Author Topic: Adding insulation to an old house.  (Read 1554 times)

Reynolds531

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Adding insulation to an old house.
« on: December 28, 2017, 06:49:35 PM »
I'm trying to decide whether or not to spend $1500 to $2000 and a ton of hours to optimistically cut $90 a year off my heating bill.

I live in a 1200sq ft single story house built in 1958. The attic, rim joists, air sealing and multiple small projects have all been done. My furnace is a 1989 Clare which my gas guy says isn't efficient but will thrive for years to come with no love. He said concentrate on insulation.

I estimate I burn $500 per year of natural gas for home heating. A new furnace will eventually lower that number. Variable rates and an ever increasing carbon tax will raise it. I have no plans to move.

Optimistically I will save about 20% by finishing my bare basement block foundation. Doing a cheap 4' hanging foundation blanket isn't really an option on blocks.

So question is....is this project worth tackling for the return I'm likely to get??
« Last Edit: December 28, 2017, 06:51:07 PM by Reynolds531 »

ysette9

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Re: Adding insulation to an old house.
« Reply #1 on: December 28, 2017, 07:40:51 PM »
I strongly favor insulation but the cost savings is a secondary reason. Living in an insulated house is just so much more comfortable. That is worth spending the money to me. In fact, we spent about $4k recently to have everything insulated in our house, including interior walls. I am very glad I did when I walk on the floors in winter without freezing cold feet and the toddler’s screams are muffled at night to not wake up the baby in the next room.

Sun Hat

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Re: Adding insulation to an old house.
« Reply #2 on: December 29, 2017, 06:52:50 AM »
I insulated my basement a year and a half ago, and am delighted by it. It had already been insulated, but the foundation cracked and all of the insulation and framing was ruined by water and mold, so I had to take it all out, get the foundation repaired and then replace the framing and insulation. It sounds as though you only have to do the framing and insulation part, which is actually quite easy.

Framing is easy to do and quite cheap. Where I live, batt insulation worked out to be far cheaper than rigid board insulation or spray foam. I used Roxul mineral batt insulation, which is better for using below grade as it retains it's insulation value and doesn't mold if it gets wet.

I highly suggest doing this job yourself - and to post on the DIY forum if you want advice on how to best go about it.

I'll be blowing in additional cellulose into my attic in a week or two for the same reasons - long term incremental returns in exchange for some hard work up front.

Also, have a look to see if your local energy provider has any rebates for insulation upgrades. Mine is paying for all of my material costs for my attic job!

mustachemountain

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Re: Adding insulation to an old house.
« Reply #3 on: December 30, 2017, 08:11:24 AM »
air sealing first, its more important than insulation.
have you had a blower door test to see exactly how tight your house is?
the biggest bang for the buck in insulation is the attic (if you have one) for like $300 and a dirty day of work i rolled out 6" thick insulation and the difference summer and winter is astonishing.
the best insulating I've seen is outsulating: foam board is applied outside of the sheathing, and then sided over. that's a major renovation project though. it results in a continuous air barrier, and no thermal bridging thru the studs. you need to calculate the thickness of the foam to match your climate or you will get condensation, rot and mold in your sheathing.
batt insulation should NEVER be in contact with below grade walls/masonry of any kind. www.buildingscience.com has tons of great science applications.

GuitarStv

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Re: Adding insulation to an old house.
« Reply #4 on: December 30, 2017, 08:24:51 AM »
+1 on air sealing first.  A drafty house sucks.  A poorly insulated one you can just keep turning up the heat.

Reynolds531

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Re: Adding insulation to an old house.
« Reply #5 on: December 30, 2017, 08:59:49 AM »
Thanks guys. I've done pretty much all that. I didn't do a blower test, but I'm signed up for a free nest thermostat from Ontario. I think they do it for you then.

I did buy and extensively use a $2 smoke pencil. I couldn't believe all the gaps I found. I was caulking etc for days.

The plan in the basement is 2" foam then framing and r14 roxol. Still thinking. I did a better estimate and came up at $2200.

mustachemountain

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Re: Adding insulation to an old house.
« Reply #6 on: December 30, 2017, 09:24:58 AM »
a before and after blower door test is the best way to see how effective your air sealing efforts were. it costs money so i didn't do it either ha. the smoke pencil can find the big ones but trust me there are more.

an uninsulated foundation is constantly conducting heat out of your house. in Florida that's great, in Canada, not so much. that's why insulating and sealing the room joist is so crucial. a thermal break between the foundation and the framing is great for new construction but a major job to retrofit. ditto exterior foundation insulation. so you gotta do it from the inside. sounds like you've read up on it, but be sure you've addressed any potential moisture issues. also, frost heave is a tiny possibility in unheated basements. building science websight covers all of this stuff.

I'm not sure of the absolute $/ payoff of this work, but as mentioned before the comfort level of your house will increase, and your energy efficiency will go up. there's nothing wrong with saving the earth, especially if there aren't catastrophic financial penalties associated with it.

pecunia

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Re: Adding insulation to an old house.
« Reply #7 on: December 30, 2017, 10:02:22 AM »
A lot of heat loss is through windows.

https://www.energyguide.com/info/window2.asp

Cheap fix is styrofoam panels over the windows of any rooms you are not in.  Hold your hand against a styrofoam panel for a minute.  Hold your hand against a window for a minute.  Which was colder?

Depending on where you live, I've seen hay bales used around basement walls to preserve the heat.

Sealing it well will also prevent the entrance of unwanted vermin into the house. 

Retire-Canada

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Re: Adding insulation to an old house.
« Reply #8 on: December 30, 2017, 10:25:10 AM »
So question is....is this project worth tackling for the return I'm likely to get??

I asked myself the same question as my situation is similar in terms of cost/payback. I decided it just wasn't worth the hassle. My house is comfortable as is and the amount of $ I can save doesn't justify the investment in time and cost.

I'll focus my spare time on things I enjoy more and/or have a better payback.

Sun Hat

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Re: Adding insulation to an old house.
« Reply #9 on: December 30, 2017, 04:18:05 PM »
While insulating your basement to R24 is ideal, have you priced out the cost of just going to R14 with the Roxul? I used a moisture barrier (a layer of vapour barrier plastic applied to the interior wall to just above grade so that any water coming in rolls down it vs into the insulation, it extends underneath the footing board) framing, roxul and vapour barrier for less than $800 on a 786 sq ft basement just 2 years ago. Figure +50% for your additional square footage, and you should still be at a much more reasonable price point.

That said, I don't know where in Ontario you are. Some places are mild enough that you may want to save the expense. I'm in Winnipeg, and since a good portion of my foundation wall is above grade, I was concerned that my water pipes would freeze if I didn't insulate my basement.  Most people just make better geography choices and avoid the issue entirely ;)