Greentech Engineering Heating & Air Conditioning

08/28/2026

Can a cooling-only A/C system with electric heat be replaced by a heat pump?

Sometimes—but the project involves more than changing the outdoor unit.

At this Irving home, the older R-22 outdoor equipment provided cooling only, while the indoor equipment supplied electric resistance heat. We replaced that configuration with a nominal 1.5-ton Daikin R-32 heat pump and a First Co. ceiling air handler.

The new heat pump supplies both cooling and primary heating. Auxiliary electric heat remains available when the thermostat and equipment controls call for it.

This was equipment replacement and a change in system function. The old R-22 condenser was not retrofitted or converted to use R-32.

For this specific project, Greentech applied the anticipated $1,600 Oncor incentive as an immediate invoice discount before installation and before submitting the incentive application. We then handled the application, and Oncor later approved the project incentive.

Eligibility, equipment requirements, funding, approval and amounts vary by project and program rules. This completed project’s $1,600 discount does not promise that another installation will qualify for the same amount.

Replacing a straight-cool A/C with electric heat? Compare the complete indoor-and-outdoor match, controls, auxiliary-heat design and written incentive terms—not only the outdoor-unit size.

Read the complete Irving case study: https://www.greentechdfw.com/blog/irving-daikin-r32-heat-pump-upgrade

08/26/2026

How many repairs are too many for an older upstairs HVAC system?

There is no single answer for every home.

At this two-level Frisco home, the homeowner reported that the approximately 16-year-old upstairs system had become less efficient, required frequent repairs and was costing more to maintain. This project replaced the upstairs system only; the home’s other HVAC system was not part of the work.

The new matched equipment included:

A nominal 3-ton Daikin R-32 air conditioner

A horizontal Daikin evaporator coil

An 80% AFUE Daikin gas furnace

The exact combination is AHRI-certified at 34,400 BTUH, 15.2 SEER2 and 12.0 EER2.

An older system should not be replaced just because of its age. Before approving another repair, compare its condition, repair history, equipment compatibility and continued maintenance cost.

See the full before-and-after Frisco case study:
https://www.greentechdfw.com/blog/frisco-upstairs-hvac-replacement-daikin-r32

08/21/2026

Should a new HVAC system automatically match the tonnage printed on the old equipment?

No. The old size is useful background information, but it should not become the new specification without looking at the home’s calculated load, the proposed equipment match and the connected ductwork.

At this Coppell home, the previous systems were nominally rated at 5 tons downstairs and 3 tons upstairs. Separate load calculations and matched-equipment data supported nominal 4- and 2-ton Daikin FIT replacements.

The comparisons were:

• Downstairs: 39,638 BTU/h calculated cooling load and 45,500 BTU/h of certified matched-system capacity
• Upstairs: 18,504 BTU/h calculated cooling load and 23,200 BTU/h of certified matched-system capacity

The project scope also addressed return, supply, branch-duct and plenum changes. Replacing the boxes without considering how air moves through the home would leave out an important part of the system.

This does not mean every 5-ton unit should become a 4-ton unit or every 3-ton unit should become a 2-ton unit. It shows why each home—and each served area—needs its own evidence.

Read the complete Coppell case:

https://www.greentechdfw.com/blog/frisco-5-ton-daikin-ac-gas-furnace-replacement

08/12/2026

Should your new HVAC equipment automatically have the same tonnage as the old system?

Not necessarily.

At this McKinney home, the previous equipment was nominally rated at 3.5 tons. A confirmed Manual J calculation and the documented performance of the proposed equipment match supported installing a nominal 3-ton Daikin FIT system instead.

Here is the important distinction:

• Nominal tonnage is an equipment-size category.
• Manual J estimates the home’s design heating and cooling loads.
• AHRI-certified capacity describes the tested performance of a specific equipment combination.

For this installation, the matched combination has a certified cooling capacity of 33,600 BTU/h. That number is not the home’s Manual J load or a field measurement.

The project also received a confirmed $1,500 Oncor incentive. That amount was project-specific; eligibility, funding and incentive amounts vary.

This case does not mean every 3.5-ton system should be replaced with a 3-ton system. It shows why homeowners should ask what calculation and equipment data support a replacement recommendation.

Read the complete McKinney case:
https://www.greentechdfw.com/blog/mckinney-3-5-ton-to-3-ton-daikin-fit-manual-j

08/05/2026

Replacing two HVAC systems in the same home does not necessarily mean selecting identical equipment twice.

At this Grand Prairie home, one served area received a nominal 4-ton Daikin two-stage R-32 system, while the other received a nominal 5-ton system. Each installed combination had its own AHRI-certified capacity and efficiency ratings.

The project also addressed the return-air side of the installation. One additional 14-inch return-air duct was added for each system, together with related plenum, transition and flex-duct work.

The completed project received a $1,430.46 Oncor incentive, passed through to the homeowner as an instant discount. This was a project-specific amount; eligibility, funding and incentive amounts can vary.

The lesson is not that another home needs the same capacities. It is that each system should be evaluated using its served area, documented equipment match and air-distribution requirements—not just brand or nominal tonnage.

Read the complete Grand Prairie case study:

https://www.greentechdfw.com/blog/grand-prairie-two-system-daikin-ac-replacement

Greentech Engineering Heating & Air Conditioning — DFW HVAC
Your comfort, our priority.

07/28/2026

Why was the upstairs AC not cooling at this Little Elm home?

Our diagnostic work confirmed a leaking evaporator coil in the home’s approximately 10-year-old Lennox system.

Refrigerant was added as a temporary measure, but that did not repair the leak. The homeowner later approved replacement with an AHRI-certified matched 3-ton Daikin R-32 system.

Verified system information:

• AHRI Reference No. 214855794
• 15.2 SEER2
• 12.0 EER2
• 34,400 BTU/h
• Recorded post-installation temperature difference: 16°F

The 16°F reading was one documented post-installation measurement and should not be interpreted as a complete commissioning test.

The project includes a 1,095-day Greentech labor warranty, subject to the written warranty terms.

Read the full Little Elm case study to see how the project progressed from an upstairs cooling complaint to diagnosis and matched-system replacement:

https://www.greentechdfw.com/blog/upstairs-ac-not-cooling-little-elm-tx

Greentech Engineering Heating & Air Conditioning — DFW HVAC
Engineers, Not Salesmen.
Call us :(469)551-6806

07/24/2026

New Daikin FIT HVAC Installation in Dallas, TX 75248

We recently helped a Dallas homeowner replace an aging HVAC system with a nominal 3.5-ton Daikin FIT variable-speed air conditioner, an 80% AFUE variable-speed gas furnace, and a Daikin One Touch communicating thermostat.

This project involved much more than replacing the outdoor unit. Our work included:

✅ Manual J-based sizing review
✅ New supply and return plenums
✅ Additional flex duct and air balancing
✅ Drain and overflow protection
✅ Refrigerant-line preparation
✅ Nitrogen pressure testing
✅ Evacuation below 500 microns
✅ Voltage monitoring and surge protection
✅ Complete startup and commissioning

AHRI Certificate No. 215490188 verifies the matched system at 41,000 Btu/h and 17.0 SEER2.

Proper HVAC performance depends on the complete system—including equipment sizing, airflow, ductwork, controls, electrical protection, refrigerant preparation, and installation quality.

Some qualifying Dallas homes in the Oncor service territory may also be eligible for energy-efficiency incentives. Eligibility and final amounts are subject to current program rules, documentation, available funding, and approval.

See the full Dallas 75248 case study and project photos:

https://www.greentechdfw.com/blog/dallas-75248-daikin-fit-17-seer2-manual-j-oncor-case-study

Greentech Engineering Heating & Air Conditioning — DFW HVAC

07/17/2026

Texas Power Grid ⚡ vs. Your New AC ❄️. Who wins?

If you don't have a dedicated surge protector, a single brownout can fry the expensive computer boards in your high-efficiency AC! We just wrapped up this massive, bulletproof thermodynamic upgrade for a single-family home in Dallas, TX (75243).

We installed a heavy-duty 5-Ton Daikin Fit Variable-Speed System to handle the large floor plan, but the real magic is in the engineering safeguards:

✨ The Engineering Upgrade Specs:
✅ 220V Voltage Monitor & Surge Protector: An electrical firewall to shield the system's inverter boards from grid fluctuations.
✅ Clean Comfort 4-Inch Media Filter: Traps microscopic dust and dander without suffocating the airflow.
✅ Custom Plenums & EEV: Surgical humidity control via an Electronic Expansion Valve.
✅ Unmatched Guarantees: 12-Year Unit Replacement & our exclusive 3-Year Labor Warranty.
✅ INSTANT Oncor Rebate applied directly to the invoice! 💸

“In the AI-driven energy era, HVAC is no longer just about comfort — it’s about how efficiently your home uses power. At Greentech, we engineer systems that reduce your energy load and prepare your home for the future.”

Don't leave your expensive home investments unprotected. Trust the mechanical engineers. Hit the link to read the full case study or to book your home diagnostic! ⚙️https://www.greentechdfw.com/blog/5-ton-daikin-fit-upgrade-surge-protection-dallas-75243
Contact us 469-551-6806

07/15/2026

Bigger isn't always better! 🛑📏 If your AC is too big for your house, it’s going to "short-cycle"—leaving you feeling cold, sticky, and frustrated with high electric bills.

We just wrapped up this thermodynamic upgrade for a single-family home in Fort Worth, TX (76116). We used strict engineering data to downsize their failing 3-Ton unit to a highly advanced 2.5-Ton Daikin Fit Variable-Speed System.

✨ The Engineering Upgrade Specs:
✅ Downsized via ACCA Manual J for perfect humidity control
✅ Replaced legacy unit with a compact, side-discharge inverter compressor
✅ Custom-fabricated new supply and return plenums for flawless airflow
✅ Installed physical dampers for precise room-by-room air balancing
✅ $1,000 INSTANT Oncor Rebate applied directly to the invoice! 💸

“In the AI-driven energy era, HVAC is no longer just about comfort — it’s about how efficiently your home uses power. At Greentech, we engineer systems that reduce your energy load and prepare your home for the future.”

Don't leave your comfort to guesswork or outdated sizing rules. Trust the mechanical engineers. Hit the link in our bio to read the full case study or to book your home diagnostic!
👉 Read the full Fort Worth Downsizing Case Study here:https://www.greentechdfw.com/blog/fort-worth-tx-76116-daikin-fit-hvac-downsize-oncor-rebate
📞 Get your system diagnosed:(469)551-6806

07/13/2026

🛑 Frisco Neighbors (75035): Is your downstairs AC running all day but the house still feels warm and sticky? 🛑

Two-story homes in Collin County put a massive strain on the downstairs HVAC unit. When an aging, single-stage AC starts to fail, it burns through electricity and completely loses its ability to control indoor humidity.

We recently helped a Frisco family fix this exact nightmare! Instead of just guessing what size they needed, our engineers ran the math with a strict ACCA Manual J Load Calculation. We upgraded their struggling downstairs unit to a whisper-quiet, highly efficient Daikin 17.5 SEER2 Two-Stage System paired with an Ecobee Premium Smart Thermostat. 🧠❄️

Because it has a two-stage compressor, it runs smoothly on low power during mild days and ramps up automatically when the extreme Texas heat hits.

“In the AI-driven energy era, HVAC is no longer just about comfort — it’s about how efficiently your home uses power. At Greentech, we engineer systems that reduce your energy load and prepare your home for the future.”

💰 The Best Part?
Because we are an Authorized Oncor Service Provider and a Daikin Comfort Pro, we handled all the utility paperwork and secured this family an instant $1,000+ Oncor Rebate right on their invoice! No waiting months for a check in the mail.

Stop settling for uneven cooling and skyrocketing electric bills. Let the engineers at Greentech optimize your home!
👉 Read the full Frisco Case Study here: https://www.greentechdfw.com/blog/frisco-tx-75035-daikin-two-stage-hvac-oncor-rebate
📞 Book your home diagnostic: 469-551-6806

Discover how we used Manual J data to upgrade a Frisco (75035) two-story home to a Daikin 17.5 SEER2 two-stage system, securing a $1,000+ Oncor rebate.