Mix and Match Air con

[Donquick]

Hi All,

I'm in the plumbing and heating section, but I think it is the nearest for an Air Con question - so here goes.

I am refurbing a flat in Spain and I want to install a combined air con and heat system. I will use the two part units, being the fan unit outside and the inverter in the rooms (is this correct so far?). Having looked at the internet i can see that some fan units can drive a number of inverters and this would make sense as it would reduce the cost and wiring requirements and space used outside, maintenance, etc.

So the question is this, are there major compatibility issues between the fan unit and the inverters or can i mix and match. I have been offered a fan unit and two inverters by somebody, but i will need two more inverters to finish the job. Assuming that the fan unit is up to spec for 2 extra units, can i just buy these irrespective of make and model or do they have to be the same make as the fan unit. Could i buy a couple of ebay inverters of different makes to save some money, etc or will i run into trouble?

[Yes, i will be having a professional installation by the way.]

Hope this makes sense and thanks in advance for the help.

 

[Corgigrouch]

No, you can't.... Avoid multi splits, if one part goes down then they all go down

 

[Donquick]

Thanks for the answer, so I need to find a fully compatible system if i am going to do this. I gather from further reading that i cannot simply use a bigger outside unit and use several internal ones either - i need a bespoke multi outside fan for this function - is this correct?

I see your point about one down, all down, but I have a small terrace whihc the rooms are around and four separate units would just be too much and look really terrible.

In your opinion is it generally possible to only condition some of the flat. The rooms are really small and i am thinking about just haveing a unit in the main bedroom and one in the living area. This would leave a smaller bedroom and the third bed/office (really tiny) without anything.

Obviously, it goes without saying that there will be warm spots in the summer and cold spots in the winter, but does it generally matter. I know what it feel like if you don't have a radiator in a room becuase i am used to it living in the UK, but does air conditioning tend to work at all between rooms with doors open or would it stay really hot in the areas without the units.

I realise this is all very difficult to answer without seeing the place, but is is a small flat with a square footprint of around 80m2. Thanks again.

 

[Corgigrouch]

You do have several choices... You can either have a multisplit unit where you have one outdoor unit and several indoor units any of which can run independently.... They sound like a good idea but you will have up to four pairs of pipes running up your wall... Every time I've had an issue, it has been with multisplits and they really can be a pain to repair...I'd really encourage you to opt for several separate units

You can have a large unit feeding multiple units indoors but they will all run at the same time (These systems are designed to cool or heat large areas that need several units to give an even temperature) you could put them in different rooms but some rooms would be warmer or colder as there is only one control unit...The advantage is that you would have only two pipes running from your unit and tee to each independent indoor unit... but the length of each pipe has to be arranged carefully to avoid an imbalance in the refrigerant flow

Another option could be (If you have room in your loft) a ducted unit, you have the outdoor unit as usual but you have a large unit up in the loft or other such area... from this you can duct the air through insulated flexible air ducts to vents in your ceiling... most air terminals are adjustable so that the room temperature can be balanced on installation to achieve an even temperature... Though I suspect that the construction of your house would not allow ducting to the lower floor

 

[Donquick]

Thanks again. This is exactly the sort of thing that i need to know, I appreciate it. I am going to avoid the multi splits on your advice but i cannot put 4 units on the terrace. Can i trouble you with one last question please. It is the one about how many units to use, given the overall small size of the flat. It seems silly to have a separate unit for a room about 3m x 2.5m for example, but is this necessary for a full solution, or will the cooling and heating effect from neighbouring areas work to a reasonable extent?

If I put a unit in the main bedroom (3.5m x 6m including en suite), a unit in the second bedroom (4m x 3.5m) and a third in the kitchen / dining / living area (5m x 6m), I am guessing that the small office, bathroom and hallway will benefit sufficiently from the system to not feel a totally different temperature. I am thinking of a hotel room with AC - when you enter the bathroom you don't feel a sudden rise in temperature as a rule.

Is there are fag packet formula for unit power to floor area please. I know this is cheeky as I have no doubt that there is a complex set of calculations to get this absolutely right, but i am trying to cost my project at the moment and get an idea of system size.

Thanks again.

 

[Richardthe3rd]

Thanks again. This is exactly the sort of thing that i need to know, I appreciate it. I am going to avoid the multi splits on your advice but i cannot put 4 units on the terrace. Can i trouble you with one last question please. It is the one about how many units to use, given the overall small size of the flat. It seems silly to have a separate unit for a room about 3m x 2.5m for example, but is this necessary for a full solution, or will the cooling and heating effect from neighbouring areas work to a reasonable extent?

If I put a unit in the main bedroom (3.5m x 6m including en suite), a unit in the second bedroom (4m x 3.5m) and a third in the kitchen / dining / living area (5m x 6m), I am guessing that the small office, bathroom and hallway will benefit sufficiently from the system to not feel a totally different temperature. I am thinking of a hotel room with AC - when you enter the bathroom you don't feel a sudden rise in temperature as a rule.

Is there are fag packet formula for unit power to floor area please. I know this is cheeky as I have no doubt that there is a complex set of calculations to get this absolutely right, but i am trying to cost my project at the moment and get an idea of system size.

Thanks again.

I'd say 3 separate units maybe your best plan. I stayed in a large villa in Costa Del Sol & it had only two units. It also had a wee stove for the Winter months. Shop around, you maybe cheaper buying here & shipping them over??

As a rough rule of thump; it takes roughly the same KW to cool as heat.

Of course the location & shading will have a big effect also, if you have a large elevation facing South then that's good, but bad for winter heating in the rooms facing north. Again, with poor shading, the South elevation will take a lot of cooling in the Summer.

Here's a link;
http://www.coolequipment.co.uk/air-conditioning
HTH

PS Any chance of a free Busman's holiday & I'll install for you.........

 

[Donquick]

Hi Richard and thanks. I will budget for three independent units and just come to terms with the asthetic blight on the terrace. The website you linked to is very interesting as the prices are very keen - thanks.

As for busman's holiday - well I would be up for it, but I don't think you will get much from the arrangement. It is a flat in China town in the heart of Valencia City (which is not the usual relaxing holiday destination by any means) and at the moment there is no water, toilet, kitchen or half of the walls. So kind offer, but I don't think you would be very happy with the arrangement

Thanks again,

 

[Richardthe3rd]

Hi Richard and thanks. I will budget for three independent units and just come to terms with the asthetic blight on the terrace. The website you linked to is very interesting as the prices are very keen - thanks.

As for busman's holiday - well I would be up for it, but I don't think you will get much from the arrangement. It is a flat in China town in the heart of Valencia City (which is not the usual relaxing holiday destination by any means) and at the moment there is no water, toilet, kitchen or half of the walls. So kind offer, but I don't think you would be very happy with the arrangement

Thanks again,

OK worth a try.....

I do hope the economy has improved??!! It wasn't good the last time I was in Spain, such a shame lovely people......