General HRV/MVHR Questions:
- What is a heat recovery ventilation (HRV) system?
An HRV system recovers heat from the stale air being extracted from your home and uses it to warm the fresh incoming air. - How does an MVHR system work?
MVHR systems continuously extract stale air from wet areas like kitchens and bathrooms while supplying fresh air to living spaces, recovering heat in the process. - What are the benefits of HRV systems?
HRV systems improve indoor air quality, reduce heating costs, and help maintain a comfortable, fresh environment. - What’s the difference between HRV and MVHR?
MVHR refers to mechanical ventilation with heat recovery, a system that both ventilates and recovers heat, while HRV is a general term for heat recovery systems. - Can an HRV system help with air quality?
Yes, by continuously supplying fresh air and filtering out pollutants, HRV systems improve air quality. - Does an MVHR system provide heating?
No, it doesn’t provide active heating but reduces the need for heating by recovering heat from the outgoing air. It reduces the need to open windows and doors to provide fresh air, which causes heat loss. - How efficient are MVHR systems?
Modern MVHR systems can recover up to 97% of the heat from the extracted air, improving energy efficiency. - How much energy does an HRV system save?
The savings depend on the efficiency of the system and the climate but can significantly reduce heating bills. See What you need to know about MVHR running costs - What is a heat exchanger, and how does it work?
A heat exchanger transfers heat from outgoing stale air to the incoming fresh air without mixing the two. - Will an MVHR system reduce condensation in my home?
It helps dramatically reduce condensation by maintaining balanced humidity levels.
Installation & Suitability:
- Can an MVHR system be installed in any type of house?
Most homes can have an MVHR system installed, but it’s ideal for airtight, well-insulated buildings. - My house isn’t airtight – can I still get an MVHR system?
Yes. If your house has issues with stale air, mould, condensation, mildew etc, it has inadequate ventilation, despite it not being airtight. - Do I need planning permission for an MVHR system?
Generally, no planning permission is required unless your home is listed or in a conservation area. - Is an HRV system suitable for a retrofit?
Yes, but it may be more complex in older homes without existing ductwork. This is why we will always perform a site survey prior to starting work. Rest assured, we’ve seen and solved most problems, but being on site we can discuss any specific concerns with you. - Can I install a heat recovery ventilation system in a listed building?
It depends on the specific restrictions, but solutions can be designed for listed buildings. - How big is a typical MVHR unit?
The unit itself is about the size of 3 microwaves stacked on top of each other. However, like a microwave, they need space in front of them for servicing and maintenance. The size varies but typically they are compact enough to fit in lofts, utility rooms, or cupboards. - Can an HRV system be installed in a small apartment?
Yes, there are systems designed specifically for smaller properties. - What space is needed to install an MVHR system?
You’ll need space for the unit itself and ducting, often in lofts or false ceilings. - How noisy is a typical MVHR system?
Properly installed MVHR systems should be very quiet, operating below 25-30 dB in living spaces. Our quotes will give you calculated values based on our tuning of the unit to the exact volumes required for your property - Can I install an MVHR system myself?
It’s recommended to have it professionally installed to ensure proper performance and compliance with regulations. A system that is not sized and commissioned properly will be ineffective at best. - How long does it take to install an MVHR system?
Installation typically takes a few days, depending on the complexity of the project.
Performance & Efficiency:
- How effective is an MVHR system at reducing heating costs?
This is very subjective, depending on the home, heating method, insulation properties etc – However, by recovering 97% of the heat from the air that would otherwise be lost, the heating system has little work to do to ‘top-up’. Plus, the removal of the need to open windows for ‘fresh air’ is removed, keeping the thermal envelope of the house intact - What percentage of heat can an MVHR system recover?
High-efficiency systems can recover up to 97% of the heat from extracted air. This depends on several factors, the unit, quality of installation, insulation of ducting, etc. - How can I calculate the efficiency of an MVHR system?
Efficiency is typically measured as the percentage of heat recovered, found in the product’s technical specifications. Contact us to discuss further. - Will an MVHR system work well in a draughty house?
It’s most effective in airtight homes, as draughts can bypass the system and reduce efficiency. - Does an MVHR system improve indoor air quality?
Yes, by continuously supplying fresh, filtered air, it helps remove indoor pollutants. - Can HRV systems reduce pollen and allergens in the air?
Yes, with appropriate filters, HRV systems can reduce the amount of pollen and allergens entering your home. - Can an MVHR system help with mould issues?
By maintaining balanced humidity levels, MVHR systems can reduce the likelihood of mould growth. - How does an MVHR system help with asthma or respiratory issues?
It improves air quality by removing pollutants, allergens, and excess humidity, creating a healthier environment. - Does an HRV system work in all climates?
Yes, but it is particularly beneficial in cooler climates where heat recovery is more valuable. - Will an MVHR system keep my house warm in the winter?
It won’t heat your home directly but helps retain heat, reducing the need for additional heating.
Installation & Running Costs:
Further information on running costs: What you need to know about MVHR running costs
- How much does it cost to install an MVHR system in the UK?
The cost ranges from £3,000 to £10,000 depending on the size of the property and system. - How much does an HRV system cost to run?
Running costs are typically low, around £50-£100 per year depending on the system’s energy consumption. - What is the average electricity consumption of an MVHR unit?
An average unit consumes between 30 to 100 watts, depending on the size and speed. - How can I calculate the running costs of an MVHR system?
Multiply the system’s wattage by your electricity rate (e.g., £0.23 per kWh) and the hours of operation per year. - Is an MVHR system worth the initial cost?
It can be, especially if you have a well-insulated home and are looking to improve energy efficiency and air quality. - How much maintenance does an MVHR system need?
Basic maintenance includes changing or cleaning filters every 3-6 months and a service check every 1-2 years. - Can an HRV system reduce my heating bills?
Yes, by recovering heat from extracted air, it reduces the amount of heating required. - Are there any government incentives for installing an MVHR system?
Incentives may be available under energy efficiency schemes, though they can vary by region and time. - Will installing an MVHR system increase my home’s value?
It may enhance the value of energy-efficient homes, especially new builds or passive houses. - What’s the payback period for an MVHR system?
Typically, the payback period is 7-12 years, depending on energy savings and initial investment.
Maintenance & Lifespan:
- How often do I need to clean or change the filters in an MVHR system?
Filters should be checked every 3-6 months and replaced when necessary, typically once a year. - How long does an MVHR unit last?
An MVHR system can last 15-20 years with proper maintenance. - What happens if I don’t maintain my HRV system?
Poor maintenance can lead to reduced efficiency, bad air quality, and system breakdowns. - Can I clean my HRV system filters myself?
Yes, most filters can be removed and cleaned by homeowners, but always check the manufacturer’s guidelines. - How often should an HRV system be serviced?
A full system service is recommended every 1-2 years to ensure it runs efficiently. - What are the common issues with MVHR systems?
Common issues include dirty filters, poor installation, and blockages in the ductwork. - Do I need to service my MVHR unit every year?
Annual servicing is recommended, though some systems may only require a service every two years. - How do I know if my MVHR system is working properly?
You’ll notice a consistent fresh airflow, and there should be no excessive noise or humidity problems. - How can I make my MVHR system last longer?
Regular maintenance, filter changes, and cleaning the system will extend its lifespan. - Is a warranty typically included with an MVHR system?
Yes, most systems come with a 2-5 year warranty, depending on the manufacturer.
Indoor Climate Control:
- Can an MVHR system help control humidity?
Yes, it helps maintain optimal humidity levels, reducing excess moisture in the air. - Will an HRV system help cool my home in the summer?
Our systems have a summer bypass function to prevent excess heat from entering during warmer months. - Can I control the temperature of the air entering my home with an MVHR system?
You can’t directly control the temperature, but heat recovery helps moderate it. - How does an MVHR system handle excess moisture from bathrooms and kitchens?
Our systems are fitted with a humidity sensor that constantly monitors the humidity of the wet rooms (kitchen, bathrooms, utility) of the house. Once a spike in humidity is detected, the system boosts by 25% automatically until the humidity reaches normal levels - Can an MVHR system handle high levels of indoor pollution?
Yes, when equipped with high-quality filters, it can reduce pollutants like dust, pollen, and fumes. - Can an MVHR system help reduce asthma symptoms?
Yes, MVHR systems help filter out pollutants and maintain a consistent humidity level, which can alleviate asthma symptoms. Just take a look at the filters in our duct cleaning area to see the the amount of dust and debris that they capture - What’s the difference between an MVHR system and a standard ventilation system?
Standard ventilation removes stale air without recovering any heat, while MVHR systems recover up to 97% of the heat, making them more energy-efficient. - Is an MVHR system better than using extractor fans?
Yes, extractor fans expel air but do not recover any heat. MVHR systems also provide fresh air to living areas, creating a balanced ventilation approach. - Do MVHR systems make noise?
Properly installed systems should run quietly, and any noise is typically confined to mechanical areas like lofts or utility rooms. Our quotes give calculated estimated decibel levels for both standard and boosted modes. - Can I turn my MVHR system off?
It is not recommended to turn off your MVHR system as it is designed to run continuously. Turning it off can result in poor air quality and condensation issues. However, if you plan to create large amounts of work in the house (dusty DIY activities like cutting/sanding, renovations, decorating etc) you should turn the unit off and ideally cover the relevant cowls in the room temporarily until the dust settles. This is to save your system from ingesting all this debris and reducing its effectiveness