Insulation Dilemma

[wilma78]

Hi all

My husband and I are in the process of renovating our 200 year old cape cod style home in New Hampshire.  My husband is doing all the work himself, which is a huge money saver (I consider myself the project manager).  Right now, we are working on the kitchen and are at a bit of a crossroads with the insulation for the walls. Bear in mind that my husband is pretty much the brains behind this renovation and I'm going to do my best to set forth out issue here. 

Clearly, the current insulation in the walls is pretty old.  The room is approx 400 sq ft and has an unheated/unfinished crawl space above it and unfinished 200 year old basement below. The room has three walls to the outside, facing north, east, and south.  We have deciduous trees on the south side, allowing for sun in the winter and shade in the summer. While we're replacing the windows and putting up new drywall, we will install new insulation.  The framing is 2x4. We could use the fiberglass rolls that have an R value of 15.  This would cost about $200 for the entire room.  We could also opt to go with spray foam insulation with an R value of 21 for a total cost of $800.

Our question is this: is it worth spending the extra money on the insulation in the walls?  Would it make more sense to go with the fiberglass insulation in the walls then spend more money beefing up the insulation in the attic and floor? I've been trying to research this, but with my limited knowledge and general dislike of the maths/calculations, I'm having a hard time, so I figured this would be a good community off of which to siphon some collective knowledge.

Thanks in advance!
Christine

[Lkxe]

Personally, I'd foam it. R21 is the top of recommended but happy and warm is good for me.  And you could foam the underside at the same time.
http://www.naima.org/insulation-knowledge-base/residential-home-insulation/how-much-insulation-should-be-installed.html

[Josiecat]

Wow!  200 years old???  That's awesome.  Please rethink replacing your windows if they are original.  Check out www.wavyglass.org the old house board and you'll learn a ton.

[paddedhat]

Definitely go with the foam. There is only once chance to get it right, before the rock goes up, and "saving" a few hundred bucks in this situation is really no savings at all.

[iamsoners]

I've been doing a lot of energy-tightening on our 85 year old home (young by comparison!) and here are my thoughts:

-I'd go with fiberglass in the walls for a couple of reasons: First, you lose most of your energy through the ceiling--going higher value in the ceiling will be a much bigger payoff than in the walls.  Second, I would be worried about water condensation with spray foam--what I've learned is that homes are systems and these old houses can't always tolerate our new insulation methods. My concern would be that the foam would drive the moisture somewhere else in the house that you don't want it to be (woodwork, windows, etc.). There is a lot of discussion on the issue of insulating old houses and no one agrees--I'm of the mindset that the risk is not worth the reward.  Just blow a bunch of cellulose into the attic and be done with it.

-+1 regarding the windows!!  Some are not salvageable but most are!  And again, the payoff on new windows isn't really there (your taking a product that can last at least 200 years and replacing it with vinyl which has an intentionally short lifespan)

[PatStab]

I am stripping and redoing windows in a 115 year old house now.  The uppers have 5 panels and I'm having to strip them inside and out.  I'm taking the casing off and redoing the sash ropes too.  I found a place online called Restoration Hardware and can find a lot of the old stuff, not cheap.  But I love the old wavy glass.  We have a glazier locally that saves the old wavy glass from old windows, I had broken a couple of panes and he replaced them.  He said the newer glass looks funny next to the old.

This house had storm windows added later but the wood on them are all in good condition.  In fact its amazing the quality of the wood in this old house.  It will just be a rental but still want it nice.

A 200 year old house that is just amazing, my best to you.

I would put bats in the side walls and insulate the ceiling heavier.  Is the floor over a basement or is
it next to the dirt.  If dirt underneath you need a vapor barrier, if a basement can put under the floor and
tack up with chickenwire.  It will make the place so much warmer.

[Spork]

I am a firm believer in foam.

[ I'm going to give an example here that probably isn't fair... take that in mind. ]

We moved from a traditionally insulated (2x4 with standard pink fiberglass) 600 sqft building into a 2300 sqft foam insulated building.  Our electric bill went down significantly.  Yes, there were other factors (more efficient AC, wood stove, more efficient appliances, etc).  But I think the foam makes a huge difference.

I also like how foam is normally done at the edge of the envelope.  I.e., at the roof.  This makes for a much nicer attic space -- and lets you run HVAC in conditioned space.

[Rural]

Foam not only insulates better, it seals so you won't have air leaks. I'd definitely go with foam unless you're planning to sell soon.

[zolotiyeruki]

If you're down to bare studs, and want to get lots of insulation in the walls, I have another suggestion:  make your walls deeper while you have a chance. That way you can stick with cheap insulation, but put in a lot more of it.

[Greg]

If you're down to bare studs, and want to get lots of insulation in the walls, I have another suggestion:  make your walls deeper while you have a chance. That way you can stick with cheap insulation, but put in a lot more of it.

This is a great suggestion!  We do this a lot in remodel jobs to even out old and new wall depths, and to allow for better insulation in the walls we have to open up.  Long term, you're foolish not to take advantage of this.

[QajakBoy]

I would go with the spray foam insulation because it provides the added benefit of air sealing.  Putting effort and $ into insulation without airsealing would be wasting much of that effort and $. 

[Smokeydave]

If you're down to bare studs, and want to get lots of insulation in the walls, I have another suggestion:  make your walls deeper while you have a chance. That way you can stick with cheap insulation, but put in a lot more of it.

I agree.  I ripped 2x4's to make my walls 2x6 nominally. I then did R19 fiberglass. 

[thurston howell iv]

Foam, foam and more foam!  I stops all the leaks and drafts. I'd foam my whole freakin' house if I could.
I think it could be worth it also in terms of future re-sale.

I did one of my houses in the spray foam (basement). The company sprayed a whole wall and rim joist. Made the place tight like an igloo cooler. It was wonderful.

[Blindsquirrel]

 Up to you but 38% of your heat loss is in the attic.    https://www.energystar.gov/index.cfm?c=home_sealing.hm_improvement_insulation_table

[TomTX]

Couple of cheaper but good options:

Dense pack cellulose.  Seals much better than fiberglass, slightly higher R value.

Spray 1" of foam to get the awesome air sealing, fill the rest of the cavity with fiberglass (or cellulose)