Cool Talk with Hartzell's | Your HVAC Questions, Answered!

Give Use A Shout DAVE: If you've got an old round Honeywell thermostat on your wall, the kind with the little mercury switch inside, you're sitting on a small environmental hazard. I pulled one off a wall in Okarche last week, and when I tilted it, you could see that silver bead of mercury rolling around in the glass tube. That's toxic stuff. Most people have no idea they're th...

Give Use A Shout DAVE: If you walked into a grocery store in Kingfisher last week and noticed the coolers look a little different, or you're a business owner wondering why your walk-in cooler guy is suddenly talking about new refrigerants, you're not imagining things. The whole refrigeration industry just went through the biggest change in 30 years, and it's not just affecting resta...

Give Use A Shout HOST A: Trane published a piece on their consumer blog that quietly puts numbers on something the trade has been arguing about for years. National range for a residential AC tune-up. $120 on the low end. $350 on the high end. HOST B: That is a wide range. I'm Dave Hartzell at Hartzell's Heat & Air in Kingfisher, Oklahoma. 45 years in the trade, Master HVAC license. O...

Give Use A Shout HOST A: Here is something that should bother every gas-furnace owner in Oklahoma. The carbon monoxide detector in your hallway, the one you bought at the hardware store for 25 bucks, is built by federal regulation to ignore the kind of CO leak that will quietly poison your family over the course of a winter. HOST B: That is a sentence I want you to back up. Because I think most pe...

Give Use A Shout DAVE: I started in this trade at 18, pulling sheet metal in 105 degree attics for $4.50 an hour. Forty-five years later I sign my own paycheck in Kingfisher, Oklahoma, and there are five distinct rungs between where I started and where I am now. Most homeowners do not know which rung the guy walking up their driveway is on, and that is exactly what decides whether their AC runs an...

Give Use A Shout HOST A: Here is a complaint we hear every July in Oklahoma. The thermostat says 72 degrees. The AC has been running. The house still feels sticky. HOST B: And the homeowner's first instinct is to drop the thermostat to 70. Then 68. I'm Dave Hartzell at Hartzell's Heat & Air in Kingfisher, Oklahoma. 45 years in the trade, Master HVAC license. On Cool Talk I cover...

Give Use A Shout HOST A: Dave, you got a call last February. Homeowner in Yukon installed an ACiQ mini-split in his detached garage workshop the previous summer. The unit worked great. Then a 6 degree morning hit and the heat pump went into defrost mode and never came out. The garage was 38 degrees by the time he called you. HOST B: That is the operating temperature range issue in a nutshell. ACiQ...

Give Use A Shout HOST A: Dave, a homeowner in Piedmont added a 400 square foot sunroom and called you for a mini-split quote. He had two other quotes already. One was 18,000 BTU, one was 12,000 BTU, you came out and quoted 9,000 BTU. He thought you were sizing too small. HOST B: He was thinking the way you would think about a window unit. More tons, more cooling. Mini-splits do not work that way....

Give Use A Shout HOST A: Here is the question I get more than almost any other one in the spring. I want to use my garage. I want to actually spend time out there working, working out, hanging out with friends, restoring a car, whatever it is. But it is a hundred and four degrees in there in August and twenty degrees in February. What do I do. HOST B: And the default answer most people land on is...

Give Use A Shout HOST A: I want to start this one with a scene almost everybody listening will recognize. You walk through your house in August at three in the afternoon, and most of the rooms feel fine. Then you open one specific door, the bonus room over the garage, or the back bedroom on the west side, or the addition the previous owners put on, and it feels like you walked outside. Ten, twelve...

Give Use A Shout I am starting a part of The Standard series most contractors skip: ACCA Standard 12, the whole-home performance and comfort evaluation. New equipment alone does not fix a house that is fighting you. This episode walks through what the standard actually asks, envelope first, blower door testing, duct measurement, thermal imaging, and the order you fix things in so the money lands w...

Give Use A Shout Oklahoma storm season does not just knock out your power, it can fry the most expensive parts in your HVAC system. I explain how surges actually damage a unit, which components die first, why a tripped breaker is sometimes the cheap version of bad news, and what surge protection is worth installing before the next round of storms. If you live anywhere storms roll through Central O...

Give Use A Shout People hear closed loop and open loop geothermal and have no idea which one fits their property. I break down the honest difference: what each one is, what each costs to install in Central Oklahoma in 2026, what can go wrong with each, and why your soil and your well decide the answer more than your neighbor does. If you are weighing geothermal on acreage, a small lot, or a proper...

Give Use A Shout When a house AC fails you sweat. When a restaurant walk-in fails, thousands of dollars of product start a countdown clock in the middle of dinner service. Refrigeration is a different animal from comfort cooling: bigger temperature lift, grease-felted condenser coils, door gaskets, defrost systems, and no cool evening to recover in. Why Oklahoma deep summer is the killing season f...

Give Use A Shout It is 105 degrees, your AC has run nonstop since noon, and the house is stuck at 78. Broken? Usually not. Central Oklahoma systems are sized to a 97 degree design day, and deep summer blows right past it while the equipment loses capacity exactly when the load peaks. I walk through what extreme heat does to compressors, capacitors, and attic ductwork, what is normal in a heat wave...

Give Use A Shout I pulled ten years of our own service records, 3,171 jobs, and counted which month actually kills air conditioners in Oklahoma. Everybody guesses August. The data says June, and it is not close: 47 no-cool calls in June against 25 in August. The first heat wave finds every weak capacitor, slow refrigerant leak, and plugged drain line that winter was hiding. What actually fails, by...

Give Use A Shout HOST A: Here is a free tool that nobody uses. NATE, the certification body for HVAC technicians, runs a public verification page. You type in a tech's NATE ID number, and it tells you in real time whether that person actually holds the certification. HOST B: Wait. Real time. From the actual certification authority. For free. I'm Dave Hartzell at Hartzell's Heat &amp...

Give Use A Shout HOST A: Dave, a homeowner in Hennessey installed a Nest two summers ago and was disappointed when his electric bill went up that July. He bought the thermostat specifically for the savings. What was happening? HOST B: His Nest was set on a learning algorithm that defaulted to hold the house at 72 around the clock. He never set up a schedule with setbacks. The thermostat was runnin...

Give Use A Shout HOST A: Dave, you got called out to a 7 year old geothermal install in Hennessey last summer. The homeowner said the system "worked fine" in the first two years and now the back of the house is hot in July. The unit is running constantly. What did you find? HOST B: The loop was undersized by about 30 percent. The original installer used a flat rule of thumb of 600 linear...

Give Use A Shout HOST A: Dave, a homeowner just south of Kingfisher called for a geothermal quote. He has 5 acres, a working irrigation well that produces about 25 gallons per minute, and a 3,000 square foot house. He asked you for an open loop quote because his neighbor has one. HOST B: And the neighbor's open loop probably works great. But before I quoted him I asked three questions: what i...

Give Use A Shout HOST A: Dave, you wrote a quote last week where the ductwork was $6,800 and the AC and furnace combined were $7,200. The homeowner asked why the ducts cost almost as much as the equipment. What did you tell her? HOST B: I told her her house was built in 1986 and the ductwork was built in 1986. The original installer ran flex duct through a 130 degree attic, joined it with cloth ta...

Give Use A Shout Dave Hartzell answers the question Oklahoma homeowners keep getting wrong: is a heat pump enough in a Kingfisher January? The old line that heat pumps quit in cold weather was true 15 years ago. It is not true now. A modern variable speed unit holds rated output down near 5 degrees and still pulls real heat below zero. I break down the operating cost math against natural gas, prop...

Give Use A Shout If you got a quote for a new air conditioner in 2026 and it came in 20 to 30 percent higher than you expected, I want to walk you through where that money is actually going. R-410A is phased out. New systems run R-454B or R-32, and the refrigerant change, the redesigned equipment, the leak sensors, and the new tooling on my side all hit the same year. Most of that increase is not...

Give Use A Shout HOST A: Dave, a homeowner called you yesterday because their AC ran fine in May and now the house won't get below 78 in the afternoon. What was your first question? HOST B: How long since the last refrigerant top off. They said two summers ago, paid 380 dollars to add freon. That tells me everything I need to know before I even drive out there. They have a leak. They have had...

Give Use A Shout HOST A: Here is the thing nobody tells you about your thermostat. The number on that little screen is probably wrong. Not broken wrong. Strategy wrong. HOST B: That is a strong opening. Walk me through it. I'm Dave Hartzell at Hartzell's Heat & Air in Kingfisher, Oklahoma. 45 years in the trade, Master HVAC license. On Cool Talk I cover the stuff central Oklahoma hom...