Insulating my house?

[nola mike]

Sorry mods, didn't know which forum this belonged in...feel free to move

My river house is cold. It's 1400 sq ft and I'm heating it with the CW2500 insert. Overnight, the temp will drop 10' in the house if it's 30' outside, and that's with me lighting a fire right before bed. In contrast, my main house might drop 5' or so, without any fire overnight. The main house has a much smaller stove, and is heating a much bigger (2000 sq ft) area. It does have one shared wall, a basement, and good attic insulation, but original (100 year) windows and no wall insulation (brick only). At the river:

1. It's cinder block construction, looks like at best I have 5/8" XPS foam on the outside. The one exterior wall I've removed just had drywall on furring strips on the blocks, so I assume I don't have full stud cavities anywhere (though I guess I should at least check)
2. It's leaky. I'm working on that.
3. It sees a lot of wind. Not much I can do about that.
4. 300 sq ft is a converted screened in porch. Basically all glass on a concrete slab. Lovely when it's warm. The area above isn't accessible from the attic, but I pulled a couple of can lights and found a half-hearted attempt to insulate that area.
5. Rest of the ceiling is accessible, and is mostly covered with a combination of blown rock wool and batts. At best I'm looking at R-21 up there.
6. Rest of the house is on a R-21 insulated crawlspace.

To add insult to injury, I only heat the place to 42' when I'm not there. I installed a wireless t-stat so I can pre heat it, but when it's real cold (ie, when I need it), the heat pump struggles. Then it takes a LONG time to get it warm in there.

So, what are my options? I've been sealing leaks, installed airtight cans. The obvious (?) next move is to blow in some insulation in the attic, but I'm skeptical that this will make much of a difference given the other obstacles. So, will the extra insulation make enough of a difference to feel it? During the day, my attic is definitely warmer than it should be, and I can see heat radiating off the roof, so I'm thinking it will...
Anything else (reasonable) that I can do?

 

[westkywood]

I'm no expert, just a home owner like yourself, but I am BIG on insulation. I'd say you need at least R-30 in your attic. Blowing insulation is easy and cheap for what you get out of it. Most of my house has no studs in the walls. I'm studding out and insulating some of the walls little by little. Each time I do, I can tell a difference. I also replaced all my old storm windows.

 

[Holiday]

Although more would be better in the attic in my opinion you wouldn't really "feel" the benefit of going higher up there if it's already at 21. This fall I blew some in and went from r5 to around a 20 for now. Made a big difference. I'll eventually put more but getting it to that point was probably the biggest payback. I'm thinking the heat is going out the walls maybe?

 

[Swedishchef]

I am a big fan of spray foam insulation. Its stops airflow and insulates at the same time.

R21 insulation is not bad...I don't think going to 30 will make a big difference. R40, maybe. But think that is overkill for your climate ( not mine though).

Heat will rise then hit an obstacle and go out wards. The key is to prevent it from leaving the structure. Seal the leaks then attic and wall insulation I think is the way to go. What good does it give to add to r21 if you have tons of cold air coming from elsewhere? If you had r5 insulation, that would be different...

Andrew

 

[nola mike]

Well, I don't know. The climate isn't too cold, but I see consistent 20's at night during the winter. I don't think insulating the walls is a cost effective option. I do know that R-21 is really best case--parts are certainly less than that. Like I said, I'm working on sealing leaks. I think I may get a blower door/energy audit. Energy.gov recommends R-38 to R-60 in the attic...

 

[jotul8e2]

Blown fiberglass is cheap - go as much as r50 in the attic where you can. Then ventilate the attic - use power vents if necessary.

Seal off the glass porch in the winter.

Look into insulated window coverings - pleated shades, insulated shades, insulated curtains, or a combination. Going from r1.5 or r2 with a window up to r5 is a big jump in reduced heat loss.

After that it gets a bit spendy. Concrete block construction does not lend itself to easy insulation. However, you could possibly glue exterior foam panels to the block and then siding over that. I like Hardiepanels. This would have the advantage of leaving the thermal mass (concrete blocks) on the heated side of the wall. The materials would not be all that much, but trimming out around all the doors, windows, etc. would be time consuming.

 

[saladdin]

Spend the 350ish at Lowes for the bales of blown in insulation and they let you borrow their blower.


Before I started cutting holes for vents I'd do some research. I was all set to do it but decided against it. It may be regional but I'd make sure I did due diligence.

 

[Swedishchef]

R60 is totally insanely overkill for Virginia......I have R40 and it gets cold here and everything is great. R50 is the new "norm" but I don't think you get that much performance difference between 50 and 60. And our average temperature (low) in the winter (where I live) is 0.3F.

Blow in insulation would be the most efficient.

As for ventilation, do you have soffit? You must. If so, add a couple of these (depending on your surface area): (broken link removed to http://www.ventilation-maximum.com/English/index.html) They work incredibly well. When in the attic near the vent, you can feel the stack effect and the air pulling through the maximum vents.

Andrew

 

[woodgeek]

With insulation, you should tackle the lowest R-value areas first. Its like you had a hummer and prius. Adding a few mpg mileage to the prius doesn't save much, adding a few mpg to the hummer makes a huge difference.

1. You said you had cinderblock walls. Assuming they are hollow. If you filled the hollow space, the R-value of that wall might double. If you can access the top of the hollows, eg in your attic, it might DIY-able, or cheap to have a company do it. Seems like poured loose-fill perlite is commonly used for that app. There are also companies that can drill holes and blow, but that might be more spendy.

2. See if you can get a cheap energy audit (utility might have an incentive....I just got a full audit for $150), and then take their advice, if it sounds reasonable. They might find some huge air leaks with a blower door/IR that are easier/cheaper to fix than your other ideas.

3. It is hard to estimate the effectiveness of old attic insulation. I have (old) blown and batts, and when I bought the house I figured I was good to go. On closer inspection, it was all collapsed to a pretty thin state. My auditor thinks it is R-12 or less in practice. On my to do list.....

 

[ironpony]

IF I read correctly you have furring strips attached to block then drywall. The block is a giant heatsink in and out, studding and insulating will be a huge difference.

 

[nola mike]

@sc: i may be wrong, but i would think ventilation would be less of a concern here in the winter. certainly no condensation or icing in the attic. i do have soffit and ridge vents thpugh.
@wg: unfortunately, walls arent accessible. and considering there are at least 2voids/ft, i dont know that drilling would be an option.
@ip: gutting my house also probably isnt cost effective. although i did just stud out my new bathroom. so i have at least r-14 in 10 ft of the house!

i think an energy audit is probably the way to go. i've found so many leaks already that i'm sure i'm missing more, and blown in insulation is cheap and easy enough that it would probably at least be worth a shot.

 

[trguitar]

Here's a link to the DOE recommended levels of insulation for homes. Just plug in your zip code, and a few other things and it will tell you what you should be using.

(broken link removed to http://www.ornl.gov/sci/roofs+walls/insulation/ins_16.html)

 

[semipro]

I'd suggest:
- Do the energy audit Woodgeek suggested first. It will be well worth it.
- Address the significant air leaks first, especially those between attic and living areas (especially since you're in a windy location)
- Figure out a way to insulate the block walls. The R value there is basically nothing plus its a huge heat sink which can work for you but isn't in your situation. I don't think adding foam on the outside will be as tough as you're thinking.
- Consider planting some trees to block the winds. This has to be done strategically but provides more benefits than just comfort, and will provide good return on investment....someday.

 

[woodgeek]

What does the top of the wall look like?? Did they put a wood sill plate or rim joist up there (in the attic)....if its just wood, you could drill 1" holes up there to fill them...If the slope is low, maybe you can't reach?

 

[nola mike]

--The slope of the roof is pretty low, tough to get to the top of the blocks. I guess I'll take a closer look. I hate bellying through all the insulation and what not in the attic though. I'm guessing there's a sill plate on top of the block. If so, it will be tough to drill with that roof slope.
--I guess the best solution to the block is probably to sheath the outside. I don't guess it would be too hard to remove the siding and put a couple of inches of foam sheath on the outside. Probably price for the foam though.
--trees aren't an option, I don't have enough land for it. On the river side (where I'd need it most) lies my septic field, not to mention that's my view.
--it's incredible how much colder the house is on a windy day. Not sure if that's due to air leaks, or just magnifying my poor insulation.

 

[Pallet Pete]

https://www.hearth.com/talk/threads/so-begins-the-insulation-pics.83224/

My insulation thread wth pics and info we couldnt be happier with it.

Pete