R50 vs R60 insulation

Old 01-26-15, 06:03 PM
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R50 vs R60 insulation

Hello all. Long time lurker first time poster.

We are currently in the process of getting our house built in Ottawa Canada. The standard attic insulation is R50 and the builder is asking whether we want to upgrade to R60 for the cost of about 500$C. This is for a 2300 square foot house (not including basement). I've tried to search the answer but it's mostly R30 to R50/60 discussions but nothing about R50 vs R60, and I don't know enough to be able to make the call.

Any insight is greatly appreciated. Thanks
Old 01-27-15, 04:29 AM
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Not worth it in my opinion. You would be reducing conduction by .05%
Old 01-27-15, 06:42 AM
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An extra 10R in a poorly insulated home would be a big improvement. If you've only got R10 in the attic and add 10 more you've doubled the insulating value, a 100% increase. When you'e already got R50 the step up to R60 is only 20% more.

Calculating your actual savings is quite a bit more complex as you have to look at the whole house; walls, windows HVAC system... You will have an energy saving but I would not say it will be huge. How long do you intend to stay in the home? Are you retired and will be in the house during the day or does everyone leave so the house is empty for most of the day. The more you are in the home and the longer you intend on staying sways more toward extra insulation. If you think you'll only be there for 5 years and you'r gone to work during the day then I'd tend to not go for the extra insulation. But... that's easy for me to say down here in sunny NC.
Old 01-27-15, 07:25 AM
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Hi Sandman and welcome to the forum,
Code recommended insulation values are considered the absolute minimum, so stepping it up is often good advice, but I would want to run the cost of the extra R-10 additional insulation. They are already there, the baffles are in place, so it would be a very small added amount of time and the materials are not that expensive. It could involve a higher coffer dam around the attic entrance and perhaps some other adjustments, but not a big change when building new. Be sure this isn't just gravy.

As for savings, going crazy with air sealing during construction would be a far better place to spend some extra money. And again, during construction, very easy to do. To go from a code built home to a very energy efficient home is not all that expensive and even at the current lower energy costs the payback (and added value) is very good.

I would need more details on the planned construction to make more suggestions.

Any alternate form of heat being included.

Old 02-06-15, 02:20 AM
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Sandman, the incremental benefit of adding insulation is not linear so adding more insulation isn't always better. I must say, though, that I'm surprised the attic R-Value recommendation for Ottawa is only R50. If you were in the US, it would likely be R-60.

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