Professional ductwork installation in Hillsborough, CA, encompasses everything from initial home assessment and load calculations to layout design, material selection, sealing, insulation, and final airflow balancing. The process addresses code compliance, permitting, and coordination with other trades, while setting expectations for timelines, disruption, and warranties. Proper sizing, meticulous sealing, and thorough testing ensure consistent temperatures, enhanced energy efficiency, improved indoor air quality, and simplified compliance with state energy standards for Hillsborough homes.

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Ductwork Installation in Hillsborough, CA

Upgrading or installing new ductwork is one of the most effective ways to improve comfort, indoor air quality, and HVAC efficiency in Hillsborough homes. Whether you are building new, renovating a vintage Hillsborough property, or replacing aging runs in an unconditioned attic, properly designed and installed ducts reduce uneven temperatures, lower energy use, and limit dust and moisture problems common in our coastal San Mateo County climate.

Common ductwork issues in Hillsborough homes

Uneven heating or cooling between rooms, especially in multi-level or older homes
High energy bills caused by leaky or undersized ducts
Mold, musty odors, or dampness from uninsulated ducts in cool, foggy coastal conditions
Poor indoor air quality and dust transfer from poorly sealed connections
Difficulty meeting California Title 24 energy requirements during remodels or additions

Understanding these problems helps define a targeted duct design and installation plan tailored to Hillsborough’s mild, often foggy microclimate and the typical construction styles in the area.

Duct design and installation process

A professional duct installation follows a logical series of steps to ensure performance, code compliance, and minimal disruption to your home.

Home and system assessment

Inspect the existing HVAC equipment, attic, crawlspace, or basement layout.
Identify thermal boundaries, insulation levels, and potential moisture or mold issues influenced by local weather.
Gather architectural details to plan routing that minimizes long runs and unnecessary bends.

Load calculation and duct sizing

Perform Manual J (load) and Manual D (duct design) calculations to determine correct capacity and duct sizes for each conditioned space.
Account for Hillsborough-specific factors like coastal humidity, sun exposure on west- or south-facing elevations, and local insulation practices.

Layout and material selection

Create a layout that balances short, direct runs with room-by-room supply and return placement for even airflow.
Choose materials (see next section) based on durability, space limitations, and efficiency goals.

Sealing and insulation

Seal all joints and transitions with code-approved methods to reduce leakage and infiltration of outdoor air, dust, and smoke.
Insulate ducts located in unconditioned spaces to prevent condensation and energy losses.

Installation and coordination

Coordinate with other trades (roofing, framing, electrical) for new construction or remodels to minimize rework.
Schedule work to limit disruption and protect finished surfaces in Hillsborough’s higher-end residential settings.

Airflow balancing and testing

Perform static pressure, airflow (CFM), and leakage testing to verify the system meets design targets and Title 24 performance goals.
Adjust dampers and registers for even temperatures and proper room-by-room delivery.

Code compliance and permits

Prepare required documentation and submit permits to the Town of Hillsborough or San Mateo County building department.
Ensure work satisfies California energy code requirements, including duct sealing and insulation standards.

Materials and methods — what to expect

Sheet metal ducts: Long-lasting, low-friction, and best for tight, permanent installations. Ideal where space and access allow.
Flexible ducts: Useful for short runs and tricky spaces, but require correct support and minimal bends to perform well.
Duct board: Insulated rigid board can save space and reduce condensation risk but must be installed carefully to avoid long-term integrity issues.
Sealing methods: Mastic, UL 181-rated tapes for flexible duct connections, and aerosol duct sealing for hard-to-reach leaks. Mastic and mechanically fastened connections provide the most reliable long-term seals.
Insulation: Wrap or insulated ductboard meeting R-values required by California code for ducts in unconditioned spaces. Proper insulation prevents condensation in Hillsborough’s cool, foggy mornings.

Airflow balancing and performance verification

Performance testing confirms the installation meets comfort and efficiency objectives:

Static pressure measurement ensures the system is not overworked. Industry targets vary by equipment, but testing confirms the blower operates within safe limits.
CFM measurements at supply and return registers verify that each room receives the calculated airflow.
Duct leakage testing quantifies losses and validates sealing work. Lower leakage improves energy efficiency and reduces infiltration of pollen, smoke, or outdoor moisture — particularly important during wildfire smoke events in Northern California.

Results are documented so you can see how the system performs compared to the design.

Permits, timelines, and disruption expectations

Permits: New ductwork and major modifications generally require permits and inspections. Installers should handle submittals and coordinate inspections with the local building department.
Typical timeline: For a standard single-family home, a full duct replacement or new duct install usually ranges from a few days to a couple of weeks depending on scope, access, and permit timing. Complex layouts or historic-home restorations in Hillsborough can extend timelines.
Disruption: Expect workers in attics, basements, and around HVAC units. Good installers protect floors and landscaping and plan access to minimize disturbance in well-maintained Hillsborough residences.

Warranty and long-term care

Installation warranty: Professional installations typically include a workmanship warranty covering proper sealing, connections, and installation practices for a specified period.
Material warranty: Duct components may carry separate manufacturer warranties.
Maintenance tips: Replace HVAC filters regularly, schedule annual duct inspections, check insulation and seals after major storms, and monitor for signs of moisture or mold in attics and crawlspaces. Timely maintenance preserves performance and extends system life.

Benefits of properly installed ducts in Hillsborough, CA

More consistent, comfortable temperatures throughout the home
Lower HVAC energy use and improved system longevity
Better indoor air quality and reduced allergen and particle transfer
Reduced risk of condensation-related mold in coastal fog conditions
Easier path to compliance with California energy codes during remodels or additions

A carefully designed and executed ductwork installation delivers reliable comfort and efficiency tailored to the specific needs of homes in Hillsborough, CA. Proper sizing, professional sealing, and verified testing provide predictable performance you can count on year round.

testimonials

hear what our satisfied clients have to say

5.0

We found Plum HVAC in 2024 after spending more than 2 months searching and comparing estimates. The owner Sam gave us a very competitive price for a Mitsubishi mini-split and the installation went off without a hitch. Our experience was so positive that we later requested their services twice more to also install A/Cs for our 2 other rooms. Their technician, Jake, led our installations each time and we were very impressed by their professionalism and quality of work. Now 1 year in and we could not be any happier, nor have we encountered any issues with our models.

Jesse Y.

5.0

Sam of Plum HVAC, responded to our Heat Pump installation request promptly and provided a very competitive estimate after an onsite visit. He was very flexible and patient to answer and explain our questions. After we signed the contract, he and his team of 4 worked very hard to deliver and install the whole Heat Pump system on time with good quality. I am particularly impressed by their problem solving skills to overcome different connection challenges for the attic installation. Each day before they started, they covered the floors with protection blankets and cleaned after they were done for the day. They also revised the drainage and electric work per the city inspection guidance. Sam and his team were professional and honest so we highly recommend Plum HVAC to any customers who need HVAC work done for their houses.

Chunshi C.

5.0

We needed to install a mini-split in a backyard unit. Sam and his team helped with this, and they did a fantastic job. Sam visited our place and clearly explained to me what needed to be done, and offered a great price. He scheduled the job for a few days later, and his team performed the job with extraordinary quality. Later, I noticed a minor issue and reached out to them. Sam helped me to fix the issue on a second visit by his team later in the week, providing top-notch customer service. I will work with them in the future for my HVAC jobs, and highly recommend them given their excellent work quality and customer service.

Majid J.

5.0

I reached out to 4 companies for mini split quotes; Plum HVAC pricing came in the lowest. Beyond that, Sam was very knowledgeable and kind during the in home consultation. He offered a quote in person, & stuck by it. They removed our old furnace, and installed a two head mini split in our two story townhouse. The work as you can see is very clean! The guys who installed it were very fun & professional. Sam & his team were communicative the whole way through including the permitting process. They took roughly one full day for install, which was very fast! Including removal & disposal of our old furnace. Natalie was very helpful throughout the Bayren Rebate process & always available for any questions! This system has changed our lives, wish we would have gotten it done sooner! It’s way better than we could have imagined.

Bobby R.

5.0

Plum HVAC exceeded my expectations in every way. Sam and his installer team were not only professional but also incredibly responsible throughout the entire process. They provided top-notch service at a very reasonable price, which is hard to come by these days. I highly recommend Plum HVAC to anyone looking for quality HVAC services. You won't be disappointed!

A Chui

5.0

I recently engaged Plum HVAC to install two mini-split units at my residence, and I'm thrilled with the outcome.Throughout the entire process, from the initial consultation to the project's completion, Plum HVAC showcased professionalism and expertise. The technician, Sam, arrived promptly and conducted a comprehensive assessment of my HVAC system. Sam took the time to thoroughly explain the technicians' tasks, the estimated duration of the project, and provided transparent pricing options.

Romero J.

5.0

Wonderful experience with Plum HVAC on a heat pump installation! I checked several companies, compared their recommendations, timelines, reputations and prices.Sam, the owner, was very professional and has almost 2 decades of experience in HVAC. When I asked dumb questions, he answered most graciously. And when I noted that some companies we queried said we could get away WITHOUT replacing our original ductwork from 1965, he gave us his honest opinion why that wasn't a good idea. (Hubby remembered later that people who worked in our attic adding insulation told us there were lots of duct leaks.)

Marlene S.

5.0

I called 8 different HVAC companies for quotes for a heat pump heating/ac system because I want to save money by switching from a forced air gas furnace to an electric heat pump system which will give me both heating and air conditioning. In addition my old furnace (circa 1991) was way oversized for my home and the air coming out too noisy. The New heat pump system is quieter and more efficient. Back to the quotes for the system, all the other 7 companies sent a salesperson/advisor to give the quote. Sam, the owner of Plum HVAC came our to give the quote. He was quick with his quote and was very knowledgeable. He didn't try to upsell me on anything and have the lowest quote of them all. His price was 60% less than the highest quote and 15% lower than the next second lowest quote.

Michael C.

5.0

Plum HVAC is an extremely professional, knowledgeable, and an established company to hire. I highly recommend Plum HVAC! Sam and his crew did a wonderful job. Sam worked with my schedule and his crew had completed the job with ease.

Blake

5.0

Sam was one of the most professional business owners I had the chance to meet over the past few years and I'm so happy I trusted him to install our new A/C unit.- He showed up on time- He was transparent (and reasonable) regarding pricing- He offered 2-3 options- His crew did a very clean/thorough jobWhat I loved the most though, was the fact he was very easy to communicate with. I would definitely use him again and recommend him to our neighbors/friends.

Bruno L.

5.0

We recently had a complicated Bryant Evolution dual fuel system with variable speed and zoning installed in our home by Plum HVAC, and we are very pleased! The team also changed the entire crawl space ducting, ensuring a comprehensive upgrade. The price was fair, and the team was always on time and easy to contact. Sam Mousavi, the head of the team, paid great attention to detail and demonstrated a strong understanding of systems. His expertise in HVAC systems and his friendly character made us feel comfortable throughout the process. We highly recommend Plum HVAC for their professionalism and excellent service.

Amirali B.

5.0

I cannot say enough about Plum HVAC, who replaced my aging heater furnace, and in particular Sam. Sam was very highly recommended by my sister, who replaced her furnace and added air conditioning.First, they gave me a good deal for a 2-stage, at the same cost as the lowest bid for a 1-stage. The other bids were dancing around some gas line work made by previous owners.

Kumar S.

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