There's no reliable square-footage rule for AC sizing, and any contractor quoting your tonnage over the phone based on square feet alone is guessing. The only accurate way to size a system is a proper load assessment, factoring in insulation, window count and orientation, ceiling height, duct condition, and how much heat your specific house gains on a 100-degree Texas afternoon. Two houses with identical square footage can need genuinely different tonnage depending on those details.

Why 'One Ton Per 500 Square Feet' Gets It Wrong

That old rule of thumb almost always oversizes a home, sometimes by a wide enough margin that it matters. A well-insulated, well-shaded home often needs closer to one ton per 1,000 to 1,400 square feet, not 500. A contractor sizing purely off square footage on a larger newer-construction home can end up recommending a system nearly twice as big as what the house actually needs.

An oversized system sounds like a safe bet, more capacity can't hurt, right, but it's the opposite. A system that's too big cools the air fast and shuts off before it's run long enough to pull humidity out of the house. That's exactly why some DFW homes feel cold and still clammy at the same time. The unit also short-cycles, wearing out the compressor faster and driving up the electric bill despite the 'bigger' system.

What a Proper Load Assessment Actually Looks At

When a contractor's quote reaches a tonnage number without asking about your insulation, your windows, or walking your attic, that's worth questioning. A correctly sized system typically saves meaningfully on the annual energy bill compared to a rule-of-thumb oversized one, and it runs longer humidity-removing cycles too, which matters more in DFW than in drier climates.

Dipson Air runs a full on-site load assessment on every system replacement quote across Richardson, Plano, Garland, Dallas, and Allen rather than sizing off square footage, since getting the tonnage right the first time is what actually keeps a house comfortable and the bill reasonable.

Square footage rules of thumb miss the right AC size more often than not. A proper load assessment is the only way to size it correctly.

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A straight AC replacement, meaning the same type of system in the same location, usually takes 4 to 8 hours and gets finished in one day. What throws people off is the total timeline: once you count getting a quote, ordering equipment, pulling a permit, and finding an open install slot, most Richardson-area homeowners are looking at 1 to 3 weeks from first phone call to cool air blowing again, longer during peak summer.

A two-person crew can usually complete a like-for-like swap in a single visit. The work is methodical: recover the old refrigerant, disconnect and remove the outdoor condenser and indoor coil, set the new equipment, run new line sets if the old ones are corroded or the wrong size, wire it in, pull a vacuum on the lines to remove air and moisture, charge the system, then test airflow, temperature split, and thermostat function before leaving.

What Turns a One-Day Job Into Two or Three

The timeline stretches when the job is more than a parts swap. Switching from a downflow to a horizontal furnace configuration, moving equipment to a new spot in the attic or garage, adding a return air duct, or upgrading an electrical panel for a higher-amperage heat pump all add hours or a second day. Older homes in Lake Highlands and Richardson's Canyon Creek with narrow attic hatches or original ductwork also slow things down simply because of access, not because the equipment itself is harder to install.

The Real Bottleneck Is the Calendar, Not the Labor

In June, July, and August, DFW HVAC companies run near capacity. A quote can usually happen within a day or two of your call, but the install date itself often lands one to three weeks out once equipment has to be pulled from stock and a crew has an open slot. This is the part that catches people off guard when their system dies mid-summer and they assume same-day replacement is standard. It can happen, but it's the exception, not the rule, during peak season.

Dipson Air quotes most straight replacements within a day or two of the initial visit and keeps common residential tonnages in stock specifically to avoid the multi-week wait that hits a lot of Richardson-area homeowners in July and August.

A same-size AC swap takes 4 to 8 hours on install day, but the full process from quote to cool air usually runs 1 to 3 weeks in the DFW area.

If your system was installed before roughly 2010, there's a good chance it runs on R-22 refrigerant. It's not illegal to keep an R-22 system running or to repair it, but the U.S. phased out new production of R-22 back in 2020, so the only refrigerant left is whatever remains in the existing supply chain, and that stock only shrinks from here.

New R-22 hasn't been manufactured or imported into the U.S. since January 1, 2020. Reclaimed and recycled R-22 is still legally available for servicing existing equipment, which is why a repair on an R-22 system is still possible, just increasingly expensive as the remaining supply gets smaller and demand stays roughly flat.

A refrigerant leak on an R-22 system is where this really shows up. Topping off a leaking system with R-22 costs several times more per pound than the R-410A used in current equipment, and if the leak is significant, the repair bill can approach a meaningful fraction of what a full replacement costs. That's usually the moment a routine repair call turns into a replacement conversation.

You Don't Have to Replace an R-22 System That's Working Fine

None of this means every R-22 system needs to go. If your system is running well with no leak, there's no rule that forces a replacement. The economics change specifically when a repair requires adding refrigerant, since that's the point where R-22's cost per pound starts driving the decision more than the equipment's actual condition.

Dipson Air gives straight answers on R-22 systems specifically: what a repair actually costs at today's refrigerant prices, and when that number means replacement is the smarter call, not just the easier upsell.

The U.S. stopped allowing new R-22 production in 2020. Existing R-22 systems are still legal to run and repair, but the refrigerant itself keeps getting more expensive.

A walk-in cooler compressor almost never fails with zero warning. The signs usually show up days or weeks ahead of a full failure: the unit running constantly instead of cycling normally, visible ice buildup on the evaporator coil, warm spots near the door or in back corners, unusual noise from the compressor, and an electric bill that's crept up without an obvious reason. Any one of these is worth a service call before it becomes a full breakdown during service hours.

A healthy walk-in compressor cycles on and off in a predictable rhythm to hold temperature. If yours seems to be running nonstop, or cycling on and off in quick, short bursts, that's usually a sign of a refrigerant issue, a failing component, or a door seal that's no longer holding, and it's exactly the kind of strain that shortens a compressor's remaining life.

Some frost is normal. A heavy, persistent layer of ice on the evaporator coil usually points to airflow restriction, a refrigerant charge issue, or a defrost cycle that isn't working correctly, and it makes the compressor work harder to hit the same temperature. Left alone, it's one of the more common paths to a full compressor failure.

Warm Spots Near the Door or in Back Corners

If certain areas of the walk-in run warmer than others, especially near the door or in corners farthest from the evaporator fan, that's often an airflow problem rather than a temperature-control failure, but it puts inventory at risk in those specific spots even while the display thermometer looks fine.

A walk-in cooler failure during service hours means inventory loss, a scrambled shift, and an emergency call that costs more than a scheduled one would have. Most of the signs above show up during normal operation well before a full failure, which is exactly the window where a same-day diagnostic visit is cheaper and far less disruptive than an emergency call at 8 PM on a Friday.

Dipson Air's vans are fully stocked specifically for commercial refrigeration work, walk-in coolers, freezers, ice machines, and food-prep coolers, so most calls across Richardson, Dallas, Plano, and the surrounding area get diagnosed and fixed on the same trip rather than waiting on a part order while inventory sits at risk.

Short cycling, ice buildup, warm spots, and rising energy bills are the early warning signs of a failing walk-in cooler compressor, before it fails on a Friday night.

The biggest red flag in choosing an HVAC contractor is a quote that comes in thousands of dollars below every other bid you got. That gap has to come from somewhere, and it's usually unlicensed labor, no permit, cut-rate equipment, or a plan to pad the bill later with change orders once the job has started. Beyond price, watch for missing licensing, vague written estimates, no mention of a permit, and pressure to sign the same day.

Why the Lowest Bid Is Often the Most Expensive One

A legitimate HVAC company quoting thousands less than everyone else is cutting something you can't see at the time of the quote: skipping the permit, using a smaller line set, sending an unlicensed installer instead of a trained crew, or planning to hit you with change orders once your old system is already torn out. Comparing at least two or three quotes side by side is the easiest way to spot an outlier before it becomes your problem.

Texas requires HVAC contractors to hold a license through the Texas Department of Licensing and Regulation (TDLR), and a legitimate company will give you that license number without hesitation. Ask about liability insurance and workers' comp too. If a worker gets hurt on your property and the contractor isn't properly insured, that liability can land on you as the homeowner.

Every North Texas city requires a mechanical permit for a full HVAC replacement, and that permit triggers an inspection that verifies the work meets code. A contractor who doesn't mention a permit is either planning to skip it, which can void your equipment warranty, or planning to charge you for it separately after you've already committed. Ask directly and get the answer in writing.

A Legitimate Quote Takes Time to Put Together

A contractor who quotes a full system replacement over the phone without seeing your attic, ductwork, or electrical panel is guessing, and that guess tends to turn into change orders once the crew shows up and finds something the phone quote didn't account for. An in-person visit before a firm number is a basic sign of a contractor doing this correctly.

Dipson Air provides its TDLR license number (#TACLA27032C) and proof of insurance on every quote request, and every full system quote includes an in-person visit and the permit cost spelled out in writing before any work is scheduled.

A quote thousands below competitors, no permit mentioned, or high-pressure tactics are the top HVAC contractor red flags in North Texas. Here's what to check before signing.

For most of a North Texas winter, a heat pump is the more efficient choice, delivering several units of heat for every unit of electricity it uses. A gas furnace pulls ahead when temperatures drop into the 20s and below, producing strong, fast heat exactly when a hard freeze hits. Because DFW gets both mild stretches and sudden cold snaps in the same winter, a lot of homeowners here end up choosing based on which trade-off matters more to them, or opting for a dual-fuel system that uses both.

DFW winters spend most of their time in a mild range, and that's the sweet spot where a heat pump operates at its most efficient. If you're not already on natural gas, a heat pump also avoids the cost of running a new gas line. Heat pumps double as your AC in the summer since the same outdoor unit runs in reverse, simplifying the whole system into one piece of equipment instead of two.

When a cold front drops temperatures into the 20s or lower, which happens most North Texas winters at least a handful of times, a gas furnace produces heat faster and holds it more consistently than a heat pump working near the bottom of its efficiency range. If your priority is fast recovery after a hard freeze, a furnace solves that directly.

The Dual-Fuel Option Most Homeowners Don't Know About

A dual-fuel system pairs a heat pump with a gas furnace and switches between them automatically based on outdoor temperature. The heat pump handles the mild months efficiently, and the system kicks over to gas only when temperatures drop low enough that gas becomes the better performer. It costs more upfront than either system alone, but for a North Texas winter that swings between mild days and sudden freezes in the same week, it removes the trade-off entirely.

Don't decide this on efficiency alone. Factor in whether your home already has a gas line, how long you plan to stay, and how much a rare hard freeze week actually bothers you versus how much you care about a lower electric bill the rest of the season.

Dipson Air installs and services all three configurations, heat pump, gas furnace, and dual fuel, across Richardson, Plano, Garland, Dallas, and Allen, and can run the actual cost comparison against your current gas and electric rates before you commit to one.

Heat pumps handle most of a typical DFW winter more efficiently than gas, but hard freezes favor furnaces. Here's how to pick, including dual fuel.

What Size AC Unit Do I Need for My House?

Why 'One Ton Per 500 Square Feet' Gets It Wrong

Why Oversizing Actually Hurts You

What a Proper Load Assessment Actually Looks At

What This Means for Your Quote