I have a 14 year old American Standard Heritage 12 (12 SEER & 9.25 HSPF - 2.5 ton) with Variable speed air handler. Our house is about 2100 sq ft with good windows and good insultation.
The unit is working fine right now but would it pay to upgrade to a newer mor eff. Unit like the Heritage 18 or 20.
Live in the north east near Philly. We are totally electric. Our 1st unit (builder grade) lasted about 10 years. This one is 14 years old but running good. Will the newer ones give more bang for the buck? Is 14 years a good time to replace. We would also like to add an air cleaner unit which we don't have now.

Thanks for your time.

The one you have now might run longer than you think. If you like to spend money then buy a new one. There are factory rebates and federal tax credits to consider if you buy new now but who knows what the future may bring.

If you are going with the 18 to 20 SEER you better make real sure the person that does the startup and charging really,really,knows what they are doing. In our testing at the university we found that as little as a one ounce charge differential between right on the money and one ounce off could cause the SEER rate to drop to 16. These are very critical charge machines that need to have the charge calculated and weighed in or charged by superheat or subcooling depending upon your flow control device used. If you are going to pay the big money make sure it is done correctly.

Also be sure to get at least 2 better yet 3 estimates and follow the attachment below.

OK since you said "The one you have now might run longer than you think"

Do you think I can get 5 more years out of this? It's running fine I just thought it would only last 10-14 years

Mt main unit is 30 years old. Getting 5 more years is posible but as you are well aware it is all a roll of the dice.

There really is no predetermined time that a unit will "last". You may have a compressor or fan or wiring go bad tomorrow, or it may last another twenty years problem free. If unit is still working great, I suggest having yearly preventative maintenance done and stick with the unit until craps out. This is of the old vantage,, if it isn't broke, don't fix it. The new seer ratings of which you are thinking about upgrading to are extremely spendy, and I have a hard time telling people that it will pay for itself in the long run, truth is, it won't.

Thanks
One more question.
I change or check the filter monthly. I vacuum the inside unit and the coils inside yearly. I hose the fins on the outdoor unit yearly. The installer told me the unit never needs oiling or charging unless there is a leak. So what preventative maintenance do I need?

If those SEER and HSPF numbers are correct, you might reduce your cooling costs a little by upgrading to a newer unit, but not much on the heating side.

My aging York is pushing 20, so you may have more years than you think. It couldn't hurt to get a periodic checkup, otherwise ride it until it dies.

Thanks
One more question.
I change or check the filter monthly. I vacuum the inside unit and the coils inside yearly. I hose the fins on the outdoor unit yearly. The installer told me the unit never needs oiling or charging unless there is a leak. So what preventative maintenance do I need?

That about covers it, just keep up the good job and hope for years of trouble free performance.