Robert11 wrote:
Hello:

Son just moved into a house that has gas, forced hot air heating (in New
England)
The ducts are also used for A/C system where the condenser is mounted
outside the house.

Realize this is a pretty general question, but nobody in family has ever
had this type of heating system befo

How often is it a "good idea" to hire a duct-cleaning company to come in
and clean out all the duct work ?

Can't know for sure, but it wouldn't
surprise me if it hasn't ever been done since the house was built 25 yrs
ago.

BTW: how do they do this ?

Thanks,
Bob



This is answered all the time in this newsgroup.
The answer is NEVER. My house is more than 25
years old and duct cleaning would be a total
waste. Save the money and change the filter every
3 months instead of the recommended 6 months or
so. if you are worried about mold, the most
likely place is the ac exchanger in the furnace
unit. Cleaning that is standard as part of
annual AC maintenance. Duct cleaning is basically
a scam based on fear of mold which is not normally
a consideration in home cold air returns (an
exception would be if water is leaking into the
duct system, in which case structure failure is a
greater consideration).