Dr. Kool‘s

Where Good Neighbors and Good Servicemen Meet

AC & Heating—Before You Buy

The time to make quality decisions is before you install new AC and heating equipment. There are lots of brands and numerous designs to choose from—it does make a difference! You need a contractor you trust, but it helps to have some background information as well.

SEER (Seasonal Equivalent Energy Rating)

If you remove a 7 SEER AC system and replace it with a 14 SEER one, your new utility cooling cost will be 7/14 or 50% of your old cooling cost. Using R-22 equipment, the highest SEER rating you can expect is 14—that's pretty good. To exceed a SEER of 14 requires fancy extras that can lead to expensive repairs later. They call it the law of diminishing returns. Let me give an example.

I inherited a customer from someone who had installed a variable speed blower nine years ago. The motor needed replacement, and I gave him a price of $1100 installed. He asked whether I could replace it with a cheaper motor, and I did, but it also required a new control board. I charged him about $300 for the new motor (installed) and $125 for retro-fitting to the non-variable speed control board. (If I had done the original installation, I would have recommended a fixed speed blower.)

Keep it Simple

Unless there's a good reason for a complicated AC/heat system, I recommend high efficiency basic equipment. I avoid variable speed blowers, multi-speed compressors, zoned systems, and heat pumps.

Often the utility savings is small, or the comfort advantage insignificant. The inflated cost of future repairs can more than offset any immediate user benefit, and repairs could be a nightmare. You might have to try several repairmen, before you find someone who even knows how to fix your problem.

Having said all that, it's your choice. If you want complicated equipment, you should be willing to pay for the equipment, and for the repairs that will someday be needed.

Expansion Valve (TXV) Metering

If your contractor is installing a new evaporator coil, my advice is to always specify TXV (expansion valve) metering. You don't have to understand what I'm about to say. All you have to do is trust Dr. Kool. A flowrator metering device is simpler and cheaper, but it's NOT the best choice. Just tell your contractor you want an expansion valve evaporator coil.

Expansion valve metering may also require a start kit, and it might add $100-$200 to the installation, but it's worth it. A TXV increases your efficiency, and even helps protect your compressor. Modern TXV's are of the screw-on type, and inexpensive to replace should there ever be a problem.

Programmable Thermostats

Programmable thermostats are right for some people, but terribly wrong for others. You should have a fairly consistent schedule.

There must be enough AC power for recovery, there should be a reason for the setback, and you must be able to program and operate the electronics. You should also teach others how to use the thermostat in your absence. (Desperate customers have asked me to remove the programmable thermostat, and replace it with a regular thermostat.)

Quality Equipment

I learned early in my repair career that some brands of air conditioners and furnaces are of higher quality than others. I'm talking about basic equipment, without the fancy extras I mentioned above.

A huge quality factor is the ease and expense of repairs. For over 20 years, I have continued as a dealer for a brand I will call ABC. At this time, I can charge only $225 to replace an ignition control for ABC, but have to charge $450 when replacing the same control for another brand.

"Why the difference?" you ask. The part is more expensive, and it takes twice as long to do the job.

Before you sign on the dotted line, here's the question you might ask your contractor: is the equipment you plan to install easy to maintain and inexpensive to repair? Is it durable?


After January 1, 2010, it will be illegal to manufacture R-22 condensers. We have to face reality, and convert to R-410a equipment in a judicious manner.

Most air conditioners are what we call split systems. This allows condensers and evaporator coils to be changed independently. To convert to R-410a requires that both the condenser and the coil be changed at the same time.

What happens when a R-22 evaporator coil fails? I prefer to convert over to R-410a at that time--unless of course, the condenser is fairly new. Under that circumstance, I recommend staying with R-22 for a few more years.

The old Freon should still be available for about 20 years, but the price will increase as it did for the automotive conversion that started in 1993.


If you are installing a new outdoor condenser, I recommend that the compressor be a Copeland scroll. Their compressor gives an extra SEER point, without increasing the size of the condenser coil. Copeland has manufactured their scroll for over 20 years, and it have shown itself to be of the highest quality.

I don't usually recommend one brand over another, but I recommend the Copeland scroll as a public service. Other manufacturers have tried to manufacture a scroll, but they have not yet proven to me, their quality.

Gas Furnace Heat Exchangers

Most warm air gas furnaces manufactured before 1992 have heat exchangers that are of the clam-shell design. The heat exchangers are much more apt to crack than other designs. These furnaces should be watched carefully—checked every fall! Some clam-shell heat exchangers are still being used in new furnaces.

The best design on the market has a tubular heat exchanger which is not likely to ever crack. My furnace has a stainless steel, tubular heat exchanger, and that's what I recommend. Because it's made of stainless steel, the heat exchanger won't rust, and because it's tubular, it won't crack. This is the ultimate in gas heat safety.

Gas Furnace Controls

When it comes to controls, there's an enormous difference between furnaces. All modern furnace controls are solid state, but some have the electronics built into the gas valve, while others have the electronics mounted on a printed circuit board. I like the latter, and despise the former.

Electronics Built Into the Gas Valve

They call it the Smart Valve; I call it the Smart Aleck valve. It can be a diagnostic nightmare, and a new Smart Valve is not cheap.

Control Board Circuitry

Furnaces that depend on control board circuitry are the easiest and cheapest to diagnose, and the least expensive to repair. The durability of the two control systems is about the same.

Gas Furnace Warranties

Some companies give a 20 year heat exchanger warranty, while others give a lifetime warranty. Which one has the lifetime warranty? The stainless steel, tubular heat exchanger. Let me repeat what I said earlier:

Before you sign on the dotted line, here's the question you might ask your contractor: is the equipment you plan to install easy to maintain and inexpensive to repair? Is it durable?

Koolness Requires Planning,

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Dr. Kool


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