Difference in quotes

[marti110]

I am having my 25 year old oil furnace replaced with a new 95% efficient Natural gas furnace. I have had 2 estimates in the last week and there are big differences between the quotes and equipment recommendations.

Estimate 1 -- 95% efficient 70,000 BTU input furnace, all new duct work (because the contractor says my old 6" ductwork will not work)

Estiamte 2-- 95 % efficient 90,000 BTU input furnace, this contractor says my ductwork is fine but he says that 70000 BTUs is way undersized for my 1300 square ft home in norther ny.

I guess wht I am wondering is how can they be so different. From what I know (which is little compared to a proffesional) I don't want to over size or under size the furnace. The only thing I know about the ductwork is that it is 8 inch galvanized metal ductwork in good condition. Not sure why it would need to be replaced. The price is quite different but obviously the new duct work is contributing to the higher first quote. My biggest concern is getting the right size furnace for my home. The oil furnace in the house now is a 1000000 BTU input Oneida Royal furnace that was manufatcured in 1984. I did a little research and it is somewhere in the 60-65% efficiency range so if I go by that (100000x65% = 65000) the 70000 seems just right.

[davefr]

You better edit out the prices. It's against site rules and makes the moderators cranky.

Capacity is determined by a thorough analysis of your home using Manual J/D.

Did either of these contractors go thru a complete analysis. Anything less is simply guessing.

[marti110]

Sorry. I have edited out the pricing.

Both contractors claimed to have done the proper calculations but R values for the house are debatable. Is it possible that on the High BTU end, that contractor estimated my insulation values lower and that is the differednce. The house is 106 years old and through different remodels over the years, insulation has been added in some of the house but not all of the house.

I also did a manual J myself just to get an idea and based on the estimated R values I inputted (which were on the low end to be safe) the results were 66000 BTU output which is right around the 70000 BTU 95% furnaces output.

[jerryd_2008]

I am having my 25 year old oil furnace replaced with a new 95% efficient Natural gas furnace. I have had 2 estimates in the last week and there are big differences between the quotes and equipment recommendations.

Estimate 1 -- 95% efficient 70,000 BTU input furnace, all new duct work (because the contractor says my old 6" ductwork will not work)

Estiamte 2-- 95 % efficient 90,000 BTU input furnace, this contractor says my ductwork is fine but he says that 70000 BTUs is way undersized for my 1300 square ft home in norther ny.

I guess wht I am wondering is how can they be so different....

Just a HO. The pro's need to address the adequacy of the duct work. But obviously adding new duct work is going to add $$$$.

Did they show you the print outs of their calculations? They may be reluctant to give it to you before you sign due to the effort/cost and competitive advantage. Does a local utility provide an energy audit that includes blower door, infrared camera and Manual J calculation? My local electric co-op did one for $100 and I used it to compare to proposals.

Not suggesting lots of work or stringing along contractors, but I contacted at least 7 contractors with different brands for proposals. Most responded and did the Manual J or used the one I had. You will probably be surprised at the large swing in costs for the same or similar equipment. But the similar system will allow you to decide based on cost, total installation features and your feeling and research on the specific contractor.

[BaldLoonie]

90,000 BTU for 1300 sq ft house? Better have a BIG duct system as that puppy will want to move a lot of air to keep from overheating. We put that size furnace in homes twice that size and we get below zero each winter!

My house is 1000 sq ft. I can turn off high fire on my 2 stage and heat it easily on 38,000 BTU! Pretty well built though. Friend heated very well built 1600 sq ft house on 36K input.

If house really needs 90K, might be wise to reduce the loss rather than throw the big furnace at it.

[DanW13]

I agree, if your not in a hurry to replace what you currently have and time is on your side I would call your local untility company and ask them if they do a home energy audit on homes they serve, as mentioned most do today and some like mine did it for free and some do it for a minimal chage to cover there cost of the audit.

But there more than willing to run a audit because it not only benefits you, but them as well by cutting there cost by not hainv go t buy more energy to serve the general population and even if you had to pay $100 it would be money well spent IMO.

For your size home and based on my home which is a few hundred ft. larger than yours 1600 sq. ft. I heat my home with a 96% 70K BTU 3 stage furnace and runs most of the time in low fire (70%) of the time.

Call the contractors back and ask them about a manual D along with the manual J and ask future contractors if there willing to provide or run both manual j, D to size both your furnace and duct work. Keep going until you find one that will, I would also ask your neighbors, family, friends who they use(d) for there frunace/AC installations and do not forget to ask for reference's to call and ask for both past and present customers of there's on how well they have been served by him and what type of workmanship he performed. It's your money and make sure you find the right guy for the job and the one who you feel most comfortable with doing the work for you.

[marti110]

My local gas company offered to do the calcualtions as well but the soonest anyone can get out to do it this time of year is 2 months. Unfortunatley the oil furnace has failed and will have to be replaced soon. Winter is coming fast up here and I don't need to get caught without heat. I have just called a third local contractor that someone I work with recommended and they are coming out tonight to give me an estimate. I asked him on the phone about the calculations and he said he definaitly will do a manual J. I guess I will see what he comes up with tonight and let you know. Thanks for all of the input.

[beenthere]

Your oil furnace might only have a 65% AFUE. But in steady state it was probably between 75 and 80% efficient.

When it was 0° outside, did it run non stop, or did it cycle on and off.

Contractor 2 is claiming you need 65 BTU's per sq ft.
Thats a good reason to improve your homes insulation and infiltration. To reduce the heat loss.

[heaterman]

What is the size of the main trunk line and how many runs (takeoff branches) are there and what size pipe are they?

[marti110]

The third contractor came and did an estimate last night. He didn't give me a price but is supposed to let me know his quote today. He did however show me his manual J calculation and he came up with 61800 BTUs as an end result. He recommended a 70000 BTU 95% efficient 2 stage furnace. I looked over his calculation and he used an R value of 5 for my exterior walls and an R value of 1 for my single pane windows. I asked how he came up with those numbers and he said that 1 was the industry standard for single pane windows with single pane storm windows and that 5 may be a low estimate for the walls but we are unsure about insulation in some of the house and he didn't want to over-estimate and under size the furnace because of that. Over all he seems like the most knowledgable and at least I know he did the calcualtion but I still wonder about the values he used.

[DanW13]

Based on your Manual J and this contractors Manual J your not that far off with regards to the heat loss so even thought he was somewhat conservative in the numbers he used I think this might be your guy. I would go thru your house and see where you can make some improvement to the envelope to air seal and then re-run the numbers and see where you end up.

you can probably get it down to under 50K heat loss and then your furnace would run in low fire most if not all the time unless you get a hard freeze.

[bateslabel]

I live in NJ. You are colder where you are, but I have a hard time believing that for 1300 sq ft 70,000 btus is undersized.

[marti110]

-25 F is not uncommon in January and February. Also the house is 106 years old and there is minmal insulation in some parts of the house not to mention single pane windows. Obviously i need to improve the heat loss in the house but unfortunately the furnace in the house now will not last the winter so the furnace is my first priority. I am kinda in a bad spot. If I buy a smaller furnace because I know I am going to improve the heat loss; what do I do this winter before I can improve it.

Also to answer a few questions from earlier.

The oil furnace did not run non-stop on the coldest days. It would cycle on and off every 30-40 minutes. The Oil furnace I have now seemed to be just about right for the house. (95000 btu input Oneida Royal) The issue is that the heat exchanger is shot and replacing it on a 25 year old furnace doesn't make any sense.

As far as duct work.

The plenum is 19x19x36 with 5 branches coming off of it.

2 branches to either end of the house - 8" round duct about 15' each
1 branch to the bathroom in the corner of the house -- 8 " round duct about 12' long
1 branch to the center of the house - 8" round duct 5' long
1 branch to the upstairs hallway 8" round about 6' long then transitioned to 4"x10" sqare about 12' long

[DanW13]

IMO here's the real pickle your in, if you go with the furnace that is sized for your homes current conditions then if and when you do improve your hoes envelope that new furnace you buy now will be oversized by how much dependson the improvements you make to the house.

If you size the home for the improvements you plan to make then when there done your new equipment will be properly sized costing you less in the long run.

I would size it for the furutre improvments and seal off your windows with 3M window kits and insulate your attic to R-49 minimum and do alittle air sealing if and when you can afford it thru out the winter season.

You just happen to be in the pickle no one likes to be in :oops:

[snupytcb]

I am having my 25 year old oil furnace replaced with a new 95% efficient Natural gas furnace. I have had 2 estimates in the last week and there are big differences between the quotes and equipment recommendations.

Estimate 1 -- 95% efficient 70,000 BTU input furnace, all new duct work (because the contractor says my old 6" ductwork will not work)

Estiamte 2-- 95 % efficient 90,000 BTU input furnace, this contractor says my ductwork is fine but he says that 70000 BTUs is way undersized for my 1300 square ft home in norther ny.

I guess wht I am wondering is how can they be so different. From what I know (which is little compared to a proffesional) I don't want to over size or under size the furnace. The only thing I know about the ductwork is that it is 8 inch galvanized metal ductwork in good condition. Not sure why it would need to be replaced. The price is quite different but obviously the new duct work is contributing to the higher first quote. My biggest concern is getting the right size furnace for my home. The oil furnace in the house now is a 1000000 BTU input Oneida Royal furnace that was manufatcured in 1984. I did a little research and it is somewhere in the 60-65% efficiency range so if I go by that (100000x65% = 65000) the 70000 seems just right.

where in northern ny are you?

[beenthere]

Ask for a quote on a 2 stage 70,000 BTU.

[jerryd_2008]

Ask for a quote on a 2 stage 70,000 BTU.

As always, Beenthere has excellent advise. I'm sure he means 95%, 2 stage, VS and possibly even modulating. I would expect lots of added comfort compared to the old on/off oil burner with a significant lower heating bill due to efficiency and running at reduced capacity most of the time.


My local gas company offered to do the calcualtions as well but the soonest anyone can get out to do it this time of year is 2 months. Unfortunatley the oil furnace has failed and will have to be replaced soon. Winter is coming fast up here and I don't need to get caught without heat. ...

I would schedule that audit for any time they will come. Heating costs can get BIG in your environment. I was raised in cold/snow environment but -25 is seriously cold especially in an inefficient house. Do you have typical heating season costs that you are working to reduce? These provide the incentive for change.

Meanwhile why not do some self-help like heavy drapes, doors/door gaskets, caulking, topping off attic insulation with 6" or more cellulose say if it's inadequate. There are many low to medium cost tasks that either you can do or others will at a fairly reasonable cost. In you heating environment these changes can have a tremendous ROI on $$$ and time spent.

If you aren't sure about the kind of improvements that really work try digging around on the web site of a national energy consultant at: http://www.dougrye.com/index.html He has a video for ~$40. He even has his phone number at the bottom ot the web page and he does take many free calls. We listen to him ever Saturday morning on radio and have seen him in person a number of times. He's kind of a ham and his web site isn't the most professional I have seen but he is a licensed architect that has worked for decades in home energy efficiency, including programs with/for many electric co-ops and the Federal Government.

[egads]

where in northern ny are you?

Why do folks come on here asking climate related questions and either do not fill out their profile or do not reveal where they live?

[marti110]

I live in Gouverneur, NY 13642. About 40 miles from the Canadian border and if you check out our weather this winter, -25 is common for days at a time some years. There are even a few instances when we hit -35 and with a wind chill of -50-60.

Snupytcb, I see you are in Pulaski. We are not far from each other. I am sure you can attest to the cold and you can definitely relate to SNOW down there in the snow belt!

beenthere: Thank you for the advice. From what I gather reading other posts and threads, you are very knowledgable and I appreciate the advice. I talked to my contractor about an hour ago and he basically said the same thing. He is going to install a 95% 70000 BTU 2 stage furnace with a variable speed blower. His quote is below both of the other 2 I got estimates from and he comes highly recommended from other people who have dealt with him. The other thing I like is he scheduled the installation for next week which is almost unheard of in this area at this time of the year.

Thank you to everyone else that positively contributed to this thread as well.

As for why people come on here and don't reveal where they live and ask "climate related questions". I did reveal where I live: NORTHERN NEW YORK and also revealed the climate I live in. WHY DO PEOPLE COME ON HERE AND NOT READ ALL OF THE POSTS AND STILL FEEL FREE TO MAKE NEGATIVE COMMENTS?

[snupytcb]

I live in Gouverneur, NY 13642. About 40 miles from the Canadian border and if you check out our weather this winter, -25 is common for days at a time some years. There are even a few instances when we hit -35 and with a wind chill of -50-60.

Snupytcb, I see you are in Pulaski. We are not far from each other. I am sure you can attest to the cold and you can definitely relate to SNOW down there in the snow belt!

beenthere: Thank you for the advice. From what I gather reading other posts and threads, you are very knowledgable and I appreciate the advice. I talked to my contractor about an hour ago and he basically said the same thing. He is going to install a 95% 70000 BTU 2 stage furnace with a variable speed blower. His quote is below both of the other 2 I got estimates from and he comes highly recommended from other people who have dealt with him. The other thing I like is he scheduled the installation for next week which is almost unheard of in this area at this time of the year.

Thank you to everyone else that positively contributed to this thread as well.

As for why people come on here and don't reveal where they live and ask "climate related questions". I did reveal where I live: NORTHERN NEW YORK and also revealed the climate I live in. WHY DO PEOPLE COME ON HERE AND NOT READ ALL OF THE POSTS AND STILL FEEL FREE TO MAKE NEGATIVE COMMENTS?

it sure does get chilli around here. and shoveling snow in it is not much fun either. most of my work is around watertown, dexter area. pretty much north of adams. i try to stay out of parish in the winter because of the blinding snow. it won't be long now:eek2:. at least the fishing is good right now.

[jerryd_2008]

it sure does get chilli around here. and shoveling snow in it is not much fun either. most of my work is around watertown, dexter area. pretty much north of adams. i try to stay out of parish in the winter because of the blinding snow. ...

The -25 or lower is bad but your snow isn't terrible. Seems like Gouverneur, NY gets about 80" per winter. Now, Boonville, NY which is more direct East of Lake Ontario and in the prevailing winds averages about 228". That's closer to where I was raised on Lake Superior. The record back home was 355" in 1978-79 and 40 miles North they got 396" that winter. That's pretty serious for any place not in the mountains. I do remember Lake Superior freezing across to Canada several winters and being below zero average for the month of January.

[heaterman]

That's not an extended plenum system, more resembles an old style radial design. Sort of a predecessor of radial gravity system

[marti110]

Heaterman: Is that a bad thing that the duct work is designed like that?

Maybe that's why the first guy I had give me an estimate wanted to replace it all.