PS: the two measurements on the calc are for the whole house (first number) vs master bedroom.

If your heat loss came in at 96,098, I'd want the 120k btu to cover for design conditions as well as have a little safety factor built in (unless this has already been added). Plus I'd rather have the 5 ton drive in the furnace. Hard to say, since in most conditions either should do fine.

Hopefully all contractors bidding told you for sure that your ductwork could handle the required airflow the furnaces need to move. Newer furnaces need to move more air to remain efficient. 4 tons A/C, you will want to move 1600 cfm on high.

Ryan, so what does that mean? Bigger furnace or the smaller one?

The smaller furnace will run longer in stage 1 to provide longer runtimes/more comfort, but the larger furnace would give you more capacity for the coldest days where there is a small chance the smaller furnace "might" not keep up 100%.

Is the one quoting the 100k furnace the one who gave you the readout above for heat loss figures? Ask if he has a safety factor included in there, and if he sized for design (approx. 20* outside) conditions? If he did both, then I'd say the smaller furnace more closely matches your requirements.

For the air conditioner, the smaller furnace matchup has an incorrect/incompatible coil matchup. You need the 4TXCC049BC3, not the 4TXCC048BC3.

I won't be able to post again until late tomorrow night, so hopefully others can advise you further.

I will say that it's hard for me to tell you to go one way or another without seeing your house and without knowing the details on what the contractor did with his load calc. The fact that he did one shows professionalism and competence. I'd follow his advice, and ask him if he feels confident the smaller furnace will cover the heat loss at ALL conditions.

What is the difference between the 2 coils?

christine

some observations and questions.

I see you live in Utah.

Here is a snapshot of your climate(for Salt Lake City).

Climate averages for: SALT LAKE CITY, UT, 84101
Hot weather Cold weather
Average days per year above 75: 122 Average days per year below 40: 121
Average high temperature: 90.6 Average low temperature: 29.2

"I live in the state of Utah, and currently my gas bill is $120 year round and my electric is about $320 year round."

Curious about why your mthly electric is so high?

how large is your home? its insulation qualities?

what is your electric rate/KWH?
what is your nat gas cost/therm?

what size is existing system both furnace and AC condenser?
this is one system? any zoning controls?
any specific problems/concerns?

who provided you the heating and cooling load calculation?
you received a copy on Man J letterhead?
what design temperature both inside and outside were used for heating and cooling?

without knowing more detailed info,I am skeptical of the 120K larger furnace.

you will need some type of air filter both for IAQ and protection of the furnace and coil. what stat is being quoted?

IMO

Thank you Tiger for addressing my question. I am not sure about the cost of electricity. My electric bill jumped about a year and a half ago, and I am not sure why. Used to be about $180 a month on an equal payment plan. Started having AC problems around that time with it frequently icing up (a 5 tom unit). Last fall my AC broke down altogether, had a company come and repair it.....they charged $1,000 and it lasted exactly 12 hours. At that point they told me they knew all along that the AC could not be repaired but not to worry, I could use the money towards a new AC as long as I bought it from them. I of course refused, took them to court, won....but the company refuses to pay the court ordered amount. That's my story in a nut shell. So now I need a new system before the weather gets too hot.

My present furnace is 130 ton I think they told me. As far as rate is concerned, a quick google searched came up with this: Power rates will be $.09/kwh up to 1,000 kilowatts. The rate for usage over 1,000 kilowatts will increase to $.1085/kwh. Gas I have no clue, the google search made no sense to me. Design temperatures used were 8* and 75*

"What is the difference between the 2 coils?"

One is approved to be used with that A/C; one is not.

If the company can guarantee the smaller furnace will always maintain your preferred indoor temperature at design conditions, that's the one to go with, no doubt about it.

Thank you, Ryan. System has been ordered and will be installed Wednesday.

Great, I hope it all works well for you, and that you informed them of the coil discrepancy. May just be a small mistake, but you certainly want the approved 049 coil.

One important thing never discussed was the thermostat. Which one are they proposing? I suggest the TCONT802 from Trane or the TCONT803, which has a setting for humidity control (it overcools up to 3* to control humidity). Those are the two best options for that setup. I have the Honeywell version of the TCONT802 and love it.

I assume you chose the smaller furnace, as the installing company ensured you it would be enough capacity? If that's the case, I would certainly choose the smaller furnace if they can guarantee its performance. Remember the heat loss figure is for extreme temperatures (design temp), and most of the time the furnace should run on low stage.

Yes, they are installing the TCONT802. :)

They also fixed the coil error, and in fact he told me he had already ordered the correct one when I mentioned what you had pointed out.

Thank you so much for your input!

christine

you are including some type of air filter cabinet?

The XL16i is a poor choice if dehumidification is a concern. If not, then it should be OK.

IMO

Tiger, I live in the desert so to speak, so humidity is no issue at all. :)

~Christine~

Christina I think the system you're getting will be great for your location and needs, provided it's installed correctly.

I do agree with Tiger above that a 4-5" pleated filter cabinet would be a great addition--change 1-2 times/year.

I have no clue what an air filter cabinet is. I do know I have very little room left where the equipment is going to go (not enough space for an air purifier for example). I presently have a gas leak in the furnace that is there, so am eagerly awaiting my new one......