MVHR & Ventilation Ireland
Insulated your home and now wondering about ventilation? Costs, system types, the limited SEAI grant, and how to tell whether your home actually needs MVHR.
Why Insulated Homes Need Ventilation
Traditional Irish homes relied on draughts, gaps, and cracks for natural ventilation. Sealing a home with insulation and draught-proofing removes those unintentional air paths, which is good for heat retention but creates a new problem: without deliberate ventilation, moisture from cooking, showering, and breathing has nowhere to go, leading to condensation and mould.
Mechanical Ventilation with Heat Recovery (MVHR) solves this by continuously ventilating every room while recovering 70 to 95 percent of the heat from the extracted air, supplying filtered fresh air in return.
Wrong order causes problems. Installing MVHR before addressing insulation is usually a mistake. If a home is still draughty, the ventilation problem MVHR solves may not exist yet. Insulate first, then assess ventilation.
Three Levels of Ventilation
Not every home needs full ducted MVHR. Match the system to what your home actually needs.
| System | What It Does | Best Suited To |
|---|---|---|
| Intermittent extractor fans | Removes moist air from one room on demand, loses all the heat | Older, draughtier homes relying on natural infiltration elsewhere |
| MEV | Continuously extracts stale air from wet rooms only | Budget-conscious upgrades, simpler than full MVHR |
| MVHR | Whole-house, continuous, recovers 70–95% of heat | Airtight, well-insulated homes, especially post-EWI or deep retrofit |
Single-room ERV units are also available as a targeted alternative, installed exactly where needed (a bedroom with condensation, a mouldy bathroom) without the cost and disruption of full ducted MVHR throughout the house.
Cost
| Item | Typical Range |
|---|---|
| MEV (basic extract system) | €1,500–€3,000 |
| MVHR, typical home (retrofit) | €4,000–€9,500 |
| MVHR, larger property (270m²+) | €10,000+ |
Retrofit installation costs more than new-build installation because ductwork must be routed through an existing house rather than installed during first fix. Common brands installed in Ireland include Zehnder, Vent-Axia, Beam, and Daikin.
No standalone SEAI grant exists. Support, typically up to €1,500, is only available when MVHR is included within a qualifying whole-home upgrade delivered through the One Stop Shop. It’s not available as an individual Better Energy Homes measure.
The Missing Piece for Your BER Target
Good Insulation, Missing Target
If a home has good insulation but is still missing a target BER band, particularly B2 for One Stop Shop eligibility, uncontrolled ventilation losses are a common, often-overlooked cause.
Closing the Gap
Adding mechanical ventilation with heat recovery can be the specific measure that closes that gap, rather than further insulation work that’s already reached diminishing returns.
Getting It Right
Assess Whether You Actually Need It
If your home hasn’t been insulated or draught-proofed yet, start there first, or consider a simpler solution like PIV.
Document Existing Problems
Photos of condensation or mould, and your before-works BER, support any grant claim.
Involve the Ventilation Designer Early
Ideally at the same planning stage as insulation or heat pump work, not as an afterthought.
Choose the Right System
Full ducted MVHR for whole-house coverage, or targeted single-room ERV units for specific problem rooms.
Installation and Commissioning
Typically 2 to 3 days for a retrofit, finished with a flow-rate test to confirm performance.
Ongoing Maintenance
Replace filters every 6 to 12 months to maintain performance and air quality.