United States version
How it works
Translate an already assessed design load into a manufacturer-rating requirement at the local cold-weather performance point.
This is the United States planning view, with monetary inputs and outputs in USD. 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
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?unitSystem=Measurement systemChoice · Optional · Default: imperial · Accepted values: imperial, metric
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?designHeatLoss=Professionally assessed design heat lossNumber · Required · Default: 27,297.133065023536
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?coolingLoad=Assessed design cooling loadNumber · Required · Default: 13,648.566532511768
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?coldCapacityRetention=Rated heating capacity retained at local design temperaturePercentage · Required · Default: 75
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?designMargin=Explicit design allowancePercentage · Required · Default: 5
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?unitRate=Material price per kW of rated thermal capacityMoney · 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
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requiredKwRequired rated heating capacityNumber · Primary output
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selectedKwLarger heating/cooling capacity requirementNumber
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tonsCooling-equivalent refrigeration tonsNumber
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materialCostMaterial costCurrency · Currency: USD
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laborCostLabor allowanceCurrency · Currency: USD
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deliveryCostDelivery allowanceCurrency · Currency: USD
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otherCostOther specified costsCurrency · Currency: USD
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taxEntered tax allowanceCurrency · Currency: USD
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lowLow cost scenarioCurrency · Currency: USD
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midMiddle cost scenarioCurrency · Primary output · Currency: USD
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highHigh cost scenarioCurrency · Currency: USD
Formula
rated heating capacity = design heat loss × (1 + allowance) ÷ capacity retained at design temperature.
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
- Professionally assessed design heat loss: Enter the quantity described by the label. The measurement selector converts this physical quantity; it does not change the underlying scenario.
- Assessed design cooling load: Enter the quantity described by the label. The measurement selector converts this physical quantity; it does not change the underlying scenario.
- Rated heating capacity retained at local design temperature: Enter the quantity described by the label.
- Explicit design allowance: Enter the quantity described by the label.
- Material price per kW of rated thermal capacity: Zero means unpriced, not free. Enter a current, scoped supplier quote.
- 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 |
|---|---|
| Professionally assessed design heat loss (BTU/h) | 27,297.1331 |
| Assessed design cooling load (BTU/h) | 13,648.5665 |
| Rated heating capacity retained at local design temperature | 75 |
| Explicit design allowance | 5 |
| Material price per kW of rated thermal capacity | 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 |
|---|---|
| Required rated heating capacity | 38,215.9863 BTU/h |
| Larger heating/cooling capacity requirement | 38,215.9863 BTU/h |
| Cooling-equivalent refrigeration tons | 3.1847 |
| Material cost | USD 0 |
| Labor allowance | USD 0 |
| Delivery allowance | USD 0 |
| Other specified costs | USD 0 |
| Entered tax allowance | USD 0 |
| Low cost scenario | USD 0 |
| Middle cost scenario | USD 0 |
| High cost scenario | USD 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.
- Cost is priced per kW of rated thermal capacity in either unit system. A supplier must verify actual model capacity, defrost, backup heat, minimum modulation and refrigerant/electrical requirements.
Frequently asked questions
What does this Heat Pump Sizing result represent?
Translate an already assessed design load into a manufacturer-rating requirement at the local cold-weather performance point. It applies the displayed formula to your inputs; it does not infer omitted facts.
Are the starting amounts verified United States prices or legal rules?
No. Numeric defaults are illustrative unless an input or dated reference explicitly identifies a researched component. Currency is USD; 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.