Green Building Forum - Whole House Air Filtration System

Whole House Air Filtration System

Victorianeco — Mon, 30 Jan 2023 07:49:39 +0000

Are there any recommended whole house air filters without going down the MVHR route?

Whole House Air Filtration System

Mike1 — Tue, 31 Jan 2023 13:10:24 +0000

This may be one time where buying the cheapest undersized MVHR unit you can find is actually worth it?

Whole House Air Filtration System

tony — Tue, 31 Jan 2023 16:19:55 +0000

Boulder one in the loft or one from a major fan company

Whole House Air Filtration System

djh — Tue, 31 Jan 2023 17:40:08 +0000

Posted By: Mike1This may be one time where buying the cheapest undersized MVHR unit you can find is actually worth it?

Not quite sure how you would use this? Why undersized - I'd have thought that was a recipe for a rapid failure and a lot of noise meanwhile?

Whole House Air Filtration System

Mike1 — Tue, 31 Jan 2023 21:54:43 +0000

Posted By: djhWhy undersized - I'd have thought that was a recipe for a rapid failure and a lot of noise meanwhile?

If filtration is the only concern (as it appears to be), rather than providing a particular air change rate, a cheap unit permanently running on a low setting _may_ be adequate. It would probably depend on the level of filtration required, and what is giving rise to the need for filtration. Hence my question mark above.

If it needs to provide whole-house ventilation too, a more robust solution would be required. Ideally MVHR...

Whole House Air Filtration System

Victorianeco — Tue, 31 Jan 2023 22:39:42 +0000

My daughter has bad eczema and so we're trying to keep all sources of allergies down.

I intended fitting MVHR years ago but decided the house is probably too leaky (Victorian mid-terrace) to warrant MVHR. We still have open chimneys wedged with pillows in bags for instance

Whole House Air Filtration System

cjard — Wed, 01 Feb 2023 08:08:02 +0000

How would it help then, if your house is so leaky? Or were you thinking of a filtering PIV?

Whole House Air Filtration System

sgt_woulds — Wed, 01 Feb 2023 12:57:56 +0000

In a similar vane is anyone aware of an iPSV system with filtration?

Ventive used to have filtration I believe, but they no longer have a PSV system suitable for domestic properties, (and they never answer enquiries so I've crossed them off my list)

Glidevale iPSV has no filtration.

We have the double whammy of a neighbour with a highly polluting wood stove and light sleepers who are sensitive to MV noise - I've never come across a truly silent mechanical vent in real life.

Whole House Air Filtration System

Dominic Cooney — Sun, 05 Feb 2023 08:41:14 +0000

Our MVHR is set to quiet mode overnight - youâ€™re not generating as much moisture from cooking or washing when you are asleep so the fan speed goes down lower (and therefore quieter).

[Vent-Axia Sentinel Kinetic]

Whole House Air Filtration System

borpin — Sun, 05 Feb 2023 17:33:40 +0000

Posted By: Dominic CooneyOur MVHR is set to quiet mode overnight

About a year ago, I started measuring COÂ² in the house and on the MVHR extract. I was surprised that the ventilation rate needed to keep the COÂ² stable and the difference one person made to that.

Humidity is pretty stable even after showers (well never to the problem levels) and the house is generally too dry and I need a Humidifier. So ventilation levels are basically set for COÂ² level control. For the 2 of us, that is on minimal setting all the time.

Side note, I started measuring the Home Office COÂ² with just me. Horrified at how high it got with the door closed (it has supply but no extract). I now leave the door ajar (and yes it has the gaps under the door) which maintains the level nicely.

Moral of the story, measure your COÂ².

Whole House Air Filtration System

djh — Sun, 05 Feb 2023 20:09:50 +0000

Posted By: borpinHumidity is pretty stable even after showers (well never to the problem levels) and the house is generally too dry and I need a Humidifier. So ventilation levels are basically set for COÂ² level control. For the 2 of us, that is on minimal setting all the time.

Our MVHR has a 'trickle' setting of 50 mÂ³/hr (approx 14 l/s) and we typically run on that up to 17 hours a day and 125 mÂ³/hr for the other seven (or longer) whilst the heater might be running. I'm curious about your humidity. What is 'too dry' as an RH number?

Whole House Air Filtration System

RobL — Sun, 05 Feb 2023 23:29:00 +0000

Posted By: borpinAbout a year ago, I started measuring COÂ² in the house and on the MVHR extract. I was surprised that the ventilation rate needed to keep the COÂ² stable and the difference one person made to that.

Side note, I started measuring the Home Office COÂ² with just me. Horrified at how high it got with the door closed (it has supply but no extract). I now leave the door ajar (and yes it has the gaps under the door) which maintains the level nicely.

Moral of the story, measure your COÂ².

We cook, dry clothes indoors, aim for 50% RH indoors. Our VH sentinel+B natively has RH, aftermarket added CO2 feedback(recommend). It can get 50% RH, but weâ€™d need to target lower than that to appreciably drop CO2 lower (maybe 800ppm typical). The unit can easily strip all the moisture out of the air if it tries! Many offices in my experience get lower CO2 than that, but are very low RH in winter - ok for a bit, but people eventually get itchy skin, and pick up infections.

Measuring RH and CO2 is a first step for anyone interested in air quality - very few people recognise either issue.

Whole House Air Filtration System

Simon Still — Mon, 06 Feb 2023 17:50:57 +0000

Posted By: Mike1
Posted By: djhWhy undersized - I'd have thought that was a recipe for a rapid failure and a lot of noise meanwhile?
If filtration is the only concern (as it appears to be), rather than providing a particular air change rate, a cheap unit permanently running on a low setting _may_ be adequate. It would probably depend on the level of filtration required, and what is giving rise to the need for filtration. Hence my question mark above.

How much money are you really going to save? You still need all the ducting and supply/extract hardware. You still need high quality fans. So the only saving would be the lack of a heat exchanger. But even in a leaky house you'd expect the heat exchanger to add some value to offset the cost of running the fans (vs running the fans without any heat exchange)

Whole House Air Filtration System

minisaurus — Thu, 16 Feb 2023 17:44:48 +0000

Posted By: borpin
Posted By: Dominic CooneyOur MVHR is set to quiet mode overnight
About a year ago, I started measuring COÂ² â€¦. Horrified at how high it got with the door closed

Moral of the story, measure your COÂ².

What is your definition of high?

Submarines use 3000 ppm I think

Whole House Air Filtration System

djh — Thu, 16 Feb 2023 18:00:38 +0000

https://www.kane.co.uk/knowledge-centre/what-are-safe-levels-of-co-and-co2-in-rooms

What are safe levels of CO2 in rooms?

250-400ppm Normal background concentration in outdoor ambient air

400-1,000ppm Concentrations typical of occupied indoor spaces with good air exchange

1,000-2,000ppm Complaints of drowsiness and poor air.

2,000-5,000 ppm Headaches, sleepiness and stagnant, stale, stuffy air. Poor concentration, loss of attention, increased heart rate and slight nausea may also be present.

5,000 Workplace exposure limit (as 8-hour TWA) in most jurisdictions.

>40,000 ppm Exposure may lead to serious oxygen deprivation resulting in permanent brain damage, coma, even death.