How To Plan For MVHR In Your New Build

Picture this: You’re building a new house and it’s likely going to be more airtight and more efficient than your current or previous home. Ventilation may not be something you’ve considered or even thought about before. You install trickle vents and extract fans at last minute to ventilate the property. Your nice, new, airtight house isn’t as airtight as you’d aimed for and your heating bills are rising rapidly. What if there was a way to keep the warm air in your house whilst maintaining a fresh atmosphere?

If you’re embarking on a new build project and considering fitting an MVHR system for the first time, there are things you can do to you plan for and enable a seamless installation in your new home. Don’t let MVHR become an after-thought with these three simple steps:

Step 1 – Where will the unit go?

The MVHR unit itself will need to be housed somewhere accessible so your future self will be able to keep up with maintenance easily. This can be a plant room, utility, loft space, cupboard, wherever you like really. It’s good to be flexible with the unit location and have a few options as this will give you more possibilities when it comes to designing how the system will be integrated with your build. It’s ideal for the unit to be located further away from main living areas to ensure no noise breakout when the system is on boost, so a dedicated area for services and appliances is best (but not essential!). The unit will also need power and drainage, so housing it somewhere that these facilities can be put in place is required.

Step 2 – Where will the duct go?

You may not have decided exactly how you’re going to build your house. Maybe you have a few options lined up or maybe you’re searching for advice here. The good news is – we can install in pretty much any type of build given that the correct provisions are made. Depending on the location of the unit, it’s likely that most of the duct is going to run in either the loft, joist space or floor. It’s important to take into account the depth of ceiling void or size of web joists before you specify them. It’s good to bear in mind that the smaller the void, the more expensive the MVHR is likely to become due to the higher cost of flat ducting compared to circular. For example, our standard duct size can’t fit through anything smaller than 254mm deep web joists. If you’re not using engineered joists, a ceiling void is going to be necessary. We offer a whole range of duct sizes and system designs, so we can pretty much work with anything from a 70mm ceiling void upwards.

If you’re not building a bungalow, you’ve probably realised that the duct will need to travel between the floors too. Our 60mm rectangular ducting that can be concealed within stud walls is an obvious choice. If you’re not using stud walls, you may want to consider creating a dedicated service riser or selecting a few key locations where duct can be hidden easily.

Step 3 – What will it look like?

Apart from the vents in each of the rooms, the system should be pretty much incognito in your house – you won’t even know it’s there. Aesthetics such as vent colours and positions can be considered further down the line and don’t need to be worried about right away. However, if you do have certain aesthetic requirements (particularly if installing in a listed building) you may be restricted on what penetrations you can make to the outside building. The MVHR system has a fresh air input and stale air output that need to be connected to the outside – this can be via the roof, wall or soffit. If you want to keep these external vents as hidden as possible, you’ll need to plan accordingly. If you don’t want the vents mounted on the front of the house, make sure your ideal location for the unit (step 1) isn’t at the front of the house. If you don’t want roof terminals, consider mounting the unit close to a gable wall or somewhere other than the loft. If you want to conceal the vents as much as possible, consider creating a deeper soffit to house them.

Hopefully these three steps have given you an idea of how to start planning for MVHR in your new build. Note that this is general guidance and each project will have individual issues and questions that aren’t answered here. If you’re ready for more info on how MVHR will work specifically with your build, use our free design service for an in depth design and quote or call our office for a chat.