Farrar Bamforth Associates Ltd
Sustainable Developments
 & Green Building
Airtight Construction

Airtight construction is one of the most important & basic tenants of an energy saving building.

Correct detailing and good workmanship can reduce air leakage by two thirds. Passive Haus design & detailing can reduce this further to less than one tenth.




1. Introduction
2. The Legislation
3. Design & Specification
4. Airtight Construction &
means of Ventilation
5. Lighting
6. Water Saving
7. Renewable Energy

Natural Ventilation
This can be as simple as opening a window to obtain fresh air. 

In an office environment windows can be opened and closed mechanically, controlled by an environmental management system.

Stack Ventilation takes this a stage further, cool air is brought in at low level and warm air is removed at high level.

In the image below, fresh air enters through windows on each floor and the stale warmer air rises through the atrium to the glazed roof, where electrically powered actuators open windows to vent the atrium. In this situation this was connected to a smoke detection system which could manually override and open in the event of a fire. 

Natural Ventilation

Mechanical Ventilation

Heat recovery systems can provide an energy efficient means to heat and ventilate a building particularly in combination with an air tight construction. These provide warm filtered air to the habitable parts of the building whilst removing stale air from humid areas.

A series of ducts extract stale moist air from kitchens, bathrooms and utilities which is then passed through the MVHR unit and ducted to the outside. Fresh air is brought from outside to the MVHR unit where the heat from the stale air is transferred to it before it is ducted to the habitable areas.

Correct specification of the whole system can have an impact on its efficiency