Sorry for the length, but grandpa has a history, I need valid opinions please.
I purchased my 2500sq ft single story ranch style (rectangle, porch on the front & back) home in 1990 under $100k. The house was built in 1962, everything in it was original and in great working condition including it's original heat & a/c. Rheem, 5-ton w/dual fans outside, 3/4 inch coolant pipes outside to inside, downdraft with 2-spd fan inside, Honeywell 3 relay control box, Honeywell thermostat.

I'm in Oklahoma, and the first summer, it wasn't handling the humidity, the service guy had a few years experience and replaced the thermostat with a programable Honeywell that did the job and made it comfortable. He said he thought the 5-ton was a commercial unit and estimated replacing the entire unit for $6-$8k, in 1990.

The next 10yrs, 1yr average electric bill - $100/mo, replaced one outside fan motor and about every 3yrs, added just a squirt of freon. The next 5yrs, 1yr avg elec bill - $125/mo, replaced the other outside fan motor, one capcitor, the inside fan relay would stick on or off occassionally, due to vibrations in the fan squirrel cage causing the belt to wear out, my mechanical husband removed, disassembled, rebuilt, reinstalled it for quiet continual operation. The last 2yrs, 1yr avg elec bll - $150/mo, the inside 2-spd fan motor stopped and was rewired to work on 1-spd, the inside fan relay sticks more often, will soon need it's 3yr squirt of freon.

For 17yrs, every service guy called to work on it has said replacing the entire system would make a big difference on our electric bill, but with the few service calls these years, it wouldn't make enough difference to justify the cost and I know there's nothing that will live as long as this one. The young green service guys have no idea how to work on it cause they've never seen one older than them and always said we have to replace it cause they don't make parts for it anymore, untrue we've always found what was needed. The older service guys that do know how to work on it (I fear ours will retire soon), have been impressed and amazed that it still works and is relatively economical, most everything has increased in costs over 50% from 1990, they request to give a quote when it does finally quit.

We've decided we've pushed our luck long enough and grandpa will soon tire. What is out there comparable to grandpa, that will do the job, hope to last say 20yrs with little service calls, will hold or make a difference on electric cost, and doesn't cost as much as a new house? I just started calling for quotes, some want to hire an engineer to determine what is needed, others say we need a unit on each side of the house, others push heatpumps. I want another unit just like grandpa but if it was a commercial unit we probably can't afford the purchase even with a home loan, we're two working class people in our 50s. I need to know what brands have capable units, do I need a commercial unit, a good guesstimated cost for the entire installtion, should we use a standard HVAC service/sales company or some mechanical company, and anything else that will relieve the panic attacks I'm now feeling. Heeellllppppp! Thank you for your time.

hvacservicetech_07

I'm not sure what would make this system comercial??? Almost every brand made today makes a 5 ton air conditioner. I'm not sure what part of the world you are in but here in southern Illinois a complete new system furnace A/c coil lineset etc... is most likely going to cost you 5,000 - 6,000 installed. The things you need to look at are, warranty, afue rating and the company doing the installation, make sure they have a good reputation if installed and maintained right any system will last you 20 years. OK, back to the comercial thing, when i think comercial i think rooftops or 100 ton chillers etc.. can you tell me why they told you this system is comercial??

hvac1000

Back in the day (1962) home A/C units were really built well. Heavy metal cabinet,great controls,semi hermetic compressors,ETC. YOU WILL NOT FIND A UNIT TODAY AS GOOD AS WHAT YOU HAVE and that is because they do not make them anymore.

Your electric bill went up because the cost of utilities went up and not because the unit is getting older.
New equiptment will breakdown and cost more to repair than the old over the years of usage.
New equiptment will use less electric to operate.
Finding old guys like me to fix your old equiptment will keep getting more difficult because we are getting old also and retiring.

If you buy new do not get the top of the line equiptment. It is a cost rip off. Do not get a variable speed motor they really do not save that much electric and cost 6X as much to repair. Get the standard 3 speed blower motor instead. If you have cold winter temps get the 90% + type furnace it will save you gas and is better than the 80% units.

The cost of repair for the new units is very high after the warrenty. Get the best warrenty you can for both labor and parts. Get a factory backed warrenty because many HVAC companies go out of business and if you get a non factory warrenty from them your warrenty goes out when the close or go bankrupt.

Good luck with your discission.

mcchasmo

I guess the service guy that said "he thought it was a commercial unit" was a lot greener than I thought and hadn't seen one like it on a residence before. The outside unit is larger than I've seen on other homes even in my neighborhood, but most of the other homes have replaced their's once or twice already. I would say it probably does look something like a small rooftop unit, a rectangle about 5' long 3' wide 3' tall.

I appreciate your comment, thanks.

mcchasmo

Thank you so much! You know what I'm talking about and understand where I'm coming from! That's the kind of advice I was looking for, I will put it to good use. I now have direction! You've help me a lot.

JackT

If your having problems with humidity, have several good contractors provide you with estimates for your home. To large of a system is just as bad as one that's to small. You may find that a 4 ton unit might be better for your size house. To big runs less, draws more current and may not remove the humidity. As hvac1000 stated there isn't much difference between a residential & commercial unit other than some options that you wouldn't need with most residential units. You may want to check with your local BBB for recommended contractors in your area.

T-Top

They don't make them like they use to thats for sure. Run that system as long as it will run. But if and when you do change it out why not go with the higher SEER unit we all like to save money on our electric bill. Yes the variable speed blower motor will save you money. A lot less startup amps and a hole lot less running amps. Most newer system come with a ten years parts and labor warranty. The government is cracking down I would say in five to ten years they will all be variable speed motors and compressors.

NorthernHeat

Yes, the old equipment was biult very well, but, if your equipment is over 15 years old it is not woth putting much money into repairs, especially at the labor rates we charge. I disagree about ECM motors tho. They are not that expensive to repair, since you will only replace one of the 2 components. They have ball bearing/bearings not found in many PSC motors. If the static pressure is right in the aplication they use much less electricity. They can be programmed with what is called a profile, so that if a unit is installed in a high humidity part of the country, the fan will dehumidify for a set period before it goes into a full cool period. They are true constant CFM motors so that they will do what they can to overcome dirty filters and homeowners who want to close all of their vents. I could go on and on, ECM motors are here to stay and are getting more dependable by the day.