Gas and Oil Home Heating Furnaces - New ducts or old?

We live in a 1800 sq. ft. ranch with existing steel ducts. We will be replacing our furnace/AC soon and can't decide if we need new plastic ducts or should we keep our existing steel ducts. Our ducts are 30 yrs. old and have never been cleaned.

When you have your dealer over to do a bid and heat load/lost, the sould tell you if your duct work will be able to handle the new system.. Also, do you have A/C in the old system? Planning on adding one?

Stay with the metal one, cuz they have better air flow vs the flex stuff.


Check with the dealer who your getting bids from and see if they offer duct cleaning

I prefer sheet metal because of its strength and durability.But there is some good things about duct board and flex pipe. First thing is it is insulated.Second it is quieter than sheet metal,you dont hear the ticking and poping noise of metal due to expanson/contration.Its usualy cheaper because of quicker install. But on the other hand the bad things are is its all taped together. You will always be working on it because tape only lasts so long.Also it seems to pick up dust and dirt like a magnet.
In my opinion good old Pittsburg sheet metal is the best.

We will be installing a new heating and AC unit, though at the present we haven't decided if we should go with natural gas or heat pump. We have to decide soon since hot weather is coming and our present system is inoperative.

We have had 3 bids thus far, and prices have ranged from $3600 for a heat pump and no new ducts, to a top of the line natural gas system costing $8700. All 3 bidders say that to install flex duct will cost $700. more.

Our house is a 1800 sq. ft. ranch in Henderson, N.C., where we have some days below 20 degrees but not many.

Go over to www.warmair.net and there you can compare fuel costs for gas, oil and electric. All we put in now are heatpumps .If they say the duct size is ok stay with it the flex and duct board have a lot more drag on the air than the sheet metal duct.;) ED

Ed, you say that about all you install now are heat pumps. Why is that? Lower cost to install, cheaper to run, or is it that you live in an area that is relatively warm?

Did you go to that www and look at the fuel cost for where you are . That will say it all. Its fuel cost and that only. This is in Missouri so it does get cold as H. But the heat pump with electric will beat out LP and Oil.Hey for a long time most we sold was oil . then went over to LP. Then electric and now the heat pumps. Its all in the fuel cost for where you are .Its the cost to run. The cost of the heat pumps area little more than the cost of the AC but over all cost to put in or install the heat and A/C are about the same as the cost to install a heat pump. ;) ED