Updating a 20yr gas furnace to new, how much improvement?

CC

Thank you Chuckles, you answered my question. I think it makes sense to wait to replace the gas fired Carrier forced air furnace until it is necessary, not optional.

I didn't realize the forum was for steam and hydronic only. I saw info here on electric radiant heat (that's how I found the site). I definately do want to install an electric radiant heat system in kitchen and utility areas when we upgrade and replace the flooring. We are leaning towards wood, 2nd choice would be tile. Currently vinyl. This system would be just to warm the floor a bit and supplement the forced air.

CC

Upgrading a 20 gas furnace to new, how much improvement?

We have a 20yr old ranch style home over a basement with the original forced air (natural gas) furnace system. The home is well insulated and has triple E vinyl clad windows. The A/C unit is new and the furnace is working well and has been regularly serviced. It has to be getting close to the end of it's service life.

We expect to live in the house for at least 5yrs. How much of an improvement, percentage wise, can we expect to receive if we replace now with the latest technology in high efficency systems instead of waiting for it to fail? What drives the decision to replace vs. continue to service as needed? Given a more efficient system, would we save enough and with the increase in home value with a new system would we recover the investment? We are also thinking of supplimenting the forced air system with radiant electric heat in the kitchen and utility areas when we replace the flooring, we are leaning towards wood.

John Ketterman

First, I know it is hard to tell from the forum title, but the discussions in this forum are predominatly about hot water and steam heat, not electric or forced-air heat.

Second, you are asking questions that no one can answer, even in the appropriate forum. We have no idea what you have and what you are going to replace it with. All you have told us is how old your current furnace is.

Speaking generally, a well-maintained furnace should last a lot longer than 20 years. My experience is that you will save only about 20% replacing an old oversized furnace that is working well with a modern condensing (90%) furnace of he right size. That is a 20% saving not in dollars but in fuel used given identical weather; the dollar savings will vary hugely depending on the price of fuel and how cold the winter is.

You can still roughly estimate dollar savings at 20% and see if it is worthwhile to you to spend the money it will cost for a new furnace. As for resale value, forget it, it makes almost no difference.

Craig Bergman

I disagree...

Two homes, about the same value, in the same neighborhood. One has a 20 year old 78% efficient(on a GOOD day) furnace. The other has a 5 year old 90%+ efficient furnace. Which home do you think will be more attractive to buyers?

My 2 cents

Bergy

John Starcher_4

CC.....

...while this forum is primarily geared toward "wet" heat, there are professionals participating here who are extremely skilled in forced air, plumbing, electrical, pumps, and even appliances.

Never ever be afraid or hesitant to ask a question, regardless of the topic. If the answer is not here, most likely someone will direct you to a more suitable forum.

Starch

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Brian_24

The whole picture

There is more to your forced air system than the furnace. I don't care what brand you install if the duct system is poor you will be disapointed with your investment. Newer furnaces need to move more cfm per btu to realize the effiency gain. If you install your new box on a leaky under sized duct your comfort and energy cost will suffer. JMHO
airhead

jim lockard

The one

with the granite counter tops and childrens swing set that conveys. Most buyers could care least whats in the basement as long as it works. My two cents. J.Lockard

CC

>>Newer furnaces need to move more cfm per btu to realize the effiency gain. If you install your new box on a leaky under sized duct your comfort and energy cost will suffer. JMHO airhead<<

How can you tell whether your ducts will handle your new furnace to take advantage of efficiency gains? The furnace I have was considered High Efficiency back in the day, (1986). Vents out the back of the house thru PVC pipe. The ducts seem to be laid out in an efficient and logical way and there are no leaks.

One other question; does it make sense to leave the vents open in the basement? Our basement is unfinished and is not presently used for living space. I figure that leaving the vents open makes sense since heat rises and will warm the upstairs floor a bit. Also the basement never really gets cold and whatever heat loss there is, I think I gain upstairs. The whole house thermostat is on the main floor, (ranch). The attic is heavily insulated, no loss of or melting of snow on the roof. We keep it at 68 and it is very comfortable.

Brian_24

Duct testing

First thing you need to check is total external static pressure. This will tell you right away if your system is properly sized. Also some testing with a flow hood will detirmine how tight your system is. Depending on total statis I may close the basement runs. If the system is not sealed with mastic it probably is leaking more than enough to cover the basement losses. Thanks for asking. For more info checkout www.nationalcomfortinstitute.com
Brian

Jim Davis_3

Brian is correct when it comes to the duct system because it can cost you 10%-20% alone. Your old furnace if it vents with plastic is comparable to most new furnaces already. Other than buying a furnace with DC motors, variable speed, that can save $200-$300 dollars a year in electricity you may not see any saving in gas.

Craig Bergman

Jim

In my neck of the woods, what's in the basement does matter. A survey of local Realitors has shown it to be one of the top 5 questions and concerns.

Bergy

jim lockard

Bergy- Point taken

But most homes need heating systems, and roofs and other minor details, which are expected by the purchasers to be in "good working order". A new roof or furnace does not add value to a home but a leaking roof or a wet basement or a worn out furnace will take away from both the buyers desire and your sales price. Best Wishes J.Lockard