When something goes wrong with the heating or cooling in an Alamo Heights home, the questions are always the same: what needs to happen, what will it cost, and how soon can someone be out. Magnum Heating & A/C handles the full range of residential HVAC work across this town, from a diagnostic call on a system that stopped cooling to a full furnace or heat pump replacement. Pricing is explained on the phone before anything is scheduled, and same-day service is often available for repairs that cannot wait.
Alamo Heights is a town of established homes, many of them carrying equipment that has been running hard for years. Older systems in well-built houses often have specific quirks: ductwork that was never quite right for the layout, controls that have aged past their useful life, or a furnace-and-AC pairing where one side is newer than the other. We handle all of it, and we tell you what we find before we do anything.
The decision between repairing a system and replacing it is not always obvious from the outside. A unit that is still running but struggling through the hottest weeks of the year may look like a repair candidate until the technician opens it up and finds a compressor that is nearly gone. At that point, spending money on the repair means spending it again on the replacement a season later.
A repair makes clear sense when the equipment is relatively recent, the fault is contained, and the cost is reasonable relative to what the system is worth. It stops making sense when the repair cost approaches a meaningful fraction of replacement cost, when the same system has needed attention repeatedly, or when the underlying equipment is simply too old to run efficiently regardless of what gets fixed. We walk through both options when we diagnose the job, and we give you a straight answer about which one holds up over time.
We treat your home and its system the way we would our own, and that means we do not recommend a replacement when a repair is the honest answer.
A system that stops working entirely is a different kind of call from a routine tune-up, and we handle it differently. Emergency no-heat and no-cool calls are taken every day from 9:00 AM to 9:00 PM, and same-day service is often available when the situation cannot wait. When you call, we confirm what is available and move urgent calls to the front of the line.
For properties where someone has to stay put, whether that is a household that cannot leave or a business that has to keep running, we work around the situation. That means communicating clearly about timing, explaining what the repair involves before it starts, and not leaving a job half-done. You are told what is happening and what comes next at every stage.
If the system is completely down and the space is not heating or cooling at all, call (830) 590-9782 and we will confirm same-day availability. We are here every day from 9:00 AM to 9:00 PM.
Not every HVAC problem announces itself clearly. A system that runs constantly without reaching the set temperature, one that cycles on and off every few minutes, or one that heats one room and ignores another all have diagnosable causes. The section below covers the fault types we see most often in residential systems across this area.
A refrigerant leak does not always mean the system stops working immediately. More often, it means the system runs longer and longer to reach the same result, until eventually it cannot cool at all. Leak diagnosis involves checking pressures, tracing the system for the source, and addressing the leak before recharging. Recharging without finding the leak is money spent twice.
These are among the more common electrical-side faults in residential HVAC equipment. A failed capacitor is often what causes a system to hum without starting, or to start and then cut out quickly. A worn contactor can prevent the outdoor unit from receiving the signal to run. A control board fault is less predictable and usually shows up as erratic behavior that does not follow a clear pattern. Each of these is a contained repair when caught early.
The compressor is the heart of the cooling system, and a failing one is one of the more serious faults a system can develop. Hard starting, tripping breakers, or a system that runs but produces almost no cooling are all signs worth investigating. Condenser coil problems, including damage, blockage, or a failing condenser fan motor, reduce the system's ability to shed heat and put extra load on the compressor. We diagnose both sides before recommending a course of action.
A system that runs for a few minutes, shuts off, and then starts again shortly after is short cycling. It is not a normal operating pattern, and it puts wear on the components that start and stop the system. The causes range from an oversized system that cools the space too quickly to a refrigerant pressure problem, a dirty evaporator coil, or a fault in the controls. Finding the actual cause is what determines whether the fix is simple or involves the equipment itself.
An efficiency rating on a piece of equipment describes how it performs under controlled test conditions. What a property actually sees once the system is installed and running depends on factors the rating does not account for: the condition of the ductwork, how well the building holds conditioned air, whether the equipment was sized correctly for the actual load, and how the thermostat is configured.
In a town like Alamo Heights, where many homes have been updated and added to over the years, the duct system sometimes does not match the current layout of the house. A new high-efficiency unit installed into leaky or undersized ducts will not deliver what its rating promises. We look at the full picture when we scope an installation, including airflow and duct condition, so the equipment we install actually performs the way it is supposed to. HVAC work sized and installed the way the manual calls for is the only way the efficiency numbers mean anything in practice.
Energy-efficiency upgrades, whether that is a higher-efficiency system, a smart thermostat, or ductwork improvements, all work better together than any one of them does alone.
There is more on the air conditioning page.
The homes in Alamo Heights cover a range of ages and configurations, and the HVAC work that comes out of them reflects that range. A call from an older home with aging equipment looks different from a call about a recently updated home where something has gone wrong with newer hardware.
A repair call usually starts with a system that is behaving in a way it should not: not cooling, not heating, making a noise it did not used to make, or running without producing a result. The technician diagnoses the fault, explains what was found, and describes the repair before any work begins. If the diagnosis turns up something that changes the scope, that conversation happens before anything additional is done.
A system that is running does not mean a system that is running well. Preventive maintenance covers inspection, cleaning, performance testing, and catching the small problems that become expensive ones if the system keeps running through them. A seasonal tune-up before the hottest months or before the first cold nights is the most cost-effective HVAC call most households make. We check the furnace. We check the AC. We leave it running right.
When a system has reached the point where repair no longer makes sense, replacement is the work that matters. Full HVAC system replacement in an established home involves more than swapping the equipment. It means confirming the ductwork is up to the job, sizing the new system correctly for the space, and handling the installation so the new equipment performs the way it should from day one. The service page carries the full breakdown of what each type of installation involves.
The price of an HVAC job depends on what the fault turns out to be, what has to be accessed to fix it, and whether a repair or a replacement is the right answer once the system has been diagnosed. A straightforward capacitor swap is priced differently from a compressor replacement or a full system installation. What changes a quote is the scope of the actual work, not a number arrived at before anyone has seen the system.
When you call, we ask about the system and the symptoms, and we give you a rate before anything is scheduled. You know what the job covers before we send anyone out. If the scope changes once the technician is on site, that conversation happens before any additional work begins. Call (830) 590-9782 for a quote on HVAC service in Alamo Heights.
We provide HVAC service throughout Alamo Heights and the surrounding communities in Bexar County, including Olmos Park, Terrell Hills, Castle Hills, Balcones Heights, and San Antonio. If you are in the area and need heating or cooling service, call and we will confirm we can get to you.
Local means we care what the neighbors think of our work, and that applies across every community we cover in this part of Bexar County.
It genuinely helps. The more detail you give us about the symptoms, the better we can prepare for the visit. Let us know whether the system is running at all, what it is or is not producing, any sounds or smells you have noticed, and how long the problem has been going on.
Once a year at minimum, and twice a year is better. A fall check before the heating season and a spring check before the cooling season catch problems at the point when they are easiest and least expensive to address. Systems that run hard through long summers benefit from that pre-season attention.
Sizing is based on the characteristics of the space: square footage, ceiling height, insulation, window area, and the local climate load. We do not size by guessing or by matching the old unit's tonnage without checking whether that size was correct to begin with. HVAC work sized and installed the way the manual calls for is the standard we apply on every replacement job.
We walk through both options clearly when the diagnostic points to a decision between repair and replacement. We explain what the repair involves, what it costs, and what the remaining life of the equipment looks like so you have what you need to make an informed call. If you need that in writing for a property file or an owner approval, let us know.
Yes, and it matters more than most people expect. A system that is too large for the space cools it too quickly, short cycles, and never runs long enough to pull humidity out of the air properly. A system that is undersized runs constantly and still cannot keep up on the hottest days. Correct sizing is based on the actual load the home presents, which takes into account the square footage, the insulation, the window area, and how the duct system is configured. We confirm sizing before any replacement is scoped.
It depends on the job and the time of year. A repair call is usually completed quickly enough that comfort is not significantly affected. A full system replacement takes longer, and on a hot day the interior will warm up while the equipment is disconnected. We work efficiently to minimize the time the system is out, and we let you know what to expect before the job starts.
Coverage does not depend on whether the property sits inside city limits or in an unincorporated area. What matters is whether the address falls within the area we serve. Call (830) 590-9782 with the address and we will confirm whether we can reach it.
For most homes in this region, yes. The winters here are mild enough that a heat pump handles the heating load without difficulty, and the efficiency advantage on the cooling side is real across the long summer. Heat pumps also simplify the equipment setup by handling both heating and cooling from a single system. Whether a heat pump makes more sense than a furnace-and-AC pairing depends on the home, the existing equipment, and what the replacement is starting from. We walk through the options when you call for a quote.
Changing the air filter on a regular schedule is the most impactful thing a property owner can do between visits. A clogged filter restricts airflow and forces the system to work harder than it should. Keeping the area around the outdoor condenser clear of debris and making sure supply and return vents are not blocked also helps.
Homes that have been standing and occupied for many years tend to develop a predictable set of issues: ductwork that has loosened or was never quite right for the layout, controls that have aged past their useful life, and equipment that has been running hard enough that the wear shows up in the efficiency numbers before it shows up as a breakdown. Airflow problems and uneven temperatures from room to room are common in houses where additions or renovations changed the layout without updating the duct system. A diagnostic call usually turns up more than the one symptom that prompted it.
A planned maintenance visit before the cooling season or before the first cold nights costs far less than an emergency repair call when the system fails in the middle of one. If the equipment in your Alamo Heights home has not been looked at recently, now is the right time to schedule it. Magnum Heating & A/C is available every day from 9:00 AM to 9:00 PM. Call (830) 590-9782 to set up a tune-up, a diagnostic, or a full system assessment before the next season puts the system under pressure.
Affordable rates. Flexible timing. Reliable comfort.
We also take work in: Terrell Hills, Kirby, Windcrest, Leon Valley.
From a fast AC repair to a full system replacement, we handle the complete range of heating and cooling work for homes and businesses in Alamo Heights and across Bexar County. The table below covers what each service includes, who it fits best, and a practical note to help you decide where to start. Call (830) 590-9782 for a quote on any of these services.
| Service Type | Scope of Work | Common Needs | Helpful Details |
|---|---|---|---|
| Furnace & AC System Replacement |
| Homeowners whose repair costs are stacking up or whose system can no longer hold the set temperature | South Texas summers accelerate wear on older equipment, making timely replacement a practical choice |
| Heating & Furnace Repair |
| Any home or building that loses heat during a cold snap | Even mild Alamo Heights winters can make a furnace failure urgent on the coldest nights |
| Seasonal Maintenance & Tune-Ups |
| Any homeowner who wants to prevent breakdowns before the next season arrives | A spring AC tune-up and a fall furnace check are the two visits that prevent the most expensive repairs |
| Indoor Air Quality & Air Filtration |
| Households concerned about dust, allergens, or airborne particles indoors | An air quality upgrade is straightforward to add when the system is already being serviced |
| Ductwork Repair & Sealing |
| Homes where the system runs constantly but comfort is uneven from room to room | Sealing the duct system often makes a bigger difference in comfort than replacing equipment |
| Heat Pump Repair & Service |
| Homes running a heat pump for both heating and cooling | Heat pumps are a common fit in South Texas and benefit from annual inspection of both modes |
| Whole-Home Dehumidification & Humidity Control |
| Bexar County homes where high ambient humidity makes the indoor air feel uncomfortable even at the right temperature | Managing indoor humidity reduces extra load on the cooling system and improves overall comfort |
| Emergency HVAC Service |
| Any home or building where the HVAC system has stopped working and waiting is not an option | We take emergency calls every day from 9:00 AM to 9:00 PM and offer same-day service when available |
| AC Repair & Service |
| Homeowners and property managers whose AC stopped cooling or is underperforming | Same-day service is often available when the system goes down during peak summer heat |
| Thermostat & Smart-Control Installation |
| Anyone who wants better visibility and control over indoor temperature | A thermostat upgrade pairs well with ductwork improvements for room-by-room comfort control |
| Full System Installation & ReplacementMost Popular |
| Homeowners and commercial property owners replacing aging or failing equipment | We go over installation and replacement costs in plain terms before anything is scheduled |
| Heat Pump Installation |
| Homeowners replacing an older system or adding comfort to a new space in a mild-winter climate | Alamo Heights winters are mild enough that a heat pump handles both seasons efficiently from a single system |
Call (830) 590-9782 to talk through your system, get a straight answer on what it needs, and schedule service at a time that works for you.
(830) 590-9782