Delta Innoveering - Innovative Engineering


A Conceptual/Simplified Building Energy Modelling

Simple tool intended to help architects at the early design stage. Not all info is needed. The architect may focus on losses through walls, windows & balconies (thermal bridges) and gains from windows only, which have the highest impact & are more directly related to the architectural design. It may be used to model a typical floor in a multi-storey building, where the roof & ground have a negligible impact.
(Free to use at your own risk. No reproduction without permission)

Building location:


Typical Values:

Solar Heat Gain, SHG = 0.5-0.8
Glazing fraction = 0.7-0.8; glazing/window area
r-shading = 0.90; reduction from shading. Less in the presence of trees, awnings
r-angle = 0.85; reduction from the angle of incidence
r-dirt=0.95; reduction from dirt
PSI-Value = 1.0 for conventional balconies and 0.20 for thermally broken ones
Energetically effeective air changes per hour = 0.1-0.2
Internal Heat Gains - typical value = 2.1 W/m2 for residential
Domestic Hot Water (DHW): 4kW heater @ 3 hours/day = 4,380 kWh/year
For questions: Email

Enter treated floor area:

Treated floor area in meters square

Enter walls info:

Walls area in meters square and R-Value in metric (RSI-Value=R-Value/5.678). Group walls of similar/same properties

Enter windows info:

Area in meters square and U-Value in metric (USI-Value=U-Value*5.678). The rest of the info applies to solar gains (Solar Heat Gain Coefficient (SHG), glazing fraction, reduction from shading, angle, dirt and orientation). Group windows of similar/same properties

Enter balconies info:

Length in meters and linear transmittance, PSI-Value, in metric (W/(mK)). Group balconies of similar/same properties

Enter ventilation info:

Volume of ventilated areas in meters cubic and energetically effective air changes (volume fraction per hour)

Enter internal gains info:

Area in meters square and gains (generated by people, equipment & lighting) in W/m2 (typical residential = 2.1)

Enter other thermal energy needs (DHW etc.):

Thermal energy needs in kWh/year.


Breakdown of losses and gains:

For questions and/or customized software: Email