Wife's Running Out of Patience

[jcurryfl]

Dash - Funny how you don’t pay attention to these things until it’s too late. From what I recall the unit ran quite a bit and struggled to keep up late in the day when the thermal loads are peaking. Recall that a couple of the estimators believed the return was significantly undersized so I don’t know what effect this would have had. I do remember that the estimator said the load calc indicator the need for slightly over 3.5 tons. I believe he said he went up to the 4 tons because of large cathedral area (20 ft ceilings) and the fact that the Carrier Infinity 16 and the Lennox XP-19 didn’t come in half ton sizes.

The other units (I have in total, ugh!) are 2 tons each. I’m not the original owner but the house is a ranch style built in 1979 and originally had ~ 2400 sq ft. The great room with cathedral ceilings split the house in two and I’m assuming since it was hard to run duct work through the great room that they put in 2 systems. The 3.5 ton cools the kitchen area and great room (~ 1260 sq ft) and a 2 ton cools 3 bedrooms, 2 baths and hall (~ 1140 sq ft). An 800 sq ft master suite and bath was added in the early 90’s. It’s serviced by another separate 2 ton unit. End result I have 3 units (total 7.5 tons) to cool 3200 sq ft.

[smittyii]

i can't see the need for a 4 ton, but maybe the contractor knows something we don't. i also don't see why u need to remove the heat from a cathedral ceiling. does someone have a hammock strung across it for sleeping? high ceilings are dead space unless they have windows (heat gain) in fla. you want living space conditioned.

[smittyii]

Down the road be aware that repair costs on a Carrier are probably going to be higher than on a Lennox.

Barrie

they must have a lennox parts house on every corner in las vegas!

[Freezeking2000]

they must have a lennox parts house on every corner in las vegas!

[/I]

cant buy lennox parts in Ct

[jcurryfl]

Thanks for everyone's inputs. Sounds like I need to have the company run through the load calc's and convince me that 4 tons is the right answer. If I went with the 4 ton Infinity 16 with the 2 - stage compressor, would the unit spend most of the time effectively running as ~ 2 ton unit with the 2nd stage available for peak summer heat loads? Would the Lennox XP-19 operate the same? Still not sure which config is right for my situation.

[RyanHughes]

Thanks for everyone's inputs. Sounds like I need to have the company run through the load calc's and convince me that 4 tons is the right answer. If I went with the 4 ton Infinity 16 with the 2 - stage compressor, would the unit spend most of the time effectively running as ~ 2 ton unit with the 2nd stage available for peak summer heat loads? Would the Lennox XP-19 operate the same? Still not sure which config is right for my situation.

If the unit is properly sized, it should spend a good amount of time in low stage. The XP19 will have more capacity in low stage with the scroll compressor. I just recently learned from someone here that to dehumidify, the ComfortSense 7000 will keep the blower on low and bump the unit outside to high stage to provide more dehumidification. Essentially, they're both good systems. You'll have to weigh all the features and benefits that each has to offer.

[lra]

Everyone has taken all of the good technical replies..so my thunder is gone. All good advice. I'd try to relocate the return in the kitchen though. Kitchens and bathrooms are no places for returns. If your wife cooks like mine, when dinner is burned evey day @7pm, the return let's us enjoy blackened food, with a side of smoke all through the air handler and every room in the house. No return in the bathroom for the same eye burning reasons.

[jcurryfl]

Ira - You're dead on with the dinner comment even though my wife's a great cook (maybe she'll read this and I'll get lucky tonight, or killed. LOL) I don't like smelling pork chops in half the house all night. I'm leaning towards the Lennox based mostly on Ryan's comments which seem to make sense even though the Carrier will probably work just as well. Thanks all.

Go Big Blue!!

[RyanHughes]

The Carrier on low will have longer run times with less capacity, so it should remove humidity well, too.

I'm just going by what M Kilgore said, "The Comfortsence will bump up the unit to high stage and leave the blower on low stage on a call for dehumidification. This removes more humidity. The IAQ uses low speed compressor and fan."

I don't think you can go wrong with either one. Lennox and Carrier make good equipment. I like the scroll compressor of the Lennox that allows the unit to switch stages on the fly, whereas the reciprocating compressor has to STOP to switch stages. Starting and stopping a compressor vs. switching on the fly, I'd choose the latter, though I wish the scroll had a lower net capacity on low stage. Carrier's Infinity 19 uses a scroll compressor, but it costs more.

Lennox combo: 17.00 SEER, 9.00 HSPF, 12.35 EER
Carrier combo: 15.80 SEER, 9.10 HSPF, 11.60 HSPF

[dash]

The Lennox may use a lower fan cfm on high stage to dehumidify,as does the Crrier,but I doubt it could be the compressor low stage fan cfm.