Top End Dual Fuel Proposals - Look Good?

[jerryd_2008]

After weeks of educating myself with much help from this forum, I have narrowed my search to 2 dual fuel heat pump/natural gas furnace proposals. Several were just way out there. I had my local electric co-op independently check the house and it is very efficient and they provided me with cooling and heating sizes. Several of the proposers also ran a Manual J calculation that approximated the co-op calculation.

The house, built in 1994 in extreme Northwest Arkansas, is about 3700 sq ft with a walk out on the lower level, extreme southerly exposure with lots of windows. The existing 80% gas furnace is an 88,000 Btu's and the split (10 SEER?) AC is a builder's model 4-ton. Both seem adequate as the house is tight, insulated, good vinyl windows, additional 6 inches of cellulose in attic on top of probably original 10 inches fiber glass.

1st Proposal:

York Affinity YZH04811 4-ton, 18 SEER, 2 stage heat pump, 410A
York Affinity YP8C100C20MP11 100,000 Btu, modulating, VS 80% furnace
ASPEN 5 ton coil (AHRI 3227959)
R-410A TXV
York Thermostat SI-THERM22P7Y 2H/2C 7-day programmable (?)
2 Tube ultraviolet light (needed for rebate)
Merv 11 Air Cleaner (needed for rebate)
10 year parts, lifetime compressor, 1 year labor with reasonable 10 year labor option
Flush and reuse line set in garage floor
New pad if needed

Contractor worked very closely with district sales manager and the unit was made to qualify for the $1,500 tax credit (AHRI 3227959) and York $1,700 Enhanced Premium System Rebate

Can't figure out which thermostat that is but has to be "matching" thermostat for the credit. Can I control humidity with it?

2nd Proposal:

Lennox 19 SEER, Dual Fuel, 2 stage, 4-ton heat pump
Lennox G60UHV60C90 2-stage VS 80% furnace
Condenser (?) XP19-048
ASPEN 60D44 coil
Thermostat YO349 (Honeywell ComfortSense 7000?)
10 year parts, 20 year heat exchanger, 1 year labor with reasonable 10 year labor option
Install new line set
New reinforced pad

Qualifies for the $1,500 tax credit (AHRI # not provided yet) and Lennox $850 rebate

I finally asked that neither propose more than 80% furnace although they had to be VS and modulating if possible. Winters here are only 1-2 months and not very serious like the Upper Mid-West gets. Both will seal the return air plenum that concentrates an upper and lower floor return in a plywood plenum exposed to fiber glass insulation before going into updraft furnace.

Really appreciate your input. They look good? Any holes you would fill?

[RyanHughes]

The AHRI # for the Lennox setup would be 1247483. 12.75 EER, 17.50 SEER, 8.60 HSPF. The York setup yields better numbers, 12.75 EER, 18.00 SEER, 10.15 HSPF. Comparable setups, but of course the York has more heating stages. The Lennox ComfortSense 7000 can control humidity, but I can't make out the York thermostat part number to find more info on it. Perhaps you can clarify that with the dealer. I know York has a VisionPRO 8000 thermostat with a part number for it, but it's not the IAQ (unless they have another one for the IAQ). The York setup includes IAQ accessories. I would at least look into a pleated media filter with the Lennox setup. You may get a bigger rebate.

[jerryd_2008]

Ryan, thank you for the quick response. Wading through all of those extra characters in the coil listings must take practice. I have already sent an email to the York contractor asking for a better thermostat designation.

Maybe you can help me with why does the York have better numbers but I believe that AHRI says the Lennox is cheaper to heat and cool in the fields under "Est. National Avg. Annual Operating Costs". Are those numbers nonsense? I have seen similar unbelievable costs for other units with high costs but great numbers?

motoguy, regarding having "sealed combustion" I lived for years with furnaces either in the laundry room or the basement. Fortunately, this unit is in a large garage so hopefully no combustion fumes will penetrate the house.

The York contractor, listed as a commercial HVAC guy on the York site, told me that the ASPEN coil is 24" wide versus 21" for the furnace and that he would center and match it up. Are both of you comfortable with going with the large ASPEN coils and the numbers they seem to carry?

[motoguy128]

On the Lennox unit, I think it needs a aftermarket Aspen coil to make a match that meets the federal tax credit limits.

I agree with you on the 80% furnace. Trane finally came out with a communicating 80% V furnace for that market. There is no payback, unless you have a very large home, on the condensing furnaces from about Northern Missouri on south. Especially with a dual fuel set-up.

Although, I do like the ideal of having sealed combustion. My furnace is installed in the basement, so when it's running, I have increase infiltration. Same with my hot water heater and clothes dryer.

[RyanHughes]

Jerry,

I don't pay any mind to the estimated national averages. The installers shouldn't just put a wider coil on top of a furnace without making a proper transition/following installation instructions (don't want to bypass any coil surface area, lowering efficiency). I checked the Aspen coil spec sheets, but couldn't determine for certain whether they had a coil matching your width. I would ask your dealer if there is a matching-width coil. The Lennox furnace is 21", and that dealer is proposing a CE60D44 coil. Perhaps that's what should be used with the York (?).

[jerryd_2008]

... The installers shouldn't just put a wider coil on top of a furnace without making a proper transition/following installation instructions (don't want to bypass any coil surface area, lowering efficiency). ...

Very good point. I believe that he said he would transition. This guy is listed as a commercial HVAC contractor so I have more faith that he knows how to customize.

Note too that that coil is a 5-ton on top of a 4-ton unit. The distributor said that this is standard practice since some units capacities are achieved doing this. Sound right?

[RyanHughes]

More efficiency is often achieved, and the coil determines the system's net capacity (along with airflow over the coil), so yes. I too would have to believe a commercial HVAC guy knows sheet metal.

[beenthere]

Cool to dehumidify, and blower control are not a listed features of that stat.

Its a commercial line thermostat.

[Norml]

beenthere,

you helped me with my York choice. so thanx.

a follow up Q about dehumidifying options.... Do you know if the York Affinity 18 SEER HP and the York 'stat (which I believe is the Honeywell IAQ; which qualifies for their $$$ rebate) allow this unit to dehumidfy aside from the cooling fxn?

Thanx again
Norm

[beenthere]

I think you'll find the York stat is he TH8321.
It does cool to dehumidify. but can't slow the blower.

[jerryd_2008]

I think you'll find the York stat is he TH8321.
It does cool to dehumidify. but can't slow the blower.

Getting a bit confused after the last question on York thermostat. The $1,700 rebate requires a "matching York programmable thermostat". The rebate is very important to the retired guy as is making this unit operate properly so could you please clarify the following:

- Does the proposed York Thermostat SI-THERM22P7Y 2H/2C 7-day programmable qualify for the rebate?

- If it qualifies, is it inadequate to properly control this heat pump/variable speed furnace ("Cool to dehumidify, and blower control are not a listed features of that stat")?

- Can I still get the rebate by asking the contractor to upgrade to a more capable thermostat AND which one should I ask for?

Really appreciate the help, guys.

[jerryd_2008]

Had the York dual fuel HP with Honeywell IAQ thermostat installed in the summer of 2009.

Both units work well and I have never seen a thermostat that maintains the temperature setting so accurately as this Honeywell unit does.

Here is my problem. We have a total southern exposure on the back of the house and the thermostat is located on the wall over the only first floor return in the living room in that area with a lot of windows. In the winter, the sun heat load frequently raises that room temperature beyond the setting while the rest of the house remains 2-6 degrees lower than the setting (70 degrees in the winter) and beyond our comfort level. We just had our youngest son with young children move into a back bedroom and it gets too cool for them as well as us in another bedroom and in the lower walkout area where I spend a lot of time.

I suspect that the advanced variable speed air handler and very accurate thermostat may also be contributing to the problem because of lower air flow speed and shorter run times.

I found on the Honeywell web site the above thermostat/digital interface combination YTH9421C1002/U and it listed as an accessory an C7189U1005/U Remote Indoor Sensor. In the installation manual it says:

This indoor sensor is designed to sense temperature at a remote location and send this information to the VisionPRO Thermostat. This sensor can be used as a stand alone sensor or as part of an averaging network. Once a remote indoor temperature sensor is connected to the thermostat, the thermostat's sensor is no longer used.

- What is "an averaging network"?

- Does that imply that several of these remotes can be placed around the house for an average reading to drive the thermostat?

- Is this a good solution for heating and cooling to the average temps in rooms not affected by the sun load?

[beenthere]

You could have 4 of the remote sensors installed, and then it would average the temp from those 4 locations, and control temp by that.