Plum HVAC outlines full-system heat pump replacement for Millbrae homes, highlighting when replacement is warranted, coastal climate considerations, and the step-by-step process from assessment to installation. We cover right-sizing with ACCA Manual J calculations, ductwork and electrical needs, permit timing, and environmental compliance. Expected timelines, warranties, and financial incentives are explained, along with the practical benefits of modern, variable-speed systems: improved comfort, lower energy use, better reliability, and alignment with decarbonization goals for Millbrae residences.

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Heat Pump Replacement in Millbrae, CA

Replacing a full heat pump system is a major decision for any Millbrae homeowner. With the Peninsula’s mild, marine-influenced climate and salty coastal air, the right replacement can deliver better year-round comfort, lower energy bills, and improved reliability. This page explains the full-system heat pump replacement process specific to Millbrae homes, common reasons to replace, technical and permitting considerations, expected timelines and warranties, and the real-world efficiency and comfort benefits you can expect.

Why replace a heat pump in Millbrae homes

Millbrae’s cool summers, mild winters, and frequent marine layer put different demands on HVAC equipment than inland climates. Salt air and humidity can accelerate wear on outdoor units, and many Peninsula homes were built decades ago with undersized systems or ductwork that no longer meets today’s efficiency goals. Typical motivations for full-system replacement include:

System age of 10 to 15+ years with declining efficiency and frequent repairs
Repeated refrigerant leaks or a failing compressor
High utility bills despite regular maintenance
Uneven comfort between rooms or inability to meet cooling/heating loads
Home remodels, additions, or conversion to electric heating for decarbonization

Common heat pump replacement issues in Millbrae

Corroded outdoor coils and components from coastal salt exposure
Undersized systems from older load calculations or added living space
Inefficient single-speed compressors replaced by modern variable-speed inverter models
Duct leakage, poor insulation, or inadequate airflow causing comfort problems
Electrical panel limitations for newer, higher-efficiency equipment

Assessment and right-sizing

A proper replacement begins with a full-site assessment and load calculation. This includes:

Visual inspection of existing equipment, ductwork, thermostat, and electrical service
Detailed load calculation (ACCA Manual J or equivalent) to determine correct system capacity based on home size, orientation, insulation, and local climate
Airflow and duct leakage testing to identify needed ductwork upgrades or sealingRight-sizing prevents oversized cycling, reduces humidity problems, and improves long-term efficiency—especially important in Millbrae where mild conditions reward properly matched equipment.

Selecting energy-efficient models

Energy-efficient options for Millbrae replacement projects commonly include:

Variable-speed inverter heat pumps for quieter operation and better humidity control
High SEER2 and HSPF2 rated units (look for models optimized for moderate coastal climates)
Corrosion-resistant coatings and elevated pads to protect outdoor units from salt exposure
Ductless mini-split or hybrid systems for rooms without existing ductworkModel selection balances efficiency, longevity, and suitability to the home’s layout. Manufacturers’ performance metrics, seasonal efficiency ratings, and real-world part-load performance should guide choices.

Removal, disposal, and environmental compliance

Full-system replacement includes safe removal of the old equipment:

Certified refrigerant recovery and disposal in compliance with state and federal regulations
Proper disposal or recycling of metal, insulation, and electrical components
Protection of the home and landscape during removal and installationGiven Bay Area environmental rules, correct refrigerant handling and documentation are essential to avoid fines and ensure proper disposal.

Ductwork, electrical, and site coordination

Many Millbrae homes require coordination beyond the heat pump itself:

Ductwork sealing, insulation, resizing, or partial replacement to ensure proper airflow
Electrical upgrades, including dedicated breakers, surge protection, or panel capacity increases for modern units
Placement considerations to minimize salt exposure, noise impact, and aestheticsWork with licensed trades to coordinate duct and electrical work in sequence with equipment delivery and permit timelines.

Permits, inspections, rebates, and financing

Heat pump replacement typically involves municipal permitting and inspection in Millbrae and San Mateo County jurisdictions. Expect:

Permit application and plan submittal for equipment changeout, duct modifications, and electrical work
Scheduled inspections upon completion to verify code complianceMillbrae homeowners may also be eligible for state and federal incentives, local utility rebates, and financing programs that lower upfront costs. Documentation of equipment efficiency and installation practices is often required to claim rebates and tax credits.

Typical timelines and warranties

Typical timelines for a full-system replacement:

Assessment, load calc, and equipment selection: 1 to 2 weeks
Permit processing (varies by scope and season): days to a few weeks
Installation: 1 to 4 days depending on ductwork and electrical needs
Final inspection and commissioning: a few days after installationWarranties usually include manufacturer parts and compressor coverage (commonly 5 to 12 years for components) and separate labor warranties from the installer. Retain documentation for both for future service or incentive qualification.

Expected benefits in efficiency and comfort

Replacing an old heat pump with a properly sized, modern system delivers concrete benefits for Millbrae homeowners:

Lower energy consumption and more predictable monthly costs from higher seasonal efficiency
Improved comfort with more consistent temperatures, reduced humidity swings, and quieter operation
Greater reliability and fewer emergency repairs
Enhanced indoor air quality if accompanied by upgraded filtration and sealed ductwork
Increased home value and alignment with regional electrification and decarbonization trends

Maintenance and long-term performance tips

To protect your investment and maximize lifespan:

Schedule annual professional tune-ups and mid-season checks for coastal environments
Replace or clean filters regularly and keep outdoor units free of debris and salt buildup
Consider routine coil cleaning and checks for corrosion-prone components
Use programmable or smart thermostats to optimize runtime and comfort in Millbrae’s mild climate

A full heat pump replacement in Millbrae, CA is a strategic upgrade that goes beyond swapping equipment—proper assessment, right-sizing, and coordinated duct and electrical work ensure the system performs efficiently for years. When replaced and maintained correctly, a modern heat pump delivers quieter, more consistent comfort and aligns with local energy and environmental priorities.

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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