What Sonoma County Homeowners Should Know About HVAC and New Construction — Why the System Choices Made Before You Move In Are the Ones That Matter Most
If you’re buying or building a new home in Sonoma County — whether that’s a new subdivision in Windsor, a custom build near Healdsburg, or a newly constructed infill home in Santa Rosa — the heating and cooling system that goes in during construction is one of the most consequential decisions attached to that property. And in most cases, buyers and future homeowners have very little say in it. Here’s what you should understand before you close escrow or sign off on a builder spec sheet, and why it pays to ask the right questions early.
Builder-Grade Systems Are Designed to Meet Code — Not to Serve Your Household
When a production home builder or general contractor selects an HVAC system, they’re making a cost-controlled decision. The goal is to pass inspection, satisfy California’s Title 24 energy code requirements, and keep the build on budget. That often means you get a system that’s technically compliant but not necessarily sized correctly for your specific floor plan, ceiling height, sun exposure, or how many people are going to live there.
This is a genuinely underexplored issue in new construction. Most homeowners assume that a brand-new system is a good system. What they don’t realize is that an undersized or oversized unit — even a brand-new one — will struggle from day one. Oversized equipment short-cycles, meaning it turns on and off too frequently instead of running through full conditioning cycles. That leads to uneven temperatures, excess humidity in winter, and more wear on components than you’d expect from something you just moved into.
If you have any input during the design or pre-close phase, ask to see the Manual J load calculation — that’s the industry-standard method for determining what size system a home actually needs. If the builder can’t produce one, that tells you something.
Duct Design in New Construction Deserves More Scrutiny Than It Usually Gets
The ductwork layout in a new home often gets less attention than the equipment itself, and that’s a mistake. Poorly routed ducts — runs that are too long, have too many bends, or are undersized for the rooms they serve — will create comfort problems that no thermostat adjustment can fix. You might find that one bedroom is always warmer than the others, or that a room at the end of a long hallway never quite reaches the temperature you’ve set.
In newer neighborhoods around Rohnert Park and Petaluma where homes are being built quickly and at scale, duct installations can be rushed. Ask the builder whether duct leakage testing was performed. California’s Title 24 code does require duct leakage testing on new construction, but the results aren’t always reviewed carefully by buyers. A duct system with even moderate leakage is quietly wasting energy every time your system runs — and you’ll be the one paying the PG&E bill.
Heat Pumps Are Increasingly the Default in New California Construction — Here’s What That Means for You
California’s building codes have been steadily pushing new construction toward all-electric systems, and heat pumps are now being installed in new Sonoma County homes more often than gas furnaces. That’s not a bad thing — heat pumps are genuinely well-suited to our Mediterranean climate, where winters are cool but rarely brutal and summers are hot but dry. A properly sized and installed heat pump handles both heating and cooling from one system and does it efficiently.
But there are things to know. Heat pumps installed in new construction are only as good as the installation behind them. A heat pump that’s paired with undersized ductwork, or set up without proper refrigerant charge, will underperform from the start. If your new home has a heat pump and you’re noticing that it runs almost constantly in colder weather or struggles to hold temperature during a summer heat wave, that’s worth having a technician evaluate — don’t just assume that’s normal behavior.
Also worth knowing: if your new construction home came with a heat pump, it may qualify for federal tax credits under the Inflation Reduction Act, and PG&E may have additional rebates available depending on system efficiency ratings. A local HVAC contractor can help you confirm eligibility and track down documentation from the builder if needed.
What New Construction Buyers Often Don’t Think to Ask (But Should)
If you’re still in the buying or planning phase, these are the questions that will save you headaches later:
- What brand and model was installed? Get the model numbers for both the indoor and outdoor units. This matters for warranty registration, future service calls, and understanding what SEER rating you’re working with.
- Was the system registered for warranty by the builder? Many manufacturers require warranty registration within a specific window after installation. If the builder didn’t do it, you may need to handle it yourself — and some warranties require proof of professional installation.
- Who installed it? Knowing the installing contractor means you know who to call if there’s an issue under the installation warranty, which is typically separate from the equipment warranty.
- Has the system been commissioned? Commissioning means a technician started the system, verified refrigerant charge, checked airflow, and confirmed that everything is operating within spec. Not all new systems get properly commissioned before the homeowner moves in.
- Where are the filter locations, and what size does it take? This sounds basic, but in newer homes with more complex air handler configurations, filter access can be in unexpected places. You want to know this before you move in.
The First Year in a New Home Is the Best Time to Catch Problems Early
New construction typically comes with a builder’s warranty, but most of those cover structural defects — not HVAC performance issues that develop over the first heating or cooling season. The practical advice here is to schedule an independent HVAC inspection from a contractor not affiliated with the builder sometime in your first year. This is especially true if the home sat unoccupied for a period before you moved in, which is common in Sonoma County’s slower resale market cycles or in spec homes that didn’t sell quickly.
At Stout’s Heating & AC, we’ve serviced new and near-new systems throughout Santa Rosa, Sebastopol, Healdsburg, and the surrounding area. We’ve seen brand-new equipment with improperly set refrigerant charge, disconnected condensate drain lines, and filters that were never installed by the framing crew. These aren’t horror stories — they’re just the reality of busy construction schedules. Catching them in year one, while systems are still under warranty, is far better than discovering them in year three when something fails and you’re paying out of pocket.
We offer maintenance and inspection services that are a straightforward way to get a baseline on what you actually have — and what condition it’s in — before that builder warranty expires.
Frequently Asked Questions
Can I upgrade the HVAC system in a new construction home before I move in?
In some cases, yes — especially if you’re involved early enough in a custom build. With production homes, it can be more difficult, but some builders will allow equipment upgrades for a cost difference. It’s worth asking, particularly if you want a higher SEER rating, a specific brand, or a zoning setup the standard spec doesn’t include.
My new home in Windsor has a heat pump but no gas backup. Is that a problem?
Not necessarily. Modern heat pumps perform well down into the low 30s and even the upper 20s, which covers most of what Sonoma County winters throw at us. If you’re in a hillside location near Healdsburg or somewhere that sees harder freezes regularly, a dual fuel or hybrid system might be worth considering — but for most of the county, an all-electric heat pump is a reasonable setup.
The builder said the system is under warranty. Does that mean service calls are free?
Not automatically. Equipment warranties cover parts, not labor. Installation warranties vary by contractor. Read what you were given carefully, and note the expiration dates on both. Some manufacturer warranties are also conditional on annual maintenance being performed by a licensed HVAC contractor.
How do I find out the SEER rating of the system in my new home?
The model number on the outdoor condenser unit will tell you. You can look it up on the manufacturer’s website, or a licensed HVAC technician can identify it during a service call. In California, new residential systems are required to meet minimum efficiency standards, but those minimums have changed in recent years — your system should have been installed at 15 SEER2 or higher under current regulations.
What’s the first maintenance task I should do as a new homeowner with a new HVAC system?
Register the equipment warranty if the builder hasn’t done it, locate all filter access points and replace any filters that were installed during construction (they’re often dirty from framing dust), and schedule a professional tune-up before your first heavy-use season — whether that’s summer cooling or winter heating. That first inspection is the cleanest baseline you’ll ever have.
Talk to Someone Who Knows These Systems — and This Area
We’ve been doing this in Sonoma County since 1992. We know what builders are putting in, what systems are common in newer developments along the Highway 101 corridor, and what issues tend to surface in the first few years. If you’ve recently moved into a new home and want a second set of eyes on your HVAC setup — or if you’re still in the planning phase and want an independent opinion — we’re happy to help.
Contact Stout’s Heating & AC, Inc. to schedule an inspection or ask a question. No pressure, no upsell — just straight answers from a local contractor who’s been around long enough to have seen it all.