HVAC FAQ — AC Repair, Replacement, Heating & IAQ Questions Answered

The most common causes — in order of likelihood — are: thermostat set to FAN or HEAT instead of COOL+AUTO (free fix), tripped outdoor circuit breaker (reset once), failed capacitor ($150–$350), low refrigerant from a leak ($200–$600), frozen evaporator coil (switch to FAN ONLY for 2–4 hours), or a dirty condenser coil. Check the thermostat setting and outdoor breaker before calling anyone.

Full guide: AC Blowing Warm Air in Texas →

First, apply the 20-degree rule: most residential AC systems are designed to cool approximately 20°F below outdoor temperature. On a 100°F day, 80°F indoors is normal operation — not a failure. If it's 95°F outside and your house is at 87°F and climbing, that's a real problem. Most likely causes: dirty filter, failed capacitor, low refrigerant, or frozen coil.

Full guide: AC Not Cooling Below 80°F →

Reset the breaker once. If it trips again — stop and call for service. A repeatedly tripping breaker means the circuit is protecting your home from an electrical fault. Running it back on repeatedly risks a fire. The most common causes are a failing capacitor drawing excess current, a dirty condenser coil causing the compressor to overwork, or a compressor beginning to fail. The capacitor is the most common and cheapest fix ($150–$350).

Full guide: AC Tripping the Breaker →

If your system is running continuously but indoor temperature is rising — you have a capacity problem. On a 100°F+ day, some rise during peak afternoon hours is normal. A house rising all day even in the evening is a failure. Check: (1) outdoor unit actually running — not just indoor fan; (2) air filter condition; (3) any ice visible on indoor unit. If those are clear, you likely have a refrigerant leak, failing capacitor, or failing compressor requiring a technician.

This is called short cycling and it's one of the most damaging patterns your AC can develop. Every startup draws a high electrical surge that stresses the compressor. Common causes: oversized system, low refrigerant, clogged filter, frozen coil, faulty thermostat, or failing compressor. Check the filter first — it's free and resolves more short-cycling calls than most homeowners expect.

Full guide: AC Short Cycling → | AC Leaking Water →

Banging or grinding: Turn system off immediately — loose or broken component. Every minute running causes more damage.
Squealing: Bearing beginning to fail — schedule same-day service.
Rapid clicking on startup (won't start): Classic failed capacitor — $150–$350 repair.
Rattling: Check for debris around outdoor unit first.
Hissing or bubbling: Refrigerant leak — schedule service.
Thwapping in rhythm: Debris in blower — check filter area.

Full guide: HVAC Noises Explained →

Almost always mold or mildew on the evaporator coil or in the condensate drain pan. Spring TX's combination of high humidity and a 9–10 month cooling season creates ideal coil mold conditions. Quick steps: replace filter, treat drain line with white vinegar, schedule professional coil cleaning ($200–$400) if smell persists. For a permanent fix, a UV air purifier installed at the coil eliminates coil mold continuously ($300–$600).

Full guide: AC Smells Musty →

Your AC is cooling but not dehumidifying properly. Most common causes: thermostat set to ON instead of AUTO (fan re-evaporates moisture between cycles — switch to AUTO now), oversized system that short-cycles before removing moisture, dirty evaporator coil, or low refrigerant. Indoor RH should be 45–55%. Above 60% creates mold risk. If AUTO mode doesn't help — the system is likely oversized or needs service.

Full guide: House Feels Humid With AC On →

Diagnostic fee waived with qualifying repair at AC Repair Expo.

Full 2026 repair cost guide →

This is the most important question in HVAC repair. A failed capacitor and a failed compressor produce nearly identical symptoms — and the cost difference is $3,000+. A proper diagnosis requires: (1) capacitor test measuring actual capacitance vs. rated value under load; (2) electrical winding test on the compressor terminals; (3) contactor test. If a technician quotes compressor replacement without showing you these specific test results — get a second opinion before approving anything.

We've seen this scenario many times: homeowner quoted $4,200 for a compressor. AC Repair Expo found a bad capacitor. Total bill: $180.

Full guide: How to Know If Compressor Is Bad →

$150–$350 installed for a single or dual run capacitor. This is one of the most important repairs in Texas HVAC — a weak capacitor forces the compressor to draw excess current on every startup. Left unaddressed, it destroys the compressor. A $180 capacitor today prevents a $3,000 compressor failure. Most capacitor replacements take 30–60 minutes same-day.

Full capacitor cost guide →

Yes — AC Repair Expo waives the diagnostic fee with a qualifying repair. This applies to AC repair and heating repair. Call 832-479-2727 or 346-445-6224 for same-day service in Spring TX 77386 and 77388.

Refrigerant doesn't deplete on its own. If your system needed a recharge and levels are low again — there's a leak that was never found and fixed. Recharging without locating and repairing the leak is throwing money away. A proper refrigerant repair costs $200–$600 and includes finding the leak, repairing it, and recharging. If someone is just "topping off" your system repeatedly without addressing the source — you're paying for the same problem every summer.

Full refrigerant leak guide →

Use these guidelines for Spring TX homes:

• System under 8 years: Repair almost always makes sense
• System 8–12 years: Compare repair cost to replacement on a case-by-case basis
• System 12–15 years: Any repair over $800–$1,000 deserves a replacement comparison
• System 15+ years: Replacement usually wins financially and on reliability
• Any age — R-22 refrigerant: A leak almost always tips toward replacement ($150–$225/lb to recharge)
• Any age — compressor failure: Get a second opinion first; may actually be a capacitor

The energy math: an old 10 SEER system costs $150–$200/month more to run than a new 16.5 SEER2 system. Over 12 months, that's $1,800–$2,400 in wasted electricity — before any repair bills.

Full guide: When to Replace AC in Texas →

The national average is 15–20 years. In Texas, realistic lifespan is 10–15 years — with most systems hitting practical end-of-life around year 12. Why shorter? Texas AC systems run 2,500–3,000 operating hours per year — more than double what a Northern system runs. Capacitors degrade faster. Coil connections fatigue sooner. Compressors wear out earlier. Annual maintenance extends life significantly.

Full guide: How Long Does AC Last in Texas? →

For systems 12+ years old in Texas, proactive spring replacement (March–May) is often financially and logistically superior to waiting. Here's why: failure almost always happens in July, when every HVAC company in Spring TX is backlogged, you're making a $10,000 decision in 100°F heat with limited options, and rush installations sometimes mean lower quality. A planned spring replacement gives you contractor availability, competitive pricing, and time to compare quotes without pressure.

Replace Before It Breaks? → | Repair vs. Replace — Start Here → | Full Repair vs. Replace Guide →

A simple guideline: if the repair cost exceeds 50% of replacement cost on a system over 10 years old — replacement almost always wins financially. A $2,500 compressor repair on a 14-year-old system that would cost $8,000 to replace: the repair is 31% of replacement cost but the system has limited remaining life, no warranty, and declining efficiency. The numbers often point toward replacement even below 50% for older systems.

Installed prices include equipment, labor, permits, and standard installation. Duct modifications, electrical upgrades, or unusual access billed separately.

Full 2026 AC cost guide → | Online cost estimator →

Carrier Comfort (16.5 SEER2): Single-stage — runs at 100% or off. Reliable cooling. Best for cost-focused buyers or shorter-term ownership.

Carrier Performance (18 SEER2): Two-stage — runs at ~65% on mild days for longer, quieter cycles that remove significantly more humidity. This is the critical advantage in Spring TX's 70–80% summer humidity. Escalates to 100% on 100°F+ days.

The Performance premium is $2,000–$3,000. It typically pays back in 3–5 years through energy savings and provides meaningfully better comfort throughout Texas's 9–10 month cooling season. For most Spring TX homeowners staying 5+ years — Performance is the better long-term value.

Full Carrier Comfort vs. Performance guide →

A complete installation should include: outdoor condenser unit, indoor evaporator coil (AHRI matched), removal and disposal of old system, copper lineset (new or verified), electrical disconnect at outdoor unit, concrete pad (or reuse of existing), refrigerant charge to manufacturer specification, permits, startup testing, and airflow verification. If a quote is unusually low — ask which items are excluded. The most commonly omitted: permits, lineset replacement, disposal fees.

How long does AC installation take? →

AHRI certification verifies that your specific outdoor unit and indoor coil combination has been independently tested together and achieves the published SEER2 rating. A mismatched system may not achieve the advertised efficiency, may not qualify for warranty coverage, and may not be eligible for utility rebates. Always ask for the AHRI reference number on any replacement quote — you can verify it at ahridirectory.org.

Full AHRI certification guide →

SEER2 (Seasonal Energy Efficiency Ratio 2) measures how efficiently your AC converts electricity to cooling. Higher = more efficient = lower bills. The Texas minimum since 2023 is 15.2 SEER2. In Texas's 9–10 month cooling season, every SEER2 point matters more than the national average suggests.

• 15.2–16.5 SEER2: Entry tier — good for shorter-term ownership
• 17–18 SEER2: Sweet spot for most TX homeowners staying 5+ years
• 19–21+ SEER2: Variable speed — maximum efficiency and comfort

Full SEER2 guide →

Once per year minimum — ideally twice (spring for AC, fall for heating). Texas AC systems run 9–10 months per year, logging more operating hours than systems in any other region. Annual pre-season maintenance catches the failing capacitor that becomes a July emergency, confirms refrigerant levels before they create capacity problems, and cleans coils before they lose 10–15% efficiency. The $100–$150 investment routinely prevents $1,500–$3,500 repair bills.

What does a tune-up include? → | Tune-up cost guide →

Every 3–4 weeks during summer cooling season for most Spring TX homes. Homes with pets: every 2–3 weeks. Near construction: every 2 weeks. In winter when the AC runs less: every 6–8 weeks. A clogged filter forces longer runtimes, can freeze the evaporator coil, and stresses the compressor. Set a phone reminder now — it takes 10 seconds and the filter change takes 2 minutes. For most Spring TX homes, MERV 8 changed every 3–4 weeks is the optimal balance.

What happens without filter changes? →

Pour ¼ cup of white vinegar into the drain line access port (the PVC cap near your indoor air handler) monthly. It kills algae before it becomes a clog. In Spring TX's humidity, your AC pulls 5–10 gallons of water out of the air every day — all going through that drain line. Signs it's clogged: system won't turn on (float switch triggered), water near the air handler, water stains on ceiling. Already clogged? A wet/dry vac on the exterior drain end clears many clogs DIY. Professional clear: $75–$150.

Full drain line guide →

78°F when home — every degree lower adds ~3% to cooling cost. 82–85°F when away (not OFF — reheating from off costs more than maintaining 85°F). Always AUTO, never ON — "ON" runs the fan 24/7, re-evaporating moisture and wasting electricity. Pre-cool to 76°F at 5 AM before peak heat, setback to 80°F when away, recover to 76°F at 4 PM. Setting it to 65°F to "cool faster" doesn't work — your AC cools at the same rate regardless of the gap to setpoint.

Full thermostat settings guide →

Check the data plate on your outdoor unit. Three types relevant to Spring TX homeowners:

• R-22: Pre-2010 systems. Now $150–$225/lb to recharge. A full recharge runs $500–$1,500. Any leak on an R-22 system should trigger a replacement comparison.
• R-410A: 2010–2022 systems. $100–$150/lb. Still available for service on existing systems.
• R-454B: 2023+ systems. The new standard for all residential equipment since EPA regulations took effect.

R-454B guide → | R-410A vs R-454B →

Both are excellent brands with similar reliability track records, comparable warranties (10 years parts when registered), and similar pricing at equivalent SEER2 tiers. The more important factor: which brand does your contractor install most frequently? Technician familiarity with the equipment has a larger impact on installation quality and repair speed than brand differences. AC Repair Expo is a Carrier preferred installer — our technicians are trained and stocked for Carrier equipment.

Full Carrier vs. Trane comparison →

The only accurate answer comes from a Manual J load calculation for your specific home. As a rough guide: 2 tons for up to ~1,000 sq ft, 3 tons for ~1,200–2,000 sq ft, 4 tons for ~2,000–2,800 sq ft. Never accept a replacement quote that sizes your system by matching the old tonnage without a load calculation — the old system may have been incorrectly sized from day one. Oversized systems short-cycle in Spring TX's humidity and leave homes feeling clammy.

Full sizing guide → | What is a Manual J calculation? →

In cooling mode, a heat pump performs identically to traditional AC. The advantage is in heating — heat pumps are more efficient than electric resistance heat and comparable to gas heat in mild Texas winters above 35–40°F. Spring TX's average January low is ~42°F — ideal heat pump territory. For homes without gas infrastructure or with high electric heating bills, a heat pump is often the better year-round choice. For homes with efficient gas heat already, traditional AC + gas furnace is simpler and less expensive upfront.

Full heat pump vs. AC guide →

Check the data plate on your outdoor condenser unit — a metal sticker on the side or back panel. The serial number typically encodes the manufacturing date. For Carrier systems, the first four digits of the serial number represent the week and year (e.g., 1015 = week 10 of 2015). Call us with your serial number at 832-479-2727 and we'll look it up immediately. Also take a photo of the data plate and store it in your phone — you'll need it for every future service call and replacement quote.

How to read your AC model number →

Check these 5 things before calling anyone:

1. Thermostat setting: Set to HEAT mode with setpoint above current room temp
2. Thermostat batteries: Dead batteries cause erratic behavior — replace and wait 2 minutes
3. Circuit breakers: Furnace and air handler have separate breakers. Reset once if tripped
4. Air filter: A severely clogged filter trips the high-limit switch and shuts the furnace down
5. Furnace door switch: Some furnaces won't run if the access panel isn't fully closed

If none of those resolve it — most likely a failed igniter ($150–$350) or dirty flame sensor ($100–$250). No emergency premiums at AC Repair Expo.

Full guide: Heating Not Working →

Full furnace repair guide →

If you suspect a cracked heat exchanger: turn the furnace off at the thermostat and circuit breaker. Open windows. Leave the home if anyone feels dizzy, nauseated, or has a headache. Call 911 if anyone feels ill. A cracked heat exchanger requires furnace replacement — it is not repairable in most cases.

Furnace repair guide →

Furnace replacement in Spring TX costs $2,500–$4,500 for a standard 80 AFUE gas furnace installed, or $3,500–$6,000+ for a 96 AFUE high-efficiency system. For most Spring TX homes, an 80 AFUE furnace is a reasonable choice — our heating season is short (October–March) and the 96 AFUE payback period is longer than in colder climates. For larger homes with higher heating bills, the upgrade may still pay back in 6–10 years.

Full furnace replacement guide →

September or early October — before the first cold front arrives. North Houston cold fronts drop temperatures 30–40°F overnight. The first week they hit, HVAC companies get slammed with calls from homeowners who discover their furnace doesn't work. The homeowner who scheduled a September tune-up has their issue found and fixed ahead of time. The homeowner who waited faces a 2-day backlog, a cold house, and an emergency service call that didn't need to be an emergency.

Heating tune-up guide →

Many Spring TX homes benefit significantly from one. Our outdoor humidity regularly exceeds 80% in summer. Even with the AC running correctly, indoor humidity frequently stays in the 65–75% range — well above the 45–55% comfort and mold-prevention target. Signs you need one: home feels clammy despite AC reaching setpoint, musty smell, visible condensation on windows, allergy symptoms worse indoors. Cost: $1,200–$2,500 installed. Operating cost: $15–$40/month. Portable units can't solve a whole-house humidity problem.

Full dehumidifier guide →

A UV purifier kills biological contaminants — mold, bacteria, viruses — using ultraviolet-C light. It does NOT remove particles (dust, pollen, pet dander) — that requires filtration. In Spring TX, the most common reason to install one is coil mold, which causes the musty smell when the AC first turns on. A UV light installed at the evaporator coil eliminates this mold continuously. Cost: $300–$600 installed. The REME HALO ($600–$1,000) is a more advanced version that sends purifying ions throughout the home rather than treating only air that passes one point.

UV purifier vs. media filter → | REME HALO review →

Excessive dust usually means your filtration isn't capturing fine particles adequately. Possible causes: standard 1-inch filter not changed frequently enough, filter MERV rating too low (MERV 1–4 catches very little), duct leaks pulling in attic air and dust, or ductwork contamination. A media filter upgrade (MERV 11–13, 4–5 inch depth, $400–$800 installed) significantly reduces dust circulation without restricting airflow the way a thin high-MERV filter can.

Media filter guide →

AC Repair Expo Heating & Cooling Inc serves all of North Houston from two Spring TX locations:

• Riley Fuzzel Rd (77386): Spring, Harmony, Benders Landing, Legends Ranch, Imperial Oaks, Spring Trails, Woodson's Reserve, The Woodlands (all villages), Conroe, 77380–77389
• Wied Rd (77388): Klein, Champion Forest, Gleannloch Farms, Windrose, Northgate Forest, Vintage Park, Tomball, Cypress, Bridgeland, Houston (northwest), 77377, 77379, 77388, 77433

We also serve: Kingwood, Humble, Conroe, Magnolia, Willis, and surrounding Harris and Montgomery County communities.

Yes — same-day service is available for most calls placed before 2 PM. We serve Spring TX 77386 and 77388 from two locations. For true emergencies (AC failed in high heat), call 832-479-2727 or 346-445-6224. We do not charge emergency premiums — pricing is the same regardless of when you call.

We repair all major residential HVAC brands: Carrier, Trane, Lennox, Goodman, Rheem, York, American Standard, Bryant, and others. For new installations, we are a Carrier preferred installer — our technicians are trained and stocked for Carrier Comfort and Performance series equipment, which means faster repairs and better installations than a contractor who works infrequently with the brand.

Yes — AC Repair Expo Heating & Cooling Inc holds Texas HVAC license TACLB43277C, regulated by the Texas Department of Licensing and Regulation (TDLR). You can verify this license at tdlr.texas.gov. Always verify any HVAC contractor's license before allowing service work — unlicensed work voids manufacturer warranties.

4 things to verify on every quote: (1) Exact equipment model number — not just "Carrier 3-ton." (2) What's included in installation — permits? lineset? disconnect? disposal? (3) Texas HVAC license number — verify at tdlr.texas.gov. (4) Was a Manual J load calculation done? If not, the sizing is a guess. A $7,000 and a $10,000 quote may be the same equipment with different installation scope — you can't tell without the model number and scope details.

Full quote comparison guide →

AC Repair Expo offers financing through ServiceFinance on qualifying AC replacement and repair projects. 0% promotional financing is available for qualifying customers. A $8,000 system at 0% for 60 months = $133/month — often similar to or less than the monthly electricity savings a new system generates vs. an aging one. Apply using the button on this page or call 832-479-2727.

Full financing guide →

Carrier offers a 10-year parts warranty (including the compressor) when the equipment is registered within 90 days of installation. Unregistered, the warranty drops to 5 years. Registration is the installing contractor's responsibility — always confirm it was done and get the registration confirmation number. Unlicensed installation voids the warranty entirely. AC Repair Expo registers all equipment we install.

What voids AC warranty? →

Home warranties have significant limitations for HVAC: pre-existing condition exclusions, refrigerant coverage caps that fall far short of R-22 costs, ductwork exclusions, replacement caps well below actual replacement cost ($1,500–$3,000 cap on a $10,000+ replacement), and service call approval delays of 3–10 business days — which in July Texas heat is a serious quality of life issue. They can make sense for cash-constrained homeowners with older systems but provide less value than the marketing suggests for most situations.

Full home warranty analysis →