02:37PM | 04/24/99
My 72-year-old house has oil/steam heat which we intend to update and keep. I have heard that it is possible to add central air with an attic-mounted (presumably electric) unit moving air through flexible ducting (run between studs) leading to ceiling registers. Anyone ever heard of this method and will it work?


10:19AM | 06/01/99

Typically, the method you are describing is for multi-zone temperature control. To complete the picture, another unit would be mounted in the basement to supply the first floor, with the unit you mentioned in the attic for the second floor. This eliminates the need for running ducting between floors (and the associated cost for keeping it all hidden) as, presumably, all first floor rooms are easily accessible from the basement, and all second floor rooms from the attic.

This design may not necessarily save you money, but it does improve the comfort level as you can control each floor’s temperature separate from the other. You probably already have that ability with your hot-water heat.

Keep I mind that you will need ample electric supply lines to take on the 30+ amps the units will each need. If your home only has 100-amp main service, you will need to consider upgrading to 200 amp or live with blown fuses or tripped circuits.

You could save money by just putting central air for the second floor for now. Since cool air drops, the first floor will cool off somewhat as well.

Good luck


07:43PM | 06/01/99
I am a heating and air contractor in Utah... we do what you are describing several times a month. The reply prior to mine pretty much covers the nuts & bolts of it. FYI the last job we did similar to yours had 12 supply air runs and we charged about $3,400

Tony D

09:08AM | 06/09/99
Is this type of air conditioning best for old houses? I am told that there is a new type that uses tubes with refrigerant that lead to small room units. These tubes are supposedly easier to install and less intrusive. Has anyone ever heard of these?


07:55PM | 06/19/99
I have, but I believe the tubes are not filled with refrigerant, but coolant. If refrigerant, the tubes would have to be a hard material, such as copper, and be insulated. Running rigid copper tubes about the home would NOT necessarily be easier than ducting, and would be almost impossible to insulate. With a coolant, the tubes used are flexible polypropylene or similar material, so they can be routed with relative ease.

I have heard of two versions of this design.

In one, an outside chiller, similar to the typical outside unit a normal home may have, chills a liquid, similar to antifreeze in a car. This liquid is brought down to a very cold temperature, where it is circulated around to inside units which are simply radiators with fans … sort of the reverse of hot water heat. I guess the individual units can be zoned the same way. Although new to residential homes, this technology has been used in grocery stores and other businesses for years.

The other design utilizes a ground water source, similar to geothermal, which is pumped inside the home where different a/c units extract the heat in the rooms and pass it into the water.

Although I have never worked with either or even seen one, I would imagine, since it is new technology, that the cost would be more than more traditional systems, at least until the idea catches on and mass-production kicks in. If someone goes that way, I would like to see a posting about it. It would be very interesting.



Post a reply as Anonymous

Photo must be in JPG, GIF or PNG format and less than 5MB.


type the code from the image


Post_new_button or Login_button

Few projects are more fun than upcycling a vintage piece in a surprising way. Outfitted with a sink and a delicately tiled... Built on a rocky island in the Drina River, near the town of Bajina Basta, Serbia, this wooden house was cobbled together ... Large steel-framed windows flood the interior of this remodeled Michigan barn with daylight. The owners hired Northworks A... Edging formed with upside-down wine bottles is a refreshing change. Cleverly and artistically involving recycled materials... A Washington State couple called on BC&J Architects to transform their 400-square-foot boathouse into a hub for family bea... Similar to the elevated utensil concept, hanging your pots and pans from a ceiling-mounted rack keeps them nearby and easy... For windows, doors, and mirrors that could use a little definition, the Naples Etched Glass Border adds a decorative flora... The thyme growing between these stepping stones adds a heady fragrance to strolls along this lush, low-maintenance garden ... Decoupage is an easy way to add any paper design to your switch plate, whether it is wallpaper, scrapbook paper, book page... Twine lanterns add pops of crafty—but sophisticated—flair to any outdoor setting. Wrap glue-soaked twine around a balloon ... When securely fastened to a tree or the ceiling of a porch, a pallet and some cushioning make the ideal place to lounge. V... Reluctant to throw away any of those unidentified keys in your junk drawer? Hang them from a few chains attached to a simp... A stripped-down model, sans screened porch, starts out at $79,000. Add the porch, a heated floor for the bath, and all the... Salvaged boards in varying widths and colors make up the dramatic accent wall in this attic space. The high-gloss white of... This garden shed has been decked out to the nines. Designer Orla Kiely created the intimate home for a flower trade show, ...
Newsletter_icon Google_plus Facebook Twitter Pinterest Youtube Rss_icon