Alf Calculation

Project name:

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Project details

Enter in your ALF project details below. Your data will be saved as you go and you can come back at any time to finish your ALF project. if you need help, you can click on the help icon or view related help on the right.

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Climate & heating 

Climate

Help. Help

Heating Schedule

Help. Help

Heating Level

Ground floors 

Suspended floor

Help. Help

Edit material

Rooms this floor applies to (complete for Moisture tab only)

Overall

Slab on ground floor

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Edit material

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Rooms this floor applies to (complete for Moisture tab only)

Roof & skylights 

Help

Add another roof Adding...

Walls & windows 

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Rotate house
Rotate counter clock-wise Rotate clock-wise

Add another wall

Thermal Mass 

Estimating the amount of thermal mass involved in the heat flow process requires some judgement. 'Thermal floor area' is floor area which is not carpeted and which is exposed to the inside.

Uncarpeted floor

 

Add another floor Adding...

Walls

 

Add another wall Adding...

Ventilation 

Air tightness classification

Chimneys for open fires

Metal flued heaters

Window passive vents

Help

Windows cracked open

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Retrofit airtightening

Kitchen vents over hob

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Mechanical bathroom vents

Help

Building wind exposure

To calculate air leakage rates, you must also fill in the overall section of the Floors tab.

Moisture

Please note this moisture calculator should only be used as a general guide to the possibility of mould growth within a room. For more detailed information on reducing mould growth please read the helpfile.

The calculations also use information from the Walls & Windows and Ventilation tabs of the ALF calculator. Please fill them out to ensure accurate results.

Living room Help

Kitchen (please enter the living room details first) Help

Note: you need to complete the ventilation section first

Passive window vents Help

Openable windows

Bathroom (please enter the living room details first) Help

Note: you need to complete the ventilation section first

Passive window vents

Openable windows

Master bedroom Help

Help

Note: you need to complete the ventilation section first

Passive window vents

Openable windows

Ensuite (bedroom must be completed first) Help

Note: you need to complete the ventilation section first

Mechanical ventilation to outside

Passive window vents

Openable windows

Current Project:

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Results Summary

BPI:
BPI target:

Specific losses

Susp. floor: W/°C
Slab floor: W/°C
Walls: W/°C
Windows: W/°C
Roof: W/°C
Air leak: W/°C
Warm-up W/°C

Energy

Loss: KWh
Warm-up load: KWh
Window gain: KWh
Internal gain: KWh
Heating: KWh

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