Insulating old house

[frenchie]

You are correct, there is a lot to think about. The worst part is for every question, there are a dozen different answers!

No, the foam is not good if it gets wet and the wood rots out. I do think, at least to some extent, that if I at least stay on top of the exterior maintenance, any rotting should be kept to a minimum. It would be one thing, if it sat and sat and sat in damp conditions for years, but, if you can catch the issue, that "should" buy some time. That theory probably works best when dealing with rain and such. The condensation is another thing all together and a real concern, because my windows ice up badly in the really cold weather!

I have googled pour foam before, but will do it again. I know there are some DIY kits, but they just seem really, really expensive. My average utitlity bill is probably $250-$300, for this 1-1/2 story, 1900 sq ft house with about 700sq ft of unfinished basement. I know that is not good by any stretch compared to today's newer houses, but it is what it is on these old houses. In fact my previous house was 1300sq ft and 1-1/2 story and it cost me about $25 per month more for utilities! My point is, it would take 10+ years to justify spending ~$10k on having someone insulate the house correctly. I just am not certainit's worth that.

I also know from experience, with watercraft, with two part foams, they do tend to get waterlogged over time. I suppose one solution which wouldn't provide excellent R value, would be to use 2" rigged foam panels, cut to size and inserted into the walls. With that, I would then leave a little "air chamber" as well throughout he outside of the wall, which would allow the wall to still breathe! Thoughts?

You're a natural! We were just talking about that approach, in a carpenter's forum the other day. You'll have to wade through a really stupid argument in the middle, but the rest of the thread is worth reading:

http://forums.jlconline.com/forums/s...ighlight=cabin
[Standard warning: that site is adamantly pro-only. There's a lot of good information there, and if you register it makes searching easier (no image verification thingy), and lets you download attachments. And anybody can register, but only people who build or fix houses for a living are allowed to post. JLC members can be really mean, nasty, rude and/or obnoxious bullies when enforcing that rule. You have been warned...]

That thread is about doing it from the inside, but same basic idea. You definitely need to find a way to drain the cavity, somehow (occurred to me later: you could just scarf the front of the bottom plate). And remember to bug-net the openings...

Worth it to spray the edges, like Dave said. Air-sealing's critical.

Ok, well I called by Owens Corning and GreenFiber. Both said I shouldn't have any issues with their blow in material IF my siding is in good shape. They said moisture shouldn't pose any problems.

But they would, wouldn't they? ...seriously, though, it might be fine. To a certain extent, blown-in can dry through the wall, same as the cavity does now.

The possible problem is that because you've insulated, the cavity's a lot cooler than it used to be (in jargon, you've changed the hygrothermic balance of the assembly). Basically, less warmth = less evaporation... So there's a risk.

It might be okay, it might cause problems. Depends on the specifics of your house, how much air leakage there is, etc.

I guess my last question is how do you determine if/when moisture might be a problem? They did ask me where I lived....

Moisture meter. Check the wall cavity before/during/after a bit of rain.

Or: open a wall somewhere, just enough to take a peek. Look for drip-marks on the backside of your siding, especially around & below windows, etc.

If you mean after insulating - the first sign of moisture issues, usually, is peeling paint on the siding.

[Master Brian]

Thanks for the link, problem is they also talk about doing it from inside out, taking one side of the wall apart. I wouldn't mind doing that, IF the siding pulls off ok, but something tells me that isn't going to be the case with 100yr wood and nails. Working one or two rows all around the house is one thing, working every board is another.

Yes, I would suppose the two companies would say that, but then again, sometimes people are actually honest and would say, no this is not what you would want.

I also checked with the Dept of Energy's website and it look like they seem to say in my area a vapor barrior isn't a necessity. I plan on trying to call my local inspection office and/or the states DOE and see what I come up with.

Another thought, I just had was there is an upstairs bathroom, which has been remoded since probably the 80's. I believe it has fiberglass batting behind drywall. Being as I plan on remodeling this bathroom in the near future, maybe I'll cut a hole in the wall and see what is going on. If it is dry with no real signs of water that has sat, maybe I'll be ok. It's probably the best answer to my question.

My lingering question here is how much different does air flow around fiberglass batting vs. blown in cellulose? I would think the cellulose would be a tighter "pack" thereby not drying as much; however, I tend to read that cellulose is better at absorbing and distributing the moisture. Hmmm..

Another thing I am wondering about is a two-fold approach, much like is discussed on the other board. What if, I was to remove the bottom 1' of siding, intall some foam panels about 1' high in such a manner as to create a stop, so that the cellulose wouldn't be allowed to settle at the bottom of the wall. My thought is I woul get good fill for 99% of wall, but if any moisture did accumulate, it could settle, via gravity, towards the bottom of the wall and then mitigate out the wall. I have attached a crude drawing.... Only problem is, this might put too much water on the bottom plate....

[Chessiec]

Assume moisture will get into walls, whatever you do. It is a when, not an if.

That was the learning from the EIS "stucco" system and all the lawsuits that resulted when relatively new homes rotted from the inside out, and more quickly than would ever be expected.

The drainage plane idea is key.

The headaches of insulating the walls right is such an expensive bother, I would make sure that all of the higher priorities of energy efficiency have been done first.
#1. Attic, including plugging all joints/gaps which create convective loops, then insulating it to the max. And don't forget to do effective sealing and insulating of all attic access points.

#2. Plug up the fireplace, if any, either permanently or by using a fireplace 'pillow' plug. Or plug by doing to a direct vent device.

#3. basement, crawl space insulation. If no water infiltration from exterior, go to a closed crawl space. Check out the great information at the Advanced Energy Corp. website on closed crawl spaces. If you are not sure that the grading of the lot, etc. keeps water away from the crawl space, insulate the floor instead of using the closed crawl system.

Of course, plug up any gaps and cracks in the exterior shell, and put insulating foam gaskets in any interior electrical outlets located on the exterior walls.

After that, I would weigh whether the windows or exerior walls were of higher priority. In part, this depends on how tight or leaky your window frames are. But no way does the building science support that old windows are near as energy efficient as decent, current dual pane windows. In my own home, b. 1948, I have 20 old windows, most of them large. They test reasonably tight in a blower door test. But I don't kid myself that they are near as good as decent new ones.

(FWIW, my background is having developed an extremely energy efficient neighborhood. I have rehabbed three houses. But I'm no expert on energy efficient rehabbing. For specific info on how to do the insulation if you move ahead, some of the prior advice sounds pretty nuts-and-boltsy.)

[Master Brian]

After that, I would weigh whether the windows or exerior walls were of higher priority. In part, this depends on how tight or leaky your window frames are. But no way does the building science support that old windows are near as energy efficient as decent, current dual pane windows. In my own home, b. 1948, I have 20 old windows, most of them large. They test reasonably tight in a blower door test. But I don't kid myself that they are near as good as decent new ones.

I am working towards everything else you have mentioned.

I hope you aren't saying that possibly replacing my windows with new units at a likely cost of $25000, is a better bet than spending $1000 on blown in insulation.

I think I just read yesterday on the Dept of Energy's website that single pane glass has an energy efficiency of maybe 65-70 and tripple pane maybe 85. Now I don't know how to exactly figure that, but I am pretty sure it wouldn't cut my energy bill in half, but for fun, let's say it would. I spend about $200 during the extreme months to heat or cool my house, that doesn't include other energy/gas uses. If it cut it in half that is $1200 per year. I have about 38 windows. New "energy efficient" units would run me about $500-$1000 per unit on up. For fun, let' say $750 each. I have some very large windows! 38 X $750 = $28,500. Let's now take $28,500 / $1200 = 23.75 years to break even. The life span of a new window is 15-30 years. I would bet that if I bought the 30 year window, it would cost about double and they'd have to be professionally installed to get the gaurantee and I seriously doubt my bill would be cut in half, maybe cut down $50 p/m at most. So with any way I figure it, it would take me more time to pay off the windows than I would ever save. In fact, before they could be paid off, I would be replacing them. How is that efficient?

I do want to slightly appologize for the rant, but I am tired of telling me I should replace my windows and get something more energy efficient. My windows do need work, but I can glaze and install storm windows far easier and cheaper than I can replace windows and I'll probably see that payback long before they need it again. These windows will also still be around in another 100yrs unlike the newer versions which will be worn out in a fraction of that time!

I can totally see energy efficiency on new homes, it's the right thing to do and doesn't cost that much more, but just because it is labeled as energy efficient doesn't automatically make it the correct thing to do for the environment as a whole!

[jadnashua]

If there's a lot of air leaking, fiberglass will just act like a filter. It only works properly in dead air. Blown in cellulose, when installed properly, is much more dense.

[Scuba_Dave]

I've looked thru a couple sites on line
R Value of single pane seems to be .85 up to 1.3 - very low
Storm windows can save heat loss by 25 to 50%
2x glaze w/argon are from R3 - 3.3
3x glaze argon R6.2 - I have seen ratings up to R10
I'm not sure how old these ratings are?

From Energy Star site:

Replacing windows is rarely cost-effective based solely on energy-savings

I found this strange as my windows have paid for themselves in savings on my energy bill.

One big advantage for me is the house is MUCH quieter

I had one window that one pane was cracked
2 windows that were fogged up
2 windows that built in vinyl "lift" along the bottom edge was cracked & breaking
I think they might have been 8-10 years old (vinyl in & out)
I ended up replacing 15 windows in the house & 3 doors

[jadnashua]

Keep in mind that an old window probably also leaks air, disregarding the fact the single pane of glass is almost like an open window by itself. New windows would cut down air infiltration AND be better insulation. They also probably have some radiant barrier effects, that make it appear to be warmer.

[frenchie]

My lingering question here is how much different does air flow around fiberglass batting vs. blown in cellulose? I would think the cellulose would be a tighter "pack" thereby not drying as much; however, I tend to read that cellulose is better at absorbing and distributing the moisture. Hmmm..

Both true. The denser pack also cuts down on airflow a lot, which in my climate is a good thing - prevents warm vapor-laden air from inside leaking into the wall, condensing against back of the siding, making water.

One the other big plus-es about cellullose is that it will store excess humidity, keeping the wood dry.

The minus is that it will store excess humidity. So if you have leaks into the wall, it'll soak it up... not goog. Also, if it gets damp often enough, eventually, it will settle.

I haven't used either one before, so this is all 2nd and 3rd hand.

Another thing I am wondering about is a two-fold approach, much like is discussed on the other board. What if, I was to remove the bottom 1' of siding, intall some foam panels about 1' high in such a manner as to create a stop, so that the cellulose wouldn't be allowed to settle at the bottom of the wall. My thought is I woul get good fill for 99% of wall, but if any moisture did accumulate, it could settle, via gravity, towards the bottom of the wall and then mitigate out the wall. I have attached a crude drawing.... Only problem is, this might put too much water on the bottom plate....

No advantage, compared to just filling the wall. Without the airspace behing the cladding, there's no drying mechanism. And moisture doesn't settle via gravity, the way bulk water does. If it did, your foam stop would also stop the moisture, re-directing it towards the inside...

[frenchie]

On the windows side-topic... like with walls, our rating systems suck. In terms of real-world performance, the R-factor of the glass is WAY less important than air leakage around the sashes, and/or around the whole unit.

[frenchie]

Assume moisture will get into walls, whatever you do. It is a when, not an if.

That was the learning from the EIS "stucco" system and all the lawsuits that resulted when relatively new homes rotted from the inside out, and more quickly than would ever be expected.

The drainage plane idea is key.

The headaches of insulating the walls right is such an expensive bother, I would make sure that all of the higher priorities of energy efficiency have been done first.
#1. Attic, including plugging all joints/gaps which create convective loops, then insulating it to the max. And don't forget to do effective sealing and insulating of all attic access points.

#2. Plug up the fireplace, if any, either permanently or by using a fireplace 'pillow' plug. Or plug by doing to a direct vent device.

#3. basement, crawl space insulation. If no water infiltration from exterior, go to a closed crawl space. Check out the great information at the Advanced Energy Corp. website on closed crawl spaces. If you are not sure that the grading of the lot, etc. keeps water away from the crawl space, insulate the floor instead of using the closed crawl system.

Of course, plug up any gaps and cracks in the exterior shell, and put insulating foam gaskets in any interior electrical outlets located on the exterior walls.

After that, I would weigh whether the windows or exerior walls were of higher priority. In part, this depends on how tight or leaky your window frames are. But no way does the building science support that old windows are near as energy efficient as decent, current dual pane windows. In my own home, b. 1948, I have 20 old windows, most of them large. They test reasonably tight in a blower door test. But I don't kid myself that they are near as good as decent new ones.

(FWIW, my background is having developed an extremely energy efficient neighborhood. I have rehabbed three houses. But I'm no expert on energy efficient rehabbing. For specific info on how to do the insulation if you move ahead, some of the prior advice sounds pretty nuts-and-boltsy.)

Welcome!

And please stick around. We could really use some building-science-cognizant people around here. I try to touch on the principles behind the specific advice, but I'm no expert on the theoretical side.

I also tend to get bogged down in the specific task at hand, the nuts & bolts.

We've been wrapped up in the minutia of insulating Brian's walls, and you're reminding us to view those tactics in context of the larger strategy, the overall goal; and to always start with the low-hanging fruit.

Thanks.

[Master Brian]

I've looked thru a couple sites on line
R Value of single pane seems to be .85 up to 1.3 - very low
Storm windows can save heat loss by 25 to 50%
2x glaze w/argon are from R3 - 3.3
3x glaze argon R6.2 - I have seen ratings up to R10
I'm not sure how old these ratings are?

Maybe I should re-state....I won't argue the new windows are more "efficient", I will argue they aren't worth upgrading to, in a turn of the century house with original windows in good condition.

From this website The solar heat gain from a single pane window is 88% from a Low-E double 65-75%. Unless I am reading that incorrectly, that is not 1/2, that is not 25%, that is maybe 23% at best, with a 10% swing towards being 13%. It's 70% solar heat gain from a triple pane and 78% from a double pane.

That 23% isn't going to directly influence 23% of my bill, it is going to represent 23% of that windows heat loss. I wouldn't possibly know how to calculate that, but I have heard about 30% of heat loss comes from windows. What does that mean? Does that mean that if I spend $100 to heat my home, if it didn't have windows it would cost $70? I doubt that is the case, but wouldn't the 23% figured earlier, be 23% of that 30%? If that is correct that # is now 6.9%. If I am figuring that somewhat correctly, wouldn't that mean that if I replaced every window, I would be 6.9% more energy efficient? ....and if the $100 p/m heating cost was correct, and $30 p/m went out the windows in heat loss, then upgrading would maybe save me $7 per month. That is only $84 per year. If the life expentancy of these new windows is 30 years, the the break even would be $2500-$5000 to replace about 38 windows. I'd love to know where to get 38 Low-e oversized windows installed for under $5000 with a 30 year guarantee.

If I am wrong, please correct me....I am sure I am off somewhere and I really do want to see the "true" benefits of replacing the windows. Everyone says it, but no one has explained it! They just throw out energy efficient as the reason. I want cost effective. Sure I can go buy a $30k, 40mile per gallon hibred to save gas, or I can drive my paid for suburban which gets 14mpg and pay for gas fo 14yrs, which would be the break even. I highly doubt I'll be driving either of them in 14yrs!!!
*side note, I just double read some stuff and the question popped into my head, is solar heat gain, good or bad? I would think the more solar heat gain would be good in the winter, as it would allow more of the sun's heat into the house! right/wrong? A single pain window without gas allows more solar heat gain. Of course that is bad in the summer, but heavy blinds can slow that down. Maybe I used the solar heat gain #'s above incorrectly in my calculations, but the numbers still shouldn't be far off....

I also have heard argon looses it benefit after a few years and the National Association of Home Builders gave me the window life expentancy info on the new windows. I took the information about the 100yr + life span on old heart wood windows from an episode of this old house where they showed how to rebuild these old windows to make them operate like new.

From Energy Star site:
I found this strange as my windows have paid for themselves in savings on my energy bill.

One big advantage for me is the house is MUCH quieter

I had one window that one pane was cracked
2 windows that were fogged up
2 windows that built in vinyl "lift" along the bottom edge was cracked & breaking
I think they might have been 8-10 years old (vinyl in & out)
I ended up replacing 15 windows in the house & 3 doors

I'm sure it'll save some, but how much depends upon more factors than just replacing. You already said one window was cracked, that kills any efficiency at all, no different that a hole. Then you point out you have vinyl windows, which are 8-10 yrs old and they are cracking and breaking. National Home Builders says windows should last 15-30yrs, but you say after 8-10 they are cracking, which tells me any argon would probably be pretty much gone as well and most new windows don't make thier life expectancy. I'm sorry, but I don't want a band-aide solution, I want my house fixed right with windows/doors that will last. Only ones that I see which will last is my original windows and the website quoted above also says that a good storm window can save almost as much on energy as a replacement window at a fraction of the cost!

Again, I am sorry, if I am offending anyone. I just am the type of person that likes to know why, I don't like to be told, "because I said so". I'm not arguing windows need to be figured into the equation, they do and in some cases, replacing the windows is the right move, but I don't think a blanket call to replace with newer windows makes sense. After all isn't energy efficiency really about saving money? I am trying to stay very open about this and appreciate any feedback or corrections in my thinking.

Chessiec, I also do very much appreciate your input on the other things to look for.

frenchie, thank for clarifing my mistake in the "baffle" idea. I wondered if it would work. I think my next step is to call central inspection and speak with an inspector to possibly see what they say as well as see if I can reach someone with the local Dept of Energy. Maybe they can tell me about cases locally. From what I gather the vapor barrier really is less important in my climate than in some. We aren't overtly rainy, dry, or humid we aren't on the extreme, extreme cold or heat sides, we just get a little of all of it.

[frenchie]

I just want to note that not everybody is telling you to replace your windows.

Like I said, in the real world, air leakage is more important than R-value (which doesn't take air leakage into account). Old windows, if the weatherstripping is in good shape, no leaks around the frame or the sashes, with storms installed as well... pretty much as good as new windows, IMO.

Most of the heat loss, in either case, is infiltration, not radiation.

[Scuba_Dave]

We have more of a heating season here (maybe 4.5 months), so my aim was to save on heating oil
The old windows were double pane, LOWE vinyl replacements
They were designed with a vinyl "lift" edge along the bottom of the window pane. This is what was used to open the window, it was too thin & this is what was cracking - no effect on heat loss
One pane was cracked on one window - but since there was still an air space better then single pain. Same with the 2 fogged windows - argon was gone - but still an air space. IMO these were very cheap replacement windows that were quickly installed to sell the house years ago

I would say the greatest return was simply replacing 3 basement single pane windows & 1 badly sealing door. And insulating the sill plate. Total cost was less then $500 & brought my basement from 45-48 up to 58-63.

For windows I go by R Value, single pane = R1, 2x pane = R3
3x better insulating value, but as said if the window doesn't seal correctly at the sash & frame that Rvalue is worthless

I spent all told maybe $4500 on 15 windows & doors
My heating cost was cut in 1/2 - more if I heat with some wood.
I save at a min 1.5 tanks of oil a year = ~400 g x $3.25g = $1300 a year. This is the 4th heating season - oil was $4g (now down to $2.25). I didn't know what I would save before I started. But so far I have saved approx $5300 in 4 years (end of this heating season). The past 2 years the heat was kept at 70 - new baby. This year we dropped it back down to 68 (same as 3rd year) - 1st 2 years we lived here was before replacing the windows

So this is my approx true cost savings over 4 years
It all depends upon your heating season & method. I expect oil prices to go back up. With the addition, sunroom, dormer of my Cape I now have a total of 48 windows, 11 doors (1 slider), & 15 skylights
I can't imagine moving into a house & needing to replace that many windows

The largest window in the house was 4x5 fixed glass & was $450
The next largest was 44x48 double hung & was under $400
The largest window in the addition is 5x7
If you only spend $200 a month to heat your house it is probably not worth it to save $100 a month. Do you have cooling costs?

At $300 (low) a window * 38 = 11,400 - say $12,000 / $400 year savings
That's a 30 year payback

One Apt I rented 4 tubes of caulking was all that was needed to reduce our heating bill due to air leaks

[Scuba_Dave]

Just to clarify the main reasons I replaced all the windows:

Cheap replacement windows were installed, & the areas that held the sash weights were not insulated

1 cracked pain & 2 fogged windows, plus the cracked thin vinyl lift

Residing the whole house, so better to put the windows in 1st - rather then have to do it 5-10 years down the road

We had the $$ to do it from the sale of 2 homes, no $$ out of pocket

More light - I like windows. The new picture window in the main room made a big difference

There is a whole look & style to a Craftsmen house
I would be inclined to insulate the walls 1st, then worry about the windows. If insulating the walls means taking the siding off, then I would look very closely at the cost/look of new windows that would match the style of your house (then decide)

As Frenchie said, its the cold air blowing in that will be the biggest problem. I had a bathroom fan vent that the outside damper was broken. You could feel a cold breeze coming in when the wind came from the East. If your windows are tight around the frame & sill then you are in pretty good shape. I don't have any grilles as I can't stand the "fake" grille look

The picture window is the only window with a grille in our house - non removeable. It also has the smaller windows divided "in the glass", seems like each one is a seperate little window

[Master Brian]

frenchie, maybe the "everyone" should have been in quotes! It just seems to be the 1st thing people recommend, couple that with about 1-2 siding, guttering, window reps coming by the house each month and it feels like everyone actually says that.

Add to that a very good friend whom builds houses. We constantly go around and around about new vs. old houses. He thinks I'm crazy for wanting to live in my 1915 craftsman, I think he's crazy for wanting to move every 2-5 yrs into a new house.

Dave, I totally understand your reasons. I have 1 window that most likely can't be salvaged, it was just neglected for too many yrs. I am going to try to see what I can do with some good epoxy, but am hopeful I can find an exact replacement for the sash(s) at a local architural salvage. You seem to have found good buys on your windows, but I'm willing to bet they are a more standard size than what I have. In my last house, I had to special order 6 (?) windows, because all that had been installed on an addition were storms and I spent about $250 per window and they were about half the size of my current windows. Judgeing from the blinds I've been buying the windows here will be special order as well, I can't seem to find a standard in anything. As soon as special order is stamped, the price seems to double.

....this just hit a nerve! I am serious though, if anyone can show me how I am financially better off, I'd go for it. I just see the hope of insulation being the best bet to save some $$. I know caulking, spray foam and window glazing are definately going to become my best friends or worst enemy's depending upon how one looks at it. I haven't even gotten started painting much past the front porch area and I've already used a case of caulk and several cans of foam.