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Calculators · Thermal engineering

Thermal engineering calculator for enclosing structures

Conditional one-dimensional calculation of a multilayer structure: GSOP, heat transfer resistance, temperature profile, selection of insulation thickness and transmission heat loss of the building.

Construction area

Building and climate

Dial source: JV 131.13330.2025.

Group influences choice policy and building type; numerical norms are taken from published sets.

m²

Room

Calculated air parameters
°C

Determined by the purpose of the room.

Interface validation range: 5…110 °C.Interface validation range: 5…110 °C.

°C

Interface validation range: 5…110 °C.Interface validation range: 5…110 °C.

%

%

Explicit reference value for partial pressure estimation.

Accepted according to Appendix A SP 50.13330.2024.

Temperature and humidity are user-entered calculation values.

Humidity conditions—
terms of Use—

Fencing

Type and outdoor environment

Preset thicknesses — engineering UI values; selection does not establish code compliance.Preset thicknesses are engineering UI values; selection does not establish code compliance.

Framed wall and sandwich-panel presets are omitted: the published catalog lacks the complete material and component properties needed for a reliable assembly model.Framed walls and sandwich panels are omitted because the published catalog does not contain the complete material and component data for a reliable assembly model.

Layers

From the inside → outward

ThermalCalc

Directory of materials

MaterialCategoryρλAλBVapor permeabilitySource

Select line, to see available features.

What does the calculator calculate?

Mode «Design» calculates the conditional heat transfer resistance, coefficient U, stationary heat flow, temperatures at the boundaries of layers and conditional seasonal transmission loss through 1 m². Mode «Building» assembles designs, rooms and surfaces, then displays transmission losses for each room and building in W and kW.

What's happened R conditional and R given

Conditional R describes a homogeneous one-dimensional area. Given R takes into account racks, fasteners, joints, corners and other heat-conducting inclusions. This calculator does not determine the reduced resistance and does not confirm the full compliance of the joint venture design.

How is GSOP calculated?

GSOP = (tᵢ − tₕ) × zₕ

The internal temperature for GSOP is set separately from the temperature of the current calculation. For Samara, the average temperature and duration of the heating season are taken from SP 131.13330.2025; for category 1.2 a period with an average daily temperature not higher than 10 °C, for categories 1.1 and 2 — no higher 8 °C.

How to choose λA / λB

The humidity conditions of the room are determined by temperature and relative humidity, then, together with the selected humidity zone, sets operating conditions A or B. From custom λA and λB select the value of the corresponding mode.

How is layer resistance calculated?

Rᵢ = δ / λ × γ

Thickness δ converted from millimeters to meters. Coefficient γ default is 1,00; any other value is explicit user input.

How to choose the thickness of insulation

The resistances of surfaces and other layers are subtracted from the basic standardized value. The missing resistance of the marked layer is converted into thickness according to its calculated thermal conductivity and γ. Round up to 10 mm is only a constructive recommendation.

Calculation Limitations

Heat-conducting inclusions are not calculated, frames, floors on the ground, vapor permeability, condensation, moisture accumulation, ventilation, infiltration and complete thermal balance of the building. For windows and doors in building mode U specified by the user or according to the manufacturer. The temperature difference of a homogeneous area is given for reference and is not a complete sanitary-hygiene check. Temperatures in corners and joints may be lower than the result for a homogeneous area.

Regulatory framework

  • JV 50.13330.2024 «Thermal protection of buildings»;
  • JV 131.13330.2025 «Construction climatology».

JV 345.1325800.2017, GOST R 54851-2011, GOST R 59985-2022 and GOST 30494-2011 provided for future expansion, but additional functions for them in v0.1 not implemented.