Preparing for next winter's heating - projects and thoughts

[joefrompa]

Hi all,

I have a 1974-built 2-story colonial that just did not seem to maintain heat this past winter. This was after I had done an air-loss audit (giant fan in front door and sealed house showed where the air was coming in). I had sealed almost all the major leaks already.

So, ok, air loss is mostly stopped (or at least close to minimum acceptable levels especially with a wood stove). So next up is insulation, right?

My 2nd-story attic space has ~6" of blown cellulose insulation and then a thick batt laid on top. Inspector said it came out to r-38 - however, the batts are laid WITH the joists on top of the blown insulation. I thought about going through and laying another batt on top running perpendicular to the joists. Thoughts on this?

I also have a 1st story attic (barely more than a crawl-space) running around 2 sides of the house. There it's only batts, about 6" thick. My thought was to run an additional batt perpendicular to the joists again there. Maybe bring the r-value up to ~r-60.

Next up is recessed lighting going into the attic space - I'm going to check if it's insulation rated, but my intention was to either replace them with insulated rated versions or use the existing ones and pile insulation both around AND on-top of the light. Is this ok?

...

After that, I'm looking for guidance. I don't want to blow insulation into the side walls - if I do that, I'll do the siding at the same time and do it from the outside, but I don't have the money for that right now. This past winter, on a 40 degree day, the heat would turn on every 20-30 minutes to keep the house at 60 degrees. I get very little solar gain (apparently).

I really want this house to retain the warmth I pour into it via wood and oil-burning, both for the savings but also for the ambiance.

Any and all advice welcome.

Joe

P.s. My back-up plan is to build a house from scratch

 

[semipro]

What are your windows like? Are your sidewalls insulated? Its hard to imagine a 1974 house without sidewall insulation.

There was a good post on in either this forum or the Green forum on upgrading can lights. There are some good options out there. Check out these threads.

https://www.hearth.com/talk/threads/62652/

https://www.hearth.com/talk/threads/63663/

edit: You say your heater ran a lot but that may not be a good measure of how much total heat you used. You could have a small heater. Is your overall energy usage too high?

 

[joefrompa]

Semipro - First winter in the home, we kept the thermostat at either 55 or 60-62, never higher. It only uses oil for forced hot air - not for hot water or anything else.

We used about 180-200 gallons of heating oil doing this + burning about 2.5 cords of poorly seasoned wood in a new wood stove (learning curve for me). The furnace is newer and is running at 84% efficiency (the furnace itself) as it was tuned in October.

It ran alot in short bursts - i.e. cycling on for 15 minutes every 30 minutes. I'm pleased with overall consumption, but we also basically spent the winter cold. We used a oil-electric radiator in our bedroom and the wood stove in the main living space and got by with blankets and such. Neighbors who kept the houses at 68-70 in similar style homes used around 2 full tanks, so I'm guessing we saved $1000 in oil.

I'm sure the sidewalls are insulated too, just don't know if that insulation has collapsed or if it's any good.

Since sidewalls is a major project, and since most heat is supposedly going out the attic, I figured I'd start there.

I'm going to check out the links now on the recessed lighting...

 

[Highbeam]

Skip the batts. Never saw a good batt job especially on top of existing blown in. Why do they even uyse batts in the attic? What you do now is blow in more insulation on top of the whole mess until you reach the target depth. You need to hope that the new blown in will seek out and fill the gaps between the batts.

Don't put insulation in contact with not IC rated cans. Replace the cans first with good IC rated AND air tight cans. They are common now.

 

[fishingpol]

How old are your windows? If they are original from 1974, they should be replaced at some point. Was this energy audit done by you or from an energy conservation group? Air sealing is very important. Every penetration from the basement if you have one should be done. Wires, pipes, around ducts and chimneys all contribute to air infiltration.

I use either an incense stick or IR thermometer to locate leaks. You can buy the plastic window sheet kits to try on a few windows next year. Box stores usually sell them cheap this time of year to get rid of them. I bought a new steel/glass insulated door and a storm door door and received the tax credit for them. It is a huge difference.

My next step is to replace a few can lights in my kitchen. When I had my audit done, blown in insulation was pushed up against my remodeling cans over the sink and they overheated. Pretty scary stuff. I have pendant lighting there now and will replace the others in the center of the room this summer.

 

[fbelec]

if you don't have i/c rated recessed lights you don't have to replace the fixture, you can build a box around it so that it is 3 inches away from the fixture then insulate around the light fixture

 

[woodgeek]

If I count your cords as ~150 gal oil, your usage is at ~600 gal equivalent at a low indoor temp. A respectable usage for a large house, too much for a small one. Sq footage?

I want a little more info on your airsealing process and measurement--what was your CFM at 50 Pa, or your ACH50 from the blower door test? The heat load from your natural infiltration can be estimated from that.

I'm a skeptic b/c I have found a HUGE amount of air leakage buried in the framing of my 1960's SE PA house, between the conditioned space and the attached garage and the attic. None of this was detectable as a 'draft' as it was distributed over a large area of wood flooring (I think). Bottom line--cleaning up the air sealing on my original
windows (scraping paint off the metal weatherstrip and adding plastic vstrip where needed) saved me ~150 gallons oil/season. Finding and sealing the ~ 10 sq ft of openings in the framing to my garage and attic saved me ~200 gallons/yr.

So, tell me that you've looked under those attic batts all over, for framing openings into your conditioned space and sealed those, plus caulked/foamed all the wall top-plates exposed in your attic floors. A PITA job, but very much worth doing (if you haven't already).

 

[joefrompa]

House setup - ~2400 square feet (not including finished basement) 2-story colonial with full exposure.

Windows - Andersen Casement windows everywhere (except one small window) that are about 8 years old. Don't know how well insulated they are, but they are tight with minimal air leakage.

Air sealing test - It was done by a friend who had been trained in it. I'm goin to kinda go from what I remember, but I had about ~2200 CFM of air loss at -50 PA. The minimum for my house/zone would be around 1400-1600. The major leaks I had were exterior-facing electrical outlets/switches (fixed with foam insulator patches), an 2 attic hatches (weathersealed), and 2 bathroom ceiling fans and a recessed light (not yet touched). I DO have a room over the garage that was majorly leaking air (felt a strong breeze coming under the door) - the only part of the room leaking was that recessed light, but now that you mention it it could be floor sealing.

Top plates in attic - Have not yet foamed. I'll take care of that this weekend, since I just had a 3rd leak develop (in 9 months of home ownership) and I need to get up there and figure out what is leaking.

...

My guess is that I used 2.5 cords worth ~225 gallons of fuel oil, not 600 gallons. There was ALOT of unseasoned wood in there plus most of the season I spent learning how to operate the stove (I spent 2 months with my liner disconnected from my stove by 2", ruining my draft and sucking up conditioned room air). So I'm guessing I used roughly 400 gallons of fuel oil or equivalent.

 

[woodgeek]

400 gallons for our climate and a 2400 sq ft house sounds like new construction performance....

Assuming 8ft ceilings, your CFM corresponds to ACH50 of about 9, or ACH_nat which is (nominally) 20x smaller, 0.44. For my (similar) house
I estimated that an ACH_nat = 1 used 33 MMBTU/yr, or 300 gal/oil (assuming 5000 HDD). So the amount of heat you're losing to residual in/exfiltration
is ~ 300 * 0.44 = 132 gal oil/yr. Doing the top plates or floors is probably worth doing, but will is more likely to save you 10% than 30% of your
heating bill (at this point).

For comparison, I started out at ACH_nat = 1.5, equivalent to 450 gal/yr, and have now beaten my air leaks down to about 1/3rd that, so I am still
losing ~150 gal oil equivalent heat. (on top of my insulation conductive loss of ~500 gal/yr equivalent).

So, it sounds like you are pretty tight. 0.44 ACH is plenty of fresh air in the winter, but probably not enough fresh air during mild weather. Have you
thought about some modest mechanical ventilation that you can turn on the other 9 mos/yr?

EDIT: math error on the calculator: (2200 cfm * 60 min/hr) / (2400 * 8 cu ft) = 6.9 ACH50. ACHnat = 0.05* ACH50 = 0.34 (approx). Air leakage loss at
5000 HDD probably 11 MMBTU, or ~100 gals/oil.

 

[orionrogue]

Skip the batts. Never saw a good batt job especially on top of existing blown in. Why do they even uyse batts in the attic?

Oh don't say that, please. in Dec. 2010 I bought a crapload of R30 that I ran cross-wise this winter in my attic!

 

[Highbeam]

To properly install batts they need to be tight to each other, and to any wall or obstruction, but not compressed. They need to somehow bend around and conform to the truss framing and electrical lines if you have them. It is so so so easy and cheap to blow in FG or even cellulose (if you're nuts!) which would eliminate the installation issues.

 

[joefrompa]

Woodgeek - Yes. We will open a window a crack when the weather is ok to get some fresh air in

In all seriousness, no, I have not considered adding any sort of fresh air machine to the house. It's decently tight but I didn't really have a draft issue once my stove was working well either (though it does benefit on cold start from cracking a window).

You can see from my air-loss though that I am focused on stopping heat transfer now. I read this sentence of yours and didn't full understand, "Doing the top plates or floors is probably worth doing, but will is more likely to save you 10% than 30% of your
heating bill (at this point)."

I got "doing the top plates/floor is probably worth doing", but "Will is more likely to save you..." didn't understand.

Also, I agree on the top plates. I have several bedroom walls that lead to the attic and I can FEEL unconditioned air come through them during the winter/summer. So I know they aren't top-sealed.

 

[billb3]

Skip the batts. Never saw a good batt job especially on top of existing blown in. Why do they even uyse batts in the attic?

Oh don't say that, please. in Dec. 2010 I bought a crapload of R30 that I ran cross-wise this winter in my attic!

Unless you were falling down drunk when you installed them you should be fine.

 

[woodgeek]

Sloppy edit---I meant that sealing is not going to provide a massive improvement, but is clearly worth doing--it seems you agree.

 

[woodgeek]

To properly install batts they need to be tight to each other, and to any wall or obstruction, but not compressed. They need to somehow bend around and conform to the truss framing and electrical lines if you have them. It is so so so easy and cheap to blow in FG or even cellulose (if you're nuts!) which would eliminate the installation issues.

Gearing up to 'batt' my attic, and reading online...
--it seems the whole 'FG loses its effectiveness at low temps' thing is really a feature of the blown in stuff (that has large passageways in between the puffs of insulation, and NOT the batts, that are much more homogeneous. Also it seems that higher density is slightly higher R-value per inch. So compressing a 9" R-30 batt under the floor decking, in the 5.5" joist bay gives R-21, versus the standard R-19 batt sold for that applications. Not enough improvement to warrant the choice, except that r-30 and r-19 batts cost the same per square foot at the local box store (~$0.50/sq ft). Has to be better than the <2" of loose-fill FG I have under there now (50 yrs old).

Opinions?

 

[Don2222]

Hi all,


My 2nd-story attic space has ~6" of blown cellulose insulation and then a thick batt laid on top. Inspector said it came out to r-38 - however, the batts are laid WITH the joists on top of the blown insulation. I thought about going through and laying another batt on top running perpendicular to the joists. Thoughts on this?

Hello joefrompa

I also did not have enough insulation in my attic. The DOE recommends R49 for Region 1 in the US. So if you have anything less, more heating fuel will be used to heat your house. Now most of your heat loss is in the ceiling so you will get back every penny you put into that area!

In my case I had 2x4 Trusts 24" on center in the attic with R7 in the floor. The inside roof was bare plywood.

So the 1st item was to staple rafter vents from the sofits up to the ridge vent. Then stapled R4 reflectix foil under the rafter vents. This makes a radiant barrier so the house will be 10 degrees cooler all summer long. Saving $$$ in cooling costs!

Then I ripped some 2x4s to 2x2s and nailed them to the 2x4s in the attic floor to make 2x6s. Then I removed the old matted R7 insulation between the floor trusts and laid down the R4 reflectix. This reflects any radiant heat in the winter right back into the living space. Then I laid down R19 6" Faced Fiberglass insulation to fill the space between the newly made 2x6s in the attic floor. Then I crisscrossed the R19 with unfaced R30 for a total of R53 !!

Since I just heard that Roxul insulation has more R value than Fiberglass, I may have went with that however it is more expensive!
5 1/2" Roxul is R23 and 7 1/4" Roxul is R28 plus R4 would be a total of R55. Not sure if that is worth the big price difference.

I know people say the blown in is really great and they do like it because it fills cracks. It is quick and easy so it is a very inexpensive way to go.
However since it is old newspaper treated with borax so the bugs do not eat it! What happens when the Borax wears off? Some people are very allergic to the Borax. It does settle and compress after time losing some of it's R value. Also fiberglass and Roxul insulation value increases as the temperature decreases. One more very important feature is working on the attic and the wiring in the floor. I prop the insulation and foil up with a stick like a tent. Then do the wiring and put the tent down when finished. Doing wiring with blown-in stuff is like the Big Dig!

The last pic below shows the R53 in the floor and some Tuff Board that has foil on both sides of insulation I screwed to the roof trusts. This prevents heat convecting out to the roof thru the rafter boards in the winter!

Just my 2cents

So my suggestion to you is to add 2x2s to your 2x6s to make 2x8s
The reason I say 2x2s is that anything larger and the electrical wiring would have to be re-done. Not enough slack!
So between the 2x8s put R4 foil and 8" R25 crisscrossed with R38 is a total of R67

 

[GaryGary]

Hi,
I would leave the batts in place and blow cellulose over them. This is an easy DIY job and won't cost much -- the big box hardwares will lend you a blower if you buy the insulation there. This not only gives you the benefit of more insulation, but it will lessen the amount of air ciruclating through the FG batts and make them more effective.
If you have not sealed all the wiring, plumbing, etc pentrations into the attic, these are a big source of exfiltration, and its better to get them before you add more insulation. Sealing with Great Stuff polyurethane foam works well.

Lots of ideas for reducing window heat loss without buying new windows here:
http://www.builditsolar.com/Projects/Conservation/conservation.htm#WindowTreatments

Do you have a basement or crawl space? These can be the source of lots of heat loss and lots of infiltration. If its a crawl space, google on Conditioned Crawl Spaces -- or look at the full page for the link just above.

Is the attic hatch well sealed and insulated?

If you have heating ducts (forced air) duct sealing with duct mastic can be a big help, and insulating any ducts that are not insulated.

You can run this heat loss calculator and get some idea where your biggest losses are:
http://www.builditsolar.com/References/Calculators/HeatLoss/HeatLoss.htm

Good book on insulating: "Insulate and Weathrize", Bruce Harely -- very hands on.

On the recessed lights, I know this is not the "right way" to do it, but, its based on the idea that I'm running CFL lights or LEDs in the can lights and they are putting out 1/4 (or less) heat than the IC lamps the fixtures were designed for. I insulate with cellulose right over the cans, and I tape over all the little holes in the sides of the cans with aluminum tape. I've logged the temperatures up in the cans with the lights operating, and I don't remember the exact temps, but they were low. But, this is probably against all sorts of codes, and you have to make up your own mind on whether its safe in your case.
Its not a huge job to just replace the can with sealed ones rated for direct insulation contact.

Gary

 

[joefrompa]

Going up in the attic with 4 cans of great stuff spray foam and several things of caulk, and while up there I'm going to take pictures of everything I need to address. I'll also kinda weigh how the top plate sealing goes to see if that's "all" i need to do right now or whether it seems like re-insulating would be worthwhile.

 

[joefrompa]

Also decided/realized that I have basically a 6" un-insulated/unsealed hole coming into my house at the dryer vent. I'm going to re-install a new hose there, seal it off really well, and then wrap insulation around the hose where it enters the wall.

 

[bogydave]

Hard to believe you have un-insulated walls.
The heat being wicked away by the walls during winter is huge & if have AC, keeping it cool has got to be tough.
If you do, maybe hire a spray foam outfit to foam them. At least get a bid. May be able to do them with out pulling one side off the walls.
You are right, tough job to remove wall siding to add insulation. But a "must do" if uninsulated.
But if you have un-insulated walls, the attic insulation could be 6' deep & not help much.
If windows are single pane, that would be next step. Upgrade.

Make sure you check with tax gurus to see if some or all is a tax deduction. May help offset some of the expense.

When you get it all done, nice & cozy, DON"T SELL, it will pay you back every year, as long as you live there, from the improvements with energy cost savings.

Good luck.

 

[benjamin]

I read "first floor attic?" and I pictured what I call a side attic where the floor framing is open to the attic because it's out of sight and out of mind. Yours probably aren't that bad, but it's a common air leakage spot.