Air Conditioning
Air Conditioning Installation, Repair & Replacement
Cool, comfortable, and efficient when the temperature rises.
The short answer
Green Core Heating & Air installs, repairs, and maintains central air conditioning for homes across Sonoma and Marin counties, including adding AC to an existing furnace and replacing worn-out systems. We size every system to your home and fix the airflow and duct problems that cause hot rooms and high summer bills.
Overview
Air Conditioning in Sonoma and Marin
Summers in the North Bay can swing from foggy mornings to hot afternoons, especially inland in Santa Rosa, Windsor, and the Sonoma Valley. Green Core Heating & Air installs, repairs, and maintains central air conditioning for homes across Sonoma and Marin counties, from adding cooling to an existing furnace to replacing a worn-out rooftop unit.
Many AC problems come from airflow and ductwork, not the equipment, so we look at the whole system. That's how we fix hot upstairs rooms and high summer bills instead of just swapping parts.
Benefits
Why homeowners choose this.
Design-first sizing
Right-sized equipment eliminates uneven cooling and high bills.
Whole-system approach
We address airflow and ductwork — not just the AC unit.
Honest repair or replace
Clear recommendations based on your system's age and condition.
Built for efficiency
Lower energy use without compromising comfort.
AC installation and replacement
If your home already has a furnace and ducts, adding a matched air conditioner and coil is often the simplest way to get cooling. If you're replacing both, it's worth comparing a heat pump, which cools exactly like an AC but also heats.
We size the system with a load calculation, not the old unit's label, and check the ducts, since undersized or leaky ducts are a common reason a new AC still can't keep up.
- Cooling added to existing furnaces
- Full system replacements, including rooftop units
- Heat pump options priced side by side
AC repair
The most common AC calls we get are warm air from the vents, a system that won't turn on, ice on the indoor coil or refrigerant lines, water leaking near the furnace, and loud or rattling outdoor units. Often the cause is a failed capacitor or contactor, a refrigerant leak, a clogged drain, or a dirty coil.
We find the actual cause and give you a written price first. If the system is older and the repair is major, we'll show you replacement options too.
AC maintenance
A spring tune-up before the first heat wave includes cleaning the outdoor coil, testing electrical parts, checking refrigerant and airflow, and clearing the condensate drain. That's what keeps an AC from quitting on the hottest day of the year.
AC or heat pump?
A heat pump is an air conditioner that can also heat. If your furnace is near the end of its life too, replacing both with a heat pump often costs less to run and may qualify for rebates. If your furnace is newer, adding an AC can make more sense. We'll price both.
Our work
Recent projects in Sonoma and Marin
Real Green Core jobs for homeowners in Sonoma and Marin, with photos from the job site.
April 2026
Air conditioning added to an existing furnace in Santa Rosa
We added central air conditioning to the home's existing furnace so the homeowners can stay cool through Santa Rosa summers.
See the job photosJuly 2026
Rooftop AC replacement in Petaluma
We replaced an aging, unreliable rooftop air conditioner, handling the permit, crane lift, and inspection from start to finish.
See the job photosAugust 2026
AC repair and refrigerant service in Santa Rosa
We diagnosed the system with digital gauges, sealed leaking refrigerant line joints, and verified electrical connections to restore steady cooling.
See the job photos
FAQ
Air Conditioning questions, answered
Can you add air conditioning to my existing furnace?
Usually, yes. We add a matched outdoor unit and indoor coil to your furnace and check that your ducts can handle the airflow. We'll also price a heat pump so you can compare.
Why is my AC blowing warm air?
Common causes are a failed capacitor, a dirty outdoor coil, low refrigerant from a leak, a frozen indoor coil, or a thermostat issue. Call us and we'll diagnose it and give you a written price before any repair.
Why is my AC freezing up?
Ice on the coil or lines usually means restricted airflow, like a dirty filter or blocked return, or low refrigerant. Turn the system off to let it thaw and call us.
What size air conditioner do I need?
It depends on your home's size, insulation, windows, and sun exposure. We do a load calculation instead of guessing from square footage or the old unit's size.
Should I replace my AC with a heat pump?
If your furnace is also aging, a heat pump is often the better choice: it cools the same way and replaces your furnace too. If your furnace is newer, adding AC may make more sense. We'll price both.
How often should my AC be serviced?
Once a year, ideally in spring before the first heat wave.
How long does an air conditioner last?
Typically 12 to 15 years with regular maintenance.
Ready to talk air conditioning?
Share a few details about your home and we'll reach out with clear, honest options.