal on the window do you mean that the casement is loose? If so then the only real answer is to replace the window. You might be able to get a replacement sash that would fix it though. Aside from that you can use DAP Peel N' Seal for the colder months when you don't operate the window. Personally I'd just install a replacement casement. Spray caulk rocks but it's a pain to get because you need to be in the loop with the company that makes it. It's not for a home owner or regular contractor. I can't use it because of the restrictions. But the stuff rocks. You can get spray foam air tightness without actually having to lower yourself to using spray foam. If you got good air sealing and your house was R 10, 20, 40, 60 (slab, basement walls, above grade walls and attic) you'd basically not need heat. You could heat your house with cooking and doing a little exercise from time to time. A really tight house (read, less than 1.something ACH @ 50) will be unpleasant without some fresh air. You'll wake up in the morning feeling not so good. Smells will stick for a long time. The whole house will be stinky. BO, onions and so on. To calculate your ACH @ 50 number you need to find the exact cubic footage of your house. So you multiply your Sq. footage by the ceiling height and don't forget to include the space in the ceiling between floors. About sealing outlets and so on. There was an article on GBA over the summer about energy efficiency myths and sealing outlets was one of them. Your sheathing should be air tight and that's your air boundary. The exception is if you use the ADA (airtight drywall approach). To do that you'd need to tear out all the walls and basically everything and caulk new drywall to absolutely everything it touches and caulk plastic pans behind and around all electrical boxes. Not much fun, and if you're going to do all that work you might as well just air seal the sheathing.

01-02-12, 12:32 PM	#36
S-F You Ain't Me Join Date: Nov 2009 Location: Northampton MA Posts: 662 Thanks: 6 Thanked 71 Times in 58 Posts	Yeah. That's the standard. # of Air Changes per Hour at 50 pascals, or the "air change fifty" number. "Taking the house to air change fifty". I'm not sure why 50 was chosen but it's the number everyone uses. There has been some talk floating around over the past year of how each blower door test should be conducted multiple times at different levels because they show different points of leakage. Even the passivehaus people use ACH @ 50 alone for their air tightness ratings (.6 ACH @ 50). .6 is absolutely what to aim for but in practice it's very, Very hard to get. There is a thread here somewhere about a house a friend of mine built here in western MA. It's a ranch with 12" walls, about R 120 in the ceiling and a 5 KW PV array. He's won a bunch of awards for it. When the LEED people did the final blower door it came out to be .9 ACH @ 50. Passivehaus standards are hard to meet and sometimes not practical. For example that house also doesn't meet passivehaus criteria because it only has R 30 under the slab, not R 45. The ROI on that extra R 15 would be about 10,000 years. The ROI on the R 30 as opposed to R 15 or 20 is probably 10,000 years for that matter. Another catch is that blower doors don't come with the ring for such low settings so no one really has them. You have to special order them. The reason is that once you get that tight it's really just a competition with yourself and the passivehaus folks over exact numbers.

01-03-12, 04:12 PM	#37
MN Renovator Less usage=Cheaper bills Join Date: Nov 2010 Location: Minneapolis, MN Posts: 939 Thanks: 41 Thanked 116 Times in 90 Posts	"Generally it's assumed that only the first several feet coming from the hot water heater or boiler need to be insulated. Beyond that the ROI is too far out." There was a sale, it was a bagged 4 pack of 3 foot sections but it worked out because I used one on the cold side and the remaining 9 feet was pretty much exactly what amount of pipe I needed to cover the main section before it splits into the 1/2" lines. "By bad seal on the window do you mean that the casement is loose? If so then the only real answer is to replace the window. You might be able to get a replacement sash that would fix it though. Aside from that you can use DAP Peel N' Seal for the colder months when you don't operate the window. Personally I'd just install a replacement casement. " No, the casement isn't loose, the seal between the two panes of glass is letting air into the gap between the panes. It looks like the glass needs to be washed but its really a film from the condensation that happens in the summer between the two layers of glass. Spray caulk rocks but it's a pain to get because you need to be in the loop with the company that makes it. It's not for a home owner or regular contractor. I can't use it because of the restrictions. But the stuff rocks. You can get spray foam air tightness without actually having to lower yourself to using spray foam. Sounds awesome! If you got good air sealing and your house was R 10, 20, 40, 60 (slab, basement walls, above grade walls and attic) you'd basically not need heat. You could heat your house with cooking and doing a little exercise from time to time. Sounds like my house when it is within 20 degrees of the outside temperature, more temperature than that and the sun and internal heat sources are less than what can maintain the temperature. I've gotten lucky a few times with it 25 degrees lower outside as an overnight but with good sun the next day. "A really tight house (read, less than 1.something ACH @ 50) will be unpleasant without some fresh air. You'll wake up in the morning feeling not so good. Smells will stick for a long time. The whole house will be stinky. BO, onions and so on. To calculate your ACH @ 50 number you need to find the exact cubic footage of your house. So you multiply your Sq. footage by the ceiling height and don't forget to include the space in the ceiling between floors." I'm at 5.1ACH50 but that is with the furnace and water heater chimney pouring tons of air into the house and before a good load of the sealing that has been done already since the energy audit. "About sealing outlets and so on. There was an article on GBA over the summer about energy efficiency myths and sealing outlets was one of them. Your sheathing should be air tight and that's your air boundary." The whole house is wrapped in 3/4" of XPS and the gap seemed tight but not caulked or anything when I pulled off and replaced a few chunks of rotten siding. Would I caulk that, is that where its all leaking through. My IR images make my outlets and switch plates on the ground level, attic hatches upstairs, and all kind of small gaps downstairs to be among the leakiest items in the house as far as I can tell. A thick cold streak comes from the outlets. If gasketing the exterior facing plates isn't the answer, how do I find and seal the sheating?