Introduction

The Heat Load Calculator is a system for calculating the design heat load of buildings in accordance with BS EN 12831-1:2017.

It is designed as an easy-to-use online tool that enables you to estimate heat loads for correctly sizing heating systems, such as heat pumps, in domestic properties.

Multiple data sources are used to minimise the amount of data that must be entered manually, whilst adhering to UK national standards.

Features

• Intuitive web-based interface that works on desktop and mobile devices
• Cloud-based storage of previous calculations in a shared account
• Predefined selection of input data:
  • External design conditions based on postcode
  • Assumed infiltration rate based on number of bedrooms
  • Internal design conditions based on room type
  • Building element U-values based on construction type
• Automated computation of net surface areas to exclude door/window areas
• Comprehensive and printable heat load calculation report
• Compliance check against MCS Heat Pump Standard (MIS 3005-D)

BS EN 12831-1:2017

BS EN 12831-1:2017 (Energy Performance of Buildings) is a British standard that provides guidance on the design and installation of heating and cooling systems in buildings, including the calculation of heat losses and heat gains.

When calculating the heat load of a building, the standard recommends that the heat load for each room should be calculated separately, taking into account factors such as the room size, insulation levels, and heat gains from occupants and equipment. These individual room heat loads are then added together to obtain the total heat load for the building.

However, it is important to note that the total heat load for the building is not simply the sum of the heat loads for each room. This is because heat loss is not evenly distributed throughout a building, and some areas may lose more heat than others due to factors such as thermal bridging or air leakage. Additionally, the heat loss from some rooms may be partially offset by the heat gains from adjacent rooms or common areas.

Therefore, the total heat load for a building calculated according to BS EN 12831-1:2017 may be lower than the sum of the heat loads for each room, depending on factors such as the building design, insulation levels, and heating system efficiency.

It is important to use a comprehensive heat loss calculation method that takes into account all relevant factors to obtain an accurate estimate of the total heat load for a building.

Disclaimer

No warranty or guarantee can be given as to the accuracy of any figures provided. We strongly recommend a property survey before finalising system design, suitability or any contractual relationships with a consumer.

More Information

For more information, please refer to the following standards and reference documents:

• Energy Performance of Buildings - BS EN 12831-1:2017
• MCS Heat Pump Standard - MIS 3005-D