MVHR stands for Mechanical Ventilation with Heat Recovery and is a whole house recovery ventilation system suitable for new and existing homes and apartments.  MVHR continuously supplys and extracts air to the home whist recovering and reusing heat that would have otherwise have been lost (extracted to the outside).  It is linked to every single room in the property - the wet rooms and the habitable rooms. 

Step by step - here's how it's working;

1.The MVHR unit is continuosly extracting moist air, and pollutants from 'wet rooms' such as bathrooms, kitchens and utility areas (continoulsy runs at trickle speed and boosts when required)

2. As this air is extracted, it passes through a filter (to protect the unit) and a heat exchanger inside the unit where up to 95% of the heat is stored (to be reused with supply air - read below)

3. Replacement (supply air) is drawn in from outside to be continously supplied to habitable rooms such as living rooms and bedrooms (this is happening at the same time as the extracting of air)

4. Before it is supplied, it passed through a filter to remove airborne particles and then through the heat exchanger where the recovered heat is transferred - this helps temper the supply air and gets you turning that thermostat DOWN!

5. SUMMER MODE: When the outside air temperature increases,  the heat recovery mode is switched OFF to avoid overheating and increasing the internal temperature - this happens automatically.!

Here's our Simple Homeowner Guide - MVHR Heat Recovery Ventilation

A heat recovery ventilation system provides many benefits for occupants and the home;

1. Helps maintains a good level of indoor air quality 
Did you know?  Indoor Air can be 5 x more polluted than outdoors?
A heat recovery ventilation system ensures pollutants, moisture and particles in the air are removed and replaced with fresher air throughout the day.  All air is passed through MVHR filters - filters can be based on your indoor air quality needs including dust, pollen and pollution options - all of which help ensure a good level of indoor air quality for occupants.  The Extract Air filter protects the motors from a build up of dust, debris and grease and the Supply Air Filters protects your indoor air quality!

2. Contributes to a comfortable indoor environment all year round
Did you know?  A family of four creates as many as 24 pints of moisture everyday in the home from cooking, showering, hanging clothes to dry and even breathing! Cotinuously moving air, extracting moisture and removing particles that may cause allergies and irritations helps provide comfort - you can't see air, but a stuffy and humid environvment, especially at night isn't something that is enjoyable.  In the warmer summer months, an effective and continuous movement of air can also contribute to a 'cooling effect'.

3. Helps reduce your heating bill by re-using heat that would have otherwise have been lost
MVHR is an energy efficient ventilation solution for homes as it recovers the heat in your home that would have otherwise have been lost or extracted to the outside.
The heat exchanger inside the unit can recover and re-use up to 95%* of the heat from the extract air into the supply air (depending on the unit model) helping you reduce the thermostat and your energy bill all in one!

Simple User Guide - MVHR Heat Recovery Ventilation
Do need to discuss a MVHR project?  Call us on 033 0223 6776 or email sales@theairshop.co.uk

Is the property well insulated?

MVHR is most commonly used in new build homes, however can also be applied to existing homes and extensions.   It is a very effective ventilation system if your property has been designed, or renovated to 'keep the heat in'.  MVHR works on the principle of recovering and reusing heat that would have otherwise have been lost.  If your home is not air-tight or well insulated, this heat will just be lost through the facade of the building and heat recovery efficiency will be reduced. 

Of course, as a whole house ventilation systems, it's still epic and will ensure comfort and good indoor air quality all year round, so a well worthwhile investment.

For starters you need to consider where the unit will be located and where the ducting will be concealed as it runs out to each room and then the outside.  Two terminations (one for supply air and one for extract air) are required and ceiling valves in every room. Call us and we can help - 0330 223 6776 or sales@theairshop.co.uk

MVHR Heat Recovery Ventilations provides many benefits to the home and occupants, but it's down to a good design, installation and regular maintenance.  If the unit isn't fit for purpose, or installed poorly, you will end up with nuisance noise, condensation, mould, leaking ducting.. to name but a few...

The key considerations, and areas, where the majority of issues occur including;

1. Sizing the unit correctly
Never undersize the unit.  It will have to work harder to do its' job and that only means one thing - NOISE!!!  A MVHR system works on a constant trickle speed (calculated by floor area, number of bedrooms and occupancy) and we would never reccommend this to be set above 70% of the MVHR Units airflow capacity. Ducting also needs to be taken into consideration as this causes resistance within the duct which has more impact on overall performance.  Airflow requirements are detailed in Approved Document F: Means of Ventilation.  If we are providing MVHR Projects services including a layout and full parts list, we will complete the airflow calculations for you. 

2. Location of the unit
We reccommend siting the unit somewhere central e.g. hall/utility cupboard or loft space to reduce noise ingress as much as possible. MVHR Units are not designed to be noisy, but you want to limit any issues as much as possible (only if they are poorly installed will they be a nuisance) MVHR is also  not a fit and forget system!  MVHR Units require annual maintenance, where access to the motors and the heat exchanger are important.  Filters (usually located on the front of the unit) also require changing at regular intervals, depending on your indoor air quality needs and the levels of pollution in the supply air.  

3. Ducting Type
A MVHR system is made up of the unit AND the ducting.  Both parts play an equal role in delivering effective ventilation to the home.  DO NOT USE FLEXIBLE DUCTING (it is reccommended only to use this directly from the unit where necseeary due to positioning)  Ducting recommended for MVHR System is rigid (circular or rectangular) or semi-rigid.  These types of ducting systems offer far better performance for the MVHR System.  At the Air Shop we favour semi-rigid ducting systems for their ease of installation, noise reduction qualities and excellent performance. 

4. Insulated Ducting 
This is one of the most forgotten aspects of a MVHR design and installation and we see issues with condensation forming in ducting a lot of the time!  If warm moisture air that is being extracted goes into a cold duct (lets say it's in the loft and the loft isn't insulated) then it will condense,and you will end up with water vapour sitting and collecting in that duct over time.  This is not ideal!  Make sure you are insulating the ducting that needs ducting to avoid this situation.

There are more considerations, but these are the main ones. If you are considering a MVHR installation - we can help - please call us on 033 0223 6776 or email sales@theairshop.co.uk

It's not that simple we're afraid!  You can see the prices of MVHR units, but ducting, terminations and other accessories are based on the number of floors, floor area and layout - costs will vary as there will be differing volumes of ducting, insulation, valves, switches per property.  You may also want to add on options including cooling, noise attentiation and high grade NOX filters.

Want an idea of costs in 60 seconds? We've built an MVHR Illustration tool which will give you some ballpark figures based on your floor area - straight to your inbox in less than 60 seonds! Request Illustration now - scroll down and fill in the form.

We're also happy to help discuss a MVHR project. Call us on 0330 223 6776 or email sales@theairshop.co.uk

Heat Recovery Units are designed with energy efficient motors to keep running costs at a minimum.
A typical unit that might be installed in a 2 bedroom flat or small house will typically cost between £35-£45 for the entire year - and remember the heat recovery process is helping recover and re-use heat so you can keep that thermostat static or turn it down a couple of degrees too!

A MVHR unit runs continuously 24 hours per day extracting stale air and replacing with new.  It has two speeds - trickle and boost.

The trickle speed runs continuously at a low level throughout the day/night.   The boost speed increases the rate of ventilation when activities such as cooking and showering takes place, as there is increased moisture/odours that needs to effectively extracted.  The boost speed is activated automatically or manually depending on the system set up;

• automatically via bathroom light (switch live)
• automatically via humidity sensing
• manually via a wired switch which is usually located in a central area/kitchen

A MVHR Unit is moving alot of air in and out of your property everyday and can quickly become clogged with dust, debris and grease.  Overtime, this can impact performance and issues such as condensation and mould may become an issue, your indoor environment may also start to feel 'stuffy' and increased noise may be experienced as the system works hard to do its job.

Filter changes are recommended every 6 months (or even sooner if you live in a polluted area or suffer with allergies or respiratory issues)
Both filters are helping protect the unit and contribute to you indoor air quality.  Filters are available in a range of grades to suit to your indoor air quality needs

A system service is recommended annually (it's more than just the filters!)
A full comprensive service should cover the key parts of the system including;

Motors and heat exchanger
In room air valves and ducting connections
Filters
Check controls and condensation connections
Test airflow rates to ensure a balanced system and trickle and boost speeds set to be effective within in the home