Ireland version
How it works
Estimate attic insulation quantity and heating savings while keeping moisture, ventilation and local resistance requirements outside the arithmetic.
This is the Ireland planning view, with monetary inputs and outputs in EUR. A currency label does not establish that a tax rate, construction price, coverage rule or legal limit has been verified locally. The inputs and limitations below describe the actual scope.
Input query strings and outputs
Use an input name in this page’s URL as ?name=value, and join additional inputs with &. Portable shared links may instead use the compact ?ac= state parameter.
Input query strings
15-
?unitSystem=Measurement systemChoice · Optional · Default: metric · Accepted values: imperial, metric
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?area=Attic floor areaNumber · Required · Default: 80
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?oldResistance=Existing total assembly resistanceNumber · Required · Default: 2
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?newResistance=Proposed total assembly resistanceNumber · Required · Default: 6
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?degreeDays=Local annual heating degree daysNumber · Required · Default: 2,500
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?heatingEfficiency=Heating input-to-useful-heat efficiencyPercentage · Required · Default: 90
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?energyRate=Heating energy price per input kWhMoney · Required · Default: 0.1
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?addedDepth=Added material depthNumber · Required · Default: 150
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?unitRate=Material price per area unitMoney · Required · Default: 0
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?laborCost=Total labor allowanceMoney · Required · Default: 0
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?deliveryCost=Delivery allowanceMoney · Required · Default: 0
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?otherCost=Other fixed costsMoney · Required · Default: 0
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?costMultiplier=Material/labor multiplierNumber · Required · Default: 1
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?spreadPercent=Low/high sensitivity around the entered totalPercentage · Required · Default: 15
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?taxRate=Explicit tax allowancePercentage · Required · Default: 0
Outputs
12-
materialVolumeAdded insulation volumeNumber
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annualInputSavingModeled annual heating input saved, kWhNumber
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annualSavingModeled annual energy savingCurrency · Currency: EUR
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paybackSimple payback, yearsNumber
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materialCostMaterial costCurrency · Currency: EUR
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laborCostLabor allowanceCurrency · Currency: EUR
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deliveryCostDelivery allowanceCurrency · Currency: EUR
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otherCostOther specified costsCurrency · Currency: EUR
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taxEntered tax allowanceCurrency · Currency: EUR
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lowLow cost scenarioCurrency · Currency: EUR
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midMiddle cost scenarioCurrency · Primary output · Currency: EUR
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highHigh cost scenarioCurrency · Currency: EUR
Formula
annual useful heat saved = area × (1/R-old − 1/R-new) × heating degree days × 24 ÷ 1,000.
Calculations retain numeric precision internally. Displayed values are rounded for readability. Quantities that must be purchased as whole units are rounded up only where the formula explicitly requires it.
Read the inputs before calculating
- Attic floor area: Enter the quantity described by the label. The measurement selector converts this physical quantity; it does not change the underlying scenario.
- Existing total assembly resistance: Enter the quantity described by the label. The measurement selector converts this physical quantity; it does not change the underlying scenario.
- Proposed total assembly resistance: Enter the quantity described by the label. The measurement selector converts this physical quantity; it does not change the underlying scenario.
- Local annual heating degree days: Enter the quantity described by the label. The measurement selector converts this physical quantity; it does not change the underlying scenario.
- Heating input-to-useful-heat efficiency: Enter the quantity described by the label.
- Heating energy price per input kWh: Enter the quantity described by the label.
- Added material depth: Enter the quantity described by the label. The measurement selector converts this physical quantity; it does not change the underlying scenario.
- Material price per area unit: Zero means unpriced, not free. Enter a current, scoped supplier quote. This is a price per displayed unit, so the price converts inversely to the physical quantity.
- Total labor allowance: Enter the quantity described by the label.
- Delivery allowance: Enter the quantity described by the label.
- Other fixed costs: Enter the quantity described by the label.
- Material/labor multiplier: Use a verified regional index only when supplied. 1 is an unadjusted scenario, not a researched index.
- Low/high sensitivity around the entered total: Enter the quantity described by the label.
- Explicit tax allowance: Enter the quantity described by the label.
Reproducible worked example
The following is a fictional arithmetic example, not a local quote, a verified claimant or a market forecast. Its values are included so the formula can be checked. The form does not automatically confirm any verification checkbox.
| Input | Example value |
|---|---|
| Attic floor area (m²) | 80 |
| Existing total assembly resistance (RSI (m²·K/W)) | 2 |
| Proposed total assembly resistance (RSI (m²·K/W)) | 6 |
| Local annual heating degree days (°C·days) | 2,500 |
| Heating input-to-useful-heat efficiency | 90 |
| Heating energy price per input kWh | 0.1 |
| Added material depth (mm) | 150 |
| Material price per area unit (/m²) | 0 |
| Total labor allowance | 0 |
| Delivery allowance | 0 |
| Other fixed costs | 0 |
| Material/labor multiplier | 1 |
| Low/high sensitivity around the entered total | 15 |
| Explicit tax allowance | 0 |
| Output | Calculated result |
|---|---|
| Added insulation volume | 12 m³ |
| Modeled annual heating input saved, kWh | 1,777.7778 |
| Modeled annual energy saving | EUR 177.7778 |
| Simple payback, years | 0 |
| Material cost | EUR 0 |
| Labor allowance | EUR 0 |
| Delivery allowance | EUR 0 |
| Other specified costs | EUR 0 |
| Entered tax allowance | EUR 0 |
| Low cost scenario | EUR 0 |
| Middle cost scenario | EUR 0 |
| High cost scenario | EUR 0 |
Interpreting a changed assumption
Start with one complete scenario and change only one input when diagnosing a difference. Recheck units, the period of every rate, whether an amount is recurring or one-off, and whether a cost is already included elsewhere. A larger calculated benefit is not evidence that an assumption is more likely to occur.
Limitations
- Material is unpriced. A zero material price is not evidence that the material is free.
- Prices and the tax allowance are user-entered planning assumptions, not a verified local quote. Low/high outputs are sensitivity scenarios, not market confidence limits.
- The multiplier applies only to material and labor; delivery and fixed costs are not multiplied.
- R-values describe the complete compared assemblies. The calculator does not infer a legally required R-value from the state or certify condensation, ventilation, fire clearance or installation quality.
Frequently asked questions
What does this Attic Insulation result represent?
Estimate attic insulation quantity and heating savings while keeping moisture, ventilation and local resistance requirements outside the arithmetic. It applies the displayed formula to your inputs; it does not infer omitted facts.
Are the starting amounts verified Ireland prices or legal rules?
No. Numeric defaults are illustrative unless an input or dated reference explicitly identifies a researched component. Currency is EUR; local quotes, eligibility and unsupported rules must be entered and verified separately.
What must I check before relying on the result?
Check the input units, supplier or authority evidence, the stated model exclusions and the period used for costs. This arithmetic does not supply missing site-specific design or local legal rules.
Can I compare or share different assumptions?
Change one assumption at a time and use the browser-local project or share controls. A shared URL contains the encoded input values; do not include information you do not wish to disclose.
Sources and reference scope
- DOE energy-use arithmetic — retrieved 2026-09-24. Energy consumption versus power; not a local tariff or an approval of this implementation.
- PVWatts: site-specific solar estimation — retrieved 2026-09-24. External site-yield model. AskCalculators uses your entered yield; it does not call or reproduce PVWatts.
- DOE insulation overview — retrieved 2026-09-24. Insulation and thermal resistance concepts; not structural or code approval.
These references support only their stated scope. They are not evidence that every local rule or price needed by the master expansion has been loaded.