Air to Air with hot water systems

graememk

https://www.boards.ie/discussion/comment/121506672#Comment_121506672

Oh yeah, but I bet who I replied to was chatting about an a2w, due to condensation on the tile.

Yeah, A2a are generally sold as air conditioning.

bilasy

https://www.boards.ie/discussion/comment/121506632#Comment_121506632

Thanks ,And any special settings the plumber needs to do while installing? Or I can just change the settings manually during summer ?

bilasy

https://www.boards.ie/discussion/comment/121506632#Comment_121506632

Sorry if you find that basic but how would I know what’s the dew point?

The devils

Screenshot_20231221-200108_ONECTA - Daikin.jpg

Hi guys this my usage for my a2a.

I really do love it - great in the summer. It's on most days (as I have solar panels like some other people in the chat.

The winter months imo is v good..heats kitchen / dining and 35 Square m extension. No gas on anymore in the morning.

Upstairs has its own unit which feeds landing area (which is small) and 2 largish bedrooms.

Example had unit on upstairs for about an hour and temp currently 20.3 from 17.7 degrees in both rooms.

I'll take pics if anyone wants of outdoor units and or indoor 🙂

suvigirl

Are these air to air systems the same as air to water, as in, do they need highly insulted houses with a high BER?

The devils

https://www.boards.ie/discussion/comment/121471717#Comment_121471717

Dc999

Sorry for delay

Still have gas central heating and stove fire.

Gas is a fail back system (I do use gas for various reasons, you know yourself) not rushing to get rid just yet.

TBH i wanted cooling in the summer and my daughter suffers with hayfever etc..so my daikin are doing a good job on her symptoms.

Having it heating in the winter is also very convenient for when I'm not there and my kids are due home from school - it's quick to heat area and also not noisy at all. Has a silent mode , which is great when watching TV and is also great for nighttime

Chat soon

graememk

https://www.boards.ie/discussion/comment/121524269#Comment_121524269

No heatpumps need a highly insulated house. a2W does need to be designed properly though, eg radiator size to be efficient.

A2A is a bit more flexible in that aspect, and can easily do cooling too. (You may have seen them in offices, hotels, shops already) at the cost of lower efficiency.

suvigirl

https://www.boards.ie/discussion/comment/121524307#Comment_121524307

Cool, so it could be a good replacement for an oil heating system?

I intend to put a stove in, and I don't like a really warm house, I border on slightly cooler........

graememk

https://www.boards.ie/discussion/comment/121524324#Comment_121524324

It really depends on your house.

Unless you put multiple indoor units throughout your house (there is a outdoor and indoor parts of it, one outdoor can drive many indoor units)

Also depends on the size of your house.

It could be complimentary to your oil, depending on how much your heating the house. And it still uses electricity, possibly the same running cost as oil unless you have solar and batteries.

suvigirl

https://www.boards.ie/discussion/comment/121524368#Comment_121524368

A small dormer bungalow? Could it work?

graememk

https://www.boards.ie/discussion/comment/121524379#Comment_121524379

Possibly, but it's not a magic bullet. It's still just a heating system. It possibly won't be any cheaper than oil.

Cheapest 24 hr rate is 33c, a2a has a nominal efficiency of 2.5-2.8

At 2.5, each kWh of heat is 13.2c

At 2.8 each kWh of heat is 11.7c

Oil is about €1.10 per litre

If you have a old boiler, will be about 70% efficient, new one 90%+, 10 kWh raw

70% each kWh of heat is 15c

90% each kWh of heat is 12c.

How much oil do you usually use?

suvigirl

https://www.boards.ie/discussion/comment/121524481#Comment_121524481

Thanks for that, I don't know cos I have only bought the house, will be moving in in January. I guess the best thing is to see how i get on for a few months. I just want the cheapest option to be honest!

DC999

https://www.boards.ie/discussion/comment/121524506#Comment_121524506

I'd suggest stay a season in the house and see. And track your energy usage so you can compare to alternatives.

unkel

https://www.boards.ie/discussion/comment/121524506#Comment_121524506

The cheapest depends very much on your heat and oil / gas rates as @graememk showed you with some sums. It is quite likely though that in the medium to long term, gas and oil will become relatively more expensive than electricity as we are transition from burning fossil fuels to zero emissions renewables.

graememk

I was going to suggest some sort of meter on your oil, so you could do some sort of measurement of how much per day you were actually using.

Unfortunately they are quite expensive (300+euro!). That buys a lot of oil or electric!

MicktheMan

https://www.boards.ie/discussion/comment/121524884#Comment_121524884

You can monitor oil usage quite easily and cheaply by hooking up an hour meter across the burner circuit. All you need to know is the burner consumption per hour to convert the hour meter data into litres of oil used.

I've had one hooked up for more than a decade and it has proven to be very accurate and cheap as chips to do.

graememk

https://www.boards.ie/discussion/comment/121526481#Comment_121526481

"All you need to know is how much it uses per hour" How do you find that out?

I presume your measuring just the burner only. Not the pumps/call for heat.

Do new oil boilers modulate down like gas can?

MicktheMan

https://www.boards.ie/discussion/comment/121526566#Comment_121526566

How do you find that out?

What I have done is initially guesstimate it based on nozzle size and oil pressure. I then cross reference every time I get a fill of oil to confirm flow rate (I always fill to brim full). I also insist on a like for like replacement of nozzle at servicing. I have found this method, while not 100%, is pretty accurate for my needs over the decade or so monitoring this way.

I presume your measuring just the burner only. Not the pumps/call for heat.

Yes, just across the burner circuit so that when the burner circuit is energised the hour meter counts.

Do new oil boilers modulate down like gas can?

I'm not aware of any on the market here. Obviously, this method of monitoring wouldn't work if modulation was happening.

davegilly

Looking at a buying a partially built new build - single story (very, very large attic area) with good insulation/air tightness in the ground floor. Attic will be a cold space for the moment until I can afford to insulate it as well.

Finished floor is already down (100mm insulation under it) bit no ufh was installed. To install UFH now (milled floor) along with A2W heat pump I'm looking at close to €28K. Rads a little lower at €24K.

Am now looking at A2A system instead but not sure if it's 100% suitable to heat a full house (approx 200m2 downstairs) Cold rooms anywhere are not an option (wife and teenagers in bedrooms) so it looks like I'll need either a ducted system (plenty of room in the attic for pipes etc) to every room or a split system with wall unit in all rooms (4 bedrooms, hall, bathroom, office and living/dining/kitchen) so looking like 8 indoor units minimum so this would mean at least 2 outdoor units? Any idea of the cost of this kind of system - even ballpark would do for the moment until I can get someone in to have a look and quote.

Does anyone have a similar system to this? I'd need to think about water heating as well as A2A won't heat this. Any advice or info appreciated. Thanks.

RetroEncabulator

Is there a particular reason why A2A is so dismissed in Ireland? It's quite common elsewhere? Just plumbing traditionalists or is there some specific reason for it?

unkel

https://www.boards.ie/discussion/comment/121545912#Comment_121545912

I'd say your theory of plumbing traditionalists hits the nail on the head.

It's consistent with what happened to me when I was looking into replacing our old gas boiler a bit over 10 years ago and I wanted a combi boiler. Basically get rid of the hot water cylinder and only heat water as and when you need it. Couldn't find a single plumber to even quote me for this. They simply didn't want to know. Although in other countries these combi boilers had been standard practise for many decades.

poker--addict

I have done a bit of research on this in the last 2 months and I remain unclear of why A2A is dismissed in Ireland, and the UK. I think there would be a humidity difference between general operation in Scandinavia versus here, but not sure how relevant that is.

There has to be more to it than traditional UK and Ire? Regs are forcing change in all aspects of home building, so it would seem odd that a2w was pushed if a2a was a solution. For retrofitting a2w makes sense as a push - given hardware already there. A2A could still be pushed for new builds. Is it just a case of not wanting us using energy in summer - hardly? ** actually a2a is indicated as an option on SEAI https://www.seai.ie/grants/home-energy-grants/heat-pump-systems/

poker--addict

I will add, as per the title perhaps - some people looking at a heat pump get hung up on their hot water tank....an immersion run at night on cheap electricity is not the end of the world if you are avoiding 1000s in installation costs....

JayBee66

https://www.boards.ie/discussion/comment/121544376#Comment_121544376

The well-known Waterford based installer of A2A has mentioned to me that they could install a ducted system. I'm not sure that I'd want all that ducting in the attic. Being a large bungalow that would mean a lot of ducting up there. I'd worry about dirt and trapped moisture too. I worry about everything. I suppose I'll go with a standard A2A install, when I finally pluck up the courage.

Daikin does an A2A system with water heating but I think they are the only manufacturer that does so. If you don't like Daikin then it's either an immersion heater, solar thermal (which I already have) or hot water cylinder with its own heat pump. I'll stick with solar thermal and immersion for the colder 6 months.

Muahahaha

https://www.boards.ie/discussion/comment/121524269#Comment_121524269

A lot depends on how low the BER on your new house is and how much air it is losing. If its losing lots of air then an air to air heat pump will have to work harder to replace it and thus end up costing you more money to run it.

I can only speak to my own situation with A2A, a quick summary

-Bought house 2018 with a D1 BER and spent a very cold winter in it with 3 very old storage heaters costing me a fortune to run, the heat was leaking out the 25 year old front door and windows

-2019 renovation removed the storage heaters and replaced with A2A heat pump to heat 40sqm open living space. Also dry lined a north facing kitchen wall that suffered condensation in winter. A2A heat pump installed cost me e1,800 at the time. Installer was a commercial refridgerent engineer who also installs A2A in residential homes on weekends and he supplied the Mitsubishi units. Install took him just under 4 hours.

-Direct comparison of bill was October/Nov 2018 my bill was 255, after the A2A install the following Oct/Nov the bill was 150 so a fair saving

-Following spring installed new triple glazed windows & front door. These made even more of a difference to the heating bill and now the living space is warm and retains the heat very well.

I dont know what my BER is now, maybe C2 or something. But for me the new windows, door matched with the air to air heat pump made for a warm space that is cheaper to heat than what I had before.

Before you do anything you should read the BER report on your new house. Also read the surveyors report as that will help too. If your BER is really low like a G or F then attic and wall insulation and new windows/doors are likely your priority, youd need to make your home more airtight before thinking of installing an A2A system.

Muahahaha

https://www.boards.ie/discussion/comment/121547539#Comment_121547539

Might be that the market demand is still towards radiators thus making air to water more attractive? It does also give the option of underfloor heating too.

Air to water with underfloor heating can be very expensive to retrofit so it makes more sense with new builds. If retrofitting then air to air would likely make more sense as it is an easy install and that doesnt involve dragging up floors for the underfloor heating and getting new radiators.

From your link they give a grant of up to 3,500 towards A2A systems. So it seems the SEAI are supporting it despite the potential extra electricity use of people using them as air conditioning in the summer. Id say it is negligible anyway, for me Ive used the air con function for about 10 day over each of the last two summers during the heatwaves we had and even then only for about two or max three hours a day. If for example its 28 degrees outside once I cool down the room to a comfortable 16 degrees I turn it off. Then maybe 3 hours later at 6pm the indoor temperature rises up to 24c and Id turn it on again for another 30 minutes to cool the room down to 16c again. Soon after that the sun is going down and you dont need it. I wouldnt have the air con humming along at 16c all day long as it doesnt need it and if you did your electricity bill in summer would likely look like a winter one.

suvigirl

https://www.boards.ie/discussion/comment/121550597#Comment_121550597

Thank you!

poker--addict

Do not have time/tools for self-install, but can a DIY job be done for air to air,aircon? And can anyone recommend anyone in the north east? I am thinking a Toshiba unit.

graememk

https://www.boards.ie/discussion/comment/121556642#Comment_121556642

All, if not nearly all need an F gas certified person to do the gas connections.

Plus they do have the gear to vacuum out the lines properly, even though the systems usually come prefilled.

davegilly

Can anyone recommend any Irish (Munster) based companies who specialise in Air to Air residential installations?

Thanks