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Furnace and HP replacements

Posted by glockman45 (My Page) on
Sat, Feb 15, 14 at 9:30

Hello all,

I am in process of replacing (due to continued maintenance problems and costs of those) 2 systems. The first system is a Rheem 4 ton HP and 100,000BTU furnace (80%). This system is about 17 years old and is used for the bottom floor of a two story house with cathedral ceilings in certain rooms.

The second unit was an afterthought add-on by the previous owner, and is a 2-ton Goodman A/C unit with a 60,000Btu furnace. This system was used for the upstairs section of the house.

I know, and have known, that this system is inefficient and probably sized incorrectly. My understanding was the Rheem unit was intended to heat/cool the entire house but for whatever reason could not. These units were in place when I bought it. My wife and I have been waiting for the opportunity to replace/redo and that time is here.

The house is about 2300 square feet, of which the bottom floor with high ceilings makes up around 1500 square feet. The ductwork has been subjected to inspection by an independent construction contractor (family member), Trane rep, and Carrier rep. All have concluded that it was properly installed and in good working order.

I am going with a Trane system consisting of 2 HP's and 2 furnaces. I explored the Carrier single system for zoning, but my wife likes the idea of two systems for the security aspect that if one system goes out we have a second system. May not be optimal but I have to live with her.

So, I have been offered a 2-system setup as follows:
1st Floor: Trane 3 ton 15i with XV95 80,000BTU furnace
2nd Floor: Trane 2 ton 15i with XV95 60,000BTU furnace

The XV95's are provided at the same cost as the XR95, and the 15i is provided at dealer cost. They are also providing a Trane 803 thermostat at no cost. This price is only $1500 over a quote for XR13's and XR95's of the same specs.

The dealer has done Man J (I don't have the results yet), so these estimates are subject to change but still do not appear to be that far out of line.

I have two questions. First, how does the overall setup sound?
Second, I currently have a Honeywell 8000. Is this considered a 2-stage thermostat or should I push for another Trane 803?

I did post this on another forum but was looking for a second opinion.


Follow-Up Postings:

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RE: Furnace and HP replacements

My initial thought is you equipment is over sized. I don't see why a house 2300 sq. ft. house would need 140K BTUs for heating and 5 tons for cooling. You need to review the Manual J calculation report carefully and see if it makes sense to you.

Are you using propane or natural gas for your furnaces? If it is natural gas, then I don't see the need for having 95%+ efficiency furnaces with heat pumps. Post your gas and electric rates so a determination can be made if the heat pump can ever operate at a lower cost than the furnace.


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RE: Furnace and HP replacements

Thanks for your input mike_home. With regard to your comment on cooling, the Carrier dealer had recommended one 4ton system for the entire home, with a 100,000btu furnace.

As for the 95% efficiency, I don't know if Trane offers the 90% for the XV line; and based on what I had read I really want the variable speed furnace.

My rates are: 9.4cents per kWh for electricity and about .8332 per cubic foot for gas. I am in WV; we do experience the range of temperatures.

Also, the entry way ceiling (which includes the upstair portion) is 24 feet. The room next to it is the family room which has a 24 foot ceiling sloping down to a 14 foot ceiling. The rest of the ceilings are 9 feet. Additionally, one bedroom upstairs is located over the enclosed garage so it does take more to heat.

This post was edited by glockman45 on Sat, Feb 15, 14 at 10:20


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RE: Furnace and HP replacements

Perhaps, I missed it but what is your location?

And where will upstairs furnace be located?

I would like to see Mdl numbers of evap coils quoted?

Air filter cabinets included? New refrig linesets?

IMO


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RE: Furnace and HP replacements

tiger dunes,
I am in Southern WV, and both furnaces are located in a crawlspace under the house. It is unfinished but insulated, and ranges in height from about 4ft to 8 ft (sloped). They are including air filter cabinets with 4 or 5" filters--I can't remember and it isn't listed on the quote. Didn't ask about the new line sets.

As for the model numbers, they aren't listed on my paperwork either.

This post was edited by glockman45 on Sat, Feb 15, 14 at 11:54


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RE: Furnace and HP replacements

I am in complete agreement that you should buy the highest efficiency variable speed furnace your budget allows. I personally don't think you need to spend the extra money on heat pumps. Your electric rates are half of what I pay in NJ, while your gas rate is about the same. I question whether is worth investing in two heat pumps.

You could combine your two duct work systems and create two zones with one furnace and AC condenser. My vote would be to keep the two HVAC systems separate and buy smaller equipment. It will operate more efficiently and last longer. This is what I have observed with the first and second floor systems in my house.

The high ceiling on the first floor do not have a big effect on the load calculation. This is where you get to challenge the contractor's Manual J calculation. He may have done the calculation but then added a fudge factor for "high ceilings".

A high ceiling is a problem in winter because all the warm air wants to rise up. Ceiling fans and returns mounted at the highest point help circulate the air flow.

Post the model numbers and prices of the quotes you are considering. Don't shop by price alone. The installation and sizing are very important.


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RE: Furnace and HP replacements

mike_home I am sorry I don't have the model numbers (yet). I also agree on shopping by price; I am paying more for the Trane contractor than for the Carrier one--all other things being equal--because I believe (and have researched his work) that he and his techs are the most capable in my area.

As far as the prices, the quote I received is for the equipment listed above, 2 media filters and any small repairs to ductwork or lines not readily apparent. It comes in right at $16K. However, the 15i's would be at cost, and this price includes the 3 and 2 ton units. Obviously, if I go downward in size the price would accordingly. Further, as mentioned he is including at least 1 of the Trane 803 thermostats, and volunteered the Man J to be sure on the sizing.

I may be way off base, and understand that all companies have good and bad employees, but I am willing to pay more for what I believe to be a more capable contractor. Honestly, if this guy sold Carrier or Rheem I would still put my business with him.


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RE: Furnace and HP replacements

You don't have a valid quote until you are given the model numbers of all equipment. Therefore it is difficult to comment whether the prices are fair or not.

It may be true the Trane contractor is very good, but quoting prices without basic model information is often not a good sign. Keep us posted how this plays out.


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RE: Furnace and HP replacements

Glockman

I assume the nat gas price you listed is for a therm, not a cu ft. With that being the case. Here is a fuel comparison calculation.

Cost per 100,000 btu of useable heat
Electric baseboard: $2.48
Heat pump: $1.00
Natural gas: $.85

I would forget the HPs as well and go straight AC condenser.

My personal choice on thermostats is HW VP IAQ.

If not that, then Trane's 803 or identical HW MDl 8321.

You do need a properly performed Man J for each zone.

Both Carrier and Rheem are solid brands to consider.

I would get those evap coil Mdl numbers.

IMO


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RE: Furnace and HP replacements

Thanks for the replies. I have gotten several estimates, none contained model numbers (any contractor). I will get those when I get the next estimates based on the Man J. From what I am reading though, I should be expecting something in the range of 2 or 2 1/2 ton as opposed to the three ton for the lower level, and maybe a 60Kbtu furnace for the lower level and a 40k but furnace for the upper level?

For the second part of the question, I am going to check on getting another Trane 803, but if that doesn't work would my current Honeywell 8000 work with the variable speed furnace? Is it a 2-stage thermostat?


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RE: Furnace and HP replacements

Which Honeywell 8000 series thermostat do you have? The 8110 is single stage only. The 8320 can control 3 stages of heat and 2 stages of cooling.


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RE: Furnace and HP replacements

And the HW 8321 which is identical to Trane's 803 and will be less expensive has the humidity over cooling feature which is nice if you live in summer climate with high humidity. Still say the HW VP IAQ is the best selection which offers dehumidify on demand feature which is independent of thermostat setting.

IMO


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RE: Furnace and HP replacements

Thanks so much for taking time to help. My thermostat is an 8320. Will it be good enough?


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RE: Furnace and HP replacements

Yes....not the best selection but will be fine for initial install...

IMO


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RE: Furnace and HP replacements

I forgot to mention that included in the house size (2300 sq ft) is a room we added on when we bought the house. Under that room is an unfinished basement--concrete floor with a cinderblock wall. The ceiling is unfinished but well insulated. I use it as a garage for the lawnmower, workbench, etc. It isn't accessible from the living area of the house, you have to go out of the house and through the basement door. It is around 192 square feet, and has 1 register there. We don't attempt to heat it as we do the rest of the house; it stays 50-60 in there year round. How much of an effect, if any, does this have on furnace size? It should technically be calculated with the first floor I guess, as it is under the living room and by keeping it heated it aids in maintaining living room temperature.

This post was edited by glockman45 on Sun, Feb 16, 14 at 19:00


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RE: Furnace and HP replacements

Ok I just received the Man J calculations from the Trane contractor as well as the new estimate. The calculations were done for 2 zones- upstairs and downstairs. I don't have them in front of me right now, but the heat loss upstairs was around 22,000btu and downstairs was around 44,000btu. He commented that the insulation was really good throughout the house (well above average). Cooling loss was around 20,000 downstairs--I don't recall upstairs.

I told him I was concerned about the 80,000btu furnace being too much; he agreed it may be "a little" oversized, but he said as a rule the company installed 80,000btu in any house much over 1200 square feet. I expressed concern about equipment performance if it was oversized; he said the two-stage furnace would handle it better than single stage but he would check with the company owner and Trane rep about getting a 60,000btu. Would the 80,000btu be oversized enough to be concerned, or does the 2-stage furnace mitigate that somewhat?

He also agreed that 60,000btu was oversized for upstairs, but said that it would help push the air up to the top of the house better than a 40,000btu as the furnace is in the basement; it does have a way to travel. He also said that the XV95 isn't available in 40,000btu. In this case would the 60,000 dual stage be better than the 40,000 single stage, or at least ok?

The heatpumps (my wife and I are still discussing straight a/c) offered are the 2 ton XL15i for upstairs and 2.5 ton XL15i for downstairs. He said the 2 ton may be ok for downstairs also, but that I was borderline.

As for model numbers, they are:
TUH2B060A9V3VA (60,000)
TUH2B080A9V3VA (80,000)
4TWX5024B1000A 2 TON
4TWX5030B1000A 2.5 TON
Sorry, I forgot evap coil model numbers but I can get them later

Price is $15,900 and includes equipment above, 2 new line sets, 2 new pads to set the equipment on, and 2 media filters/cabinets. Also includes new exhaust duct run correctly and Trane 803's.

My concerns are the heating and cooling of my downstairs with the high ceilings (I have vaulted ceilings of 24 feet in the entry way, 24 feet sloping to 14 feet in the living room, and 14 feet in the family room. The kitchen and den is at 9 feet). I also have a lot of windows downstairs, mostly 4 feet but I have three that are 8 feet.

Would be replacing a 4 ton Rheem with 100,000btu furnace downstairs and a Goodman 2 ton A/C 60,000btu furnace upstairs.
Thoughts?

This post was edited by glockman45 on Tue, Feb 18, 14 at 18:39


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RE: Furnace and HP replacements

It is great that the contractor does a load calculation. What I don't understand is why he chooses to ignore the numbers. Over sized furnaces waste energy, are noisy, drafty, and don't last as long as ones which are properly sized.

Why are you spending money on heat pumps when the numbers show the furnace can heat your house at a lower cost?


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RE: Furnace and HP replacements

Mike thanks again for your help. I am not certain I am going to spend the money on the heat pump; the reason I am on the fence at all is according to the calculation above there is such a small difference in cost between the two, it may be worth it to pay a "convenience" fee to insulate myself against the possibility of rising gas rates. PLEASE correct me if I am wrong.

And speaking of wrong, I was in one of the numbers from the calculation. The corrected numbers are as follows:

First Floor: BTUH loss 40,648 (heating, I assume loss)
gain 20,889 (for cooling, I guess it is gain)
Second Floor: BTUH loss 28,502 (heating side)
gain 12,883 (cooling side)

As far as ignoring the numbers, I guess technically you are right. His argument, to a layman, is somewhat compelling regarding the larger size needed to push air upstairs (I am guessing 40 feet straight, maybe longer considering twists and turns).

What is your opinion of the equipment. I understand you think it is oversized; but do you believe based on these numbers that 60k would be ok for downstairs, or is 80k with the variable furnace acceptable?

Same question for upstairs- 60K variable or 40k single?

What about HP's? I "think" the two ton would work for the 1st floor, and maybe even 1.5 ton for the 2nd floor. And for argument's sake, how would these respective smaller HP's heat? Again, not sure I would get them, just exploring options.

Also, the quote includes metal work, wiring, etc.

Thanks very much.

This post was edited by glockman45 on Wed, Feb 19, 14 at 0:24


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RE: Furnace and HP replacements

I would forget the heat pumps altogether.

For downstairs system, I would install 60 K XV95.

For upstairs system, I would install 40 K XT80.

You either trust the load calcs or you don't. Ask the dealer to redo plus you do them yourself for comparison purposes. I can provide a link if interested.

Still I would want to know what design temps were used for each system both cooling and heating.

IMO


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RE: Furnace and HP replacements

I agree with Tigerdune's recommendation for the first floor furnace. The first floor AC should be 2 tons.

The second floor is more problematic in that there are not a lot of choices for 40K BTU furnaces and 1.5 ton AC condensers. Since the upstairs furnace is going in the crawl space then I would recommend the XT95 40K BTU. The XV95 60K would work, but it is going to spend most of its time in the low stage. You are not going to get much benefit for the extra money.

I am not sure what Trane has to offer in the 1.5 ton size. Going with a 2 ton for 800 sq. upper floor feet seems very over sized. I might do the 2 ton if it were 2-stage, but I would want to know the capacities of the high and low stages.

I don't buy the argument of needing to over size the furnace in order to get better air flow to the second floor. Air flow problems are a result of small and leaking duct work. They should be fixed as required.

I know someone else who spend extra money four years ago on heat pumps as a hedge for rising gas prices. Gas prices have continued to drop since then. I would take the money and invest it in a good mutual fund.


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RE: Furnace and HP replacements

The reason I said XT80 is because it gets closer to the heating load calc for upstairs zone. But I won't quibble about the XT95.

Both XL15i and XR15 AC condensers are available in 18 K model sizes.

IMO


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RE: Furnace and HP replacements

Thank you very much for responding. We are on the same page regarding the first floor. With regard to the second floor, Trane does offer a1.5 ton unit. I'm not sure of the effectiveness, but the btu calculation is around 20k (from memory), it's about 4k-6k less than the 2 ton unit.

As far as the furnace, I can get the XV95 for the same price at the XT95 for 60kbtu. That said, I would be getting the XT95 40k. Would I get a better furnace in the XV95 even if I get the 60kbtu. I understand it would spend most of the time in the first stage. Would that be harmful?

Also, ductwork is in good shape but any changes needed due to sizing drops?

This post was edited by glockman45 on Wed, Feb 19, 14 at 14:03


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RE: Furnace and HP replacements

Shouldn't be same price as XT80 or XT95 should be less. the XT80 or the XV80 will not require venting to outside. What efficiency is your current furnace for upstairs zone and how is waste gas vented now?

But if you go that route with XV95, ask that the high stage be locked out. You'll never need it. I would want a price on the XV80.

IMO


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RE: Furnace and HP replacements

They are less, but the Trane dealer is "giving" me the XV95's at the same cost as the XT 95's-- for those with comparable btu's. Obviously the XT95 40k would be less, but if the XV95 is that much better - even locked on the low stage- and 60k btu would not be detrimental to the furnace wouldn't I be better off to get the XV95?

This post was edited by glockman45 on Wed, Feb 19, 14 at 14:35


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RE: Furnace and HP replacements

Second time

What efficiency is your current furnace for upstairs zone and how is waste gas vented now?

Post back.


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RE: Furnace and HP replacements

80% vented out of tubes going out of the crawl space.


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RE: Furnace and HP replacements

All,

So many of these posts/questions go unresolved, and I think with the time and effort you guys put in (for free) you deserve a resolution.

Today I agreed to the equipment as posted, with the following changes:
60K Btu XV95 2 ton HP downstairs
40K Btu XR95 1.5 ton HP upstairs

I know, and concur, I should have gone straight AC. Even the salesman suggested it. However my wife was adamant for the heat pump. I explained everything to her, but she wanted the "insurance" against the fluctuating gas rates. As I said, I have to live with her, and the price difference really wasn't that much (considering how much you guys saved me by teaching me how to downsize effectively). I was shocked at how much the contractor did not want to trust the Man J. I had to force the sizes. I really don't think it was about the money; he really believed in oversizing. Been in business over 40 years, I guess change is tough.

Anyway, especially Mike and tigerdunes: Thank you. Because of the information on this and another site, I have gone from an initial estimate of 80K XR13 with 4 ton HP/60K XR 13 2.5 ton HP to what was contracted. Not only did I save money, but I got better and more efficient equipment in the process.

This post was edited by glockman45 on Wed, Feb 19, 14 at 22:32


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RE: Furnace and HP replacements

The heat pumps are a mistake. Also the XR95 is a mistake. Should be at least the XT95.

I'm done here.

Good Luck....


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RE: Furnace and HP replacements

The XT furnace has a high efficiency motor. I am curious why you chose the XR model. The price difference should not have been that much.

I understand you are trying to keep peace in the family concerning the heat pump. All I can say been there, done that.

I suggest you lock out the heat pumps until the day gas prices rise, or electricity prices fall. Running the heat pump in the winter creates additional wear and tear on the equipment. This is the reason heat pumps have a shorter life expectancy than AC condensers.


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RE: Furnace and HP replacements

I meant XT. Hit the wrong letter. Mike thanks, I had planned on doing that as well. And really, the price difference between the HP and straight A/C was right at $500 combined.

I appreciate the input and advice.

This post was edited by glockman45 on Thu, Feb 20, 14 at 12:08


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