window units and fans. Cheapest by far.

There are several types of air-conditioners on the market. Trane, Mitsubishi, for two. They are located outside the house and a vent coming into the house carries the cold air. It has to be located in a spot where it does the most good of course.

Call Mitsubishi, they make a good unit.

My son has a house with no ducts, he went with a unit which looks like a dehumidifier only larger. You set it in the area you want to cool and you can run a small flexible duct to a window to expel the hot air, humidity and noise to the outside. This is very quick and easy to install. He used it this way the first year and then set it in a different location and permanently installed a duct similar to a dryer vent( thru thre wall). Works great. Do not know the brand, but he did buy it off ebay, I have seen them at the local farm supply. This requires no hook up of line set or charging, very simple fast installation.

Small window air conditioners say, 5000 – 5500 BTU in conjunction with pedistal fans work very well. I was surprised just how effective this is. I can cool about 1500 sq. ft. with 2 AC’S and 2 fans and the best part of it is, the AC’s were about $89.00 each. Good luck!

the mr slims are the best way to go they are split systems. Be sure to buy a heat pump not just a ac. because you will spend the same and the unit will heat and cool the space. the only thing run into the house is power needed for both units indoor/outdoor and the line set (pipe) and a drain line for the indoor unit.

if like me you heat with oil it is nice to heat with electric when electric is cheaper. you will have a choice of heating and if the burner goes out you have a back up heating system. This is how the industry is going.

You may want to invest in some window air conditioners for a couple of rooms. 10,000 BTU’s or higher. Most will cool a whole room off depending on the size of the room and the BTU’s you get. That’s the cheap way I think. Since you don’t have ducts. Good luck.

Fans next to windows will definitely help. Without ducts, not much you can do. Best of luck!