Air sealing success stories

[DBoon]

I just iterated on a lot of little things (wall insulation, EPDM gaskets on bottom of double hung windows, bronze weatherstripping on double hungs, spray foam on above grade basement walls, etc.) to get the infiltration lower. No one things does it all until you get to the end...

I couldn't even tell you how bad my ACH was before I did all this. All I know was that my wife complained of breezes through the house in the wintertime, and the smell of other peoples wood smoke in our house...

The last blower door test I had done came up with an ACH (at 50 Pascals) of 5.5 (1800 CFM for a 1200 square foot house with a full basement). The blower door technician suggested two things for me to seal better - the attic hatch and a basement door, and by his estimation if I did those two things (I did) I would drop that by 40% (to about 3 to 3.5). I've read that the natural ACH is the ACH50 divided by ~10, so that would give me a pretty small value. The house sure feels pretty comfortable now, and with the new oil boiler using outside air for combustion, I feel pretty good about the air sealing work I've done.

 

[DBNH22]

I have fiberglass batts in my attic to R30. They're probably performig more like R20. I pulled them up and airsealed as much as I could with Great Stuff this spring but I think I might have a professional come out and so it. As I've read on here, most DIYers actually miss a lot in the attic when they do the air sealing themselves.

My basement rim joists are being spray foamed today.

In the spring I think I may have some blown in cellulose added to the fiberglass batts to get me to R50. Need to install new baffles first though.

 

[DickRussell]

... I've read that the natural ACH is the ACH50 divided by ~10, so that would give me a pretty small value.

The depressurization to 50 pascals is intended to get well beyond "natural" leakage, which is driven by both wind pressure and that resulting from air density differences due to outside temperature. Clearly, leakage is worst when it's very windy and bitterly cold outside and nearly nonexistent when it's mid-60s and calm outside. That's one reason why any argument that you should "build tight, but not too tight - the house has to breathe" is so flawed and simply doesn't work. There is no way to design in any amount of "leakage" that is just right for any set of conditions, let alone all the time. Anyway, to approximate "natural" worst case leakage from the ACH50 number, one would divide by a number more like 18, plus or minus, and which depends on the house configuration (single story vs two) how well it is protected from wind by trees and topography, and climate.

 

[DBoon]

Hi DickRussell, I've seen a lot of different values indicated for the "divisor" for ACH50 to get natural leakage - I'm hoping you can point me to some further references on this topic...thanks.

 

[woodgeek]

I've seen some of those, and while they might be useful in some contexts, they are statistical models. If your air leakage in your ACH50 is all at the bottom on one side of the house, then natural convection will be squat (think hot air balloon) and wind driven air will also be squat (compared to CFM50). You can imagine other permutations....all leakage is low, but on opposite sides, half the leakage is high, half low, etc. The bottom line is that it is impossible to infer ACH_nat or ACH_wind from ACH_50 in anything other than a statistical sense. ACH50 is a great way to define airtightness in a building code or to validate airsealing work during a retrofit, but is not useful for energy modeling in a single house.

Myself, I like 15-18 for the 'best guess ratio' of ACH_50 to ACH_nat.

 

[GaryGary]

Hi,
Here is a method for converting the 50 Pa ACH to nautural ACH that takes into account some of the variables like climate, sheltering, height of house...

http://www.builditsolar.com/Projects/Conservation/BlowerDoor/FlowRates.htm#Natural

See the LBL method.

Gary

 

[EatenByLimestone]

While I was down in the basement tightening up and sealing air leaks I smelt a bit of the natural gas perfume. I got some soapy water and checked all of the joints, but still couldn't find anything. I called National Grid. The guy with the fancy equipment couldn't find any at first, then he switched to a different setting (I'm guessing a little more sensitive) and found the leak. He had to shut me off... But at least he realized I was somewhat competent when I explained what I had done to try to find it and only turned off the valve at the meter. He didn't seal it. He said, "Just replace the csst with black pipe and leak test it. Then you'll be good to go." Well that's what I did and just finished my 2nd leak testing.

With the woodstove I wasn't too worried, but I don't like not having backup heat when we're supposed to be down to 3 tonight.

I think there was probably enough air moving around before I started sealing up the area that I never noticed the leak before. On disassembling the CSST pipe I found the original contractors overtightened a compression joint and crushed a ring/gasket.

 

[drewmo]

Great thread as we had the rim joists sealed and basement walls insulated to a minimum of 3 feet below grade just recently on our 1920s-built home. With this cold settled over us, my basement is now about 50 degrees with no radiant heat (furnace was removed over the summer). Over the last couple of days I've done some additional insulating (plastic over windows and other miscellaneous areas of air infiltration). I've seen a 2-3 degree rise in basement temperature even with the outside temps dropping. Last winter with no insulation and no radiant heat, the basement would hover around 36 on the coldest of days. Way too cold for my comfort.

 

[DBNH22]

Great thread as we had the rim joists sealed and basement walls insulated to a minimum of 3 feet below grade just recently on our 1920s-built home. With this cold settled over us, my basement is now about 50 degrees with no radiant heat (furnace was removed over the summer). Over the last couple of days I've done some additional insulating (plastic over windows and other miscellaneous areas of air infiltration). I've seen a 2-3 degree rise in basement temperature even with the outside temps dropping. Last winter with no insulation and no radiant heat, the basement would hover around 36 on the coldest of days. Way too cold for my comfort.

Yikes. What did you first floor floors feel like prior to the basement insulation? I just had my rim joist but not basement walls spray foamed and it made a noticable difference in how the floors feel.

It certainly is cold today here in southern NH. On my drive in to work this morning the car thermometer read -5.

 

[drewmo]

Yikes. What did you first floor floors feel like prior to the basement insulation? I just had my rim joist but not basement
walls spray foamed and it made a noticable difference in how the floors feel.

It certainly is cold today here in southern NH. On my drive in to work this morning the car thermometer read -5.

Floors were a bit cold, but I'm thankful for a wife who can spot a man (and child) without slippers from a mile away. While I'm not exactly thrilled about this cold snap, I'm kinda happy that it came early to give the insulation a good testing.

 

[DBNH22]

Great thread as we had the rim joists sealed and basement walls insulated to a minimum of 3 feet below grade just recently on our 1920s-built home. With this cold settled over us, my basement is now about 50 degrees with no radiant heat (furnace was removed over the summer). Over the last couple of days I've done some additional insulating (plastic over windows and other miscellaneous areas of air infiltration). I've seen a 2-3 degree rise in basement temperature even with the outside temps dropping. Last winter with no insulation and no radiant heat, the basement would hover around 36 on the coldest of days. Way too cold for my comfort.

Did you use spray foam for this and have it come out of the rim joist area over the sill plate down the walls? I had considered doing that an dhving it go down four feet on the walls as I'm told that that's where the forst line is in NH. But the extra cost for material and time is not something I was ready to absorb righ tnow. I just wanted to get the rim joist done and maybe next year I'll tackle the basement walls.

 

[newbieinCT]

love this thread! All these success stories are motivation. Just moved into a 2200sqft, oil-heat 1890s farmhouse. We are house poor but through CT programs, we are eligible for rebates and financing for insulation. We are about to pull the trigger on attic insulation, whole house air sealing and most likely wall insulation (debating that one...not sure but will probably go for it). It's scary to say you are going to invest so much when you just got for your first few mortgage payments, but we are going to do it. Stories like the ones abovet make me feel better about it! Add on a new stove to the air sealing and insulation and I'm hoping we will be toasty warm
Thanks everyone!
meg
ps: a few weeks ago this entire thread would have been gibberish to me - ACH, R ratings, perlite, rim joists. Big learning curve but everything on here made sense to me...and I'm nodding my head in agreement as I read along. Seriously, thanks everyone!

 

[DBNH22]

love this thread! All these success stories are motivation. Just moved into a 2200sqft, oil-heat 1890s farmhouse. We are house poor but through CT programs, we are eligible for rebates and financing for insulation. We are about to pull the trigger on attic insulation, whole house air sealing and most likely wall insulation (debating that one...not sure but will probably go for it). It's scary to say you are going to invest so much when you just got for your first few mortgage payments, but we are going to do it. Stories like the ones abovet make me feel better about it! Add on a new stove to the air sealing and insulation and I'm hoping we will be toasty warm
Thanks everyone!
meg
ps: a few weeks ago this entire thread would have been gibberish to me - ACH, R ratings, perlite, rim joists. Big learning curve but everything on here made sense to me...and I'm nodding my head in agreement as I read along. Seriously, thanks everyone!

It may be scary but it makes good financial sense if you plan on being in the home for a long period of time. Some of the heating systems/insulation/air sealing and other projects discussed on this site are far more costly than others and will have a longer payback time. I think air sealing and insulating rim joists tends to fall on the lower end of that scale and payback time is relatively short for most who do it. After it's paid for itself it's nothing but savings as long as you live in the home. It always amazes me that people will drop 10k, 20k or even more on something like new kitchen cabinets or a bathroom remodel but never once think about there home's energy use. Granted some of the aesthetic upgrades can sometimes add value to a home but usually not the amount you spent on them.

Like you all of this talk abour R values, rim joist, air sealing etc was foreign to me just a short time ago. Last year's heating bills put a pretty severe scowl on my face. Having to order 100 to 130 gallons of oil every three to four weeks was downright miserable when oil prices were bouncing around 3.79 - 3.99 a gallon. Being the frugal sort I figured that there had to be a better way to heat my home so I began doing research on oil alternatives. Along the way I've learned a great deal about wood pellets, wood pellet boilers, natural gas, r values, air sealing, the whole nine pertaining to making a residence as energy efficent as possible. Along the way I stumbled on this site and have found it to be a great source of free, invaluable information. There are a lot of great people on here willing to share their experience and knowledge. Making my home as energy efficient as possible has now become somewhat of an obsession. My wife doesn't mind because we have two very young childran and plan on staying in the home for at least another twenty years barring life throwing some major league curveballs our way. She sees the bottome line made out of $$$$ under all that spray foam and those bags of wood pellets.

 

[EatenByLimestone]

I'm considering doing the upper 4 feet of basement walls with this:

http://www.reflectixinc.com/basepage.asp?PageIndex=622

It's pretty much bubble wrap with a radiant barrier on both sides. Since radiant barriers work best when they can reflect heat back into an air space it should work well against the wall reflecting heat back into the room. Without the air space it's R-3.?. With the air space it should be much more effective. The main sellng point to me is that it's cheap enough I won't feel bad if I decide to tear it out when I eventually get the outside of the walls insulated.

 

[EatenByLimestone]

I think air sealing and insulating rim joists tends to fall on the lower end of that scale and payback time is relatively short for most who do it.

Most of my air sealing was done with caulk. Some of it was more expensive and specialized than other caulk, but it was caulk. The payback is real quick for that stuff.

My wife doesn't mind because we have two very young childran and plan on staying in the home for at least another twenty years barring life throwing some major league curveballs our way.

My wife is more concerned with the comfort aspect. I'd rather not pay lots of money for her comfort. I want her to be comfortable, but I don't want to go broke doing it!

 

[woodgeek]

I'm considering doing the upper 4 feet of basement walls with this:

http://www.reflectixinc.com/basepage.asp?PageIndex=622

It's pretty much bubble wrap with a radiant barrier on both sides. Since radiant barriers work best when they can reflect heat back into an air space it should work well against the wall reflecting heat back into the room. Without the air space it's R-3.?. With the air space it should be much more effective. The main sellng point to me is that it's cheap enough I won't feel bad if I decide to tear it out when I eventually get the outside of the walls insulated.

I still think that stuff is junk. Overpriced junk at that. I'd start at an inch of foamboard.

With hollow blocks, pouring in perlite would be easy, and work better than that stuff.

 

[DBNH22]

Most of my air sealing was done with caulk. Some of it was more expensive and specialized than other caulk, but it was caulk. The payback is real quick for that stuff.

My wife is more concerned with the comfort aspect. I'd rather not pay lots of money for her comfort. I want her to be comfortable, but I don't want to go broke doing it!

Making the home more comfortable and more energy efficient are often one in the same. I hear you about going broke doing some of these things though. For me there has to be demonstrable proof that the money invested will produce a significant savings at some point down the road. Otherwise it doesn't get done.

 

[DBNH22]

I still think that stuff is junk. Overpriced junk at that. I'd start at an inch of foamboard.

I've never seen that stuff before but I'd have to agree with you on the foamboard for basement walls. When I get around to doing mine the only two materials I'll consider will be spray foam or 2" XPS rigid foam. I'll have to see which is more cost effective at the time. if I go with the rigid board I'll install it myself but if I go with spray foam I'll have someone do it.

 

[newbieinCT]

It may be scary but it makes good financial sense if you plan on being in the home for a long period of time. Some of the heating systems/insulation/air sealing and other projects discussed on this site are far more costly than others and will have a longer payback time. I think air sealing and insulating rim joists tends to fall on the lower end of that scale and payback time is relatively short for most who do it. After it's paid for itself it's nothing but savings as long as you live in the home. It always amazes me that people will drop 10k, 20k or even more on something like new kitchen cabinets or a bathroom remodel but never once think about there home's energy use. Granted some of the aesthetic upgrades can sometimes add value to a home but usually not the amount you spent on them.

Like you all of this talk abour R values, rim joist, air sealing etc was foreign to me just a short time ago. Last year's heating bills put a pretty severe scowl on my face. Having to order 100 to 130 gallons of oil every three to four weeks was downright miserable when oil prices were bouncing around 3.79 - 3.99 a gallon. Being the frugal sort I figured that there had to be a better way to heat my home so I began doing research on oil alternatives. Along the way I've learned a great deal about wood pellets, wood pellet boilers, natural gas, r values, air sealing, the whole nine pertaining to making a residence as energy efficent as possible. Along the way I stumbled on this site and have found it to be a great source of free, invaluable information. There are a lot of great people on here willing to share their experience and knowledge. Making my home as energy efficient as possible has now become somewhat of an obsession. My wife doesn't mind because we have two very young childran and plan on staying in the home for at least another twenty years barring life throwing some major league curveballs our way. She sees the bottome line made out of $$$$ under all that spray foam and those bags of wood pellets.

I'm scared to see a winter's heating bill here...we haven't been here long enough and, like you, plan to be here long term. This site is pretty amazing...so many options. I want to walk into the nearest Harman dealer right now and buy the biggest stove we can afford..but there's some kind people on here saying there are other options, other brands, pellet boilers, geothermal. We have a lot to think about, esp b/c we have a crazy layout. We plan on doing some stuff ourselves - rim joist and basement insulation type stuff (you should see the mess in our crawlspace below the kitchen!). We are thinking of it the same way - insulate and air seal before rehabbing the kitchen. it's hard to do when the kitchen something you see everyday but hopefully we will FEEL the difference. I think we are only hesitant about retrofitting all the walls w/ dense pack cellulose. Hear great things but people say it's not worth all the money if you have properly sealed house and insulated attics. We'll see.

I'm starting to talk about R values in my sleep..and dream it! I was telling my husband this morning about the 3rd contractor that came. He said "but we only had two come". Apparently, the 3rd one was part of my dream last night! I'm need a vacation from insulation
Meg

 

[woodgeek]

I'm scared to see a winter's heating bill here...we haven't been here long enough and, like you, plan to be here long term. This site is pretty amazing...so many options. I want to walk into the nearest Harman dealer right now and buy the biggest stove we can afford..but there's some kind people on here saying there are other options, other brands, pellet boilers, geothermal. We have a lot to think about, esp b/c we have a crazy layout. We plan on doing some stuff ourselves - rim joist and basement insulation type stuff (you should see the mess in our crawlspace below the kitchen!). We are thinking of it the same way - insulate and air seal before rehabbing the kitchen. it's hard to do when the kitchen something you see everyday but hopefully we will FEEL the difference. I think we are only hesitant about retrofitting all the walls w/ dense pack cellulose. Hear great things but people say it's not worth all the money if you have properly sealed house and insulated attics. We'll see.

I'm starting to talk about R values in my sleep..and dream it! I was telling my husband this morning about the 3rd contractor that came. He said "but we only had two come". Apparently, the 3rd one was part of my dream last night! I'm need a vacation from insulation
Meg

I'd be scared of the oil man too. In your climate, I would cross the 'geo' off the list. Performance on geos is generally overstated, and within spitting distance of mini-splits, and they would cost 3X as much as minis for installation. Might be a case for geos in the far north and new construction, but minis are chasing them out of most of the lower 48 IMO. Assuming natgas is not available, I would think your budget options would be wood, pellets or mini-splits, or some combination of those. Any of those will be a few $k up front, but prob save $500-1000/year.

 

[EatenByLimestone]

I still think that stuff is junk. Overpriced junk at that. I'd start at an inch of foamboard.

With hollow blocks, pouring in perlite would be easy, and work better than that stuff.

Foam board would have to be covered and with the 30 down in the basement I'd rather not leave it uncovered! I don't want to finish off the basement. My ceiling is barely 6 feet from the floor.

 

[DBNH22]

I'm scared to see a winter's heating bill here...we haven't been here long enough and, like you, plan to be here long term. This site is pretty amazing...so many options. I want to walk into the nearest Harman dealer right now and buy the biggest stove we can afford..but there's some kind people on here saying there are other options, other brands, pellet boilers, geothermal. We have a lot to think about, esp b/c we have a crazy layout. We plan on doing some stuff ourselves - rim joist and basement insulation type stuff (you should see the mess in our crawlspace below the kitchen!). We are thinking of it the same way - insulate and air seal before rehabbing the kitchen. it's hard to do when the kitchen something you see everyday but hopefully we will FEEL the difference. I think we are only hesitant about retrofitting all the walls w/ dense pack cellulose. Hear great things but people say it's not worth all the money if you have properly sealed house and insulated attics. We'll see.

I'm starting to talk about R values in my sleep..and dream it! I was telling my husband this morning about the 3rd contractor that came. He said "but we only had two come". Apparently, the 3rd one was part of my dream last night! I'm need a vacation from insulation
Meg

The guy I had do my energy audit said the rule of air sealing/insulating a home is the ABC rule, attic, basement, center in that order. You get more bang for your buck starting with the attic as that is where most of your heat will leave your home if it's not properly sealed and insulated. I only have R19 fiberglass batts in my walls but I'm not as concerned with the walls as I am the attic and basement. If you have not already learned about the stack effect you should read up on it on the internet. It's the phenomenon whereby the warm air in your home esacpes at the top causing the pressure at the lower lefels of your home to decrease and cold air to be sucked in. Sealing both the top and bottom of your home will reduce this.


This is your first winter in New England Meg? Although CT is considered part of New England Danbury and that whole southwest corner tend to culturally identify with NYC more than New England. More Giants fans there than Patriots fans. Where are you from originally?

 

[semipro]

Foam board would have to be covered and with the 30 down in the basement I'd rather not leave it uncovered! I don't want to finish off the basement. My ceiling is barely 6 feet from the floor.

Wouldn't you have to cover the Reflectix too? I don't think its a proper thermal (flame retardant) barrier.
If you don't want to finish the basement and don't want to install a thermal barrier over the insulation wouldn't something like Roxul work or is to too expensive for you?

 

[woodgeek]

Foam board would have to be covered and with the 30 down in the basement I'd rather not leave it uncovered! I don't want to finish off the basement. My ceiling is barely 6 feet from the floor.

Aaah. I see. Still think the reflectix is a waste of time. Perlite (or any other cavity fill) is easy, permanent, cheap and non-combustible.

A list of R-values before and after block fill... http://www.schundler.com/rvalues.htm

 

[EatenByLimestone]

Wouldn't you have to cover the Reflectix too?

I hadn't heard that. I'll look into it.

It has a Class A/ClassI fire rating. The same as brick. Wood has a Class II and plywod Class III.

Aaah. I see. Still think the reflectix is a waste of time. Perlite (or any other cavity fill) is easy, permanent, cheap and non-combustible. A list of R-values before and after block fill... http://www.schundler.com/rvalues.htm

Am I understanding the chart right in that I can bring a 10" block (not lightweight) from 2.31 to 5.95 by filling each and every cavity?

How is that better than R 3.7? Especially if you consider time invested?