HVAC and Solar Services Serving All of Solano, Napa & Contra Costa Counties, and the Bay Area

Our Reputation speaks for Itself

A-1 Guaranteed is a family-owned and operated business that serves HVAC and Solar Services Serving All Of Solano, Napa and Contra Costa Counties, Fairfield, Vacaville, and the Bay Area with Heating and Air Conditioning, Solar, Tankless Water Heaters, Windows, Insulation and/ or Duct Replacement needs. As one of the premier service businesses in the area, we have helped thousands of satisfied, loyal customers improve the energy efficiency of their homes and offices.

We are available Monday through Friday and by appointment on Saturday. Our fast and efficient attention to your needs will prove our dedication to our customers is the foundation of our business. Our professional staff is knowledgeable and looks after your best interests when it comes to your environmental comfort needs. We are an Energy Upgrade CA participating contractor. We are honored that our customers consider us #1 in providing trustworthy service and dependable comfort.

Why Choose

A-1 Guaranteed?

  • Voted best heating/cooling company for 14 years
  • Voted Best of The Bay for 5 years of KRON 4 TV
  • Commercial and Residential Installation
  • Angie’s List Super Service Award for 2 Years
  • Energy Upgrade Participating Contractor
  • Factory Trained Installers and Techs
  • Drug-free Environment Enforced and Maintained
  • Better Business Bureau Honor Roll 20 Years
  • Diamond Certified Company
  • North American Technician Excellence (NATE) certified
  • Bay Area Certified Green Business
  • All employees fully background checked for your safety
Recent News


How Ductwork Works and When to Replace Yours

The Importance of Ductwork Maintenance

Arguably one of the most important parts of an HVAC system are its air ducts, but too many homeowners don’t regularly inspect or maintain those ducts. In order to understand why air duct maintenance is so important, we need to take a look at the four different components that go with duct work and how exactly each one affects your energy bills, the longevity of your system, and even your health. These four components of air duct systems are cleanliness, Thermal Efficiency, Static Pressure, and Leakage.


People often make the mistake of thinking that the only maintenance ducts need is sealing leaks. However, doing this only prevents leaks – it does not remove debris and dirt that could be harmful to people’s health. It is also believed that cleaning out old ducts is beneficial, but in reality, this is not always effective – and may even make air quality issues worse. Attempting to clean the duct improperly can agitate the dirt, causing it to get into the air, which may lead to health problems. If you’re looking for ducts for HVAC in Walnut Creek, you should know that new ones are hypo-allergenic and if they are properly installed, they will remain perfectly clean for the entire life of the system.

Thermal Efficiency

One of the most crucial factors that go into duct work is insulation thickness, or “R-value”. New ductwork can have a high efficiency rating of R8; in contrast, many old ducts only measure at R2. The newer ducts can be 100% more efficient than most old ducts, keeping more air moving where it needs to go instead of seeping out the sides of ducts into your basement or crawl space!

Static Pressure

Static pressure is the measured amount of pressure that is inside your duct system. If the ducts are improperly installed or they are too small, excess pressure can occur. This amount of pressure relates to the loss or gain of energy, which directly affects the lifespan of the system. The majority of systems have levels of static pressure that are double what they should be. If the pressure is higher than recommended, the fan inside of the system cannot get the desired airflow where it needs to be, which will result in more energy trying to make up for the lost amount of air flow. This will decrease the life of your system drastically and increase your energy bills. Contact our experts in HVAC in Contra Costa to check the pressure in your system.


Usually when you seal your ducts, there is only one concern being recognized here: air leaks. Oftentimes, sealing with good old duct tape won’t completely seal leaks. The target leakage rate that goes with sealing ducts is 15% for older ducts and 6% for new ducts. There will always be some amount of leakage with any ductwork system, but anything above these percentages translates to lost energy for you.

It is important to know when it is time for your ducts to be replaced. Contacting a professional to service your ducts can alert you to maintenance needs that may have been ignored for too long, whether it be because of leakage, too much static pressure, or if the ducts are dirty and unhealthy. Your comfort and health are important, and making sure your ducts are operating at max efficiency without being a risk for your health is crucial.

Contact us today with any questions you might have regarding your ducts to see if they need to be serviced or replaced.

The Importance of Furnace Filters

Why Changing Furnace Filters is Important

During the winter, you are going to be using your furnace more often than you would during any other time of the year. This means that your furnace filters are going to be collecting more hair, dirt, and other gunk than during the spring, summer, or fall. It is important to check on the condition of your furnace filter because not only does it provide you with cleaner air that is distributed by your HVAC system, but it also can help lengthen your unit’s lifespan.

What Are Furnace Filters?

Furnace filters are responsible for protecting the blower fan in your unit from any small amounts of debris the return duct may bring in. While this is the main function of furnace filters, it also improves the quality of the air inside your home because of how it removes any potential contaminants from circulating in your home.

How Do Furnace Filters Actually Clean Air in Your Home?

Small particles of dust, dander, bacteria, dirt, and even mold travel through the air – this is normal. The furnace filter in your system allows air to pass through as it is distributed to your home. The particulates get trapped in the filter, since the filter has miniscule holes in it that are only large enough for air (and the tiniest particles) to get through. Hence, those nasty particles become trapped in the filter instead of circulating through your home.

Do Furnace Filters Have to Be Changed Regularly?

Just like any type of filter, eventually furnace filters have to be changed. In a month, a furnace filter collects an incredible amount of debris and if it is not replaced, it becomes a fire hazard. Not only that, but if the filter is not changed, the contaminants would be released in the air that your HVAC system produces. Change your filter at least every other month in off-seasons and about every 30 days during the winter.

The Importance of Furnace Filters

One of the most important parts of your HVAC system is the furnace filter. It comes between the debris your return vents bring in and the air you breathe. Making it a priority to change your furnace filter every month will result in a longer lifespan for your HVAC system and will also lower the chance for a fire to start. At A-1 Guaranteed, we recognize the importance of being on top of the changing of furnace filters and make it a priority to inspect the furnace filter on a maintenance visit.

If you have any questions or if you require more information regarding furnace filters, contact us today.

What to do After a Power Outage

Steps to Follow when the Power Goes Out

Believe it or not, there are certain things that should be done in the event of a power outage and also after power has been restored. Many people simply just wait until the power comes back on, but there are steps you should take to ensure everyone and everything in the house stays safe. Here are a few things you should do during and after a power outage.

During a Power Outage

  1. One of the first things that should be done after your power goes out is unplugging any electrical electronics or appliances. This way the risk for spikes to occur after the power is restored is minimal. If you want to be extra safe, sensitive devices and electronics should be plugged into surge protectors at all times.
  2. Leave one light on so that you’re able to see when the power comes back on.
  3. Keep the refrigerator and freezer doors closed to avoid your food spoiling.
  4. Use a flashlight or other battery-powered lights. Most people turn to candles for light when the power goes out, but lit candles are a fire hazard.
  5. Turn the AC unit off so a surge does not occur when the power comes back on; this surge could cause damage to your system.
  6. During the winter, put on extra layers to remain warm.

After the Power Comes Back On

  1. If you notice after the power has come back on that your HVAC system will not turn on, you may have to restart it completely. First, turn off the thermostat, then reset the circuit breaker, and wait thirty minutes. After the allotted time, turn the thermostat to “cool” and set the temperature five degrees cooler than the current temperature. (In cold weather, turn the thermostat to “heat” and set the temperature five degrees warmer.) If your unit still does not turn back on, contact your local HVAC repair professional for assistance.
  2. If you’ve turned off the main circuit breaker during the outage, when you see that the power has come back on, wait a few moments before turning it back on. This is to give your electrical system some time to stabilize. Turn on crucial appliances like your refrigerator and freezer before turning on other electronics.
  3. Reset all of your digital clocks, network routers, timers, alarms, and other essential electronics.
  4. If you have an automatic garage door and you had to open it manually using the emergency release cord, you may have to reconnect the door to the remote control. Your service manual should have the necessary information to reconnect the two.

It is incredibly important to know how to act during and after the power goes out. Taking the necessary actions will ensure that when power comes back to your home, your electronics will be in working order and there are no risks of power surges.

If you have any questions about what to do in the event of a power outage or if you require more information on conserving your indoor heat or cool air during an outage, contact us today.

How to Reset Your AC After a Power Outage

Steps for Resetting Your AC

After a power outage, your AC may need to be restarted in order for it to go back to working at its maximum efficiency – or working at all. If the air conditioner doesn’t start functioning on its own when the power to your home is restored, it doesn’t necessarily mean the unit is broken; it may just need to be reset. Here are 4 steps you should do if your AC needs to be reset after a power outage.

1. Set the Thermostat to “Off”

The first thing you should do is turn your thermostat to “off”. This stops the thermostat from asking your AC unit to send cool air. For thermostats that are battery-operated, the issue may be that the thermostat needs new batteries and that is why the AC is not working. If your thermostat is not battery operated, the next step will lead you to your breakers.

2. Reset Your Breakers

If your power went out in the event of a thunderstorm, a power surge may have overloaded the circuit that your air conditioning unit is on. Resetting a breaker that has been “tripped” is not difficult, nor is it dangerous. Find the breaker box, which is often located outside your home, in the laundry room, basement, or garage, and search for the circuit labeled “air conditioning/HVAC”. If you see the switch that is in the neutral position, this means that it is neither on nor off. Flip the switch to the right, turning the circuit off, and then back to the left, turning it back on.

3. Wait About a Half an Hour

After resetting the breaker, your air conditioning unit needs some time in order to reset the internal circuit breaker. Waiting a half an hour will give your unit the necessary time it needs to fully reset. During this time, make sure the thermostat is still turned off. If the thermostat is calling for cool air, this is not allowing the air conditioner time to reset properly.

4. Set the Thermostat to “Cool”

When you have waited the thirty minutes to give your AC time to reset, turn the thermostat to its “cool” setting and set the temperature about 5 degrees less than room temperature. Your AC unit should kick on when the thermostat requests cool air from the AC.

If you tried using the steps above to reset your air conditioning unit and found no success, contact a professional at A-1 Guaranteed so we can come look at the unit as soon as possible. There may be an issue that is best left to professionals, so to preserve not only your safety, but also the functionality of your air conditioning unit, contact our local HVAC service technicians.

For any questions or for more information to reset your air conditioner after a power outage, contact us today.

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