A customer service oriented contractor always begain's by figuring out why you had problems mentioned with old system. Knowing that is the begaining of making sure new system cure's old problems. The trouble might be structrial,insulation,duct leaks,duct size or any number of issues but it can and should be solved. IMO,any contractor who fails to use avaliable program tools while installing hvac equipment is not worth hireing. With that said,you might not require complete reducting,added supplimental returns and/or supplies might be all that's needed. And of course everything should be leak tight.

I live in Southeast Michigan, where the climate is very cold in the winter and mild in the summer.

None of the contractors suggested making the systems bigger due to the issues I have. Part of my problem is that when I finished the basement, the contractor did nothing with the ducts other than adding new outlets and returns in the basement. I didnt know any better at the time.

Since the basement is finished, drywall all around, it is very hard to get to all the ducts. We can see them going from the furnace out throughout the house but other than that I would have to tear up drywall to check all of them.

Not sure what else to do. Thanks.

have you asked any of the quoting dealers to provide a written load calculation both heating and cooling?...seems all want to oversize you especially in heating...can't believe you need more than a 100 K high eff furnace...I like QT #3 best with 100 K model Infinity furnace max and I would upgrade condenser to a 2 stage Infinity Mdl 24ANB7....then you would have a top of line fully communicating system...what Mdl coil was quoted?...I would point out to dealer all hot/cold spots in home and ask for recommendations to improve...you should know that basements below grade carry little heating and cooling loads.

IMO

I will inquire again with #3 on the load calculation. I believe the mdl quoted is CNPVP. I have an email out to obtain the exact numbers for all items.

If I stick with the performance 16 condenser, will I lose anything by not having the infinity condenser? In Michigan, most contractors have recommended no more than seer 13 as it does not get that hot out here and not for long periods. I thought going to 16 would be a big enough upgrade and not break the bank. Thanks.

Carrier ACs

If you are set on the Infinity furnace, then I would want an Infinity condenser so you have a fully communicating system...otherwise you are just cheating yourself and unable to take full advantage of the Infinity furnace and Infinity controller. Carrier does offer an Infinity Sgl stage condenser, I believe 24ANB6. Otherwise, I would drop down to the Performance Var Speed furnace and Edge Thermostat. That would save you some bux...I just don't care for the idea of Infinity Furnace, Infinity controller paired with Performance condenser.

IMO

Very good points, I appreciate it. I am waiting on an estimate from the same company for the performance 96 furnace with the performance 16 condense and coil. I have a nest, so not sure I need the carrier thermostat if I dont get the infinity?

Despise these lifestyle thermostats especially the NEST...I do not recommend using it period especially on the systems you are considering. Sorry...

IMO

If you use the Nest thermostat you will lose several of the communication features of the Infinity system. Sell the Nest on ebay and put the money towards the Infinity controller.

If the summers are mild, then why are these guys quoting 4 tons of cooling? You are not going to get good humidity control with an over sized AC even with a 2-stage condenser.

None of the contractors suggested making the systems bigger due to the issues I have.

You currently have a 120K BTU input furnace @ 80% AFUE = 96K BTU output

Quote 1 : 135K BTU @ 96% AFUE = 130K BTU output

Quote 3, 4 120K BTU @ 96% AFUE = 115K BTU output

Quote 2: furnace size unknown

You have at least three quotes where the quoted furnace is larger. The contractors may not have suggested making the furnace larger, but they seem to be doing that.

I agree on the nest if i use the infinity system. Is it okay on the performance system?

Quote #2 is 120,000 BTU. You are correct that quote 1 suggest more output at 135k but he didnt have a clue what I even had and I would not consider that company.

For the furnace, if i was at 120k btu at 80 and they suggest 120k btu at 96%, that is bigger? I guess I dont understand that. Do you multiply the btu by the afue to get an effective rate?

For the AC, they are quoting 5 ton. SE Michigan is not that bad. we will generally use the AC for 3 1/2 months out of the year, only because my wife likes it cooler in the house. But it doesnt get over 100 and rarely gets to 95. Humidity can get high at times but is not a huge issue.

Load calculation needed both heating and cooling whether all Infinity or all Performance series...I continue to be amazed that lifestyle thermostats are used in nice high end systems that will cripple full functionality of the system, especially the Nest!

no more than 100 KBTU condensing furnace, let the load calc be your guide!

For the furnace, if i was at 120k btu at 80 and they suggest 120k btu at 96%, that is bigger? I guess I dont understand that. Do you multiply the btu by the afue to get an effective rate? ... YES...pay attn to output BTUs...

IMO

Furnaces are specified by input BTUs. To calculate the output you multiply the input by the efficiency. If the input the is the same, the output becomes larger as the efficiency increases.

The highest summer design temperatures for the state of Michigan is 87-88 degrees. Anyone quoting 5 tons of cooling for your house should seriously consider a carrier other than HVAC.

I have some additional information that I wanted to share on the quotes I got. I spoke with the contractor for quote #3. He calculated a total heat loss of 105,000 at 0 degrees. He said he is sure both the 100k and 120k would be fine but he feels that when it is extremely cold the 100k unit will struggle to keep up. Additionally, I

have the benefit of the two-stage system which will run at a lower output for long cycles and will frequently heat the home on low without staging up.

On the condenser, he said it measured out at 4.2 ton. Since there is not a 4.5 ton, he went up to 5 ton.

I inquired about getting an Infinity condenser to match the infinity 96 furnace. He stated that the Infinity 16 is not commonly used and is special order. The infinity 17 is a good system but older. He said if I wanted an Infinity system he suggested an Infinity 19(24VNA9). He said it is significantly more but there are more credits.

He said that the most common pairing he sells is the Infinity 96 furnace and Performance 16 condenser. He said that would work well in my home.

My questions are:

1. Should i go with 100k or 120k on the furnace?

2. Should I go with 4 ton or 5 ton on the condenser?

3. Should I stick with the Performance 16 condenser or go with the Infinity 19 or something else? Still waiting for the estimate.

Thanks.

Answers:

1. You should go with the 100K BTU furnace.

You currently have a 120K BTU input furnace @ 80% AFUE = 96K BTU output

The new furnace at 100K BTU input furnace @ 96% AFUE = 96K BTU output

Did your old furnace ever fail to keep you warm on the coldest nights? If the answer is yes, then why would you want a bigger furnace?

2. You should go with the 4 ton condenser.

What indoor and outdoor design temperatures did the contractor use to calculate the 4.2 tons of cooling? What temperature do you normally set the thermostat in the summer?

You said the humidity can get high at times. If the 4.2 tons is accurate (I am skeptical about the calculation) then you are better off slightly under sizing than over sizing. You will be amazed how comfortable it will be at 40% humidity in the summer. The lower humidity will allow you to raise the thermostat setting 1-2 degrees. This is how you will save some money and feel more comfortable.

The Infinity 16 (24anb6) is a single stage condenser. I would rather see you spend the extra money on a 2-stage AC. The Infinity 17 (24anb7) would be a good choice in my opinion. Get a quote on that model in a 4 ton size. The Infinity 19 (24VNA9) is the Greenspeed variable speed compressor. It is going to be much more money and is overkill for your climate. I would only consider it if after credits and rebates it was close in price to the 24anb7. If not then it is not worth it in my opinion.

Based on your feedback, I am going to get the 100k BTU Infinity 96 and get a price on the Infinity 17 4 ton. Also, need to get a price on the Performance 96 4 ton. What would be a reasonable price difference to go up to the Infinity 17?

If I do decide to go with the Performance 16 Condenser in 4 ton is that a bad match for the Infinity 96 with wifi controller. I know I would lose some functionality since it is not Infinity but I wasn't sure if it was that much were I should pay the difference to get the Infinity 17?

Thanks again for your feedback.

In the past Carrier has offered bigger rebates on the Infinity systems compared to the Performance. You may find after the rebate that the cost difference is very small. You can mix the Infinity and Performance equipment as long as it is a listed AHRI match.

I will wait to find out what the cost difference is and make a decision. I will also check AHRI to make sure that these are a match if I go with Infinity/Performance. Thanks.

I was speaking with another carrier contractor today and was told that the 24ACC6 has been discontinued and that I should get a quote on the 24ACB7. Is this correct?

It is still listed on Carrier's web site. Call Carrier to find out.

Update

I contacted Carrier and they confirmed that the 24ACC6 is still in production.

I did get prices on the 24ANB7 and 24VNA960 and after rebates both are within $50 of each other. The VNA960 is the cheaper one. Both of these units are approximately $1200 more after rebates then the 24ACC6.

I currently have a 10 seer and going to 19 seer would be a big difference. My electricity rate is .094 for Power Supply and .056 for Delivery. Not sure how this would calculate out for savings. We use our air June through August most of the time and some in May and September.

Is it worth spending $1200 more to go to the VNA960 which is higher seer, quieter, works better with my infinity furnace/AC.

I am going with the Carrier Infinity 96 59TN6, Cased N evaporator coil, bypass humidifier and Infinity Thermostat SYSTXCCITC01-A, 10/10 warranty on both.

Just need to match the right condenser.

I have another call with the contractor Monday to talk about the load calc. He feels confident in the 120k BTU and 5 ton AC. He said the cost difference for 100k BTU is $135 and for 4 ton AC is $400 on Infinity and $150 on Performance.

Appreciate all thoughts. Thanks. Jim

".094 for Power Supply and .056 for Delivery. Not sure how this would calculate out for savings."

Ask your electric supplier for an estimate based on past kw consumption. Depending on how well organized your supplier is in energy audits they might have additional information that help's your decision. Most energy suppliers will at minium tell you how effecient your home is plus where and how to improve. Knowing where to put the effort can often turn 2 hours of your time and $25 worth material into worthwhile savings even in new homes.

You are paying $0.15 per KWh, not as high as mine, but higher than the national average.

You can get gross estimate of what it costs to cool your house. This is how I do it. Find the average electric usage of the months you don't use the AC (a good average would be Oct-Apr). Then take the average number and multiply by 12 to get the annual electric costs without AC. Then subtract that number from the total electric usage for the whole year. The difference is the amount of electricity for AC usage. This assumes your electricity usage is about the same each month. If you have a lot of Christmas lights or use electric heaters in the winter, you will have to make some adjustments.

If see no good reason not to get the 25VNA960 if it is $50 cheaper than the 24ANB7. Going from 10 to 19 SEER is a 47% savings. If you can raise the thermostat a degree or two in the summer, the savings will be greater.

Why do you want to spend an additional $535 to over size the furnace and AC? Most houses don't have the duct work to support 2000 CFM of air required for a 5 ton condenser. I still stand by my previous recommendation.

I definitely don't want to oversize. I am only going to listen to him and then make my decision. I am definitely leaning toward the smaller systems.

I agree the 25VNA960 is better than the 24ANB7. It is really down to whether I pay the 1200 from the 24ACC6. There definitely seems to be some big comfort advantages to the more expensive unit. We definitely have some challenges in the house with swings in temperature throughout the house.

I really wish there was a better way to fix my basement temperature as it is always cold. I understand this will help some but is not the total answer. I assume, it should also help with the up stairs being hot all the time. Is this correct?

I will work on the calculation and see how it comes out. Thanks.

Actually, it looks like my cost is more than .15. Here is my most recent bill

Power Supply Energy 493 KWH @ 0.07888

38.89
952 KWH @ 0.09423 89.71

Delivery Charges:

Service Charge 6.00

Distribution 1445 KWH @ 0.05666 81.87

Energy Optimization 1445 KWH @ 0.003344 4.83

LIEAF Factor 0.98

Other Delivery Surcharges** 2.82

Residential Michigan Sales Tax 8.95

Total DTE Electric Company Current Charges 233.76

I averaged the kwh from October to April and it is 55 and from June to September is is 63, which is about 15% more during the summer months.

I can't quite figure out the numbers below as it says different kwh times the cost. For example in this bill it said my usage was 49.8.

Any help is appreciated.

With only 15% diff accross 12 months,most people would be ecstatically happy reciving $233 bills.

I pay about $3500 per year, average monthly bill is $288.