Heat Recovery Ventilation systems present a number of questions and doubts.
This constantly updated section, provides answers to frequently asked questions about MVHR and Helty Flow systems.
The electricity consumption of a punctual MVHR unit is very low and comparable to that of an LED light bulb. All Helty Flow systems for residential use are rated energy class A and help reduce energy consumption thanks to their highly efficient heat recovery performance. Read the entire FAQ
A well-designed and properly installed MVHR system is not noisy. Helty decentralised MVHR units stand out for their acoustic performance: both the wall-mounted MVHR models and the wall-recessed Flow30 and Flow40 units have a minimum sound pressure level of just 18 decibels. Read the entire FAQ
The hygrometric sensors in Helty’s MVHR systems are designed to monitor indoor humidity, allowing the machine to automatically adjust the airflow rate in each individual room. Read the entire FAQ
A decentralised MVHR system is the ideal solution when redeveloping existing buildings or homes which require ventilation or to address localised problems such as mould or stale air. It allows a controlled mechanical ventilation system to be installed quickly and without invasive work (no installation of air distribution networks). Read the entire FAQ
Yes, you can use the Helty Home app if you have a Helty MVHR unit from 2025 or a model produced after January 2023 with compatible firmware and a cloud control panel. It is not compatible with earlier units. Read the entire FAQ
MVHR Helty models equipped with Modbus protocol allow simultaneous remote management of several units via home automation systems. It is otherwise possible to manage the machines via a special App, with a home Wi-Fi network. Read the entire FAQ
A decentralised dual-flow MVHR allows for continuous replacement of extracted stale air with fresh air intake, meaning better results in terms of energy efficiency and purification of incoming air. Read the entire FAQ
Helty Flow MVHR systems replace and filter the air; they are not air conditioners. Under certain outdoor temperature conditions, the MVHR can be used to deliver cooler or warmer air and contribute to the air conditioning of an indoor room. Read the entire FAQ
Decentralised MVHR systems are the ideal solution for minor renovation projects or work carried out in existing buildings, as they do not require air ducting, suspended ceilings or dedicated service spaces. Read the entire FAQ
The packaging contains all the main components required to install and commission the Helty MVHR unit. Tools and materials needed to drill the two 80 or 100 mm wall openings are not included. Read the entire FAQ
Helty MVHR solutions can be installed underneath an air conditioner without any problems, the important thing is to respect the minimum distances indicated in the installation manual. Read the entire FAQ
A wall-mounted MVHR can be installed quickly and without costly work. Simply drill two 80mm cores on the perimeter wall, prepare the power supply and fix the unit to the wall using screws and dowels. Read the entire FAQ
The installation templates for Helty Flow wall-mounted MVHR models are available for download in the reserved area and include holes distances, coring dimensions and overall dimensions. Read the entire FAQ
Installing a concealed MVHR system requires a creating a recess in the perimeter wall where the ventilation system will be positioned, which needs to served by the power supply. The hole dimensions are available in a reserved area. Read the entire FAQ
Flow40 concealed MVHRs require a perimeter wall with a minimum thickness of 335mm. Flow70 and Flow100 systems require perimeter walls with a minimum thickness of 460mm. Read the entire FAQ
The CO2 and VOC sensors measure the concentration of carbon dioxide and volatile organic substances in the indoor environment, allowing the MVHR unit to automatically adjust the air flow rate to allow the parameters to fall within preset limits. Read the entire FAQ
Indoor air quality levels can be assessed and monitored by looking at parameters such as CO2 (carbon dioxide) and VOC (volatile organic compounds). Read the entire FAQ
A continuous dual-flow MVHR system with heat recovery helps reduce energy waste and improve comfort throughout the year. The heat exchanger preheats incoming air in winter and helps cool it in summer by using the properties of the outgoing air to transfer both sensible heat – temperature – and latent heat – humidity. Read the entire FAQ
Replacing indoor air with fresh air from outdoors that is continuously filtered and cleaned eliminates the problems associated with stale air, prevents the onset of mould and reduces the risk of exposure to dangerous indoor pollutants. Read the entire FAQ
Natural ventilation through manual window opening is impractical, difficult to manage and energy-consuming. A mechanical ventilation system allows you to fully automate stale air removal and fresh air intake, delivering continuous indoor air purification and greater energy efficiency. Read the entire FAQ
Mechanical ventilation allows for a continuous and sufficient replacement of the air volumes in enclosed spaces through stale air extraction and fresh air intake. This helps to reduce the presence of viral bioaerosols that might otherwise remain suspended in the air and spread by air. Read the entire FAQ
Yes, proper ventilation of all spaces and rooms is essential for removing excess moisture and preventing condensation and mould. Read the entire FAQ
Radon gas can enter a building from the ground, mainly by rising through cracks, service penetrations and cavities. In some cases, building materials may also release radon, although generally to a lesser extent than radon originating from the soil. Ventilating indoor spaces is essential to help reduce indoor radon concentrations. Read the entire FAQ
Measuring radon gas at home is a fundamental step in protecting indoor health, especially in areas at risk. This can be done using passive measuring devices, which assess radon concentrations over a longer period, or active devices, such as the Helty Radon Monitor, an innovative instrument designed for use with MVHR systems and capable of providing real-time readings. Read the entire FAQ
In Helty MVHR systems, the fresh outdoor air supplied to indoor spaces is first filtered by a special high-performance filter that prevents the entry of particulates down to PM2.5, as well as dust, smog and pollen. Read the entire FAQ
A sensible heat exchanger is a component used in MVHR systems to transfer heat between the air extracted from indoor spaces and the fresh air supplied from outside, without mixing the two airflows. It mainly recovers the energy associated with air temperature, but not humidity. This distinguishes it from an enthalpy heat exchanger and means that, under certain conditions, condensate management may be required. Read the entire FAQ
An enthalpy heat exchanger recovers both the sensible thermal energy (the heat) and the latent energy (the humidity) from the air flow. It has the advantage of offering better overall energy efficiency without over-drying the incoming air. Read the entire FAQ
It depends on the model and version. Helty MVHR units with an enthalpy heat exchanger do not require a condensate drain. Versions with a sensible heat exchanger introduced from March 2026, however, require provision for condensate drainage. Read the entire FAQ
The performance of the Helty ventilation systems are recognized by the Casa Clima Quality Seal and have obtained the SIMA and BioSafe validations
