Guides
Field guides
Straight explainers on the questions that come up on the job — each paired with a free calculator that shows the math.
Electrical
Can My Panel Handle an EV Charger?
It's a load calculation, not a guess — and load management can often skip the service upgrade.
Plumbing
Do You Need a Bigger Gas Line for a Tankless Water Heater?
Usually yes — and the reason is length, not just the size printed on the pipe.
HVAC
Flex Duct Size Chart: CFM at 0.10 Friction Rate
Flex moves less air than metal of the same diameter, and a sloppy install makes it worse.
HVAC
Superheat vs. Subcooling: Which One to Charge By
The metering device tells you which reading actually reflects the charge.
Electrical
What Size Wire for a 50 Amp 240V Circuit?
The short answer is #6 copper — but a straight 50 A load, a long run, or aluminum all change it.
HVAC
Why a Bigger AC Isn't Better: The Oversizing Trap
The most common HVAC mistake is buying too much capacity. It costs more and works worse.