HVAC air circulation with open windows?

galvo_clare

Hi

Currently in the process of building a house (just before tender stage)
I want the best possible insulation although I'm using normal cavity walls.
I'm just wondering how essential a HVAC system is - the yokes that suck out stale air, clean it and recirculate it via a big machine in the attic.
I'm also wondering if you had one of these installed, is it possible, or a good idea to open a window while the system is in operation?

TIA

shane0007

galvo_clare wrote: »

Hi

Currently in the process of building a house (just before tender stage)
I want the best possible insulation although I'm using normal cavity walls.
I'm just wondering how essential a HVAC system is - the yokes that suck out stale air, clean it and recirculate it via a big machine in the attic.
I'm also wondering if you had one of these installed, is it possible, or a good idea to open a window while the system is in operation?

TIA

With HVAC systems your most important issues will be carbon monoxide poisoning and bacterial problems. I have not come across a HVAC system that is interlocked with a carbon monoxide alarm, so where warmer rooms are, the HVAC will generally be sourced its warm air from are generally kitchens and living rooms where the most source of carbon monoxide is produced. The colder rooms, i.e. bedrooms, will be the target of this warm air and potentially carbon monoxide could be pumped from those source rooms to the bedroom whilst you are sleeping.

Secondly, tests have proven that should the filter not be replaced, approx 20 million times more bacteria will be found on your home surfaces after 12 months than if a HVAC was not installed in the first instance.

I personally would not install one, but I would go with air tightness. Once air tightness was achieved, then I would install the required air vents with baffles to supply sufficient natural clean air from outside that are sized accordingly.

brophis

shane0007 wrote: »

galvo_clare wrote: »

Hi

Currently in the process of building a house (just before tender stage)
I want the best possible insulation although I'm using normal cavity walls.
I'm just wondering how essential a HVAC system is - the yokes that suck out stale air, clean it and recirculate it via a big machine in the attic.
I'm also wondering if you had one of these installed, is it possible, or a good idea to open a window while the system is in operation?

TIA

With HVAC systems your most important issues will be carbon monoxide poisoning and bacterial problems. I have not come across a HVAC system that is interlocked with a carbon monoxide alarm, so where warmer rooms are, the HVAC will generally be sourced its warm air from are generally kitchens and living rooms where the most source of carbon monoxide is produced. The colder rooms, i.e. bedrooms, will be the target of this warm air and potentially carbon monoxide could be pumped from those source rooms to the bedroom whilst you are sleeping.

Secondly, tests have proven that should the filter not be replaced, approx 20 million times more bacteria will be found on your home surfaces after 12 months than if a HVAC was not installed in the first instance.

I personally would not install one, but I would go with air tightness. Once air tightness was achieved, then I would install the required air vents with baffles to supply sufficient natural clean air from outside that are sized accordingly.

It's my understanding that a HRV system extracts warm air then heats the incoming filtered air but does not mix the outgoing with incoming. So you're getting fresh warmed filtered air in and out goes the carbon monoxide. Is that about right?