BattWise
R-value targets by climate zone, and what it takes to hit them.
| Sections | Latest |
|---|---|
| Attic | 6 |
| Walls | 5 |
| Floors & Crawlspace | 2 |
| Materials | 4 |
| Climate Zones | 4 |
| R-Value by ZoneIECC minimums by climate zone and assembly, converted into the inches of each material it actually takes. | 3 |
| Blown-In InsulationHow many bags of blown-in insulation an attic takes, and how deep to blow it — calculated from R per inch and settled density so you can check it against the bag in your hands. | 3 |
| Wall Insulation BattsBatts for a framed wall, and the effective R-value after thermal bridging — the number that describes the wall rather than the number printed on the bag. | 3 |
| Insulation Savings & PaybackWhat adding insulation actually saves in dollars a year, and how long it takes to pay for itself — with climate, fuel and the diminishing return of each extra R all in the arithmetic. | 2 |
| HVAC SizingRoughly how much heating and cooling a house needs — and, more usefully, how much smaller the equipment gets when the envelope is tightened. | 1 |
- How R-Value Is Measured, and Why the Label Is a Laboratory Number
The figure on the bag is real and it was produced under conditions your attic will never reproduce. Three of the differences move it in opposite directions.
- Cathedral Ceilings: The Same R-Target, Half the Depth to Put It In
The code target does not soften because the ceiling is sloped. Either the rafters get deeper, the material gets better, or the insulation goes on top.
- Batt Widths: Why 15 Inches Fits a 16-Inch Stud Bay
On-centre spacing is measured stud middle to stud middle. The gap you are filling is narrower than that, by exactly one stud.
- Installation Grade Beats Nominal R — What Grade I Actually Requires
Gaps do not just remove insulation from that spot. They let air move, and moving air carries far more heat than conduction does.
- Mineral Wool or Fiberglass Batts? Four Differences, Only One Is R-Value
The per-inch difference is about half a point. Everything that actually separates them is a property the R-value does not describe.
- What "R-13+5ci" Means, and Why Codes Started Writing It That Way
Two numbers separated by a plus sign, because they do different jobs. One fills the cavity, the other covers the timber that the cavity cannot.
- Attic Insulation Cost by State — And Why It Barely Moves
Insulation is the one trade here where the state you live in barely changes the price. Labor is only 45% of a blow, so the whole country lands within 35% of $1,900.
- Blown-In Attic Insulation Cost per Square Foot — Priced by Depth, Not by Area
Two quotes at the same dollars per square foot can differ by a third in insulation delivered. The number that matters is dollars per square foot at a stated R-value.
- Attic Insulation Removal Cost — When It Is Necessary and When It Is an Upsell
Removal roughly doubles the cost of an attic job. There are four situations that justify it, and being old is not one of them.
- Spray Foam vs Blown-In Cost — Three to Five Times the Price for What
Foam costs three to five times loose fill at the same R-value. It earns that only where air sealing, moisture control or structural stiffness is the actual job.
- Cost to Insulate a House — Priced by Assembly, in the Order That Pays
Whole-house insulation quotes hide the fact that the four assemblies pay back at wildly different rates. Done in the right order, the first third of the budget does most of the work.
- HVAC Size per Square Foot — the Rule of Thumb and Where It Breaks
Six hundred square feet per ton is the number every contractor carries in their head. It is also the number that makes a well-insulated house humid.
- Whole House Fan Cost, and the Attic Venting It Demands
A whole house fan is cheap to run and cheap to fit. It is also the one appliance that will not work unless the attic venting is doubled first.