MVHR vs DCV: Which Ventilation System Is Best for Your Home?
Choosing between MVHR and DCV is a major decision for any modern Irish home. As airtightness levels improve in NZEB and low-energy builds, the right system has a direct impact on comfort, energy bills, and indoor air quality. Today, the most common options are MVHR (Mechanical Ventilation with Heat Recovery) and DCV (Demand Control Ventilation).
But when comparing MVHR vs DCV, which system actually suits your home, your budget, and your long-term goals?
Below, we break down how each technology works, along with the advantages and limitations of both.
What Is MVHR and How Does It Work?
MVHR – Mechanical Ventilation with Heat Recovery (also called heat recovery ventilation) is a balanced, whole-house system. It extracts stale air from wet rooms such as kitchens, bathrooms, and utilities, and supplies fresh filtered air to bedrooms and living spaces. Crucially, MVHR recovers heat from outgoing air and uses it to warm incoming air, improving efficiency and reducing heat loss.
Key Benefits of MVHR
- Recovers up to 90% of heat
- Provides consistent 24/7 airflow
- Ideal for airtight homes, Passive House and NZEB builds
- Filters allergens, moisture, dust, and pollutants
- Reduces heating demand and long-term running costs
Potential Drawbacks of MVHR
- Higher upfront investment
- Requires professional design and duct layout
- Needs filter changes and yearly maintenance
Best for: New builds, Passive Houses, NZEB homes, and airtight properties.
What Is DCV (Demand Control Ventilation)?
DCV, or Demand Control Ventilation, adjusts airflow using humidity or CO₂ sensors. It increases extraction only when required, making it an energy-efficient option for simpler layouts. Most DCV setups are extract-only and do not offer heat recovery or filtered supply air.
Key Benefits of Demand Control Ventilation
- Lower installation cost
- Minimal ducting required
- Very practical for retrofits
- Energy efficient — ventilates only when needed
Potential Drawbacks of DCV
- No heat recovery, meaning higher heating bills
- No filtered fresh air supply
- Less suitable for airtight homes
- No particulate or pollen filtration
Best for: Retrofits, small apartments, tight budgets, and older homes.
Important Update: MEV Recognised Under DEAP
SEAI now recognises Mechanical Extract Ventilation (MEV) within the DEAP methodology for BER calculations. MEV must:
- Provide continuous extract ventilation in wet rooms
- Use background ventilators in habitable rooms
- Be properly sized, installed, and commissioned
- Include a signed commissioning sheet compliant with Part F airflow requirements
While DCV is not separately listed, a DCV system may still qualify if it operates as a fully compliant MEV installation with measured airflow rates and continuous background ventilation.
MVHR vs DCV — Side-by-Side Comparison
| Feature | MVHR | DCV |
|---|---|---|
| Air Supply | Yes (balanced supply & extract) | No (extract only) |
| Heat Recovery | Up to 90% | None |
| Filtration | Yes | No |
| Best For | New builds, airtight homes | Retrofits, older homes |
| Complexity | Medium–High | Low–Medium |
| Cost | Higher upfront, lower long-term bills | Lower upfront, higher heating cost |
| Maintenance | Filter changes | Minimal (sensors) |
Which System Should You Choose?
When comparing MVHR vs DCV, your building type and airtightness are the deciding factors.
- Choose MVHR if you are building a new low-energy home, Passive House, or NZEB-level property. It delivers the best indoor air quality, the lowest running costs, and excellent comfort.
- Choose DCV if you need a straightforward retrofit solution on a smaller budget. It still improves ventilation but offers fewer long-term benefits and almost no heat recovery.
Final Advice
Ventilation is a long-term investment. For the best results, match your system to:
- Building type (new build or retrofit)
- Airtightness test results
- Energy targets
- Budget and maintenance expectations
If you’re unsure whether MVHR or DCV is the right fit, a professional assessment can clarify airflow requirements, compliance obligations, and running costs. The right design makes a massive difference, especially in modern airtight homes where moisture control, heat loss, and indoor comfort are all linked.
Eco Vent Ireland provides expert support with MVHR and DCV system design, installation, commissioning, and Part F compliance.
Contact us today for professional advice and a quotation.
