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Overall Heat Transfer Coefficient Calculator

Combine film coefficients, wall layers, fouling, and contact resistance into an overall heat-transfer coefficient.

Overall U inputs

Calculations are performed locally in your browser and are not submitted to a third-party calculation API.

Calculation mode

Display precision

Overall U resistance layers

Heat-transfer coefficient

Heat-transfer coefficient unit

Area

Area unit

Temperature difference

Signed delta temperature. Positive means heat added or hot-to-cold in the stated convention.

Temperature difference unit

Hot-side fouling resistance

Hot-side fouling resistance unit

Cold-side fouling resistance

Contact resistance

Plane layers

Layer 1 thickness

Layer 1 conductivity

Layer 1 contact R''

Layer 2 thickness

Layer 2 conductivity

Layer 2 contact R''

Layer thickness uses m; conductivity uses W/(m·K); contact resistance uses m^2·K/W.

Result section

warningarea-normalized

Overall heat-transfer coefficient

1.65865 W/(m^2·K)

Secondary results

Total area-normalized resistance: 0.6029 m^2·K/W
Heat-transfer rate: 165.865 W
Heat flux: 16.5865 W/m^2
Heat-flow interpretation: Positive heat transfer follows the stated hot-to-cold or heat-added sign convention.

Unit conversion summary

Unit-normalization summary: SI base units; area-normalized

Warnings

Thermal properties can vary with temperature, pressure, composition, grade, direction, phase, surface condition, manufacturing process, and data source. Verify all values for the actual operating condition.

Assumptions

Calculations are performed locally in your browser and are not submitted to a third-party calculation API.

Calculation steps

Sum layer, film, fouling, and contact resistances1.65865 W/(m^2·K)

Overall U from area-normalized resistance

U = 1 / Rtotal''; Qdot = U A deltaT

Technical visual

Calculate overall U from area-normalized resistance layers or a total thermal resistance.

Engineering interpretation

Positive heat transfer follows the stated hot-to-cold or heat-added sign convention.

What is overall heat-transfer coefficient and how does this Overall Heat Transfer Coefficient Calculator work?

The overall heat-transfer coefficient combines convection films, wall conduction, fouling, and contact resistances into one area-based conductance. Its value depends on the selected reference area and geometry, so inside-area and outside-area U values cannot be compared without that convention.

Overall Heat Transfer Coefficient Calculator applies this concept to its defined inputs and workflow. This overall-U calculator sums user-entered area-normalized thermal resistances and layer L/k terms to compute U = 1/Rtotal. Its governing relationship or workflow is stated as follows: Overall U from area-normalized layer, film, fouling, and contact resistances.

The calculator evaluates Calculation mode, Temperature difference, and Display precision and returns Overall U, base-unit normalization, formula substitution, and calculation steps using the stated method. The selected units and sign or reference conventions must describe one consistent physical case. Users should interpret the output within the assumptions shown on the page and repeat the check with trusted reference values when the result affects engineering or research decisions. Thermal properties are treated as constant user-entered values.

How to use the overall heat transfer coefficient calculator

Enter film coefficients and any fouling/contact resistances.
Add up to five plane layers with thickness and conductivity.
Review total resistance, U value, heat rate, and heat flux.

Input explanations

Layer resistance is L/k on an area-normalized basis.
Fouling and contact terms are entered as area-normalized resistance.
Use a consistent reference area for U and heat rate.

Notation

Formula notation
Symbol	Meaning	Unit
U	Overall heat-transfer coefficient	W/(m2 K)
R''	Area-normalized resistance	m2 K/W
L/k	Layer area-normalized resistance	m2 K/W

Worked examples

For Rtotal = 0.1 m2 K/W, U = 10 W/(m2 K).

Cross-tool workflow

The overall-U calculator sums user-entered area-normalized thermal resistances and layer L/k terms to compute U = 1/Rtotal.

Use U with LMTD

Common mistakes

Mixing total K/W resistance with m2 K/W area-normalized resistance.
Using a cylindrical geometry without converting to a consistent area basis.
Leaving out fouling or contact terms that are important in service.

Limitations

Thermal properties are treated as constant user-entered values.
The tool does not select material, fluid, steam, refrigerant, phase-change, or fouling data automatically.
Results are preliminary engineering estimates and do not certify code compliance or safety.
Multidimensional effects, transient storage, contact details, and property variation must be evaluated separately when important.
The layer workflow is plane-wall and area-normalized; radial U calculations require careful reference-area treatment.

References

Fundamentals of Heat and Mass Transfer: Incropera, DeWitt, Bergman, and Lavine, Fundamentals of Heat and Mass Transfer.
Heat and Mass Transfer: Cengel and Ghajar, Heat and Mass Transfer: Fundamentals and Applications.
Heat Transfer: Holman, Heat Transfer.
Compact Heat Exchangers: Kays and London, Compact Heat Exchangers.
SI units: BIPM, The International System of Units (SI Brochure).
NIST unit guidance: NIST Special Publication 811, Guide for the Use of the International System of Units.

What assumptions does the overall heat-transfer coefficient calculator use?

It uses the stated steady or lumped formula with user-entered properties and does not infer hidden losses, standards factors, or temperature-dependent property data.

Are Celsius and Fahrenheit temperature differences handled as offsets?

No. Absolute temperature and temperature difference are separate quantities. Temperature differences use delta units without absolute-temperature offsets.

Can I use the result for final design approval?

No. Use the result for education, estimation, and preliminary review only. Critical work must be checked with standards, validated software, measured properties, and qualified engineering judgment.

Does the calculation run on a remote thermal-property API?

No. Calculations are performed locally in your browser and are not submitted to a third-party calculation API.

Engineering disclaimer

This tool is intended for educational, estimation, and preliminary engineering use. Always verify critical heat-transfer calculations with applicable standards, validated software, measured properties, and qualified professional judgment before using results in real design, manufacturing, construction, safety, or compliance decisions.

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Overall U inputs

Calculations are performed locally in your browser and are not submitted to a third-party calculation API.

Calculation mode

Display precision

Overall U resistance layers

Heat-transfer coefficient

Heat-transfer coefficient unit

Area

Area unit

Temperature difference

Signed delta temperature. Positive means heat added or hot-to-cold in the stated convention.

Temperature difference unit

Hot-side fouling resistance

Hot-side fouling resistance unit

Cold-side fouling resistance

Contact resistance

Plane layers

Layer 1 thickness

Layer 1 conductivity

Layer 1 contact R''

Layer 2 thickness

Layer 2 conductivity

Layer 2 contact R''

Layer thickness uses m; conductivity uses W/(m·K); contact resistance uses m^2·K/W.

Result section

warningarea-normalized

Overall heat-transfer coefficient

1.65865 W/(m^2·K)

Secondary results

Total area-normalized resistance: 0.6029 m^2·K/W
Heat-transfer rate: 165.865 W
Heat flux: 16.5865 W/m^2
Heat-flow interpretation: Positive heat transfer follows the stated hot-to-cold or heat-added sign convention.

Unit conversion summary

Unit-normalization summary: SI base units; area-normalized

Warnings

Thermal properties can vary with temperature, pressure, composition, grade, direction, phase, surface condition, manufacturing process, and data source. Verify all values for the actual operating condition.

Assumptions

Calculations are performed locally in your browser and are not submitted to a third-party calculation API.

Calculation steps

Sum layer, film, fouling, and contact resistances1.65865 W/(m^2·K)

Overall U from area-normalized resistance

U = 1 / Rtotal''; Qdot = U A deltaT

What is overall heat-transfer coefficient and how does this Overall Heat Transfer Coefficient Calculator work?

Symbol

Meaning

Unit

Overall heat-transfer coefficient

W/(m2 K)

R''

Area-normalized resistance

m2 K/W

L/k

Layer area-normalized resistance

m2 K/W

Limitations

Thermal properties are treated as constant user-entered values.

The tool does not select material, fluid, steam, refrigerant, phase-change, or fouling data automatically.

Results are preliminary engineering estimates and do not certify code compliance or safety.

Multidimensional effects, transient storage, contact details, and property variation must be evaluated separately when important.

The layer workflow is plane-wall and area-normalized; radial U calculations require careful reference-area treatment.

References

Fundamentals of Heat and Mass Transfer: Incropera, DeWitt, Bergman, and Lavine, Fundamentals of Heat and Mass Transfer.

Heat and Mass Transfer: Cengel and Ghajar, Heat and Mass Transfer: Fundamentals and Applications.

Heat Transfer: Holman, Heat Transfer.

Compact Heat Exchangers: Kays and London, Compact Heat Exchangers.

SI units: BIPM, The International System of Units (SI Brochure).

NIST unit guidance: NIST Special Publication 811, Guide for the Use of the International System of Units.

Engineering disclaimer

Overall U inputs

Calculation mode

Overall U resistance layers

Plane layers

Result section

Secondary results

Unit conversion summary

Warnings

Assumptions

Calculation steps

Overall U from area-normalized resistance

Technical visual

Engineering interpretation

What is overall heat-transfer coefficient and how does this Overall Heat Transfer Coefficient Calculator work?

How to use the overall heat transfer coefficient calculator

Input explanations

Notation

Worked examples

Cross-tool workflow

Common mistakes

Limitations

References

Related tools

Print summary

Engineering disclaimer

Need Professional Support?

Overall U inputs

Calculation mode

Overall U resistance layers

Plane layers

Result section

Secondary results

Unit conversion summary

Warnings

Assumptions

Calculation steps

Overall U from area-normalized resistance

Technical visual

Engineering interpretation

What is overall heat-transfer coefficient and how does this Overall Heat Transfer Coefficient Calculator work?

How to use the overall heat transfer coefficient calculator

Input explanations

Notation

Worked examples

Cross-tool workflow

Common mistakes

Limitations

References

Related tools

Print summary

Engineering disclaimer

Need Professional Support?