How to Choose the Perfect Ventilation System for Your Home
As there is a wide selection of ventilation products available, it can be confusing when it comes to fitting an appropriate product. The most efficient ventilation system on the market doesn’t mean it’s the right one for your project.
We’ve seen it all; MVHR selected as a retrofit product ducted to the top floor of property only, MEV systems with no supply ventilation strategy, horizontal passive stack, bathroom fans fitted in habitable rooms, and there are plenty more examples out there.
What makes you choose a particular ventilation strategy for retrofit or property maintenance?
Are you:
- Trying to solve existing condensation or mould issues?
- Managing or maintaining housing stock?
- Combating over ventilation?
- Trying to find the cheapest solution?
- Seeking the most efficient system available?
- Searching for a strategy not compromised by user controllability?
- Trying to find a ventilation system for a project that has no room for typical ventilation products?
- Trying to meet your mechanical specification?
As a result, there is an endless list of factors that influence our decisions. The correct ventilation system for a particular dwelling or site can be difficult.
Two fundamental functions of residential ventilation and air movement that you need to consider are:
- How are you bringing air into the property to ventilate? Positive pressure ventilation.
- How are you balancing this air and getting rid of the air that you don’t want? Negative pressure ventilation.
Air needs to be available and requires a means to draw it. What happens when MVHR isn’t an option?
A ventilation strategy must provide air to habitable rooms. This includes living rooms, bedrooms, home offices, dining rooms, games rooms, etc. Often when there’s a problem, we assume that a property isn’t getting rid of moisture or pollutants.
Think mould. Why do we see it so frequently in bedrooms?
Upgrading the windows to double or triple glaze is great, but do the new windows have trickle vents like the old ones? If not we have a problem,
How do we ventilate this room?
- Correctly sized window vents.
- Perhaps this particular dwelling has wall vents; are they demand control?
- Blocked window vents
- Closed completely.
- Similarly, a central air supply system like PIV Furniture may be pushed tight against a wall, floor undercuts might not be providing adequate air transfer, Blocked air valves, and intake terminations could be blocked.
What’s available to provide supply air where there are no longer window vents?
Mechanical supply; most commonly used are PIV Systems. The Brookvent Airplus PIV System comes with or without a heater with a unique and practical-mounted switch. https://brookvent.co.uk/product/aircycle-one-plus/
PIVs are a great solution to recurring mold and condensation issues where a dwelling isn’t drawing in enough air. Its benefits include: quick installation, only one supply air valve required, airflow controllability to suit your dwelling, filtered air is typically drawn from a loft, heater option to temper air, supply air heat gain from loft space and long life filters. But it has downfalls, using the heater is costly, cool drafts from the central valve location, no heat recovery is provided and the system does not suit all dwelling shapes
If the supply rooms you are trying to reach are not accessible to the landing/ hall that the air is being supplied to, or if you have physically no room to locate the system, It is not the right system for your project
- Demand Control Wall Vents; Brookvent offers a pressure-based wall vent AquPress and the humidity-activated Aquwall. Both come with a range of available external terminations, attenuation, and supporting airflow data.
AquPress and AquWall
AquPress is ideal to prevent over ventilation and ensures that no matter the weather conditions or wind force, only the amount of air selected makes its way into a property. The AquWall increases or restricts airflow based on room humidity levels.https://brookvent.co.uk/aquwall-hy/
A hole is to be cored to the outside to fit a wall grille.
Like the PIV option, these do not offer means of heat recovery following, they are an effective way of ensuring each room requiring background ventilation has the air available for the overall system.
- Single room heat recovery. The air cycle ONE and ONE+ are ideal for providing filtered air on a decentralised basis. Again, the room these are fitted to requires a hole to be cored, however here not only do you benefit from heat recovery, but user controllability offers occupancy-based controls and different flow speeds. Single room heat recovery operates per MVHR for supply air, however, it can also extract. https://brookvent.co.uk/product/aircycle-one/
- Retrofit window vents are also available, look at our range online and get in touch if you require any assistance in sizing. https://brookvent.co.uk/introduction/
Remember when it comes to supply air/ background ventilation, your ventilation products require a higher free area for intermittent fans than they do for continuous running systems like DMEV, or MEV. Continuous systems with a trickle and boost speed are always drawing air and therefore background ventilation products can be sized smaller than their intermittent counterparts. If your background ventilation is sized for system 3 continuous extract, it will not provide adequate air to a 4” intermittent extract fan causing under-ventilation.
If your background ventilation is sized for system 1 intermittent extract ventilation, then swapping in a 4” DMEV without adjusting to the supply product will cause over ventilation and unnecessary heat loss and drafts.
Negative Pressure
When it comes to negative pressure, choosing the right means of the extract depends on what you want to achieve. As we’ve seen with the background ventilation – there are factors outside of extract fan size or system type that impact the effectiveness of your system. Bathrooms, Ensuite, Kitchens, some utility stores, and for our sanitary accommodation requires extract ventilation.
The Brookvent Xe & Xe+ range of intermittent fans provide a simple, quiet controllable means of decentralised extract. They come with a run-on timer and integral humidity options. The 150mm Xe airflow can even provide an alternative to the need for a cooker hood. Typically, Intermittent fans are not going to be the solution for condensation or mould issues.
https://brookvent.co.uk/product/intermittent-extract-ventilation-airstream-xe-fan/
The Brookvent Airstream MEV & DMEV offer centralized or decentralised continuous extract. Centralised systems are great where you can fit ductwork, however, DMEV offers the same solution through the wall. These systems like MVHR connect to demand control devices like PIRs to activate the boost. The constant draw of air coupled with adequate background ventilation provides the right amount of ventilation and continuous air movement is a key factor in clearing condensation and preventing mould issues.
https://brookvent.co.uk/product/airstream-dmev/
Single Room Heat recovery is also an extract solution. Extract rates for SRHR are significantly higher than for MVHR. Don’t fall into the trap of under ventilating by assuming that all heat recovery systems work of System airflows.
https://brookvent.co.uk/product/aircycle-one/
To Conclude, we have to work to find the right solution for the property we’re working on. Knowledge is power! Brookvent offers CPDs and is a provider of the BPEC Domestic Residential Ventilation course. Get in touch to find out more on 02890616505 or Hello@brookvent.co.uk
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