Just got into a house with forced hot air system, which actually seems to work very well.

As we're cleaning the place up I would like to also replace the various inlet/outlet grills, clean out ducting, etc.

I was thinking that filters on the inlet sides of the air system would be a good idea, but none of the grills I've seen so far seem to have provisions for that. Is that not something typically done or is it just not mounted in the grill itself?

What sort of regular maintenance should be performed on the ducting system? Is it a good idea to pull it apart to clean it out inside?

Any specific insulation good for use on the ducting? Right now none of it is insulated, and there is quite a bit of duct work.

Thanks for any suggestions/tips.

Rule #1


Duct tape



Is NOT for ductwork



Aluminum Foil Tape does not burn and/or melt



They should outlaw "Duct Tape" or at least call it something different

[This message has been edited by ohioindy (edited 09-04-2009).]

are you talking about a system that uses a blower fan, or one of the older types that feed thru the ducting withOUT a fan to push it ?

What is the heat source? Electric, oil or gas. I had a heat pump when I was in NY with electric backup. Electric only = $$$.

There should be some sort of filter on the air handler..the big box in the basement or a filter on the cold air return.

We had forced air in our mobile home, when I first got married. The filters were in the blower's housing. The system was gas and heated up the house real quick. The ducts were under the house and heavily insulated. The system worked pretty good and wasn't too expensive to operate back then. My house now has a heat pump. It handles both heating and cooling. The only downside is that it is all electric. At least the electric rates aren't too bad here, compared to Connecticut.

quote Originally posted by ohioindy: Rule #1 Duct tape Is NOT for ductwork Aluminum Foil Tape does not burn and/or melt They should outlaw "Duct Tape" or at least call it something different

I'll keep that in mind if I put anything on the seams, I would have automatically grabbed Duct tape just because I thought that was its actual intended use. I think I may actually have some of the aluminum tape around.

quote Originally posted by rogergarrison: are you talking about a system that uses a blower fan, or one of the older types that feed thru the ducting withOUT a fan to push it ?

Actually, I'm not certain and will have to check. Going by the amount of air that it moves through the number of rooms its connected too I would assume it has a fan. The air flow is very good even in the farthest rooms from the heater.

quote Originally posted by Old Lar: What is the heat source? Electric, oil or gas. I had a heat pump when I was in NY with electric backup. Electric only = $$$. There should be some sort of filter on the air handler..the big box in the basement or a filter on the cold air return.

It is oil fired, I'll check down there for the filter system. I believe there are a couple inlet grates in the floor, is it normal for them not to be filtered as well? I would imagine that the inlet duct must fill with dust.

quote Originally posted by avengador1: We had forced air in our mobile home, when I first got married. The filters were in the blower's housing. The system was gas and heated up the house real quick. The ducts were under the house and heavily insulated. The system worked pretty good and wasn't too expensive to operate back then. My house now has a heat pump. It handles both heating and cooling. The only downside is that it is all electric. At least the electric rates aren't too bad here, compared to Connecticut.

These ducts aren't insulated at all yet, I will be going through and insulating them all. Hot water pipes as well, since they seem to be only half-heartedly insulated in only a few areas.

I know its not the most efficient system ever designed, I just want to keep it working at its best.

In a forced-air system, it is typical for there to be only one filter, mounted in the return air duct just before it enters the return air plenum in the furnace housing, or just before the fan intake; I've never seen a system with filters in each return air register.

Ducts are normally insulated only where they pass through unheated space (e.g. sub-floor crawl space or an unheated attic). The same rule applies to water pipes. (I personally believe in insulating hot water pipes anyway.) Round ducts can be insulated with fiberglass batts, wrapped around them and secured with duct tape; these batts usually have a plastic vapor barrier on the outside. Square or rectangular ducts can be insulated with either fiberglass batts or semi-rigid insulation panels cut to size and glued or taped in place.

Hint: Before applying aluminum tape (or duct tape) to duct joints, be sure and clean all the accumulated dust off first. Tape doesn't stick well to a 20 year accumulation of dust. Been there, done that.

[This message has been edited by Marvin McInnis (edited 09-05-2009).]

quote Originally posted by Marvin McInnis: In a forced-air system, it is typical for there to be only one filter, mounted in the return air duct just before it enters the return air plenum in the furnace housing, or just before the fan intake...

Second this.
Both houses that I've owned have been that way.
Find the furnace/air handler.
The filter will be there.

Oddest one I’ve seen is a filter installed in the return air intake at the unit, mounted in an attic. This was a newer house and the owner didn’t know there was a filter. Hadn’t been changed in years and finally the A/C iced up. Usually you don’t have to crawl up in the attic to replace a filter but some are in a duct-work tray close to the exchange unit located in a closet or garage.

[This message has been edited by spark1 (edited 09-05-2009).]

My house in Florida has the main filter in the (hot air) return, located in the ceiling, great needing a ladder to open up the screen to replace the filter. The one in the air handler is an oddball size and I cant find a filter that fits. The filter does get quit dirty after a few months and a good one costs ~$15.

That sounds like a filter I had in a rented office. The one that fit was 2" thick and if you tried to use a standard filter it would get crossways. The 2" ones have a larger outer dimension and fit snug in the swing down lid. Had to buy them by the case from a distributor, they weren't available in any regular store.

[This message has been edited by spark1 (edited 09-05-2009).]