Why a property needs ventilation
Indoor air quality is an important consideration for homeowners in Ireland, particularly due to the country’s damp and rainy climate. Good ventilation plays a crucial role in maintaining a healthy and comfortable home environment by regulating temperature, controlling moisture levels, and improving air quality.
In Ireland, the high levels of humidity and rainfall can lead to moisture buildup and dampness in homes, which can cause structural damage and foster the growth of mold and mildew. Good ventilation helps to remove excess moisture from the air, preventing these issues and protecting the integrity of the building.
Furthermore, poor indoor air quality can lead to a range of health problems, including respiratory issues, allergies, and asthma. Good ventilation helps to circulate fresh air throughout the house, reducing the concentration of pollutants and contaminants and improving overall air quality.
In addition to improving health and preventing structural damage, good ventilation also helps to regulate temperature and improve energy efficiency. Proper ventilation can help to maintain a comfortable temperature throughout the year and reduce the need for artificial heating and cooling.
The BER is affected by ventilation in two ways: the amount of air that flows in and out of the property through draughts and ventilation units; and the amount of energy that is used by a ventilation system.
Improving the BER by reducing draughts
If your home is full of draughts, then the air that has just been expensively heated by the central heating system won’t take long to escape, so it’s worth trying to make sure that it is properly sealed up, to a point.
Ensuring that all windows, doors and attic hatches are draught stripped is a simple way of gaining a slight improvement in the BER. Draught stripping is where a a rubber strip is fitted a to a window frame, a door frame or an attic hatch to seal off the airflow through any gaps. Suspended wooden floors will often have vents on an external wall below the floor height, these can also be sealed off.
Unfortunately, fireplaces are a terrible source of draughts and having one in a property will negatively impact the ventilation and heat source aspects of the BER. These should be be sealed off too but they can’t simply be stuffed with newspaper, they need to be permanently sealed off and plastered over. If keeping the fire is essential, then having an energy efficient wood burning stove installed will still help with the BER, although not as much as sealing off the fire. Air will still pass through the stove but the closed flue going up the chimney is sealed and will significantly reduce draughts through the fireplace.
There are other openings throughout a property that will add to airflow through it, including: mechanical ventilation units, boiler flue, and entry points for plumbing and electricity. The entry points for electricity and plumbing do not have any effect on the BER grade unless the an airtightness test has been carried out on the property by a certified professional. They can help locate areas of a property that are “leaking” air and seal them off. They can then produce a certificate which gives the rate of air flow through a property. This cert can be used in a BER assessment and if the works are carried out properly, the BER will be improved.
There are no individual SEAI grants available for ventilation upgrades. However, there are grants available for homeowners taking part in the “One Stop Shop” scheme which involves a property undergoing a full deep retrofit up to a B2 BER.
Types of ventilation in a Property
There are different types of ventilation systems that homeowners can use to improve indoor air quality and maintain a comfortable and healthy living environment. The main types of ventilation systems are natural ventilation with single extract vent units, whole-house mechanical ventilation, and whole-house mechanical ventilation with heat recovery.
Natural ventilation with single extract vent units involves the use of one or more extractor fans installed in key locations throughout the home, such as the kitchen or bathroom. The fans draw air out of the house and exhaust it outside, creating negative pressure inside the house, which draws fresh air in through windows and other openings. This type of ventilation is the simplest and least expensive option, but it may not provide sufficient ventilation in all parts of the house and can result in increased heating energy consumption due to too many air leaks.
Whole house mechanical ventilation involves having ventilation ducts for each room, allowing for a centralised fan to pull fresh air into the home and force old air out. The BER is affected negatively by the amount of energy that mechanical ventilation units use to keep a controlled airflow through the home. This is considered by the amount of electricity required to power the fans and to heat the fan coils that are on some units to warm up cold air as it enters a property.
To get the best BER, if a whole house mechanical ventilation system is being installed, it is advised to have a system that is designed to recover heat from the air before it is extracted from the property.
Whole House Mechanical Ventilation and Heat Recovery
Whole-house mechanical ventilation is a system that provides continuous airflow throughout the entire house to improve indoor air quality, remove pollutants, and maintain a comfortable living environment. Unlike natural ventilation, which relies on passive airflows, mechanical ventilation uses fans and ductwork to supply and exhaust air from the home.
The main components of a whole-house mechanical ventilation system are the supply and exhaust fans, air filters, ductwork, and controls. The supply fan draws in fresh air from outside and distributes it throughout the house, while the exhaust fan removes stale air and pollutants and exhausts them outside. Air filters are used to remove airborne particles, such as dust and allergens, from the incoming air.
Whole-house mechanical ventilation systems can operate in different modes, depending on the homeowner’s preferences and the local climate. In the summer, the system can be set to bring in cool air from outside to help reduce the temperature inside the home. In the winter, the system can be set to preheat the incoming air to reduce the workload on the heating system.
One variation of whole-house mechanical ventilation is heat recovery ventilation (HRV). HRV systems are designed to recover heat from the outgoing air and transfer it to the incoming air. This is done through a heat exchanger, which is a device that allows two separate air streams to exchange heat without mixing. The heat exchanger can recover up to 80% of the heat from the outgoing air, which can help reduce heating costs and improve energy efficiency.
The main difference between whole-house mechanical ventilation with heat recovery and without heat recovery is the energy efficiency. While both systems provide continuous airflow throughout the house, the heat recovery system can recover heat from the outgoing air and use it to preheat the incoming air. This reduces the workload on the heating system and can result in significant energy savings. However, the heat recovery system is more expensive to install than the non-recovery system, and it requires regular maintenance to ensure optimal performance.
