Do I need to clean my ducts?

If the ductwork has no leaks, you never need to clean your ducts!

Our top priority is your health and safety. That’s why we’re taking extra care in reducing risk to you and your family through these safety procedures.

Spring cleaning often includes a deep clean of your home. Sweep out the gutters. Check for leaks and water damage. How about cleaning your air conditioning and furnace ducts? Surely getting your ducts spic and span will promote healthier indoor air, right? Not so fast.

The US Environmental Protection Agency recommends getting your air ducts cleaned only in special situations:

  • If there is mold growth inside ducts
  • If the insulation in your air ducts get wet or moldy
  • If ducts are infested with rodents or insects
  • If ducts are clogged with excessive amounts of dust and debris

What should you do instead? First, diagnose the problem properly.

At RC Mechanical, we focus on fixing the root problem with your A/C or furnace, not just the symptoms. We address the underlying causes of A/C and furnace issues. Otherwise the problem will recur and cost you more money. You may end up installing a new A/C or furnace unnecessarily. And addressing the underlying problems starts with a thorough inspection.

Schedule an HVAC Assessment

Getting a thorough assessment of your furnace and air conditioner will determine if you need your ducts cleaned or replaced. If there is excess debris in your ducts, chances are this is caused by a leak in your HVAC ductwork. We will conduct a thorough inspection of your furnace and air conditioner to identify the root problem before recommending the best solution for your situation.

If the ductwork has no leaks, you never need to clean your ducts! Cleaning them will unnecessarily blow dust particles into your home.

The EPA also recommends preventing water and dirt from entering the A/C or furnace system as the first priority. It is more important to look for leaks than for dust in your ductwork system. A leaking ductwork forces your air conditioner or heating system to overwork which can lead to higher energy bills.

A well-maintained A/C or furnace ductwork system traps indoor allergens in the air filters. This reduces allergens by trapping particles and preventing them from circulating through your home.

If Your Ducts Do Need Cleaning or Replacing

If an HVAC inspection uncovers mold, rodents, or excessive amounts of dust in your ductwork, this could require cleaning or replacing your ducts.

When hiring an HVAC contractor, ask that they provide you with before-and-after photos of the ducts so that you have assurance that the ductwork does have a problem(s) and that the problems have been fixed.

Ensure that the HVAC contractor cleans ALL components of the heating system or air conditioner, not just the ducts. Failure to clean one component can contaminate your entire air conditioner or heating system. This would erase any benefit your HVAC system received from the duct cleaning.

RC Mechanical Is Your Trusted HVAC Contractor

For over 20 years, RC Mechanical has been a trusted HVAC contractor for homeowners on the Peninsula and throughout the Bay Area who rely on us to deliver high-quality service. We’re taking these extra precautions to protect the health and safety of our customers and employees.

RC Mechanical, Redwood City’s best HVAC contractor, is a trusted local company that will quickly diagnose and resolve your indoor comfort and air quality issues. Whether you need help selecting a new air conditioner, installing a furnace, or conducting a home energy audit, you can count on RC Mechanical for superior and cost-effective HVAC service. RC Mechanical is a local veteran-owned business and has provided expert furnace and air conditioning repair and installation to the Bay Area with integrity for over 20 years. Homeowners in Redwood City and throughout the Bay Area count on us for all their heating and air conditioning needs. Call us today at (650) 575-3915 and we will respond within 24 hours.

Keeping Warm at Night

The San Francisco Bay Area enjoys mild winters. However, in the first weeks of this month, temperatures plummeted to the 30s for cities along the Bay like Redwood City, San Carlos, and Burlingame.

Are you and your kids not sleeping well because everyone is cold? Here’s what to do to make sure your house is comfortable:

Check for leaky ducts

When rooms don’t stay warm, there may be leaks in your furnace ducts. This causes your furnace to work harder and take longer to get to the desired temperature.
If some rooms stay warm but other rooms feel cold, then you may have a furnace air flow problem. We can correct this by adjusting the furnace air that blows into each room. We do this through automatic zoning so you are warm and cozy wherever you are in your home.

Change your furnace filter

Dust and dirt prevent free air flow through the heating system. This could make the furnace’s heat exchange overheat and turn itself off.

Check the time on your thermostat

Did you adjust the thermostat for daylight savings time? Set your furnace thermostat to “On” instead of “Auto.”

Do you have the right size furnace for your home?

Our experts can determine the right size of furnace is most appropriate for the size of your home and the Bay Area climate. An overpowered furnace drives up heating bills, while an underpowered furnace struggles to keep you warm on cold days. We can help you evaluate whether it is time to replace your existing furnace and install a new heating system.

Get an inspection for your heating system

Your HVAC system is like your car and needs regular checkups and maintenance. Maintenance can lengthen the life of your furnace.

RC Mechanical, Redwood City’s best HVAC contractor, is a trusted local company that will quickly diagnose and resolve your furnace issues, and recommend repair or replacement. RC Mechanical is a local veteran-owned business and has provided expert furnace and air conditioning repair and installation to the Bay Area with integrity for over 20 years. Homeowners in Redwood City and throughout the Bay Area count on us for all their heating and air conditioning needs. Call us today at (650) 575-3915 and we will respond within 24 hours.

6 ways to prepare your home for summer

Before you know it, the summer heat will be upon us. With a little bit of preparation, your home will be ready to keep you comfortable through the dog days of summer.

Turn your AC on early

Turning on your AC will allow you to find out if it is in working condition. If you hear the equipment cranking up, then it is working. Then go to each register in the house to make sure that cold air starts getting blown in within 5 minutes. If not, then there is a problem. Call your AC technician to schedule an appointment.

Change the filter

Filters clean the air of some impurities before that air is forced into the home. A cleaner filter means that the HVAC (Heating, Ventilation, Air Conditioner) will be able to move the air through the filter effortlessly. This leads to not only cleaner air, but also more energy efficiency leading to lower utility bills. A dirty filter, on the other hand, will make the HVAC work harder to push air through the filter leading to a higher utility bill and a stressed HVAC system.

Change the filter in the spring to help your AC running smoothly throughout the summer and check the air filter every month. If it is dirty, replace it.

Keep area around AC clean

AC works by pulling in air from its surroundings, cooling the air, and then forcing the air into the house through the ducts and vents. If the AC is installed outside the house, there should be at least 2 feet of clearance around the equipment. Make sure that there are no plants growing within 2 feet of the AC and clear out any yard debris from around the equipment to ensure proper air flow.

Do a visual inspection of the equipment, and if any coils look like they are frayed, then it is in need of repair. You may need to call your HVAC technician for help.

Close your windows

Curtains, blinds, and drapes are not only for aesthetics, but also serve a purpose. They block the harsh sun that can otherwise damage wood floor and furniture over time. They also help keep the house cooler by blocking the sun. A cooler house means that the HVAC has to do less work to keep the home comfortable, leading to a lower utility bill.

Clear and clean the registers

Make sure nothing is blocking the registers, such as furniture, drapes, and other items. Keeping the register area clear would enable the air to be better distributed in the room.

Over time, register grills can accumulate dust and grime. When the air is forced into the house, these get blown everywhere, which can affect people suffering from asthma and other respiratory ailments. Be sure to keep these grates clean with soap and water.

Schedule an HVAC tune-up

It is a good idea at the beginning of the season to get an HVAC technician to inspect your equipment to make sure there are no leaks or other damages. The technician should also be able to inspect your ductwork for proper alignment and to make sure that it is fully sealed.

Call us today at (650) 575-3915 to make an appointment. We’ll keep you cool and comfortable through the summer.

How to tell if you have leaky ductwork

Ducts are a vital part of your HVAC system. They distribute the air from your furnace or AC to different parts of your house.

However, when air is lost through gaps in the ductwork, your HVAC has to work harder to achieve the desired temperature in the house. Even if you have a super energy-efficient AC or heating unit, leaky ductwork will mean you won’t see the savings in your utility bills.

Here are a few signs to watch out for:

Rooms are hard to heat or cool

When there are leaks in your ducts, the heated or cooled air is lost through the gaps in the ducts. This causes the HVAC to work harder, and take longer, to get your room to the desired temperature.

It is unusually dusty in the house

When there is a hole in the ductwork, the air from the the surrounding area (attic, garage, or the outside) can get sucked into the ducts. Then this air gets pushed into the house. You don’t want this because air from garages and attics is generally much less clean than the air in the house.

If you notice that you are vacuuming more often and the house still stays dusty, then you may want to check for leaky ductwork.

Your utility bills are higher than they should be

When you have leaky ductwork, conditioned air that was meant for the house escapes, so your HVAC has to work harder to keep the home at a comfortable temperature. Overworking your HVAC wastes both energy and money.

You notice a weird smell

A leaky duct will draw air from the surrounding areas. If this air is from a place like an attic or garage, then the contaminated air gets pushed into your house. For example, if you have a leaky duct in your garage, you might notice the smell of auto exhaust. If you notice strange smells, have your ductwork checked.

Animal sounds from the ductwork

When there is a leak in the duct, small animals that could gather near the leak for some comfortable air. Over time, as the holes in the duct get bigger, animals can get into the ductwork. You might hear animals scampering in the ducts, or their droppings in the ductwork could create a weird smell in the house.

If you suspect a ductwork problem, we advise you to contact an HVAC professional. We at RC Mechanical can do a home analysis to find issues with your HVAC system. Call us today at (650) 575-3915 with any questions.

Energy saving tips for winter

When the temperature goes down, the cost of keeping your home comfortable goes up. Here are some ways you can lower the cost of keeping your home cozy and keep your bills low.

Maintain your furnace

Keeping your furnace in good condition is important for allowing the system to run efficiently and on less energy. Maintaining your furnace also prolongs its life.

A dirty filter can impede air movement and make the system have to work harder. This in turn increases the energy usage.

A filter keeps the air in your home clean. Change the filter at least every 6 months.

Don’t wait until the beginning of the cold season to call you HVAC technician. Remember that everyone else will want to fix their furnace at that same time!

Install a programmable thermostat

The easiest way to keep your home at a comfortable temperature is by installing a programmable thermostat. You can program the thermostat to maintain certain temperatures throughout the day. Why run the furnace at night when everyone is under their covers? Instead, the furnace can keep the house at, say, 70 degrees during the day and turn off at night. Then, it can turn back on automatically when the people in the house get up.

It is easier to program a learning thermostat like Nest. Based on the way you adjust the thermostat during the day, it learns what temperatures you like at what times of day and programs itself to meet your needs.


Most heat loss in your house happens around windows and doors. There could be small places through which the warm air can escape the house. These can be plugged with weatherstripping.

Warm air can rise through the chimney of your fireplace and allow cold air to replace it. Use weatherstripping to prevent this.

Curtains and blinds provide insulation. They reduce the heat loss through the windows.

Add insulation to walls

Heat can be lost through walls. Since they make up most of the house’s structure, heat loss through them can be significant.

Adding insulation to your walls can reduce that heat loss. You can also add insulation to the attic.

Prevent heat loss from the water heater

Water in the water heater can lose its heat through the walls. And since water heaters are usually installed in an unheated garage, heat loss can be significant.

Cover the water heater with insulation to prevent heat loss.

The average temperature setting for water heaters is 145 degrees. Lowering the temperature to 120 degrees could save you money.

Check ducts for leaks

According the US Department of Energy, 20-40% of air going through the insulation system in most houses leaks through the ductwork.

If your utility bills are higher than average, then get your duct work examined by a professional HVAC technician. You may have a leaky duct.

Make your home comfortable

Does it ever feel that certain parts of the house are very comfortable and others are not. They could either be too hot or too cold.

This could happen even if the furnace is working well. The main culprit is the duct design.

When the furnace is actively blowing warm air into the home, they tend to pool in certain areas. Warm air rises. So the upstairs would be much warmer than the downstairs.

Even though the same type of pooling of warm and cold air happens in the summer as well, the comfort level will be better downstairs in the summer. This is because we are looking to keep ourselves cool.

If this sort of pooling occurs, then run your fan. The main job of the fan is to push the air into the room. The duct work should be designed to deliver the correct amount of warm/cool air to a specific room.

If you have a 2-story house with only a furnace, and the upstairs is warmer than needed, then most likely you have a air flow balance issue. This is corrected by adjusting the amount of air that goes into each area.

If you have a 2-story house with one furnace with AC, if you have issues of comfort, that can be achieved by automatic zoning. This is by having 2 thermostats (noe upstairs and one downstairs) and redirecting air as needed. Call your HVAC guy to achieve this.

Imagine you are filling your bathtub with warm/hot water to take a bath. The water just under the spout will be much warmer than the side of the bathtub farthest away. Before getting into the bathtub, we mix up the water or wait until the water is evenly warm everywhere.

This is exactly what we are trying to do with the fan. The fan circulates the air from all parts of the house and keeps the whole house at an even temperature.

During the fire season, you can keep your inside air clean by running the fan. This filters the air of impurities. Remember to change the filter often when the air is declared unsafe for outside activities. Check your filter more often and replace if needed.

There is another advantage to using the fan. Since the air goes through the duct is blown into the home, the air has to pass through the filters. This makes the air cleaner. So if you suffer from allergies, then running the fan is a great way to filter out the allergens in the air by running the fan.

Questions to ask your HVAC contractor

Before you hire a heating or air conditioning contractor, you need to know how they are going to do the work. Even if you don’t know anything about HVAC, you should be able to get a good idea of their work ethos with these questions.

1. How are you going to size my HVAC equipment?

Getting the right-sized equipment for your house and your needs is very important for efficiency and energy use. Why get a bigger and more expensive size HVAC equipment, when a smaller and less expensive one will do?

When it comes to an HVAC equipment, bigger is not better. If it is bigger, it will turn on and off frequently. This will significantly lower the life of the equipment.

One of ways to do the sizing of a furnace or air conditioner is by Manual J which is the protocol that is used to determine how much heating/cooling a home needs to stay cool and dry in the summer and warm in the winter.

2. How do you keep up-to-date on the current regulations?

The Department of Energy creates and revises its energy efficiency standards and other regulations. It is important for the HVAC contractor to stay on top of these regulations so your equipment and the installation meet those regulations. In extreme cases, it may be harder to sell your home unless the installations are up to code and it could run you thousands of dollars to bring a bad installation to code.

3. Who is going to do the work?

If the contractor is going to do the work, then he is going to do the best work he can. If he is going to hire other people to do the work, then the quality of the work will depend on the expertise of those workers.

4. If you are going to hire others to do the work, how are they paid? Hourly or by the job?

If the hired workers are paid by the job, they will try to finish the job ASAP to get to the next job. This could result in the job being rushed and the quality of the work could suffer.

5. What kinds of materials will you be using for the duct work? Will you be doing any custom fabrication for the furnace?

Many contractors use wire flex pipe. The advantage is that they are made of plastic and fairly inexpensive. Unfortunately these pipes are generally not installed correctly. Also, rodents could chew on these pipes!

Remember that you have an already existing furnace, then the HVAC contractor should do custom fabrication to ensure proper air flow without any leaks.

6. Are you going to look at the whole house for inefficiencies, determine the size of the equipment needed, installation, etc. or are you just going to sell me the equipment?

Does the contractor want to sell you a metal box aka furnace? If your house wasn’t getting heated or cooled properly because of a leaky duct, replacing the equipment isn’t going to solve the problem. So it is important for the contractor to evaluate the system you have in place instead of simply installing new equipment.

7. How are you going to determine that the system is running to its full capacity?

Your HVAC contractor should have a process in place where they show you how well the system is working.

8. Are you going to get the permit?

Any time you replace your furnace, the state requires you to get a permit. And it is the contractor’s responsibility to get the permit. The contractor is responsible to know the rules. A permit ensures the minimum requirement for the work is met.

9. Will you teach me how to do basic maintenance on the equipment?

Whether it is changing the filters or looking for issues, the contractor should give you instructions on how best to take care of your heating or air conditioning installation.

10. Are you and/or your company licensed and insured to work in my state/city?

Yes, there are companies and individuals out there who are not licensed to do any heater or air conditioner installations, but routinely do it. This puts you, your home and your family at risk for possible gas leaks, fires or pushing contaminated air into the house. Always ask to see your HVAC contractor’s license and liability and check their validity on your state government website.

RC Mechanical is an owner-operated Redwood City business and has provided expert furnace and air conditioning repair and installation to the Bay Area with integrity for over 20 years. Call us today at (650) 575-3915. Homeowners in Redwood City and throughout the Bay Area count on us for all their heating and air conditioning needs.

Duct work

Properly installed duct work

The basics of an HVAC system

There are 3 main factors that go into determining if your furnace will work at its peak efficiency. They are:

1. The furnace itself
2. The duct work
3. The installation

If any of these has a problem, you will know that your furnace/air conditioner is not working to its full capacity. This blog post will deal with the least sexy part of this sytem: the duct work.

The job of duct work is to distribute hot/cold air all through the house equitably. When the duct work is installed properly, the furnace or AC keeps all rooms in the house at a comfortable temperature.

An improperly installed duct system would render your home uncomfortable even if the furnace or the air conditioner is sized correctly for your home and functioning properly.

This is analogous to buying a Mercedes-Benz S-class with tires and inner tubes from the 1970s. Sure, the automobile is high end, but without good tires, you are not going to get the pleasure or the comfort of driving such a exclusive vehicle.

Improperly designed or installed duct work lowers the efficiency of the equipment. If there is a leak in the duct work, your energy bills will be higher even though you may have bought an energy-efficient furnace/AC. The same is true if the duct work is not insulated.

Is your furnace is working to its full capacity?


When you buy a furnace, the equipment comes with the specifications that tells you the temperature rise of the equipment. To see if your furnace is working to its full capacity, turn up the thermostat to 5 degrees over the ambient temperature. This should turn the furnace on.

After about 15 minutes, check the temperature in the register closest to the furnace. You can use a meat thermometer for this. Then check the temperature in the return air.

The temperature difference between the two should be within the range specified in the factory specifications for temperature rise.

If it is not within this range, check the furnace filter. If it is dirty, replace it. Next, make sure that the supply and return registers are not closed or obstructed in any way.

If both these are ok, then it is time to call your HVAC specialist.

RC Mechanical is an owner-operated Redwood City business and provided expert furnace and air conditioning repair and installation to the Bay Area with integrity for over 20 years. Homeowners in Redwood City and throughout the Bay Area count on us for all their heating and air conditioning needs.Call us today at (650) 575-3915.

Prep your AC for the summer

HVAC air conditioner

Check if your AC works before the summer season hits

Since the weather is still fairly cool, you may not think that it is time to worry about AC just yet. This is precisely the time you should!

It is important to make sure that your AC is working well before the summer’s hot days are upon us.

As a homeowner, prepare your AC for the summer months by first testing it yourself. If you are lucky, your equipment may have weathered the winter just fine.

Follow the 4 steps below to check if your AC is ready for the summer.

1. Physical inspection

This involves physically looking at the AC equipment and clearing the dust, leaves and other debris around it. Clear out cobwebs and dirt from around it. You may also use your hose to give the equipment to clean the exterior of the AC. Check for any missing panels.

Change your air conditioner’s filter at the beginning of the season.

2. Turn system on

Before you turn the AC on, visually ensure that the electrical wiring is not damaged.

Turn the AC on. If it starts, hooray! If not, check to see if the equipment is plugged in!! The air conditioner’s plug could have gotten accidentally dislodged from the outlet.

Make sure all the the circuit breakers and fuses are in place and turned on.

Also, set the thermostat to ‘cool’ and make sure that the thermostat is working properly.

3. Check the ducts

Air conditioning ducts carry the cool air from the AC to all the rooms. Ducts are hidden from view. The way to check the ducts is to find out if the air is coming out of all the registers in the house. Initially the air may not be cool and that is ok. At this point, we are just checking to see if the air is coming out of all the registers in the house. If it is, then the ducts are working well.

If the air doesn’t come out the register with the same force as in the other registers, then we may have an issue with the ducts. Call your AC contractor.

4. Check the temperature

The last step is make sure that the AC is actually pushing cool air. You can use a regular meat thermometer for this.

After 30 minutes of running the AC, the temperature of the air being pushed at each of the registers should be 55 degrees. If it is not, then your AC may be low on freon or there may be some other issue with the AC.

Summer days will be here soon enough. Make sure you are ready for them with a well-maintained and efficient air conditioning system.

RC Mechanical is an owner-operated Redwood City business and has served the Bay Area with heating and air conditioning expertise for over 20 years. Call us at (650) 575-3915 if you need any help getting your AC ready for the summer. Homeowners in Redwood City and throughout the Bay Area count on us for all their heating and air conditioning needs.

Filters & Allergies

Allergy season

Would you like to make sure that your home is a safe haven from allergies?

Often people buy filters for their heating and air conditioning installations but then are disappointed when their allergy symptoms don’t improve. In fact, having an air filter is just one of many things that need to be done to make your home safe from allergens.

When you call us to request changing your air filter, we first ask about the sensitivities you have. Are you allergic to mold, dust, pollen? We can’t control the outside, but we can certainly make sure that the air you breathe inside your house is keeping you comfortable.

Then we test the house for a variety of issues. We measure the rate of air changes per hour. The standard is 3-5. If it is 5 or more, then that means that there is air leakage into the home. The air is most likely coming in from either the attic or the crawl space.

Depending on how many symptoms you want to tackle, we can recommend the best air filter for your needs. Filters have merv ratings. The higher the number, the better the filter. Merv ratings go from 1 to 16.

We recommend an IQAir Perfect 16 filter for homeowners who want their air to be as clean as possible. These filters have a merv rating of 16. When we install this filter, we just don’t tell you how this filter is operating; we show you. We take air quality readings before and after we put the filters in.

When you use a cheaper air filter with a merv rating of 2 and under, you are helping protect the furnace but not doing very much to protect your health.

Have any questions about filters? RC Mechanical is an owner-operated Redwood City business and has served the Bay Area with heating and air conditioning expertise for over 20 years. Homeowners in Redwood City and throughout the Bay Area count on us for all their heating and air conditioning needs. Give us a call at (650) 575-3915 and let us help you.