I have a split system - rooftop 1.5 ton condenser, with an old Gaffers and Sattler handler/electric heater. The handler has been inspected and is shot (27 years old, clogged, etc).I'm only getting a 10-14 degree temp drop, and that is not cutting it in this south facing LA condo. Two different contractors have proposed the following: 1) Replace the air handler, although there may be a warranty issue since the 5 year old roof mounted condenser was installed with no filters, so there may be debri getting into the new handler. 2) remove the air handler, cut a hole in the roof, and install a new heat pump. This contractor has already done the same on another condo with good results. I'm sure #2 is more costly, but it sounds like the way to go, since I was told replacement of the split system air handler restricts it to 10 seers. But I just wondered will the single system (heat pump) be more costly to replace if needed later? Any pro opinions on this and the whole project are much appreciated!

You've been given strange and silly advice. A new roof-mounted split outdoor unit would have no place to install filters, so there wouldn't be such problem of warrantee. If you leave the old indoor unit and install a new outdoor unit, then a filter/drier is wise.

The only hole you would need is for running the tubing and wire between the inside and outside units, As this is normal installation, there should be no problem worth mentioning.

The instruction about the SEER should be opposite; keeping the old indoor blower unit could restrict it to 10 seer; but installing a matched indoor and outdoor unit would allow any seer.

A 1.5 ton unit is a toy for experienced installers and usually the smallest to be made as ordinary heat pumps. Don't worry about replacement; if you get a quality unit installed by a competent, certified installer who leaves no leaks, you won't replace it for decades.

Thanks for your reply, Harold. I think I did a poor job of explaining what they told me, or misinterpreted it.

1) They told me the best air handler with a heater that would fit my hallway are only 10 seer, so that would limit a higher rated rooftop condensor.

2) The second contractor proposed a custom job where the whole unit is on the roof (no split system -I don't know what you call that). He said he would not need inside access to repair in the future with such a configuration, since the whole unit would be on the roof. He did this for my neighbor, and he raves about the performance (I have not seen). I presume he would have to cut air intake and outake holes since he said there would be no air handler inside.

I sure am having problems with this. These are my 3rd and 4th A/C contractors. The first overcharged my unit, and told me I had a leak in the condensor, "but it is not worth looking for since they are too hard to find" The second, took some freon out that the first guy put in, but did not want to deal with the dirty/clogged air handler since it is so hard to access. These last two guys come with good recomendations. However, after 1 week, I am still waiting for a quote from both of them! I have spent hundreds of dollars, and still have the same weak system since the air handler is so clogged.

Bob

I would be a little confused as well.

As to replacing the airhandler - Diffferent companies make airhandlers and they are all different sizes. More efficient coils are usually larger but with a more efficient coil (one with an expansion Valve (TXV) you can use a smaller coil and get the same cooling out of it. You might want to explore some other brands.

As to the roof top unit - They are called Package or gas/electric units or package heat pumps - it might be the way to go. If they install a return Filter grill then you would have access to change the filter from inside the house. They would need to install a roof curb and seal the roof connections as any penetration through a roof is a potential leak.
The main advantage would be you have a wide range of efficiencie to choose from. Trane make package units from 10 seer up to 16 seer. They also have Variable speed HP's that would be more comfortable for you as well.

The only real disadvantage to a package unit is that if you need to replace the a/c you need to replace the whole unit.

From a distance, it looks like the package unit would be the option I would favor.

Call them back and tell them you want a bid by a date or you are calling someone else for bids.
Good Luck

Steven always gives great technical advice. I would only add that installing rooftop package units is more likely done by contractors that do commercial work and are more aware of roof leaking problems and sealing against them using proper mounts on the roof and therefore might be a way to select out the less experienced. Rooftop packaged units are what cool the mall stores and commercial buildings everywhere. A rooftop unit would be easier to maintain and service for a repairman rather than having to come inside and work in a tight space if you keep the split system. Replacing a packaged unit in the future would mean there would be almost no work to be done inside when a new unit is placed on the roof mounts. A packaged rooftop unit is charged and sealed at the factory, so there should be less likely future scams to recharge the unit until a leak ever occurs due to earthquake trauma or an airplane hitting the roof. As the installer doesn't have to attach tubing because it is already done for him, there is less likely a mechanical sealed system failure problem due to poor workmanship.

It is possible to use a new matched split system if there is space near the old blower unit if you have some wall space that can be spared. If it is a small apartment, then the rooftop unit is a way to go.

Thank you both for your expert advice. It sounds as if the packaged rooftop system is the way to go for the long term. It will cost more, but ultimately be a better system.

Gee Harold, The efficiency of the variable speed is well documented inspite of your last statment

The Cost savings are determined by the wattage of the motors under similar operating conditions and times. In other words- the moter will opperate at approx 1/4 the cost of a average motor so you can run this variable speed motor full time for the cost of a average motor running as you stated only 1/4 of the time. If you ran the VS motor in auto then the costs would be 1/4 the cost of running an average motor the same way. Apples to apples

I think that running a motor full time so it increases comfort, increases filtration efficiency and capacity, improved the seer rating of ANY a/c system, allows for increased dehumidification AND in a heat Pump System gives you increased supply air Temps would be a good thing.

I belive you know a lot more than I on Hydronic system but dont try to tell me, Based on your last statement that yoou know more than I on this matter.

Have a good weekend

Efficiencies can only be documented under controlled factory test conditions. The efficiency of a motor is a matter of input vs output; but that is not a direct relationship to the efficiency of a system. As you said:

In reply to:

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under similar operating conditions and times.

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Apples vs Apples. There is no way YOU can run an air conditioning efficiency test in the field that has meaning after it is installed in a home. Don't be fooled by a name. Work in factory testing labs is possible for a man named Moe.

A high efficiency system can actually lose more efficiency by blowing air out the seams of leaky duct connections for a full hour instead of shutting off (see the ACEE web site.) The SEER rating will usually be optimistic when the unit is actually applied in the field. Constant circulation is often the complaint of a breeze by heat pump customers; that is why the older generation buys hot water systems and floor radiant.

Once a system is installed, constant circulation can not improve a SEER rating because it is a rating done at the factory. It does help increase dehumidification AND it lowers the duct temperature where cheesy insulation becomes soaked and drips water from the registers. Assuming that ALL situations are improved by using high tech can lead to disasters with untrained installers and repairmen.

Constant circulation and its benefits are not new, the concept was promoted in the 1960's when I installed speed relays for it in the homes of White-Rodgers executive engineers. My 1978 Fedders heat pump output temperature was improved by using a gas line temperature sensing switch to go from high speed to low on the heat pump heating cycle while I was the Fedders national training manager; although it did up the running amps. The Lennox two-speed heat pumps and air conditioners I installed in 1980 provided excellent cooling and heating; but the builders at times hired electricians to check out the compressors and the 9-volt batteries in their VOM's burned out the 6-volt sensors in the compressor windings at BIG bucks because they never read the bulletins and knew EVERYTHING.

Don't get so wrapped up in your self-importance that you discount the knowledge and experience of those that taught your generation the basics and advanced beyond the marketing words. There are hundreds of thousands of certified techs and many thousands of instructors who were there before you. Lest us know when you become the official Trane instructor for the nation. It is cute that you want to try to impress someone who taught the generation before you how to speak HVAC jargon; I'm sure it impresses the laymen you serve; but, it bores me to hear things repeated the same way for 40 years by people who recently discovered them. You have yet to realize the real differences in efficiency between systems. As long as you stay insulated from the majority of BAD techs, you can preach how great high-tech is.

Get used to the future. After the government declares that ALL heaters must be over 94% efficiency and variable-speed becomes the standard, there will be NO MORE marketing impressiveness left and homeowners will look for GOOD ductwork.

Harold,
I was talking about the efficiency of the MOTOR - It is evident that you keep moving the discussion into new areas (system efficiency & Duct Leakage) so you can always be right. I do not know what your problem is but I am getting tired of the rants.

I am not sure this forum is worth putting up with you so at the very least- this will be the last time I respond to your messages. I am still unsure if I will continue withthe forum.

If I want someone to continually point out imaginary shortcomings or lack of knowledge - Well I have a Mother In Law all ready

I do not know what your problem is but I am getting tired of the rants.)

,,, I can tell ya right off the bat what his problem is,, no one knows anything but Harold, Harold is always right, He hates DIY's , He dont think anyone should or could know anything other than a feild their in, He thinks changing a 60 watt light bulb takes a degree in electrical engenerring,He never has leanerd some folks are multi talented (thats can do more than one thing Harold thought id explain that to ya since it wasnt cut and pasted to a link for reference) He tells me i dont understand combustion with diesel fuel Plese harold i work with Diesel engines and them Injector nozzles see far far greater pressure than a wimpy Oil Burner nozzle of about 100-120 PSI. Injectors are in the Thousand's of PSI and i understand how spray patterns have to be right , But their is no sence in arguing with a Brainless Man who thinks he is gods gift to HVAC, Whene in reality he is Making him self loose credibility time after time with his insults and Rants.. What he needs is someone to jack slap him a few times maybe thene he would see reality , for the first time in his life .

All in all Harold has stired up crap in other forums besides thois one , Harold if you can not answere by your own knowledge with out cutting and pasting , to links . Can not answere with out having a tone of a grizzly bear thats ass hit a camp fire , Remove your self from this place Their is enough experinced well knowledgable folks to help and the world is not going to end wether u belive it or not , A mecanicaly inclined person can bleed out a oil burner for crist sakes with out combustion test equipment . Nothing has changed Harold i get so tired of that rant whene someone runs out of fuel once fuel is restored if it was combusting right ( thats Burning of a fine spray of fuel being ingnited by the electrical arc from the igntion elctrodes, Which depending on setup could be constant or intermetant, Harold) It sure as hell will be burning correctly once the air is removed from the syestem . and a full charge of fuel is restored to the nozzle either soild or hollow cone depends again on set up . I think i know little more than u think Mr HVAC Tough guy ,