Rex says
Money math without the spreadsheet headache. Plug in your numbers and I'll show you exactly where the dollars land.
Try a scenario
Click to load — tweak from there.Inputs
Result
Payback period
6.5
Annual energy savings
$276
Reduction in attic heat loss
61%
Net savings after 10 years
$955
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One click, a permanent link with your numbers baked in.
How to use this
- 1Enter current attic r-value.
- 2Enter target attic r-value.
- 3Enter annual heating + cooling cost ($).
- 4Enter attic's share of heating/cooling loss (%).
- 5Enter insulation job cost ($).
- 6Read your payback period on the right — it updates as you type.
- 7Hit Share to keep the scenario or send it to someone.
About this calculator
Estimates annual heating and cooling savings from raising insulation R-value, using the basic heat-loss relationship that conduction loss is inversely proportional to R-value. Going from R-19 to R-49 in an attic (a very common upgrade, since most homes built before 2000 are under-insulated) doesn't cut heat loss through that surface by 2.5x proportionally to R-value ratio in isolation — this calculator applies that ratio to the attic's estimated annual heating/cooling load contribution, not your whole bill, which is the mistake most rough estimates make. It reports the simple payback against material and labor cost for a typical blown-in attic job.
Worked example
Using the values the calculator loads with:
Inputs
- Current attic R-value: 19
- Target attic R-value: 49
- Annual heating + cooling cost: 1800 $
- Attic's share of heating/cooling loss: 25 %
- Insulation job cost: 1800 $
Results
- Payback period: 6.5
- Annual energy savings: $276
- Reduction in attic heat loss: 61%
- Net savings after 10 years: $955
What each field means
Inputs
- Current attic R-value
- The current attic r-value used in the calculation. Starts at 19 so you have a working example on load. Accepted range: 0–60.
- Target attic R-value
- The target attic r-value used in the calculation. Starts at 49 so you have a working example on load. Accepted range: 10–70.
- Annual heating + cooling cost ($)
- The annual heating + cooling cost used in the calculation, measured in $. Starts at 1800 $ so you have a working example on load.
- Attic's share of heating/cooling loss (%)
- The attic's share of heating/cooling loss used in the calculation, measured in %. Starts at 25 % so you have a working example on load. Accepted range: 5–50 %.
- Insulation job cost ($)
- The insulation job cost used in the calculation, measured in $. Starts at 1800 $ so you have a working example on load.
Results
- Payback period
- Returned as a decimal number and shown as the headline result. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Annual energy savings
- Returned as a money amount in US dollars. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Reduction in attic heat loss
- Returned as a percentage. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Net savings after 10 years
- Returned as a money amount in US dollars. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
FAQ
Why doesn't doubling R-value halve my whole bill?
The attic is only one heat-loss pathway among walls, windows, air leaks, and the foundation. Even a dramatic R-value increase in the attic only affects the portion of your total energy bill attributable to attic heat loss, typically 20-30% of the total in an average home, which is why this calculator asks for that share explicitly rather than assuming the whole bill moves.
What R-value should I target?
The DOE recommends R-49 to R-60 for attics in most of the US (zones 4-8, covering the northern two-thirds of the country), and R-30 to R-49 in warmer zones 1-3. Most homes built before 2000 have only R-11 to R-19, so a jump to code-recommended levels is usually the single best-payback energy upgrade available.
Does air sealing matter more than insulation?
Often yes — air leakage through attic bypasses (can lights, plumbing chases, the attic hatch) can account for more heat loss than the insulation's R-value alone suggests. A blower-door-directed air seal before adding insulation typically improves the real-world result beyond what this R-value-only model predicts.
Is blown-in or batt insulation better for attics?
Blown-in cellulose or fiberglass fills irregular joist spaces and around obstructions more completely than batts, and is usually cheaper for topping up existing insulation to a higher R-value. Batts make more sense for new construction with open, uniform stud/joist bays where a contractor can fit them precisely.
Accuracy and limitations
- Results are estimates before tax, fees, and inflation unless an input explicitly covers them.
- Rates are treated as fixed for the whole period — variable-rate products will drift from this projection.
- This is educational maths, not financial advice. Check anything contractual with the lender or your accountant.
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Cite this calculator
Writing about this topic? Grab a citation — every link helps keep these tools free.
RevenueLab. (2026). Insulation R-Value Upgrade Payback Calculator. Retrieved from https://www.revenuelab.fyi/toolbox/insulation-payback
<p>Source: <a href="https://www.revenuelab.fyi/toolbox/insulation-payback" target="_blank" rel="noopener">Insulation R-Value Upgrade Payback Calculator — RevenueLab</a> (2026).</p>
Source: [Insulation R-Value Upgrade Payback Calculator — RevenueLab](https://www.revenuelab.fyi/toolbox/insulation-payback) (2026).