Inverter vs Fixed Speed

[Abe]

I have an order for a couple of 2.5Kw and 3.5 Kw wall splits
My question is:

Do I go for the inverter units which work our about £100.00 more expensive per unit than the fixed speed version.

Its a Domestic installation.

Plus points for the inverter are obviously running costs, start current, and less noise

But is the fixed speed unit any less superior to the inverter given that these are just babies, and any cost savings will be minimal

Ant thoughts appreciated

Abe

[LRAC]

Hi Abe
Go for the inverter systems the lights wont dim in the house when thay start up.

Kind regards
Lrac

[Karl Hofmann]

Inverter for me too. I have a fixed speed in my living room (Artcool mirror, please dont laugh) and i find it cycling on and off pretty tiresome. The temperature changes in the room are pretty wide too and I find inverters maintain a far more even temperature and take our varying weather in to in their stride. Why not price for both and explain the differences to the customer?

[frank]

Fixed speed compressors on air conditioning systems are becoming a thing of the past Abe.

Go for the inverter and you won't be dissapointed.

Oh -- and make sure you buy a D****N

[cool#9]

Hi
Inverter seems to be the best choice but... after sales service is more expensive, so i suggest maintenance contract to my customers with a bonus of two or three years guarantee (spare parts not included but at the lowest price only for daikin, hitachi, toshiba, mitsubishi electric) , they usually agree.
Sell an inverter as a flat tv!
rgds
cool#9

[electro]

If noise is a problem outside, double check the outdoor unit as a speed controller - I think that's the only feature my 2.5kW Mitsubishi MSZ-GA25VA lacks, the compressor is amazingly quiet, but its drowned out by the noise of the fan. I still regard it as quiet though, even if it could of been a bit better

[Professor]

I must say inverter driven, the incentive is to save our planet from wasting energy, if this saves money for the end user we should sell it with this in mind.

The noise reduction is also good news for the neighbours who should be taken into consideration. Remeber cheap costs more.

Regards, Professor

[monkey spanners]

Ive got one of each in my house, both panasonic. The inverter one you can hardly hear running, but the non inverter one makes the wall hum ever so slightly. I blame the installing engineer

[Slim R410a]

Fixed speed compressors on air conditioning systems are becoming a thing of the past Abe.

Go for the inverter and you won't be dissapointed.

Oh -- and make sure you buy a D****N

If you go for a D****n, you will have to go for an inverter as they dont do fixed speed in any splits/multi's anymore. They now do the C series wall mounts which are around £100 cheaper than normal D series, heat pump and energy label A.

[Electrocoolman]

Hi Abe,
Inverter units for me. Also these can be run from the 13A supply, and dont require a dedicated supply cct from the distribution board, thus your 100 ukl price just got less!

Adrian.

[Abe]

I had to make an executive decision and Ive specified ALL inverters. Six in all. 1 x 5 Kw, 1 x 3.5 Kw, and 4 x 2.5 Kw

I have also instructed Electrician to provide dedicated circuits for each one, so no cost savings spurring up to a ring main, but then a professional job in the offing.

The location is a high density residential area, so the lower noise aspects, and the modulation controls were obviously a big factor.

Thanks everyone for the input in assisting on this decision.

[Makeit go Right]

Suggest you quote for both options, and strongly urge the customer to take the inverter system, for the reasons given above.

That way, if a flyby-competitor puts in a non-inverter price, the customer will consider it appropriately, rather than just looking at the £60-120 saving they might make on the install (ignoring electrical run-cost and the other vitals).

[Electrocoolman]

Hi Abe,
Re read your original post and noticed its a domestic install. Have you gone for all individual units or Multisplits? The latter cuts down on outside units and could save on number of power ccts, need for a new dist board (if not enough spare ways) , and can make for a much neater install. Anyway just a thought.
Adrian.

[Abe]

I must admit my experience of multi splits is limited, and not much by way of info emanating from the Distributors.

From what I gather, these are basically 2 or more indoor units linked to one outdoor. There is some sort of branch unit from whence the pipework branches out to the various indoors.

Also is it true the outdoor has 2 compressors?

And. do the pipe runs have to be as the same for each branch, ie: What if one branch extends say 5 metres, and the other 10 metres.

Im thinking here unequal distribution of refrigerant to the various outdoors.

And finally, control. What if customer wishes to run only one outdoor, or maintain one aea at say 18: c and the other at 22C.

Is each location independent of each other??

Thx in advance

[Electrocoolman]

Hi Abe,
The modern inverter multisplit can have up to 4 indoor units connected to one outdoor unit which only has one compressor.
Each indoor unit runs independantly and can be of different duties, the duty of one indoor unit being limited by the duty rating of the indoor unit + the number of indoor units actually running + the total duty of the outdoor unit......I know thats a mouthful but a look at the manufacturers data will give you the various (variable) duties. Basically the total duty of the outdoor unit is shared by the indoor units that are running.

Note that all indoor units on a system can only run in the same mode - ie all heating or all cooling/drying (only one reversing valve), but the temperature setting of each is individually controlled (individual Electronic Exp Valves). Normally the first unit 'on' sets the mode for the system.

Each unit connects to the outdoor unit via its own pair of pipes, there are no distributors required. The pipes do not need to be the same length but there are restrictions on the max length of a pair of pipes and a max total length of the combined lengths. These are normally very generous and do not cause problems.

As there is only one outdoor unit (admittedly larger than a small split and also heavier) it is easier to site than four small units and there is only one supply. It also makes for a neater install. Also the outdoor unit can run with less than the full complement of indoor units connected which can offer an easy future upgrade (selling point!). (e.g. A 4 way unit will work with only 3 units connected - there often being very little cost difference between a 3 way and 4 way unit).

I have used units from Sanyo and also have just quoted for some Toshibas.

Looking at Thermofrosts price list for Toshiba it works out cheaper than individual systems as well:
eg outdoor unit for single 2.5kw = 530 list
outdoor for 2x 2.55 kw (size 18) = 870 list
outdoor for 3x 2.47 kw (size 26) = 1425 list
outdoor for 4x 1.98 kW (size 27)= 1750 list
(duties shown are size 10 indoor units when all run together)
Hope this helps, Adrian.

[Abe]

Thanks Adrian,

Thank you so much for the information. Its cleared the fog in my mind. Something I must now consider for future jobs.

And the costing makes a lot of sense as well. Appreciate your help

Thx
Abe