As a fellow NJ'er, it sounds like both units may be oversized. What is your square footage and general location?

Did any contractor present you with (do) a heat calculation? What equipment are you replacing. Model numbers would be nice.

V

mrklean

I agree with "V".

what size is your home? what size both furnace and AC are you replacing? have you updated any windows and/or insulation since existing system was installed. It was quite common not so long ago to oversize HVAC-that was a mistake.

Now to the hot water heater, Not an expert. Where is existing hot water heater located. This is gas or electric. How is existing vented? Any idea of the code for your location? Why the need to replace liner? How much is this?

As far as the equipment listed, I would say either if correctly sized would be OK. With Carrier's Infinity, you want the Infinity controller. With the Lennox G71. you want the HW VP IAQ. I would lean towards the Carrier.

IMO

Thanks tiger and V,

The house is approx. 2500+ sq. ft. and is location in the Union County. The house is a center hall colonial with a brick front is 68 years old. We haven't made any significant changes to the house...same windows, doors, siding, etc.

The current system is a Lennox gas furnace G124E-137-7 installed in 1985 - before us. The size was 137,000 BTUs. There's also a two-stage A/C (I believe 3 1/2 ton) and not sure of the brand. The only expense I have incurred in 23 years was replacing the furnace blower motor about 10 years ago. Both estimates were based upon existing system.

The hot water heater is gas and is located near the furnace. It is currently vented through the chimney with the furnace. The cost of adding a liner to the chimney was not identified by the Carrier contractor. The Lennox contractor recommended replacing the hot water heater with a "direct vent" type for that reason. He did not want to add a new liner.

One cost that I didn't calculate into the Carrier proposal was the cost of annual maintenance - which the contract says is required to maintain the warranty. The Lennox dealer included 5 years of bi-annual maintenance.

We are looking for the most efficient system for the house....without overkill...and still taking advantage of the available federal and utility credits.
After scouring the forum, it sounds like the forum is leaning towards Carrier...?

I hope to finalize this on Monday. I do have a few more questions for the contractors. The weather forecast is for colder temps by Wednesday.

Thanks.

During the December cold snap, did your furnace run constantly (or nearly so), or did it cycle with on/off periods?

I could not find any info on your furnace, but if your furnace has a standing pilot, it is assumed to have an efficiency of between 60 & 70%. If as you state, the INPUT to your furnace is 137,000 BTUH, then the output (available for heating) is in the range of 82,000 - 96,000 (probably closer to the lower figure).

I live in Camden Cnty and am close to Philadelphia. My outdoor design temps are 90/14; yours (closest is Newark) are 91/14. I am a little more humid than you.

My house is 2500 SF, 2 story (no bricks) and is 21 yrs old. The windows are excellent; insulation is good to very good. My heat calc is just under 60,000; cooling is 3.5 tons.

Unless you get a heat calc (in writing), they are just guessing. You want units sized that will run (nearly) full time at 'design temperatures'.

Note: the calculated amounts, above are what are required; not what your units deliver. I would NOT recommend going with a 4 ton a/c unless they can prove you need it.

My contractor 'convinced' me to upsize to a 4 ton unit (2 stage). The 'rationale' is that it will run mostly in first stage and save money. Well, I just finished my second cooling system and the unit has never run in 2nd stage except when tested, or on a rare setback.

P.S., you can do your own calc for $49. You can try it out at hvac-calc.com.

Good luck.

V

Quickie addendum: When your heating/a-c runs, is it noisy?

Do you get sonic BOOMS when your system shuts off?

These are signs of a 'less than ideal' duct system. Your proposed units would probably attempt to deliver more air and thus, be very noisy.

V

One cost that I didn't calculate into the Carrier proposal was the cost of annual maintenance - which the contract says is required to maintain the warranty.

Read the manufacturer's warranty carefully. I don't know what Carrier's says specifically, but some brands don't require annual maintenance contracts. They just state that they won't cover damage due to a failure to maintain the system, or words to that effect.

Some (probably a lot) of contractors are using this language to pressure customers into buying annual service contracts.

Carrier advertises heavily, which is one reason for its "popularity." Get a good installation from a reputable contractor, and brand should not matter, although Lennox does seem to have a less than stellar reputation for parts availability and pricing.

V: The furnace cycled on and off during the cold spell. Our current furnace had an electronic ignition system. The a/c system didn't have any sonic booms or significant noise (other than the fan)...

Is there any benefit to directly vent the water heater than install a liner in the chimney? We actually rebuilt our chimney (from the ground up) a few years ago and I'd hate to cause any problems again...

Thanks for all your great comments. I'm still undecided but hope to finalize tomorrow after speaking the both contractors.

Steve

Hi, Steve. You might see my recent posts. I settled on a Bryant system, which is Carrier with a different label, as far as I can tell. All dealers told me that I would need a liner in the chimney if I went with the high-efficiency furnace. I was not getting a water heater. The 80% efficient furnace could go ahead and vent as it was before. It might have just been the physical layout of my house, I don't know.

Just my two cents of recent knowledge.

Jane

By 'sonic booms', I was referring to the noise that the return ductwork makes when the furnace shuts off.

I had concern about venting my water heater when my HE furnace was installed. Found info in the NJ Codes (Gas).

Here's a link: http://www2.iccsafe.org/states/newjersey/NJ_FuelGas/FuelGas_Frameset.htm

Good reading.

V

mrklean

I will assume you will make a decision today or tomorrow.

I would go with Carrier. Either way, I would place a stipulation in the contract that they perform a Man J heat/cool load calculation before the install. Insist on this and get it in writing. Average time to properly perform would be about two hrs. This will give you proper sizing.

Both dealers are Factory authorized dealers?

I would put the water heater on hold to gather more facts or go with a direct vent method or a high eff tankless type. I would not go with the new liner for an old water heater without a good reason. you have not been provided that reason.

IMO
Good Luck!

I plan to call the contractors (both are factory authorized) with a few follow-up questions. The Lennox dealer didn't identify the specific humidifier in the contract and I was going to ask about the HW VP IAQ thermostat. I am also going to pose the Man J question to him.

The Carrier dealer will also get the Man J question. By the way, any thoughts on the Aprilaire 2210 air cleaner, Aprilaire 600 humidifier and Infinity thermostat?

v: thanks for the link. It does seem that a chimney liner is required if installing a HE furnace.

By the way, the Lennox dealer was providing 10 years of parts and labor and 5 years of maintenance. Th Carrier dealer was offering 10 years parts and labor.

Thank you all for your input.

Steve

mrklean

just to clarify. the chimney liner would be for your existing furnace's waste exhaust and gas water heater. it is not for today's high eff condensing furnaces which you have been quoted. those furnaces require venting for both exhaust and fresh air out the side of your home. you might review with your dealers.

again the question I would raise is why the need for a new liner? codes have changed for hot water heaters. discuss with dealers.

I assume your gas HW heater and furnace are located in crawl space or a basement.

IMO
Good Luck!

Tiger,

I just spoke with the Carrier dealer and he indicated that since we have an outside chimney, the code requires a chimney liner for venting the existing water heater. They will be venting the HE furnace directly to the outside.

By the way, our furnace and water heaters are in the basement.

Thanks.

mrklean

that is correct. however, why the need to replace existing liner? and if you did replace existing hot water heater now or in the future, then code might require you to vent outside. I would want to know exact reason for replacing existing liner. what is the problem with it?

IMO

We've decided to go with the Lennox system for a number of reasons - comfort with the dealer, happy with the brand (existing system lasted 25+ years with no problems), discounts, maintenance plan and just announced Lennox rebate of $1000. So all in all we feel it was the best choice for us.

Now my last question on this topic hopefully. My dealer they were going to install the Lennox 7000 series thermostat. I've read on this site that the HW VP IAQ was recommended. What is the main difference with the 7000, 8000 and IAQ?

Thanks.

Steve

What is the size (BTU) and efficiency (% AFUE) of the furnace you chose?

How about the a/c; size (TONS) and stages?

You indicated cycling during the cold spell. Tends to indicate oversizing.

V

with the G71, you want the stat that takes advantage of the true modulating ability of this furnace. I believe this begins with 40% of furnace's output capability. you need to verfify this with your Lennox dealer. you don't want a tstat that just stages its output. I can not emphasize this enough-this is a big deal with this mdl furnace.

BTW, what size did you elect?

and what about the HW heater?

Congrats
IMO

The furnace is the G71 100,000 BTUs which is 95% AFUE. The A/C is the XC 21 4ton with two stages and SEER of 20.50. I am also getting the Healthy Climate 10 Media Air Cleaner and the 17 Bypass Humidifier.

We are also replacing our water heater with the Rheem "direct vent" 50 gallon version with a 10 year warranty.

I'll discuss the t-stat with the dealer. They start this afternoon tearing out the old and will install eveything tomorrow. Just in time as I heard colder weather and snow forecasted for later in the week.

Thanks again for your advice.

Steve

mrklean

the G71 does not come in a 100K mdl.either 90K or 110K.

dealer needs to perform a load calc for heating.

IMO

Here is a link that might be useful: Lennox G71MPP Consumer Brochure

Good luck with your new system.

Be sure to post back and let us know how everything works out.

V

My typo - system IS 110,00 BTUs. I'll update following install and use this weekend.

Thanks again.

Steve

mrklean

any update on your new install?

TD