I bought a Lennox AC and it has needed regular, expensive repairs over the years. You can read some other Lennox owners reviews on the Lennox Facebook page where a lot of them have similar complaints about reliability problems with Lennox. The qualified contractor I bought the system from no longer recommends Lennox and he was a premier dealer at the time I bought the system. They also had a class action lawsuit brought against them due to defective coils in their AC units which they eventually settled with their customers. You might want to do more research before you buy a Lennox AC.

I personally don't like Lennox HPs....would recommend looking at Trane or sister company American Standard, primarily because I think they are more reliable and for EDD-electronic demand defrost feature...

IMO

Different manufacturers are all pretty much the same as far as inherent reliability is concerned. If you had problems, it was either a predictable manufacturing defect (eg leaking copper coils - EVERY manufacturer has had this problem in recent years) or poor quality installation. Don't fret over brand, just get a quality install.

for above poster, not exactly true as far as HP condensers go. There are only several HP brands that offer true EDD-electronic demand defrost feature. The leader would be Trane and sister company Am Standard. Want to know the benefits of EDD? It eliminates/reduces unnecessary defrost calls over the cheap time/temp defrost method. Not to mention the wear and tear to the condenser, And saves money from having strip heat kicking in on these unnnecessary defrost calls.

IMO

Are you sure you have 12 returns and not 12 supply vents? Is the installer providing a Lennox coil? How was the 4 ton size determined? Did anyone do a cooling load calculation? Is the heat pump going to be installed as part of a dual fuel configuration?

Load calculation... 60 year old home and 20 year old Heat pump.

If the calculation isn't right by now there isn't much hope is there? (If you do find it is wrong, don't forget to replace the entire duct system.... otherwise the new system will struggle under extremes in weather.)

Trane the leader of the heat pump free world, LOL. I highly doubt it. I haven't sold that many heat pumps, but I've seen enough Trane gimmicks to last me a lifetime... I can tell you that much.

They only like to make you think they are special. In my experience they're not.

Tiger, you almost have to work for Trane in some form.

Obviously the above poster is not as smart as he would have you believe if he is unfamiliar with EDD...a gimmick, hardly...

IMO

you are right--it is 12 supply vents

Tiger, a heat pump is best designed for warmer climates. Many of these locations have average winter temps at or above 32 degrees Fahrenheit. So the problem you suggest you have isn't present 99% of the time. It's the cause and effect of taking an ant hill and making it into a mole hill. It's not the problem you think it is. You are more likely to have installation problems that are causing situations.

With that said you can put a heat pump in a colder climate, however what is going to happen to poor little heat pump during heavy snow? EDD is not going to do much for you in such a situation.

The gimmick part is making you think there is a problem where none exists only to try to sell something. One dimensional thinking.

Houston weather winter averages:

With time / temp defrost how likely is there going to be a problem with defrost cycle given the normal ambient conditions listed above?

Cue Final Jeopardy music...... (don't listen to me I have no idea what I am talking about.)

Hint: Normal heat pump operation does not create a defrost requirement. Defrost requirement is due to lower out door ambient conditions and long run cycles to heat the home. Humidity content in the air or rain can effect this as well with lower out door temps.

What's your solution to an all electric house located in the northern part of the US?

Mike if you were in the HVAC service business, would you focus on solutions for areas of the country in which you do not serve?

While I offer advice on this board for areas in which I do not serve, it is not my goal to service these areas. It would be the same if you called me on the phone and you live outside my service areas.

My goal is merely to inform, for those befuddled with Manufacturer induced geek speak and 'try' to separate fact from fiction. Probably pointless in doing so, but I drink my coffee of a morning while I am here.... so you have a little understanding of why I even come to this board.

A heat pump's purpose and design is to pull heat out of the outdoor air and place it indoors (heating operation in winter time).

The problem is as it gets colder outside there is less heat in that air and this not only causes the heat pump to run longer it also causes the refrigerant pressure to drop below freezing. This in turn causes the coils of the heat pump condenser to frost and /or freeze. This in turn cause detrimental (heat) performance until eventually the coil must be defrosted.

You can put any kind of fancy control on this to help with the process of defrosting the heat pump. But because of the freezing nature and (typical) poor performance in colder weather, I would not recommend a heat pump for a colder climate. (Below 32 degrees, natural gas and propane will always have their place in some locations.)

As stated before EDD will never go far enough (for a colder climate) because you will also have to contend with snow fall / or ice encasing the heat pump (depending on location).

With that said, EDD is over kill for a warmer climate. It may never be really needed in a warmer climate. In a colder climate a heat pump, while not a good choice for such a climate could be used as supplemental heat for when the climate is appropriate to use it. As long as the user understands the limitations, but in this world and to this day you have people who set 'a crazy number' on the thermostat thinking the magic box outside will do whatever you want.

While Houston / Katy / Cypress is a perfect heat pump climate, they are quite rare here..... because people enjoy the occasional chill as opposed to spending the extra cost on a heat pump or the home has natural gas and a heat pump is unnecessary for such a short winter season in this location.

Remember these functions /choices are part of the design of a system. The nature of this market is to sell you a 'gimmick' that will only work under a certain set of circumstances.

You don't have to agree with me. I've given you enough information in this thread to prove it to yourself.