House U-Value and Energy Calculator with Comparison

Basic Configuration

House Area (m²):

Wall Height (m):

Wall Thickness (m):

Wall Material:

Insulation Thickness (m):

Insulation Material:

Number of Doors:

Door Width (m):

Door Height (m):

Door Material:

Number of Windows:

Window Width (m):

Window Height (m):

Window Glazing:

Temperature Difference (°C):

Duration (hours):

Alternative Configuration

House Area (m²):

Wall Height (m):

Wall Thickness (m):

Wall Material:

Insulation Thickness (m):

Insulation Material:

Number of Doors:

Door Width (m):

Door Height (m):

Door Material:

Number of Windows:

Window Width (m):

Window Height (m):

Window Glazing:

Temperature Difference (°C):

Duration (hours):

How the U-Value and Energy Calculator Works

This calculator estimates the energy consumption of a house by calculating its U-value and determining the total energy required to maintain a given temperature difference. The U-value indicates the rate at which heat transfers through building components such as walls, doors, and windows.

The calculation involves the following steps:

Calculating U-Value for Walls

Calculate the R-Value for the wall using its thickness and thermal conductivity.
Formula: R = Wall Thickness / Thermal Conductivity
Calculate the U-Value by taking the reciprocal of the R-Value.
Formula: U = 1 / R

Considering Insulation

If insulation is present, calculate its R-Value similarly using the insulation's thickness and thermal conductivity.
Add the R-Values for the wall and insulation to get the combined R-Value.
Calculate the U-Value for the combined wall and insulation:
Formula: U = 1 / (Wall R-Value + Insulation R-Value)

U-Values for Doors and Windows

Doors and windows have typical U-Values based on the materials used and glazing types.
Use standard values from reference tables for different door and window types.

Calculating the Total U-Value for the House

Find the weighted average U-Value considering the surface areas and U-Values of each component:
Formula: Total U-Value = (Wall U-Value × Wall Area + Door U-Value × Door Area + Window U-Value × Window Area) / Total Surface Area

Calculating the Total U Heat transfer

Calculate the total heat transfer (Q) based on the U-value, surface area, and temperature difference:
Q = U × Area × ΔT

Estimate the total energy required over a given duration:
Energy = Q × Duration (in seconds) / 3,600,000 (to convert to kWh)

Thermal Conductivities for Wall Materials (λ in W/(m·K))

Material	Thermal Conductivity
Brick	0.7
Concrete (non-insulated)	1.7
Concrete (insulated)	0.8
Wood	0.15
Stone	2.0
Steel	47.0
Fiberglass	0.04
Foam	0.03
Wool	0.04

Door U-Values (Average)

Door Material	U-Value
Wood (solid)	1.5
Wood (insulated)	0.7
Metal (insulated)	1.2
Metal (non-insulated)	2.5
Fiberglass	1.0
Plastic	1.3

Window U-Values (by Glazing Type)

Window Glazing	U-Value
Single Glazed	4.5
Double Glazed	2.0
Triple Glazed	1.0

To use the calculator, enter the house area, wall height, wall thickness, and the materials used for walls, insulation, doors, and windows. Additionally, provide the temperature difference between inside and outside, and the duration in hours. The calculator will then compute the U-values and total energy consumption for the given configuration. This information can be used to assess the energy efficiency of different building designs and compare the energy consumption between two configurations.

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