Building regulation changes from 15th June 2022 – trickle vents
New building regulations that came into effect from 15th June 2022 have implications for any windows that are installed after this date.
All new and replacement windows will need to meet these regulations or will fail the FENSA inspection, and will therefore not be eligible for a FENSA certificate.
Natural ventilation
The specific focus of the building regulation updates is to ensure adequate natural ventilation.
This is achieved though the installation of appropriate ‘trickle vents’.
What are trickle vents?
Trickle vents are positioned at the upper frame of a window or door. They provide a constant, small amount of ventilation into the room, even when the window or door is closed. They are available as a permanent, fixed vent or as controllable vent that can be opened and closed.
Their overarching purpose is to improve the quality of air in a room, and a reduction in condensation.
The important details
It is our role to understand the intricacies of building regulation requirements, so that we take this concern away from you.
As a FENSA registered installer, we are recognised by the government-authorised scheme that ensures all replacement windows and doors are installed in compliance with building regulations.
Here is a brief summary of the updated stipulations that need to be adhered to where windows are being replaced:
- When replacing windows which have background ventilation (or trickle vents), it is necessary to ensure that new trickle vents are no smaller than the vents in the original window, and they must be controllable either automatically or by the occupant.
- When replacing windows without background ventilation (or trickle vents), replacement of the windows is likely to increase the airtightness of the home. Therefore, the regulations specify that the ventilation provision must meet a minimum requirement, by installing appropriate trickle vents.
The installation of appropriate trickle vents involves careful assessment of the room that needs to be ventilated and the positioning of the vents within the building’s façade. This will ensure comfortable and adequate ventilation, whilst managing draughts and external noise.
The specifics of Ventilation: Approved Document F
The updated building regulations specify that the ventilation in your home must be a minimum of 8000mm2 equivalent area, although this drops to 4000mm2 equivalent area for bathrooms or any rooms with an extractor fan fitted.
The “equivalent area” is calculated as the area of a “sharp-edged circular orifice which air would pass through at the same volume flow rate, under identical applied pressure difference, as through the opening under consideration”. In simple terms, it’s a measurement of the amount of air that passes through the vents.
Generally speaking, trickle vents each allow 4000mm2 of ventilation, therefore two trickle vents are required for most rooms.
If it isn’t technically feasible to achieve the required equivalent area, then the ventilation should get as close to the minimum value as possible.
Read the full building regulations for homes.
Replacing windows in commercial premises
Similar rules apply to non-domestic buildings. These are the specific guidelines from the building regulations:
Existing windows with background ventilators
If the existing windows have background ventilators, the replacement windows should include background ventilators. The new background ventilators should comply with the following conditions.
- Not be smaller than the background ventilators in the original window.
- Be controllable either automatically or by the occupant.
If the size of the background ventilators in the existing window is not known, the ventilator sizes below may be applied.
Existing windows without background ventilators
Replacing the windows is likely to increase the airtightness of the building. If ventilation is not provided via a mechanical ventilation system, then increasing the airtightness of the building may reduce beneficial ventilation in the building. In these circumstances, it is necessary to ensure that the ventilation provision in the building is no worse than it was before the work was carried out.
This may be demonstrated in any of the following ways.
- Incorporating background ventilators in the replacement windows equivalent to the following.
- Occupiable rooms.
- For floor areas up to 10m2 – minimum 2500mm2 equivalent area.
- For floor areas greater than 10m2 – minimum 250mm2 equivalent area per m2 of floor area.
- Domestic-type kitchen – minimum 8000mm2 equivalent area.
- Bathroom (with or without a toilet) and shower rooms – minimum 4000mm2 equivalent area per bath or shower.
- Sanitary accommodation (and/or washing facilities) – minimum 2000mm2 equivalent area per WC.
- Occupiable rooms.
- Other ventilation provisions, if it can be demonstrated to a building control body that they comply with the general requirements of these building regulations (see section 3.2 of the regulations).
Note: If it is not technically feasible to adopt the minimum equivalent areas, the background ventilators should have equivalent areas as close to the minimum value as is feasible.
Note: If an exposed façade is close to an area of sustained and loud noise (eg a main road), then a noise attenuating background ventilator should be fitted.
For further information please see volume 2 of the ventilation building regulations, which applies to buildings other than dwellings.
Energy efficiency requirement
The new building regulations coming into effect from June also specify certain requirements for thermal efficiency – this means that a particular ‘U Value’ needs to be achieved:
- Achieving a thermal efficiency U Value rating of 1.4 W/m²K or less is required for all new and replacement windows and doors.
Certain types of window glass have superior energy efficiency built-in, which enable them to meet the required regulations. These products have a technologically-advanced coating that captures the natural energy from sunlight, whilst retaining heat within the home.
The products that Window Wise supply and install all comply with the U Value requirement stipulated in the last building regulations.
Read the full energy efficiency building regulations for homes.
Similar building regulations also apply to commercial premises, with a requirement for replacement windows to have a U Value of 1.6 W/m2K or less. In addition, commercial premises have limitations on the area of openings allowed.
Read the full Conservation of fuel and power: Approved Document L guidance for buildings other than dwellings.
Talk to us about replacement windows
If you have any questions about replacing your windows or doors, please call us on 01444 45 71 45.