Heating & Cooling Experts

My wife & I are considering buying a century home, a 100 year old Victorian.
It’s quite a beautiful home but is heated with a boiler system, radiator’s in every room, no ductwork.

I’m a stickler for ice cold Central air conditioning, what options do we have without ducts to pipe in Central Air conditioning?

Would we have to resort to putting in window units in each of the rooms?
Your help/suggestions are appreciated.


One option involves using a ductless system, or rather systems. As you know, with window units, the unit contains all the components for providing cool air via the compressor and fan and they can be very noisy. An alternative is to install the compressor outside with the freon lines running to a built in wall air handling unit and they’re very quiet. The air handling unit cools the air exactly like a window unit less the built in compressor and associated noise.

One outside compressor can handle several inside air handling units and most installations require more than one out side compressor in order to serve the living areas.

Usually, in older homes, a conventional central a/c system with ducts can be utilized on the 1st floor with ducts installed in the basement/crawl space leading to the cool air supply vents located at the floors on the 1st floor. The problem concerns how to supply air to the upper level and the ductless system can be a solution. Naturally, it’s a little more costly than a conventional system but may be worth looking in to.

Thanks Derek,

That’s reassuring to know there is a viable option.
My wife loves the place and I had visions of me having to suffer in miserable heat during the summer.


I’ll second Derek’s suggestion. You’ll want to do research on “Ductless” or “Split System” Air conditioners. As he said, this is where the compressor is located somewhere outside the house and the individual freon lines are run to each room that you want cooled. These freon lines can be run outside the house so you won’t have to rip up the plaster walls quite as much. Each room would then have it’s own evaporator. This has the advantage of being much quieter (over a window unit) since all you’ll hear is the small evap fan and it’s, by definition, zoned so each room will be at whatever temperature you want it at. The downside is that the inside units are somewhat bulky, there’s different styles, but they look kind of like baseboard heaters mounted on your wall up near the ceiling.

They used a split system on “this old house” a few seasons ago. IIRC, there were two out door units feeding eight zones. In one case they installed to evaporator inside the ceiling. They also had two units in the kitchen/great room so the cook could have cooler air while the stove and ovens were in use.

Some of the units even have remote controls for adjusting fan speed and temperature.

I oversaw the installation of hundreds of split units. One additional nice thing about them is that you don’t have to install them near a window. In fact, you can put them up high on a wall or anywhere else they seem convenient. Some models also have heat strips, but that’s going to run your electric bill up.

This is an interesting thread. I was pondering what sort of system I could use if I went for the home expansion I’ve been planning, and this ductless system sounds like a good option. If I had, say, 4 ductless units, could I turn off/on individual units and save energy, if I was only in one part of the house?

Another option is to install a central air system that has really small ducts. They make them now so that the “ducts” are just thin pipes, which are much easier to install and make pretty.

Here’s one example. Note that I have no experience at all with this particular manufacturer and their system may be a piece of junk, or it may be great. I have no way of knowing.

One thing to watch out for with these systems is that the air in the pipes is at a much higher pressure than in a conventional duct system. If not installed properly, the change in pressure when the air comes out of the ducts and goes into the room can be quite noisy and annoying.

The advantage of this over a ductless system is cost. Air pipes are a lot cheaper than freon tubes. Everything is all in one central location, so you are also less likely to develop freon leaks and the like as the system ages. This is basically just a conventional central air system with a fancy blower on it.

Forgive me nit pick. Whats freon?

Refrigerant. In very basic, incredibly oversimplified layman’s terms. It’s what makes your AC (or fridge) cold.

When you turn on your AC and the compressor in your backyard kicks on. It’s compressing freon from a gas into a liquid. The freon then travels to the evaporator where it turns from a liquid back into a gas and gets cold (or absorbs heat). The same way a bottle of compressed air gets cold in your hand when you use it. It then goes back to the compressor and starts the cycle again.

This was done in my uncle’s old house, which also had only radiators for heat. The technicians were able to run ducts in various unnoticeable places, like inside closets on the first floor to reach rooms on the second floor, or up to the attic and down from there into rooms.

It was took longer and was more expensive, but it ended up working quite well. There is a bit of a ‘boom’ when the fan kicks in, so I think it uses a higher pressure blower. But they said that they adjusted pretty well – that doesn’t bother them any more. (Of course, the reason for installing this was because they live directly under an airport runway landing pattern. So their ability to ignore noises is pretty well developed!)

Look into this before looking at split A/C systems – those are usually even more expensive, and have more possible maintenance costs over the years.

I’m not sure this would be possible if all 4 units were connected to the same compressor nor am I aware if one compressor would be capable of handling 4 separate air handling units. Naturally, if you turn off the units connected to a single compressor and use only the units connected to another compressor, you would save energy.

The units we installed had one unit per compressor, but multiple units shouldn’t be a problem to operate independently. They all would have their own switching for the fans and their own evaporator coils, and the compressor would be designed to operate under a variable load. Here’s Sanyo’s home page. Note the multiple unit. These are heat pump units, which would likely be much more efficient than the radiated heat presently in the home.

SpacePak, Small Duct High Velocity Central Heating & A/C System