Air to Air v.s. gas

Jane Blonde

Hi Guys,


Recently my Gloworm flexicom 15hx started giving the F22 error, my plumber replaced the valve in the hotpress but it's still gives a F22 error, just less frequently.
It's April now, come next October I've a feeling that the 10 year old boiler will pack up completely.


So I'm thinking of replacing it with an Air to Air heat pump which I believe is far more efficient.


But where would I start, I've no idea what these are only that they look like air conditioners.


Is this a good idea? What are the pros/cons or heat pumps compared to gas other than saving the world?

John.G

Hi Jane, Are you sure you mean Air to Air vs Air to Water?, Air to Air means that you blow hot air around your rooms to heat them whereas Air to Water uses hot water to heat your house.

Goto, Bords-Topics-Home&Garden-renewable Energies and you will get lots of info there.
Also have a look at this link.... https://www.boards.ie/vbulletin/showthread.php?p=105986396

Jane Blonde

I was thinking air to air as we have an electric shower, and I can replace the hot water for sinks with a simple pump like an electric shower.

But to be honest, I really don't know much about this. on your link I see a quote for of 2400 for a 3 bed house, then later in the post it links to Electric Ireland where the estimates are 8k to 12k.

Is an Air to Water a replacement for a gas boiler?

ercork

Hi Jane,

That was me writing in the post above. All the figures I quoted were for air to air. 8k to 12k would be for air to water. I've had my air to air for two winters now and I have to say I am very happy with it. I got it in as a replacement for electric heating (storage heaters mostly) and it's a huge improvement. Gas is not available in my estate and I did not fancy having an oil tank in my back garden (which already is too small) so the air to air heat pump was the best option. I went for a single indoor unit which hangs on the wall in my living room and blows out warm air. The downstairs of my house is mostly open plan so this works well here. The upstairs is heated by rising air from the downstairs - it's not as warm as the downstairs but I prefer it that way. I kept the two electric heaters on the walls in the bedrooms to give an extra bit of heat on the very cold days - these have had minimal usage so far.

If your house is larger or less open plan you might want to get two heat pumps installed - one to the front and one to the rear. Or else get a multi-split system where several indoor units run off a single outdoor unit. This increases the costs significantly as I outlined in the other post. In your situation, as you already have the infrasturcture installed (pipes, rads, etc.) you might be as well off to just get a new condensing gas boiler. I think these cost about 3-4k? You will have to weigh up the two options carefully - let me know if I can be of any help here.

Jane Blonde

Thanks Ercork,

Combi boilers are about a grand, your right, it's probably the easiest and cheapest to just replace it.

I'm trying to weigh up the pros/cons on this as I think it would be great to get away from gas.

A quick search on indoor air to air and I've found this unit, is this like yours?
https://www.elettronew.com/en/air-conditioners-samsung/air-conditioner-samsung-ar35-25-kw-9000btu-a-a-r32-25777.html?gclid=CjwKCAjwqJ_1BRBZEiwAv73uwMedciTa_w6A5c9_3Fh76nRXIdR-xcqk6x4C_75TAQAvrHB7C3AtQhoCduAQAvD_BwE

ercork

Yeah, that's exactly what mine looks like. It's incredibly cheap though. My unit is a Mitsubishi MSZLN35 - it has a 4kW output as opposed to 2.5kW in the one you linked to. Including installation and commissioning by a person qualified to handle refrigerant gases (this is required under regulations as the chemical in these units is a very potent greenhouse gas) it came to €1900. As far as I remember he was quoting a 3kW system for about €1700. All these systems have a wifi module which gives you fantastic control wherever you are.

If you could find a qualified person willing to install a couple of those cheaper systems you show in the link you could have a heating system installed for a little overr €1000. Although claiming against the warranty and getting support might be problematic. It's also a good idea to have someone who knows what they're talking about have a look at your house to see if the layout would be suitable.

Jane Blonde

So this is the one you have:
http://www.mitsubishielectric.com/products/airconditioning/ln/index.html

The Samsung equivalent is:
https://www.elettronew.com/en/air-conditioners-samsung/air-conditioner-samsung-ar35-35-kw-12000btu-a-a-r32-25778.html

It's not as pretty but it's half the price.

My thinking at the moment is that I could replace my gas boiler with a heat pump downstairs and electric rads upstairs for around 600 more than a boiler. and probably make up the cost difference in a couple of years.

I think that heat pumps are definitely the future, but I'm not sure they are the present just yet. But then again, I need to think about the planet too.

Thanks for all your help.

ercork

One other thing to look out for is the SCOP - the seasonal coefficient of performance. This is a measure of its efficiency, the higher the better. If the SCOP is 4 that means for each unit of electricity you use you get 4 units of heat (1 from the grid and 3 from the air if you want to think about it that way).

Best of luck if you go down that route - I'd say your biggest hurdle will be finding a qualified person to do the installation. The aircon/refrigerant companies would be your best bet.

Calahonda52

ercork wrote: »

....
If you could find a qualified person willing to install a couple of those cheaper systems you show in the link you could have a heating system installed for a little overr €1000. Although claiming against the warranty and getting support might be problematic. It's also a good idea to have someone who knows what they're talking about have a look at your house to see if the layout would be suitable.

Where does the 1000 come from?

Let's say the heating requirement in 28kW, before HW.
assuming a COP of 3 seasonal, that posts to 9 kW input.
You had 4 done for 1,900 so how will 9 be less than that.

Calahonda52

Jane Blonde wrote: »

....
My thinking at the moment is that I could replace my gas boiler with a heat pump downstairs and electric rads upstairs for around 600 more than a boiler. and probably make up the cost difference in a couple of years.

I think that heat pumps are definitely the future, but I'm not sure they are the present just yet. But then again, I need to think about the planet too.

Thanks for all your help.

Even on night rate, they still have a COP of 1 so the math does not stack.

Jane Blonde

Calahonda52 wrote: »

Even on night rate, they still have a COP of 1 so the math does not stack.

Thanks for this but can you explain why to a noobie?

ercork

Calahonda52 wrote: »

Where does the 1000 come from?

Let's say the heating requirement in 28kW, before HW.
assuming a COP of 3 seasonal, that posts to 9 kW input.
You had 4 done for 1,900 so how will 9 be less than that.

The €1000 was based on getting two of those Samsung systems in the OP's post plus several hundred for installation. I have no clue what the OP's heating requirements are so can't say if that would satisfy them - that is why I recommended having somebody knowledgeable survey the house first.

Out of curiosity, you mentioned a possible heating requirement of 28kW - would it really be as high as that? My HP only produces a max of 4kW and even at that I wouldn't expect it to be operating at full capacity most of the time. I'd guess it pumps out 2-3kW each hour. Granted, my house is very small (~65m2).

headtheball14

Hi Jane. I have an air to air heat pump. Situation similar to er cork . My experience wasn't as positive as theirs but overall for specific circumstances I would recommend it.
However in your case with existing gas connection and radiators in place it doesn't make any sense at all.

Your bills will be larger than gas heating and unless gas cost increases massively compared with electricity it will work out very expensive compared to a new boiler. If I had an option for gas that's what I would have gone for. Compared to storage heaters its slightly better but i got some whoppers of bills .

Jane Blonde

Thanks headtheball14, it's supposed to be much cheaper to run. Maybe its best to wait until it advances.

John.G

Here is a relatively simple Spreadsheet which will give you a good feel for savings, the big and only "unknown" is the SCOP, but 3.0 might be a reasonable assumption, if so, and you input the other known or easily obtained numbers, then that spreadsheet is 100% accurate!!.

0lddog

Jane Blonde wrote: »

Thanks headtheball14, it's supposed to be much cheaper to run. Maybe its best to wait until it advances.

I think it probably would

I posted about a house that I look after some time ago

https://www.boards.ie/vbulletin/showpost.php?p=110367807&postcount=20

This heating arrangement is very satisfactory

BUT

No natural gas was available and the house did not have a functional CH rad system - so an oil / gas boiler based system wasnt on


( be aware that there are some A2A units that are optimized for heating - useful COP down to quite low temperatures, fast system defrost times etc. etc. The Samsung unit that you found is primarily for cooling with the ability to do heating and so would not be a great choice if the main purpose is heating )

Jane Blonde

thanks John.G

dmboards

https://www.boards.ie/discussion/comment/113303138#Comment_113303138

Hi ercork

Wondering if you are still happy with A2A heat pump? Is the internal unit noisy and does it circulate dust around your room?

I think I read in another thread that you originally moved from storage heaters to electric rads (Lucht or ecovolt) but subsequently deciced to go with A2A pump (??)

I'm in the process of renovating a house that had storage heaters but unlike many people my house was warm all day so I was happy wiht them excepot for the cost. Downstairs is no open plan (50 sqm) and I the original plan to combine a Dimplex Quantum with two Luchts, and install PV solar with battery to help reduce costs in winter. But the quotes for a correctly sized solar system are well above 10k (and I woudln't get grant) which lead tme to start checking out A2A.

Any feedback much apreciated (eg did you need much new cabling for the outside unit)?

Thanks, DM