which would use more electric?

central air on and off throughout the day and night (approx. 15 hours) or an AC wall unit in window on all of the time?

Re: which would use more electric?

One wall AC unit to cool the whole house would have to be massive. To cool the whole house, you're going to need several wall units. Are you planning on keeping the whole house cool with the wall/window units, or just one or two rooms?

How many square feet do you plan on cooling with the CAC and the wall units?

Re: which would use more electric?

sorry, I should have been more specific. it is for the apartment in our home downstairs. it is approx 800 sq ft. we have 2 seperate thermostats for each level of our home (hi ranch) but the one downstairs is on our side of the house. we are trying to save as much money as we can but the tenants are asking for the air on all of the time. we are thinking of putting in a wall unit in one of the windows. the floor plan of the apartment connects all in a circle.

Re: which would use more electric?

http://michaelbluejay.com/electricity/cooling.html

On this chart, a wall AC unit uses 900 watts of electricity an hour, while a 2.5 ton CAC unit uses 3500.

For a whole house, it's more efficient having the bigger CAC unit, since most houses would need 4 or 5 window AC units to cool the equivalent of a 2.5 ton CAC unit.

http://www.greenbuildingadvisor.com/blogs/dept/musings/window-mounted-air-conditioners-save-energy

It sounds like getting a windows AC for the apartment would be your best bet, energy-wise.

Re: which would use more electric?

thank you!