Frequently Asked Questions (FAQs)

Manx SAP Calculator

1. What is an indicative Thermal Mass Parameter (TMP) of a dwelling?

Taken from the SAP2012 document:
Thermal mass  TMP (kJ/m2K)

2. What is a Building Part?

Building parts are used to define parts of the building that have been constructed at different times. If there was an extension to a dwelling then this would be defined as an additional building part to the main dwelling and would include definitions for the constructions included in the extension for the walls, floor, roof etc.

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4. How is the Energy Use shown on the report determined?

The Energy Use value shown on the report is the rate of primary energy, in kWh/m2, corresponding to the delivered energy that is consumed in the dwelling. The primary energy is calculated as the sum of the product of all the delivered energy consumed in the dwelling and the relevant primary energy factor of the fuel used to produce it. The primary energy attributed to a dwelling accounts for space and water heating, space cooling, ventilation, and lighting, less the energy saved by energy generation technologies.

5. How do I use the tool to demonstrate compliance for an extension to an existing dwelling?

When constructing an extension, two project models for your building will need to be run. First, model the existing dwelling with a Building Part extension that is the same size as that proposed but which complies with the Reference Method Fabric Standards given in the Approved Document L1B. The SAP rating result of this calculation will set the standard to be achieved. This model should then be duplicated and the U-values and definitions for the extension should be modified to reflect the proposed work to be done. The SAP rating result of the model of the existing dwelling with its proposed extension, together with any improvements made to the existing dwelling, must be no worse than the SAP rating result recorded from the first calculation.

6. How do I know what fuel prices were used in the calculation?

The fuel prices used during the calculation are shown in a table at the end of the report. This includes the prices for all of the relevant fuels used in the dwelling. Some fuels will also have an additional standing charge.

7. What is meant by delivered energy?

Delivered energy is a measure of the energy consumed in a building. It does not take account of the type of fuel used to produce it or the generation, transmission, and distribution efficiencies and losses associated with this fuel source.

8. What is meant by primary energy?

Primary energy is a measure of the energy consumed in a building that factors in the type of fuel used and the associated processing required to generate, transmit, and distribute energy from this fuel source.