I'm about to get the A/C installed in my new apartment, and was wondering which of the following two situations would be more efficient:
(a) Cooling 2 rooms on a single A/C compressor (same system)
or
(b) Cooling 2 rooms on their own separate A/C compressors (different systems)
*both of these rooms are likely to have the A/C on at the same time, and are likely to run through most of the same times of the day (say, 11am – 8pm)
Some background:
My new apartment has 3 bedrooms, a living room and a dining room that I would like to have air conditioning in. Each of these rooms will be fitted with an air-conditioning blower, and I can have up to a maximum of 2 A/C compressors on the outdoor ledge meant for that.
Two of the bedrooms will be converted into our 'offices' – a computer workspace for me, and a piano room for my wife. Both of these rooms will likely need to be air-conditioned throughout the daytime, but will likely be turned off at night.
In the other areas, ie. our master bedroom, living and dining areas, I think we are more likely to use the fan since we won't be there much while it's hot in the daytime. However, we'd still want to have air-conditioning available since it can get insanely hot in some parts of the year (even at night) here.
Our current plan is to have two A/C compressors, one for 3 blowers, and one for 2 blowers. Should we have both 'offices' on one compressor so that in the daytime only that compressor is used? Or should we go for having them on separate compressors so that both compressors are used in the daytime, but are each at a lower load.
I think our main concern is the energy consumption of either option, since electricity costs are pretty high here. I understand that from a reliability standpoint, having our offices on separate systems might be good, but I think we can deal with that, especially since air-con servicing here is pretty easily available.
Best Answer
I would install a split system with a single compressor. A mini split system is very efficient and is designed to supply cooling seperatly where needed the compressor condenser units only run at the speed needed to supply the load on the units I have installed. Electricity is expensive but a 2nd compressor will end up costing significanty more compared to 1 compressor with 2 evaporators (or more) because with 2 you now need 2 disconnects and the extra wiring since they will be in the same location. The only time I would suggest to have 2 compressors is when the home is large and the pressure and suction lines to the evaporators get long in this case it can be cheaper to have units located on opposite sides of the home reducing the line set length. But since the compressors will be located in the same location I would go with a single sized for the evaporators you need.