An old AC that limps through the Oklahoma summer usually quits on the hottest day, when everybody needs me at once. If yours is on its last legs, let me look now while I can still get you on the schedule. Free estimates on new systems, and I keep same-day spots open for no-cool calls across Kingfisher and Central Oklahoma. $99 dispatch, $111 diagnostic on repairs. 4.8 stars across 289 reviews. Call 405-375-4822 or book at hartzellsheatair.com.
Straightforward pricing
- $99 dispatch on every truck roll. Free on new-install estimates.
- $111 diagnostic, credited toward the repair if you accept within 14 days.
- Free estimates on new installs. No charge to walk through replacement options.
Call (405) 375-4822. 4.8 stars / 289 reviews.
HVAC System Sizing Calculator
Free tonnage estimator for Oklahoma homes. 4.8 stars, 289 reviews.
I’m Dave Hartzell. I’ve been sizing HVAC systems in Central Oklahoma for 45 years. Use this calculator to get a ballpark tonnage, then call me at (405) 375-4822 for a free in-home Manual J load calc before you buy anything.
Warning. This is a rough estimate. It is not a substitute for a full Manual J load calculation. Do not buy or self-install equipment based on this number alone. Wrong tonnage costs more in comfort, humidity, and energy than the equipment itself. Call (405) 375-4822 for a free load calc.
How this calculator works
Base load for an Oklahoma home is roughly 20 BTU per square foot of conditioned space. From there I adjust for ceiling height, insulation, sun exposure, occupant load, and window count. The output rounds up to the nearest half ton because residential AC equipment comes in 0.5-ton increments. This is a fast approximation. A real Manual J pulls infiltration rates, exact window areas and orientations, wall R-values, and duct losses. It always beats a square footage rule.
Why right-sizing matters
In a humid climate like Oklahoma, oversized AC is worse than slightly undersized. Too big means short cycles, no humidity removal, clammy walls, and a compressor that wears out years early. I’ve ripped out 4-ton units installed on 1800 sq ft homes that should have had a 3-ton. Right-sized runs longer, dehumidifies properly, and lasts 15 plus years.
Frequently asked questions
How many tons of AC do I need in Oklahoma?
In Oklahoma’s mixed-humid climate, plan on roughly 1 ton of cooling per 500 to 600 sq ft for an average home. A 2000 sq ft home with average insulation usually lands at 3 to 3.5 tons. Insulation, sun exposure, window count, and ceiling height swing that number, which is why I do a Manual J load calc before quoting equipment.
What is a Manual J load calculation?
Manual J is the industry-standard heat load calculation published by ACCA. It accounts for every wall, window, door, ceiling, floor, infiltration rate, internal gain, and orientation in your home. It’s the right way to size an HVAC system. I do them free for Kingfisher and Central Oklahoma customers.
Why is over-sizing my AC bad?
An oversized AC cools too fast to pull humidity out of the air, so you end up with a cold clammy house. Short cycling also wears compressors out early and burns more electricity. Right-sized is better than bigger, every time.
Does Hartzell’s do load calcs?
Yes. Free in-home Manual J load calculations for every estimate. I’ve been doing HVAC 45 years and I will not quote a replacement system without one. Call (405) 375-4822.
Ready for a real Manual J?
Free in-home load calculation. No pushy sales pitch. Just the right size.
Hartzell’s Heat & Air, 602 S Main St, Kingfisher OK. 4.8 stars, 289 reviews.