Air-conditioner two circuits to choose from

Hi there
I'm wanting to purchase an air-conditioner for a property that I rent. The house runs 240 volts. I'd like to purchase a portable or window/based
air-conditioner
There are two electrical circuits that I may be able to install the air-conditioner to.
One circuit runs the lounge and kitchen. Another runs to three bedrooms.
---On the lounge/kitchen circuit we run:---
Microwave 1.3kW 5.5A output 650 watts Fridge Input145w Defrost Input 150w - small, only 284 litres Laptop - approximately 40-60 watts PC - Pentium 4 3Ghz with 17" LCD screen - not running games TV - 180watts 74cm, 29" CRT VCR DVD 2x lights at 7watts
---The other circuit runs a mid-size 19"? CRT TV and some alarm clocks.---
I *really* would like to run the air-con in the lounge but I think I'll overload the circuit.
The other option is to run the air-con in the bedroom with the laptop. (Put the laptop on a UPS to protect the hard drive from the air-con off/on surges)
Moving isn't an option right now. $700 on a new power board for the rented house isn't a pleasing thought.
Is it possible for me to put air-con in this house? Are there any soft-start devices/air-conditioners that could help the situation? And what of a UPS?
Many, many, thanks to anyone who can answer this.
Darren
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What country? What final circuit arrangement?
Most portable and some window based units are pretty useless, because they draw air from the house to cool the condensor, so they are causing outdoor air to be sucked into the house, largely overpowering the aircon.
To be effective, they have to use outdoor air to cool the condensor, which means either a split unit with indoor and outdoor sections, or a combined unit with completely separate air paths which means it will have separate inlet and outlet air ducts outdoors, and not just an outlet.
--
Andrew Gabriel
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I'm in Australia.
I've used wall/window mounted air-con's in other homes with great effectiveness, so I guess they must have had a separate inlet and outlet duct.
I really just want to walk into a shop and buy a 10amp unit, whether it's window based or portable and know that I'm not going to blow up anything on the same circuit. I believe one portable model, (portable is less desireable), was approximately 1200 watts input power. It claimed up to 14,000 btu's.
Split-air is great but I'm not keen on this type of installation as it would cost $600+ AUD in installation costs, plus another $700 for a replacement circuit board, and the unit will have to remain with the home.
Final circuit, I'm too ignorant on this topic to know what you mean at this point, I'm sorry. The until will be 10 amp maximum, so I guess 2400 watts max?, plugged into a standard household power-point. The circuit breaker is 15 amps on those circuits I believe.
I can see from typing this email that I have quite a lot more research to do.
Thank you for your time and reply Andrew.
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Wall and window units normally have some sort of divider that separates the indoor (evaporator) and outdoor (condenser) air paths, with separate fans (possibly driven by the same fan motor) for each. So they're OK.
The problem that the previous poster was talking about is portable units where the whole thing is inside the house, rolling around on wheels. Some of these have two ducts connected to a window, so their condenser air both comes from outdoors and is exhausted outdoors (which is good). But some draw *indoor* air to cool the condenser, and have only one hose to exhaust it outdoors. Those ones draw hot humid outdoor air into the house via air leaks, removing much of the benefit of the unit.
    Dave
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Thanks Dave
That'll help me with choosing an indoor unit if it comes to that.
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Darren wrote:

Ideally you should install a dedicated circuit, but if you need to use what you have it should be the bedroom circuit. You are more likely to trip the breaker on the kitchen circuit with the microwave and refrigerator.
--
Benjamin D Miller, PE
www.bmillerengineering.com
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Thanks Ben, (and to Roy)
I'll need to install the unit on the bedroom circuit then.
(The owner simply will not pay any monies directly, nor indirectly to the air-con or any other house project, so I'm unwilling to spend too much towards the infrastructure of the house.)
I was wondering if I can safely use my laptop on the same circuit as the air-con, (if I use a suitable UPS/or 'soft start' device that I've heard of, as well)? Also, another thought is, could I use a 5 metre extension cord to run the laptop, with the laptop power coming from the other circuit?
Does any of this sound feasible folks?
Many thanks
Darren

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