Air To Air - Anyone have it?

davegilly

Hi.

Building a new 180m2 bungalow in Kerry and looking into an A2A ducted system to every room. Has anyone here installed a similar system?

Would prefer not to use mini splits but would be open to this possibly if it worked well. Would love to see either installed in a new house and see how well they worked. Thanks

Calahonda52

whats the thinking, in the context of mech ventilation running side by side with a hot air system

Every room under positive pressure as u describes means you are actively pumping hot air out

davegilly

With MHRV you will always be pumping warm air out - it uses the recovered air to heat the air coming in.

This is a different system - A2A is essentially air conditioning which is used in commercial businesses the length and breadth of the country. It's popular in residential homes in the US/Australia and in Europe but not in Ireland for some reason. There is a load of info/installers in the UK also but little to no information here.

I'm just trying to weigh up all options - because something like A2W is the most popular doesn't mean it's the right system for everyone! The house is likely to be ICF so will be very air tight and insulated so not sure I need the expense of A2W to heat it.

Any advice appreciated.

Calahonda52

Well then go full passive and heat the house with a hairdryer

MacDanger

We considered A2A when building our new house (ICF also) last year, mainly for the option of having cooling available; didn't go with it in the end as we couldn't get talking to anyone with much knowledge about it other than the vendors so we decided it would be safer to go with A2W since there will be loads of people who are used to working with it if we ever have issues in the future

davegilly

https://www.boards.ie/discussion/comment/122721995#Comment_122721995

Yea, that seems to be the problem, nobody has any experience of it. How did the ICF build go for you? Who did you use? Was it just walls or the foundation and roof as well?

MacDanger

https://www.boards.ie/discussion/comment/122722335#Comment_122722335

ICF build went well overall, did a Kore passive foundation and the rest in ICF.

We used Thermohouse but we had one issue with the ICF during the build and they were absolutely zero help with it so while the product itself was good, the guys in the company were very poor so I couldn't recommend them overall. The builder said (afterwards) that they usually use Amick so they may be worth considering

ongarite

Check out the Renewables forum here. There is some good experience with users installing A2A and split air heat pumps in their homes.

mike_2009

I'm Building passive and going A2A for space heating. There's a good youtube video from channel "Tim & Kat's Green Walk" called "A tour of our air-to-air heat pump system - heating AND cooling" and there are a few adjacent videos about pros and cons. Worth a watch. Also "The EZ Puzzle" channel has "Air to Air (A2A) Toshiba heat pump - First full winter costs incl payback". Also very informative.

Thespoofer

I got it done. Just for context, old cottage which I refurbished.

External/internal insulation, new windows/doors, etc.

Was going to go the grant route initially, had an energy assessor in, then paid fir air tightness test. In the end tightness test came reasonably good ( 2019 standard) but not quite enough to qualify for grant.

In the end decided not throwing any more good money at more assessors/tests etc and paid to have it in.

Delighted with it. I know for a fact that alot of the houses with a2w and ufh during the Summer have their windows open ( too hot inside ). Us, we have everything closed and nice and chilled ( even at low setting ).

Also something I discovered by accident after a few years of having are tilt and turn windows. I never knew there was a third function in these ( besides the tilt or turn ) and its called micro venting. Basically a position you put the handle allows the window to open by few mm but still ' looks closed'. Works good to keep the house comfortable.

The house is not perfect but we're very happy with it. Never buying a bag of coal again.

Muahahaha

Have had A2A almost four years now. On the ground floor it replaced three 25 year old storage heaters with a single unit indoors and up at ceiling level. Works great and has lots of bells and whistles like producing cool air con on the days of the summer you really need it. Then also air purifying mode and it is a dehumidifier too. Wifi operability allows me to switch the heat on 15 minutes before arriving home which is handy to walk in to a warm house on demand.

The indoor and outdoor Mitsubishi units cost me €1300 and then the installer charged €500 back in 2020. Took him about 4 hours to install it, was very quick. He is a commercial refrigerant engineer who does A2A installs as nixers so he was reasonable in price. I know prices have gone up since then but the few A2A companies out there are quoting a lot more than what I paid. For retrofits it should be a lot cheaper solution than A2W because it is a lot less invasive but Ive heard of some big installation quotes in the region of €10k for a split system in a 3 bed semi. Eventually I'll get the upstairs of my house upgraded to air to air too, would expect to pay about €4k to do it with a unit in each of the 3 bedrooms.

Having had A2A for four years now it seems strange to me that it hasnt had more widespread adoption. The SEAI grants lean heavily towards A2W which is probably a big part of the reason.