St. George, Utah · Booking service
Heating and cooling help in St. George
Tell us the ZIP where the work is needed. We book the appointment and match you with an independent licensed contractor covering that address.
- We book the appointment
- A licensed contractor does the work
- You contract directly with them
How this works
- You tell us the ZIP. It decides which contractor covers your address — St. George and the surrounding county are not one single service area.
- We book the appointment. Old Red Heating & Air is a booking and matching service. We are not a heating and cooling contractor and we hold no trade licence.
- A licensed contractor shows up. They diagnose, they quote, and they contract with you directly. We never quote prices, because we are not the ones doing the work.
St. George is a cooling town
Washington County's cooling design temperature. That is the 1% summer design figure listed for this county in RESNET's Appendix A, drawn from the ASHRAE 2017 Handbook of Fundamentals. Salt Lake County's is 96°F. Utah County's is 92°F.
A thirteen-degree gap sounds small. It is not. It is the difference between equipment that holds temperature on a July afternoon and equipment that runs flat out from noon and never catches up. Sizing rules of thumb carried down from the Wasatch Front undersize systems here, and a system that is undersized for the design day cannot be fixed with a thermostat setting.
Almost everything that matters about heating and cooling here follows from that number. The cooling season is long, the equipment runs hard for months at a stretch, and the failures people call about cluster in July rather than spreading evenly through the year. Furnaces matter, but they sit idle for most of the year and they are asked for far less when they do run.
That shapes what is worth spending on. Capacity and airflow on the cooling side earn their keep here in a way they do not in Ogden. So does keeping the outdoor coil clean, and so does honest load calculation rather than swapping like for like because that is what was there.
What we book
Why equipment here gets dirty faster
This is the northeastern edge of the Mojave. The air carries fine mineral dust most of the year, spring wind events push a lot more of it, and a condenser sitting outside is pulling all of it across the coil every time it runs. On top of that, sustained construction on the Washington Fields side means graded dirt upwind of a lot of houses.
Two practical consequences. First, a dirty outdoor coil cannot reject heat, so the system runs longer and hotter for the same cooling — on a 109°F design day that is the difference between keeping up and not. Second, filters load faster here than the interval printed on the box assumes, and a loaded filter starves airflow across the indoor coil, which is a common route to a frozen coil and a system that blows warm.
Check the filter monthly through the cooling season rather than trusting the number on the packaging, and follow the equipment manufacturer's guidance for your specific system. If you can hold it up to a light and not see light through it, it is past due.
How to check the contractor's licence yourself
Utah licenses heating and cooling contractors through the Department of Commerce, Division of Professional Licensing. The classification to look for is H100 — HVAC. DOPL's current contractor classification list no longer carries the older S350 HVAC specialty; new HVAC applications moved to H100, with the updated application requirements taking effect 20 April 2026.
Under the current requirements an H100 applicant has to complete a 25-hour pre-licensure course, pass the H100 written trade exam, and document 4,000 hours of qualified HVAC employment within the past five years using W-2s, K-1s or tax returns. DOPL also sets general liability insurance minimums for the classification, and a fingerprint-based background check requirement begins 1 January 2027.
You do not have to take anyone's word for it, including ours. Utah publishes a free licence lookup: secure.utah.gov/llv. Search the business name before work starts.
Where we book
This territory covers St. George and the surrounding Washington County communities.
ZIP codes currently in the service area: 84770 84790 84780 84765 84783 84737 84745 84738.
If your ZIP is not in that list, put it in the form anyway. We will tell you straight away rather than taking a booking we cannot fill.