(888) 550-1280 [email protected]
California HVAC Repair Pros

Rated #1 Trusted Local Air Conditioning and Heating Specialists Near 95762

Are you facing any problem with your hvac system in 95762? Our local team provides expert Emergency HVAC Repair & Installation Services throughout El Dorado Hills, CA to keep your home comfortable in any weather. As Local Air Conditioning and Heating Specialists, we handle everything from restoring restricted airflow and clearing frozen coils to updating thermostats and securing electrical connections. Whether you require an urgent cooling restoration or a high-efficiency heating replacement, call (888) 550-1280 for the most reliable mechanical support in El Dorado Hills today!

Call Now Our Services

0

Projects Completed

0

Happy Clients

0

Positive Reviews

25 Years
Experience
El Dorado Hills, CA AC & Heating Team

Your El Dorado Hills, CA HVAC Repair & Installation Experts Serving 95762 Homes

California Heating, Cooling & HVAC System Service Company understands how sudden breakdowns and uncomfortable indoor climates disrupt life and business. When temperatures spike or a furnace fails, you need a trusted team that responds fast and fixes it right the first time. We specialize in Emergency HVAC Repair and Installation Services El Dorado Hills, CA — Immediate Relief for home and commercial emergencies, combining licensed technicians with transparent pricing and industry-leading parts.

Our technicians are certified, fully insured, and trained on modern systems from smart thermostats to high-efficiency heat pumps. We diagnose problems quickly with advanced tools, minimize downtime, and restore safe, reliable climate control for every property. Serving communities across California, we focus on energy-efficient upgrades, durable installations, and comprehensive preventive care.

  • 24/7 rapid response and same-day emergency HVAC service to limit downtime and discomfort.
  • Licensed, NATE- and EPA-certified technicians for safe repairs and compliant installations.
  • Transparent, up-front pricing and free estimates to eliminate surprise fees and stress.
  • High-efficiency system installs and retrofit expertise that lower energy bills and carbon footprint.
  • Comprehensive diagnostics and long-term warranties for dependable peace of mind.
  • Skilled commercial and residential crews experienced with rooftop units, furnaces, ACs, and heat pumps.
  • Indoor air quality solutions and ductwork optimization to improve health and comfort.

Core Services

Emergency HVAC Repair

We handle urgent breakdowns on air conditioners, furnaces, heat pumps, and rooftop units with priority scheduling and rapid dispatch. Our crews perform thorough diagnostics, replace failed components, and restore safe operation while protecting indoor air quality and system efficiency.

HVAC System Installation & Replacement

From high-efficiency central AC and modern heat pumps to complete furnace replacements, we design installations that match building load and budget. We focus on proper sizing, duct balancing, and smart thermostat integration to maximize comfort and long-term savings.

24/7 Rapid Response & Diagnostics

Around-the-clock availability means a certified technician can be on-site fast to diagnose electrical faults, compressor failures, refrigerant leaks, or safety concerns. Fast diagnostics reduce repair time and prevent secondary damage to systems and structures.

Commercial & Residential HVAC Solutions

We provide tailored solutions for homes, multi-family buildings, offices, and retail spaces—from rooftop unit maintenance to multi-zone system installs. Our project managers coordinate permits, inspections, and efficient scheduling to keep operations running smoothly.

Indoor Air Quality, Ductwork & Controls

Improving ventilation, sealing and repairing ductwork, and installing advanced filtration or UV systems enhances comfort and reduces allergens and volatile organic compounds. Smart controls and zoning deliver precise temperature control and energy savings across every space.

What Customers Say

“Fast, professional, and clearly priced — they had our AC back up in hours during a heatwave.” — Maria R., El Dorado Hills, CA
“I appreciated the honest assessment and energy-saving upgrade recommendations; the new system pays for itself.” — Daniel T., El Dorado Hills, CA
“Technicians arrived on time, explained every step, and left our shop cleaner than they found it.” — Aisha P., El Dorado Hills, CA
“24/7 response was real — they fixed an overnight failure and saved us from lost revenue.” — Carlos M., El Dorado Hills, CA

California Heating, Cooling & HVAC System Service Company delivers Emergency HVAC Repair and Installation Services El Dorado Hills, CA with fast response, certified expertise, and commitment to lasting comfort. Contact us any time for emergency dispatch, system upgrades, or a preventive maintenance plan that keeps your HVAC system reliable and efficient.

Residential Emergency HVAC Repair & Installation Services

Get Professional Residential Local Air Conditioning and Heating Specialists Services in El Dorado Hills, CA

Commercial Emergency HVAC Repair & Installation Services

Get Professional Commercial Local Air Conditioning and Heating Specialists Services in El Dorado Hills, CA

Call Us Now
Why El Dorado Hills, CA Picks HVAC Experts

Why Choose Us for Reliable El Dorado Hills, CA Heating & Cooling Repairs

California Heating, Cooling & HVAC System Service Company delivers fast, dependable Emergency HVAC Repair and Installation across California with 24/7 response, certified technicians, and a commitment to getting your home or business comfortable and compliant — fast. We combine rapid dispatch, transparent pricing, and expertise in California building codes to restore systems the same day when possible and install efficient replacements that lower energy bills.

Why choose us: - Rapid 24/7 emergency response with same‑day service for broken air conditioners, furnaces, heat pumps, and rooftop units. - Team of licensed, NATE‑certified technicians and EPA‑trained specialists for safe refrigerant handling and code‑compliant installs. - Proven experience with Title 24 compliance, permitting, and navigating California utility incentive programs to maximize rebates. - Comprehensive work: diagnostics, ductwork repair, thermostat upgrades, and indoor air quality solutions (including wildfire smoke filtration and HEPA/UV options). - Clear, upfront estimates, workmanship warranties, and preventative maintenance plans that extend equipment life and improve efficiency. - Residential and commercial service with expertise in coastal corrosion protection, Central Valley heat challenges, and southern California humidity control.

Most Viewed Customer Reviews ### Most Viewed Customer Reviews - Maria S. — 24/7 emergency AC repair, Los Angeles: “Within an hour a technician arrived, diagnosed a compressor failure, and had my home cool again the same day. Honest pricing and fast service.” - David L. — Heat pump installation (same‑day replacement), San Francisco: “They handled permits, Title 24 paperwork, and left a clean install. My energy bills dropped immediately and the rebate guidance saved us hundreds.” - The Rodriguez Family — Commercial rooftop unit emergency replacement, San Diego: “When our restaurant lost AC on a busy weekend they replaced the rooftop unit overnight. Professional crew, minimal downtime, and follow‑up maintenance.”

Ready to restore comfort now? Call California Heating, Cooling & HVAC System Service Company at (888) 550-1280 or schedule a consultation online for immediate assistance and same‑day emergency service.

Bold experience, California expertise, and certified workmanship — we’re the team Californians trust for emergency HVAC repair and efficient system installations.

Get a Free Quote
Licensed & Insured
Expert Team
24/7 Support

Top Emergency HVAC Repair & Installation Services – Fast & Efficient in El Dorado Hills, CA

We offer comprehensive Emergency HVAC Repair & Installation Services solutions tailored to your specific needs. Our team of experienced professionals is dedicated to providing exceptional service with attention to detail and commitment to quality.

24 Hour Emergency HVAC System Service and Repair

Has your heating or cooling system stopped working unexpectedly in El Dorado Hills, CA? Our HVAC specialists provide emergency diagnostics, repairs, system troubleshooting, and component replacement for residential and commercial systems. Call (888) 550-1280 now for 24-hour emergency HVAC service. Fast response helps restore comfort, prevent equipment damage, and reduce downtime.

Get a Quote
Air Conditioner Repair

Is your air conditioner blowing warm air, making unusual noises, or failing to cool in El Dorado Hills, CA? Our HVAC technicians diagnose and repair compressors, capacitors, coils, refrigerant issues, and electrical components. Call (888) 550-1280 now for air conditioner repair services. Prompt repairs help restore cooling performance, improve efficiency, and prevent costly breakdowns.

Get a Quote
Furnace Repair

Is your furnace failing to heat your home properly in El Dorado Hills, CA? Our heating specialists repair burners, ignitors, heat exchangers, blower motors, and control systems. Call (888) 550-1280 now for furnace repair services. Professional repairs restore reliable heating, improve efficiency, and extend equipment lifespan.

Get a Quote
Heat Pump Repair

Is your heat pump struggling to heat or cool your property in El Dorado Hills, CA? Our technicians diagnose and repair compressors, reversing valves, refrigerant systems, sensors, and electrical controls. Call (888) 550-1280 now for heat pump repair services. Fast service helps restore year-round comfort and system performance.

Get a Quote
Boiler Repair

Is your boiler leaking, making noise, or failing to provide heat in El Dorado Hills, CA? Our specialists repair pumps, valves, heat exchangers, pressure controls, and circulation systems. Call (888) 550-1280 now for boiler repair services. Reliable repairs help restore consistent heating and system efficiency.

Get a Quote
HVAC Troubleshooting

Are you experiencing inconsistent temperatures, airflow issues, or system malfunctions in El Dorado Hills, CA? Our HVAC technicians perform comprehensive diagnostics to identify mechanical, electrical, and performance-related problems. Call (888) 550-1280 now for HVAC troubleshooting services. Accurate diagnostics help prevent unnecessary repairs and restore system reliability.

Get a Quote
HVAC System Inspection

Are you unsure about the condition of your HVAC system in El Dorado Hills, CA? Our specialists inspect heating equipment, cooling components, ductwork, airflow, thermostats, and safety controls. Call (888) 550-1280 now to schedule an HVAC system inspection. Professional assessments help identify issues early and improve long-term system performance.

Get a Quote
New HVAC System Installation

Building a new property or upgrading your comfort system in El Dorado Hills, CA? Our HVAC installation team designs and installs energy-efficient heating and cooling systems tailored to your needs. Call (888) 550-1280 now for new HVAC system installation. Proper system sizing and installation improve comfort, efficiency, and performance.

Get a Quote
Old HVAC Replacement

Is your aging HVAC system costing more to operate and repair in El Dorado Hills, CA? Our specialists replace outdated heating and cooling equipment with modern, energy-efficient systems. Call (888) 550-1280 now for HVAC replacement services. Upgrading your system can improve comfort, reliability, and energy savings.

Get a Quote
Air Conditioning Installation

Looking for a new air conditioning system in El Dorado Hills, CA? Our technicians install central air conditioners, condensers, evaporator coils, refrigerant lines, and control systems. Call (888) 550-1280 now for air conditioning installation services. Professional installation ensures efficient cooling and dependable performance.

Get a Quote
Air Conditioning Replacement

Is your current air conditioner struggling to keep up in El Dorado Hills, CA? Our HVAC experts replace outdated cooling systems with modern, high-efficiency equipment. Call (888) 550-1280 now for air conditioning replacement services. A new system can improve cooling capacity, energy efficiency, and indoor comfort.

Get a Quote
Heating System Installation

Need a dependable heating solution for your property in El Dorado Hills, CA? Our team installs furnaces, heat pumps, boilers, and complete heating systems. Call (888) 550-1280 now for heating system installation services. Proper installation ensures efficient operation and long-term performance.

Get a Quote
Heating System Replacement

Is your heating system nearing the end of its lifespan in El Dorado Hills, CA? Our specialists replace outdated equipment with energy-efficient heating solutions. Call (888) 550-1280 now for heating system replacement services. Modern systems improve comfort, reliability, and energy efficiency.

Get a Quote
Furnace Installation

Planning a new furnace installation in El Dorado Hills, CA? Our heating experts install gas furnaces, electric furnaces, venting systems, thermostats, and airflow components. Call (888) 550-1280 now for furnace installation services. Proper installation supports efficient heating and dependable operation.

Get a Quote
Furnace Replacement

Is your furnace becoming unreliable or expensive to repair in El Dorado Hills, CA? Our technicians replace aging furnace systems with high-efficiency models. Call (888) 550-1280 now for furnace replacement services. Upgrading improves heating performance and reduces operating costs.

Get a Quote
Heat Pump Installation

Looking for an energy-efficient heating and cooling solution in El Dorado Hills, CA? Our HVAC specialists install heat pumps, refrigerant systems, air handlers, and smart controls. Call (888) 550-1280 now for heat pump installation services. Professional installation helps maximize efficiency and year-round comfort.

Get a Quote
Heat Pump Replacement

Is your heat pump losing efficiency or performance in El Dorado Hills, CA? Our team replaces aging heat pump systems with modern, energy-efficient equipment. Call (888) 550-1280 now for heat pump replacement services. New systems provide improved comfort and lower energy consumption.

Get a Quote
Gas Furnace Installation

Need reliable gas heating for your property in El Dorado Hills, CA? Our specialists install gas furnaces, venting systems, gas lines, safety controls, and thermostats. Call (888) 550-1280 now for gas furnace installation services. Proper installation ensures safety, efficiency, and long-term performance.

Get a Quote
Gas Furnace Repair

Is your gas furnace failing to heat properly or cycling incorrectly in El Dorado Hills, CA? Our technicians repair burners, ignition systems, gas valves, thermostats, and airflow components. Call (888) 550-1280 now for gas furnace repair services. Prompt repairs help restore safe and reliable heating.

Get a Quote
HVAC Tune-Up Service

Want to improve HVAC performance and prevent unexpected breakdowns in El Dorado Hills, CA? Our tune-up service includes cleaning, inspections, airflow testing, and component adjustments. Call (888) 550-1280 now for HVAC tune-up services. Routine maintenance helps improve efficiency and extend system lifespan.

Get a Quote
HVAC System Maintenance

Looking to keep your HVAC system operating efficiently in El Dorado Hills, CA? Our maintenance specialists inspect, clean, test, and optimize heating and cooling equipment. Call (888) 550-1280 now for HVAC maintenance services. Regular service helps reduce repair costs and improve reliability.

Get a Quote
Seasonal HVAC Maintenance

Preparing your HVAC system for changing seasons in El Dorado Hills, CA? Our technicians perform seasonal inspections, cleanings, adjustments, and performance testing. Call (888) 550-1280 now for seasonal HVAC maintenance. Preventive service helps ensure dependable heating and cooling throughout the year.

Get a Quote
AC Maintenance

Want to keep your air conditioner running efficiently in El Dorado Hills, CA? Our maintenance service includes coil cleaning, refrigerant checks, airflow testing, and electrical inspections. Call (888) 550-1280 now for AC maintenance services. Routine maintenance helps improve efficiency and reduce breakdown risks.

Get a Quote
Ductless AC Installation

Looking for flexible cooling without ductwork in El Dorado Hills, CA? Our specialists install ductless air conditioning systems, indoor units, outdoor condensers, and controls. Call (888) 550-1280 now for ductless AC installation services. Ductless systems provide efficient, zoned comfort and energy savings.

Get a Quote
Ductless AC Repair

Is your ductless air conditioner not cooling properly in El Dorado Hills, CA? Our technicians repair mini split components, refrigerant systems, sensors, and electrical controls. Call (888) 550-1280 now for ductless AC repair services. Fast repairs help restore efficient cooling performance.

Get a Quote
Mini Split Installation

Need targeted heating and cooling for specific areas in El Dorado Hills, CA? Our HVAC specialists install mini split systems, indoor air handlers, and outdoor units. Call (888) 550-1280 now for mini split installation services. Professional installation delivers efficient comfort and zoning control.

Get a Quote
Duct Repair

Are damaged ducts affecting airflow and energy efficiency in El Dorado Hills, CA? Our technicians repair leaks, disconnected sections, damaged insulation, and airflow restrictions. Call (888) 550-1280 now for duct repair services. Proper repairs improve comfort and system performance.

Get a Quote
Air Duct Cleaning

Concerned about dust, debris, or contaminants inside your ductwork in El Dorado Hills, CA? Our specialists clean air ducts, vents, returns, and HVAC airflow pathways. Call (888) 550-1280 now for air duct cleaning services. Clean ductwork supports better airflow and indoor air quality.

Get a Quote
Indoor Air Quality Testing

Are you concerned about pollutants, allergens, or poor indoor air quality in El Dorado Hills, CA? Our specialists test air quality, humidity levels, airborne particles, and ventilation performance. Call (888) 550-1280 now for indoor air quality testing services. Professional testing helps identify issues affecting comfort and health.

Get a Quote
Indoor Air Quality Maintenance

Looking to maintain healthier indoor air in El Dorado Hills, CA? Our team services filtration systems, air purifiers, humidity controls, and ventilation equipment. Call (888) 550-1280 now for indoor air quality maintenance services. Ongoing maintenance helps improve comfort and air cleanliness.

Get a Quote
Air Purifier Installation

Want cleaner indoor air throughout your property in El Dorado Hills, CA? Our HVAC specialists install whole-home air purification systems designed to reduce airborne contaminants. Call (888) 550-1280 now for air purifier installation services. Improved filtration helps support healthier indoor environments.

Get a Quote
Whole House Air Filtration

Looking to reduce allergens, dust, and airborne particles in El Dorado Hills, CA? Our team installs whole-house air filtration systems that integrate with your HVAC equipment. Call (888) 550-1280 now for whole-house air filtration services. Advanced filtration helps improve air quality throughout your property.

Get a Quote
Humidifier Installation

Is dry indoor air causing discomfort in El Dorado Hills, CA? Our specialists install whole-home humidifiers that work with your HVAC system to maintain balanced humidity levels. Call (888) 550-1280 now for humidifier installation services. Proper humidity control helps improve comfort and indoor air quality.

Get a Quote
Dehumidifier Installation

Are excess humidity and moisture affecting your indoor environment in El Dorado Hills, CA? Our technicians install whole-home dehumidification systems for improved moisture control. Call (888) 550-1280 now for dehumidifier installation services. Balanced humidity helps protect your property and improve comfort.

Get a Quote
Smart Thermostat Installation

Looking to improve comfort and energy efficiency in El Dorado Hills, CA? Our specialists install smart thermostats with programmable controls, Wi-Fi connectivity, and automation features. Call (888) 550-1280 now for smart thermostat installation services. Smart controls help optimize HVAC performance and energy usage.

Get a Quote
New Thermostat Installation

Need a new thermostat for better temperature control in El Dorado Hills, CA? Our HVAC technicians install digital, programmable, and smart thermostat systems. Call (888) 550-1280 now for thermostat installation services. Proper installation helps improve comfort and system efficiency.

Get a Quote
Thermostat Replacement

Is your thermostat outdated or no longer functioning correctly in El Dorado Hills, CA? Our specialists replace faulty thermostats with modern control systems. Call (888) 550-1280 now for thermostat replacement services. Updated controls help improve HVAC performance and reliability.

Get a Quote
Thermostat Repair

Is your thermostat causing temperature inconsistencies or system issues in El Dorado Hills, CA? Our technicians diagnose and repair wiring, sensors, calibration problems, and control failures. Call (888) 550-1280 now for thermostat repair services. Accurate repairs help restore dependable HVAC operation.

Get a Quote
Thermostat Wiring and Setup

Need professional thermostat wiring or configuration in El Dorado Hills, CA? Our specialists handle wiring connections, system integration, calibration, and setup for all thermostat types. Call (888) 550-1280 now for thermostat wiring and setup services. Proper configuration helps ensure accurate temperature control and efficient HVAC performance.

Get a Quote

Our Completed Projects

We've successfully completed Metal Roofing projects in these El Dorado Hills zip codes 95762

Nearby Cities We Serve

We also work in
Lathrop, Oregon House, Mokelumne Hill, Round Mountain, Fillmore, Orangevale, Paramount, Tahoe Vista, Redlands, Los Gatos, Santa Paula, Squaw Valley, La Verne, Standish, Valley Center

Call for a Free Quote
El Dorado Hills, CA HVAC FAQs

El Dorado Hills, CA HVAC Repair FAQs – Quick Answers for Common Issues

Integration requires verifying fan capacity and static pressure. Call (888) 550-1280 in El Dorado Hills, CA. We test system airflow, choose appropriate HEPA solutions (bypass or dedicated units), and ensure filtration improves IAQ without causing system strain.

Conversion requires flue changes, condensate drainage, and gas pressure adjustments. Call (888) 550-1280. We evaluate compatibility in El Dorado Hills, CA, outline costs, and handle permits for safe, efficient upgrades.

Technicians measure static pressure and CFM to confirm airflow remains adequate. Call (888) 550-1280 in El Dorado Hills, CA. We adjust fan settings or recommend alternative filters if high MERV reduces system flow.

Best practices: verify vents, monitor performance, check carbon monoxide detectors, and review maintenance schedule. Call (888) 550-1280 for post-service guidance in El Dorado Hills, CA. We provide written instructions and follow-up checks to ensure safety.

Call (888) 550-1280 to arrange a professional load calculation in El Dorado Hills, CA. Accurate sizing prevents short cycling, inefficiency, and premature failure. Our certified techs measure heat gain/loss, recommend properly sized equipment, and provide documentation for warranties and permits.

Recurring inspections catch leaks, pests, and contamination early. Call (888) 550-1280 to schedule periodic duct inspections in El Dorado Hills, CA. We set intervals, document findings, and proactively address issues before they become emergencies.

Keep dated notes, photos, invoices, and technician reports. Call (888) 550-1280 to request documentation templates and service history access in El Dorado Hills, CA. Organized records help track patterns and support decisions on replacements.

Heat and Cool System Repair El Dorado Hills, CA Reviews

What El Dorado Hills, CA Homeowners Say About Our Trusted HVAC Services

I’m a homeowner in El Dorado Hills, CA and had to call California Heating, Cooling & HVAC System Service Company in the middle of a heatwave when our air conditioner failed. Their emergency HVAC repair and installation services were exactly what I needed. The dispatcher booked a same-night visit and the licensed, insured technicians arrived within the quoted emergency response window. They quickly diagnosed a compressor failure and provided a clear, written estimate for emergency AC repair vs. full HVAC installation. Because our system was old and inefficient, they recommended a high-efficiency heat pump installation to replace the failing unit. The crew handled the emergency repair to get us cooling immediately and scheduled the installation the following day. They also checked ductwork, performed thermostat calibration, and explained permit requirements and rebate options for energy-efficient equipment. What stood out was their transparency—no upsell pressure, fair pricing, and a parts/labor warranty on both the emergency repair and the new HVAC installation. The new system is noticeably quieter and uses less energy, and their follow-up maintenance plan keeps everything running smoothly. For anyone in El Dorado Hills, CA needing 24/7 emergency HVAC repair, air conditioner or furnace repair, or a professional HVAC installation, I highly recommend California Heating, Cooling & HVAC System Service Company for fast response, skilled technicians, and honest service.
Uma Baker

El Dorado Hills, CA

I found California Heating, Cooling & HVAC System Service Company online while searching for "emergency HVAC repair and installation in El Dorado Hills, CA." Their website was straightforward, listing 24/7 emergency response, same-day diagnostics, and detailed installation services — everything I wanted for a sudden AC breakdown. I called late afternoon and a licensed, insured technician answered promptly, confirmed availability, and arrived within the quoted window. Technician assessed the system quickly, explained the issue in plain language, and provided a transparent, written estimate for both repair and a replacement option using energy-efficient models. They handled permits and code compliance for the installation, and their team coordinated ductwork adjustments and thermostat upgrades professionally. I appreciated the follow-up call after service and the maintenance plan they offered to prevent future emergencies. What stood out was clear communication, fair pricing, and knowledge of furnaces, heat pumps, and central AC systems — plus fast parts turnaround. If you need reliable emergency HVAC repair and installation in El Dorado Hills, CA, California Heating, Cooling & HVAC System Service Company is a strong choice for prompt service, quality workmanship, and peace of mind.
Paul Evans

El Dorado Hills, CA

I called California Heating, Cooling & HVAC System Service Company in El Dorado Hills, CA for an emergency HVAC repair and was impressed by their prompt, professional service. Their 24/7 response got a certified technician onsite quickly to diagnose a compressor issue and a refrigerant leak. The tech performed a thorough diagnostic—checking the condenser, evaporator coil, capacitors, blower motor and thermostat calibration—then explained the repair options and transparent pricing before proceeding. Beyond the immediate fix, they evaluated ductwork for leaks, measured airflow, and discussed indoor air quality improvements like MERV-rated filters and UV air purifiers. For a planned system replacement, they offered a Manual J load calculation, helped select energy-efficient heat pump and variable-speed blower options, and outlined permit and code-compliance steps. Installation was tidy, used OEM-compatible parts, and included system commissioning and thermostat programming. What stood out was their emphasis on preventative maintenance: a clear maintenance plan, seasonal tune-ups, and warranty coverage to extend life expectancy and improve efficiency. Communications were clear, technicians were licensed and insured, and safety checks (including carbon monoxide considerations for furnaces) were standard. Overall, California Heating, Cooling & HVAC System Service Company is reliable for both emergency repairs and full installations in El Dorado Hills, CA. Their combination of fast response, technical expertise, and commitment to energy-efficient solutions makes them a solid choice for residential HVAC needs.
Jack Knight

El Dorado Hills, CA