I have a 12' X 40' lap pool in an enclosed room attached to my house. The water is heated by a gas pool heater located outside. I control the humidity in the room with a humidistat and exhaust fan built in to one wall of the room. The air is the room is not heated, however, so it is impractical to use the pool during winter months.

I am considering having one of the house furnace ducts (one that I keep blocked off all the time) rerouted to the pool room, in attempt to heat the air so I can use the pool during the winter. The company who installed my new heating/air conditioning unit last year can do the work. The only negatives they came up with were that the cholorine may corrode the rerouted duct prematurely. They also said the air in the pool room may not get as warm as I would like, but had no other concerns.

I am concerned that I may damage my central heating/air unit. Is this possible, and is there anything else I should be worried about?

PRIME,

It sounds like your pool room is quite large and that you would like to utilize it in the winter but cannot until it is properly heated.

Depending on how large the one duct you had planned on moving is (6",8",etc), you may not have enough heated air supplied to the pool room to be comfortable enough to use it in the winter. As far as damaging you HVAC system with chlorine, it also depends on whether or not a return air duct will be added to the pool room. The chlorine should really only damage the duct and not your HVAC system if no return air duct is added.

Another thing to think about is whether or not you new furnace is properly sized for the pool room. If it was designed and installed for you home only and not the additional heat the pool room would require then it could have adverse effects the rest of your home's heating.

Depending on the anwsers to the above, I would suggest looking at a seperate system for just the pool room. I would possibly look into a ductless split system heat pump system. Mitsubishi makes a system called the "Mr. Slim" that would probably work well with you current situation. You can find more information on their website http://www.mrslim.com.
The ductless system requires no ductwork and provides both heating and air conditioning. This allows the temperature of the pool room to be controlled all year round, plus you won't have to actual heat or cool the room unless you want to use it.

If you change your current system's ductwork, you'll be heating and cooling the pool room regardless of whether or not you're actually using it.

Hope this helps.

I would add it's important to keep the pool area under negative pressure (exhaust more air than you bring in) to ensure that chlorine doesn't get in the house.

A Mr. Slim system would work very well here since it won't mix air with the rest of the house BUT ask your installing contractor to make sure the system is sent to a coatings company (such as MJC in Atlanta) to apply a protective coating over the copper and aluminum components before it is installed around a pool. Chlorine reacts with copper and aluminum which are found on all HVAC coils and the result is very short equipment life.