Most hvac services projects don't fail because a contractor made one dramatic error — they fail because small, cheap-looking decisions stack up.
These are the mistakes we see most often on Houston jobs, and the ones we vet every scope against before we start.
1. Skipping the Manual J
Rule-of-thumb sizing = comfort problems forever. A room-by-room load calc is the standard.
2. Oversized equipment
Big units short-cycle and never dehumidify. In Houston, humidity comfort matters more than cooling capacity.
3. Single-stage compressor
Runs full-blast then off. Variable-speed runs long and low, and actually dries the air.
4. Leaky, un-insulated ductwork
Attic ducts lose 20–30% of capacity. Mastic seal and R-8 insulation are the minimum.
5. 1" pleated filters in a 4" cabinet
Restricts airflow and starves the coil. A 4–5" media cabinet is the right answer.
6. No dehumidifier for tight new construction
Tight envelopes cant dehumidify with AC alone. Whole-home dehumidifiers are often required in Houston.
7. Skipping the float switch on condensate
This is the #1 attic-unit failure that ruins ceilings. A $15 switch prevents it.
8. Bedrooms without a return path
Closed doors starve returns. Transfer grilles or jump ducts fix pressure imbalance.
9. Ignoring humidity control on the thermostat
A cooling-only thermostat cant manage humidity. Use one that reads and reacts to RH.
10. Using unlicensed or non-authorized installers
Warranties on modern equipment require factory-trained installers. No credentials = no coverage.
How to vet your contractor
Read your hvac services bid line by line and ask which of these mistakes are being avoided — in writing. A contractor who welcomes the question is the one you want; a contractor who deflects is the one to walk away from.
If you'd like a second set of eyes on a scope of work or an existing bid, we're happy to walk through it with you.
