Poor ventilation is one of the leading causes of condensation, black mould and poor indoor air quality in UK homes. As properties become more airtight for energy efficiency, fresh air circulation becomes limited — trapping humidity, carbon dioxide and household pollutants indoors.
UK building regulations require one air change in homes every two hours to meet up with the health of occupants. Traditional extract-only ventilation struggles to meet with these demands thereby putting the wellbeing of occupants at risk, especially with modern building in temperate regions which are designed to be air-tight.
Air tightness in modern buildings require right ventilation. Fresh air needs to be brought into the building and as such, the need for Heat Recovery Ventilation has become obvious, for air recirculation and for the home space to either heated or cooled appropriately. Energy can be saved by transferring heat from the outgoing air stream to the ingoing air stream.
MVHR (Mechanical Ventilation with Heat Recovery) is designed for modern homes and apartments, it provides continuous fresh air without losing heat, it also introduces fresh air to a building making it a powerful solution for ventilation, energy efficiency and health.
MVHR is a whole-house ventilation system that:
Extracts stale, moist air from kitchens and bathrooms
Supplies fresh filtered air to living rooms and bedrooms
Recovers up to 95% of heat from outgoing air
Reduces heating costs and prevents damp problems
MVHR is now widely installed in new builds, refurbishments, apartments, and retrofit projects (PAS 2035).
Mechanical ventilation systems circulate fresh air via ducts and vents and use continually running fans when in operation. Based on the diagram above, MVHR uses two airflows aided by 2 running fans (a supply fan and an extract fan) running through a heat exchanger inside a central unit and follows the steps below:
Stale extract air ➝ Heat is recovered ➝ Fresh air supplied warm
No windows need to be left open — saving energy
|
Common Problem |
MVHR Solution |
|
Condensation on windows |
Removes moisture |
|
Black mould in corners |
Prevents damp |
|
Stuffy, humid bedrooms |
Constant fresh air |
|
High heating bills |
Saves heat energy |
|
Allergies or asthma |
Filters pollutants |
Like a boiler, MVHR systems need servicing. If filters get blocked, the system loses efficiency and can circulate dirty air.
|
Task |
Frequency |
Benefit |
|
Clean MVHR filters |
Every 6 months |
Keeps airflow healthy |
|
Replace filters |
Every 12 months |
Prevents dust build-up |
|
Check heat exchanger |
Every 1 year |
Improves efficiency |
|
Inspect fans |
Every 1 year |
Prevents failure |
|
Clean ducting |
Every 5 years |
Removes dust |
❗ Tip: Never switch off an MVHR unit for long periods. It can cause mould inside the ducts.
MVHR is ideal for:
Q: Does MVHR bring in cold air?
No – heat recovery keeps incoming air warm.
Q: Will MVHR reduce mould?
Yes – it removes moisture before it settles.
Q: Is MVHR expensive to run?
No – similar to the cost of a light bulb per day.
Q: Can I turn it off?
No – MVHR must run continuously to prevent condensation.
ARC Facilities Ltd provides professional MVHR servicing, filter replacement, installation and repairs across London.
TrustMark Accredited
Retrofit & ventilation specialists
Fast response in London
Over 10 years experience
Affordable servicing plans
Prevent damp, mould and airflow issues
Protect your home and health