Sleepy eyes but too many people in the house sharing the same air conditioner would make you feel clumsy. Why not make the situation easy for everyone in the house by buying a new air conditioner? If you have this plan, then it should not take much time for you to surf online and list down the best models. When none of the models seem to be matching with your budget or else matching with your requirement, then do not worry, the shanco heating and air product range would definitely make you feel comfortable as the selection would be done in minutes.
The product range would be addressing every question you have about the distance that the air conditioner would cover and the duration for which the appliance would work without generating overheat. Of course, the sound is one aspect which you may not like with the appliances that you already have at your home. There are two solutions of which you could choose the one best fits your financial situations. Call for a service person and get the existing appliance serviced and the second is to buy a new appliance altogether. When you prefer second option the only advice is not to be strict about following the budget. You should and must be ready to spend a little extra if you feel like the next model would last long and is also the model that fits the needs of future generation.
Having said this, reading the details about the various air conditioners would give me a better clarity about which model to pick for your personal use. Do not mess up with the product range that is for commercial use. Buying on the credit system would always give you ample time to repay off for the appliance while it is in use.