MVHR Experiences

[Stevo129]

Hi

Is there anyone who is using a recently installed MVHR on a new build. Are they efficient producing cost savings. Are the vents noisey. I have read finding someone to service is a problem.  Is Controlling heat in different rooms an issue or have you to accept all the rooms will be the same temperature. Any advice we’ll received.

[Nickfromwales]

3 minutes ago, Stevo129 said:

Hi

Is there anyone who is using a recently installed MVHR on a new build. Are they efficient producing cost savings. Are the vents noisey. I have read finding someone to service is a problem.  Is Controlling heat in different rooms an issue or have you to accept all the rooms will be the same temperature. Any advice we’ll received.

Hi.

 

What you need to do, sir, is take the rest of the day off and plug yourself into the BH search engine. Delete everything you think you know, or what you've heard elsewhere, and go dig up the wealth of gold-standard information that resides here. 

 

Don't be afraid of blowing the dust off topics and adding new questions, as that is the best way of keeping our library here in good order  

 

I've installed many ( for clients ) which ( subject to them not buying cheap 'Chinese' units ) have been whisper quiet or completely inaudible. 

 

MVHR does not move / control heat, that would be HVAC or forced air systems with huge ducts and monster air flow rates  

[joth]

The easiest way to think of it is:

1. Building a very airtight and well insulated house is what creates lots of cost savings.

2. An MVHR is necessary in an airtight house to stop the occupants from suffocating. (the alternative is to pump cold fresh air in directly from outdoors, which completely defeats the purpose of all that hard work making an airtight house.)

 

As Nick says, providing heat source and moving it around is not the job of MVHR. It's primary role is about providing fresh, breathable air.

 

 

[Adrian Walker]

Vents are noisey when the airflow is too high, caused by not enough vents and/or diameter small ducting. Ducting is relatively  cheap and a small price to pay for a silent MVHR system.  To test that an MVHR system is doing its job, measure the CO2 (not CO) levels in each room.

Edited May 2, 2022 by Adrian Walker

[JohnMo]

Servicing - just a matter of replacing filters in the main unit and at extract nozzles.  While you are changing filters have a look round hoover out excess debris and give s general clean.

 

They generally save about 3 to 4 times the running cost in recouping lost ventilation heat.  Expense compared to not installing, if your air tight better than 3 you have to install to comply with building regs.

 

Flows are not sufficient to move much heat around, also not noticeable sir movement in the house.  We are in a bungalow bedrooms are cool, rest of house is not.

 

A thought about install should not be noisy event in boost it will only just be heard if you are looking for the noise.  Deathly silent compared to normal extract fan.

[Temp]

We have no issues with noise from any of the indoor vents. Outside the main inlet/outlets make some noise due to the airflow through them. This is quieter than a boiler flue but still significant if standing near them. We mounted the fan/heat exchanger unit in a void above a porch over the back door with the in/out vents pointing downwards. 

 

The filters on our system are on the fan unit inlet. They are a large pore/coarse foam but get pretty well clogged with bugs and dust in about 4 months. Because access is a bit difficult I recently fitted a 3D printed filter holder to the inlet vent itself. I can remove this easily and wash it out under a tap.  

 

The extract vents in bathrooms have a dust filter that also clogs. When they do they fold in a way that means they don't block the sirflow but obviously that allows dust into the ducts.

 

Ive no way to know if it saves any money but the constant fresh air makes the house feel so much nicer. Clothes and towels dry on racks overnight and far less dusting to do.