Q. What does MVHR mean?
A. MVHR stands for Mechanical Ventilation with Heat Recovery (often referred to as Heat Recovery Ventilation)
Q. How does a heat recovery ventilation system work?
A. The warm, stale, moisture-laden air from all wet areas in your home i.e. bathrooms, wc's, kitchens and utility areas etc. is continuously extracted and filtered back through the heat recovery unit. This exhaust air passes through the heat exchanger where the heat energy is transferred to the incoming supply air. As a result you will have a continuous supply of fresh, filtered, tempered air to all habitable rooms in the home i.e. bedrooms, living rooms and dining areas etc.
Q. How much heat is recovered?
A. All our MVHR units are up to 92% efficient, however these efficiencies can only be achieved with a well-designed and highly insulated ductwork system. Some ducting systems have poor quality insulation or none at all. A poorly insulated ducting system will dramatically reduce the efficiency of any MVHR unit.
Q. What steps can I take during the build to ensure the MVHR system operates as efficiently as possible?
A. The most important step is to make your home as airtight as possible. Dwellings built to a poor air tightness standard will have numerous uncontrolled drafts and air leakage points. If you add mechanical ventilation to this scenario, you will effectively create an environment that is over ventilated and much more difficult and expensive to heat. We have carried out thousands of air tightness tests over the past decade. We have the knowledge and expertise to identify problem areas and recommend the most suitable remedial action. Our aim is to help you create a home that is easy to heat and comfortable to live in.
Q. Does the same air get recycled?
A. No. The stale air extracted from the dwelling will flow through a completely separate duct-line to the fresh incoming air. The cross-counter flow heat exchanger within the MVHR unit is designed to keep both air-streams completely separate from one another. This type of heat exchanger is typically used in buildings with rigorous hygienic standards such as laboratories, medical surgeries etc.
Q. What are the health benefits?
A. Studies have shown that good indoor air quality can dramatically reduce the effects of asthma and allergy suffers. The MVHR system is designed to continuously remove stale, moist air from the home and replace it with fresh, filtered outdoor air. This in turn will make your home a more comfortable and healthy place to live.
Q. Is the system expensive to run?
A. No. We only supply MVHR units with low energy, high efficiency EC/DC fan motors. In a typical 200m² dwelling the electrical consumption will be approximately £50 per year.
Q. Will the system be noisy?
A. No. We only install ultra-quiet acoustically encased MVHR units. During normal running conditions the MVHR unit shouldn’t be any louder than a fridge. We put careful consideration into the design and installation of our ductwork to guarantee quite operation.
Q. How often do I need to clean or replace my ventilation filters?
A. Depending on your surrounding environment, we recommend that you clean your filters every 6 months and replace them every year. As part of our ongoing customer service we will send you an email reminder every 6 months to clean or replace your filters.
Q. Can I change the filters myself?
A. Yes. Simply open the access flaps on the front of the unit, remove the filters and clean or replace as necessary. If you are unsure please refer to the user manual our contact us on 028 8675 1025.
Q. How often does my ventilation system need to be serviced?
A. We recommend that you have your ventilation system professionally serviced every 5 years. This will include; removing the heat exchanger and cleaning it, cleaning the fan blades, cleaning or replacing the filters. The airflows should be checked to ensure the system is still operating correctly.
Q. Does the MVHR unit have a summer bypass facility?
A. Yes. All of our MVHR units come with a built-in summer bypass mode as standard. In the summer months the intake air will not be tempered as it is diverted around the heat exchange block. Summer bypass mode will activate automatically once the internal temperature rises above 22°C and the outside temperature is above 14°C, thus preventing the dwelling from overheating.
Q. Can you heat the incoming air?
A. Yes. We can incorporate a Low Pressure Hot Water Heater Battery into the ventilation ductwork system. This is a duct mounted heating coil designed to increase the temperature of the supply air traveling to the habitable rooms e.g. bedrooms, living room etc. You will be required to make provisions for hot and cold pipework from house heating circuit, and include zone stat controls. You will have to appoint a suitably qualified plumber to undertake these works.
Q. What warranty comes with the system?
A. All our MVHR units have a full 5 year manufactures warranty on parts and a full 1 year manufactures warranty on labour. All ductwork installations undertaken by Atlantic Air have a full 5 year warranty on parts and labour.
Q. When do you install the system?
A. Once the roof is on, the ductwork can be installed.
Q. Can I install the system myself?
A. Yes. We can supply the MVHR unit and all necessary ducting for a DIY installation. We can also provide ductwork layout drawings prior to installation and a BPEC commissioning certificate on completion. However to eliminate the risk of noise, insufficient airflows etc. we would recommend that you allow our team of engineers to install the full system.
Q. Where in the dwelling will the heat recovery unit be located at?
A. The unit is most commonly located within the attic. However it can be wall mounted anywhere on the ground or first floor (e.g. utility room, hot press etc.) depending on your requirements.
Q. What is air tightness?
A. Air tightness refers to the infiltration of cold air into the building and the loss of heated air from inside through gaps, holes, cracks etc. in the building fabric.
Q. How airtight does my house need to be?
A. You should try make your house as airtight as possible (i.e. less than 2 m³/ (hr*m²) @50 Pa), the tighter your house the more efficient your MVHR system will be. Atlantic Air have carried out thousands of air tightness tests over the past decade. We can provide expert advice, identify potential problem areas and recommend appropriate remedial action.
Q. Can I open my windows?
A. Yes. Opening the windows will have no effect on the day to day running of the MVHR system. However, you shouldn’t feel the need to open windows as the MVHR system is continually extracting the stale air and replacing it with fresh outdoor air.
Q. Do I deed trickle vents?
A. No. With an MVHR system you will no longer require trickle ventilation in your windows.
Q. Do I still need an extractor fan in my bathroom or En-suite?
A. No. You will no longer require intermittent extractor fans in any wet areas e.g. Kitchen, Utility, Bathroom, En-suite etc. The MVHR system will extract directly from these rooms.
Q. What will I see in each room?
A. You will see a supply air valve on the ceiling in each habitable room and an extract air valve in on the ceiling in each wet-room. The ductwork will be concealed within ceiling voids, stud walls and attic spaces.
Q. Do I still need a Kitchen Cooker-Hood fan?
A. Yes. The MVHR system isn’t designed to handle airborne grease or fat. You can either install a cooker hood fan that is ducted directly to the outside. Or you can install a recirculating cooker hood with integral charcoal filters. The charcoal filters are designed to capture the airborne grease and fat whiles the MVHR extraction point will remove the warm moist air from the kitchen. The MVHR extraction point must be located at least 1m away from the cooker.
Q. Do I need to leave a space under the internal doors?
A. Yes. To comply with building regulations you are required to leave 10mm space under all internal doors. This allows air to move from supply points in habitable rooms e.g. bedrooms, living room etc. to extraction points in the wet areas e.g. bathroom, kitchen etc. even when the doors are closed.
Q. Can I install a stove in my house with a heat ventilation recovery system?
A. Yes. The stove will not affect the performance of the ventilation system, however Building Control will ask you to provide an independent air supply for the stove.
Q. How do I get a quotation?
A. If you would like a quotation for any of our products or services please complete the contact us form on our website and attached your house plans. If you would prefer to speak with one of our technical team, please call us on 028 8675 1025.