







Free written scope consultation - allowances, timeline, and change-order rules on paper before a single trade is scheduled
Why Thousand Oaks Homeowners Choose Ameristar Construction
Ameristar in Thousand Oaks equipment is everywhere, from M4AC3 condensers humming behind tract homes near Wildwood to M4PG3 package units bolted onto commercial flat roofs around the Janss Marketplace. We’re Mason Remodeling Co Thousand Oaks, and we’re an independent Ameristar service provider, which means we fix and install Ameristar systems every week but we’re not tied to a dealer agreement that limits how plainly we can talk about costs. If you own an Ameristar air conditioner, heat pump, furnace, or package unit in the 91360, 91362, or 91320 ZIP codes, we bring the parts, the know-how, and a written price before work starts. Call (805) 309-3386 and a live person answers. Same day, every day.
What most Ameristar in Calabasas and Thousand Oaks homeowners discover quickly is that Ameristar’s M4-series is incredibly popular because it’s affordable to install, and that popularity means independent shops like ours see hundreds of these units every year. We’ve learned exactly how they fail here, in this specific climate. That’s the information you will not find on a manufacturer’s spec sheet. We’re not authorized by Ameristar, and we’ll say that plainly. Being independent is what lets us install the part that actually makes sense for your budget rather than defaulting to the most expensive factory component every time.
- Independent Ameristar service: full diagnostics, repair, and replacement for M4AC3, M4HP3, M801P, and M4PG3 systems.
- Written price before work: no verbal estimate that grows on the final invoice, every time.
- Roof, storm, and package-unit expertise: when an Ameristar package unit rusts through and leaks into your building, we fix the roof, the curb, and the unit.
- One call, real person: (805) 309-3386, answered 24 hours a day, seven days a week.
Why Trust Mason Remodeling Co Thousand Oaks for Your Ameristar Construction?

Isaac Pruett has been building and rebuilding homes across Ventura County for years. He grew up in Los Angeles and learned the trade at Los Angeles Trade-Technical College before putting that foundation to work on real job sites, from whole-home renovations near Lang Ranch to smaller kitchen and bath builds. What that means for your Ameristar equipment is a contractor who treats an HVAC diagnosis the way he treats a retaining wall drainage problem: find the actual cause, write the real fix, and stand behind it.
Ameristar units are economy-minded but workhorse machines. The M4AC3 air conditioner and M4HP3 heat pump use single-stage Copeland compressors that are simple and durable, but the supporting components around them fail more often. The start capacitor, the contactor, the condenser fan motor. Those are the parts we replace most in Thousand Oaks, and we stock Titan HD and Supco aftermarket components on our trucks to do it fast. For valves and coils where integrity matters, we use OEM Ameristar parts. That’s the honest balance, and it’s the same standard we apply to our General Contractor and remodeling work: use the right material for the job, not the most profitable one.
We’re not an authorized Ameristar dealer. We don’t have to be. After years of servicing M4-series equipment in Thousand Oaks’ hot, dry summers and mild, wet winters, we know the failure patterns, the compressor amperage ranges, the refrigerant charge nuances, and the roof penetration details for package units. Homeowners receive a written price before any work starts, and every completed job carries a guarantee with plainly stated terms. If something’s not right within 365 days of completion, we make it right at no cost, no dispute process.
Styles & brands we work with







Common Ameristar Construction Problems We Fix in Thousand Oaks
We see the same five problems on Ameristar gear in Thousand Oaks over and over. Here’s what they are, why they happen, and what we do about them.
- M4AC3 condenser coil pinhole leaks. The aluminum fins and copper tubing on these coils are thin to keep the unit affordable. After five to seven years of Thousand Oaks heat cycling and the occasional Santa Ana dust blast, the coil walls can develop microscopic pinholes. The unit slowly loses refrigerant, runs longer, and stops cooling. In coastal-adjacent parts of Thousand Oaks, salt air wafting up the canyons accelerates the corrosion. We pressure-test, pinpoint the leak, and tell you honestly whether a coil replacement makes sense or whether the system’s age means replacement is the better call.
- Dual capacitor failures during heat waves. When Thousand Oaks hits 95 degrees for a week straight, the single-stage compressor in the M4AC3 works hard and the dual capacitor takes the brunt of it. A swollen or leaking capacitor causes hard starts, a humming condenser that won’t spin up, or no cooling at all. We keep Titan HD capacitors on the truck in every common MFD rating, so this is usually a same-visit fix.
- M4PG3 package unit rust-through on flat roofs. Thousand Oaks has plenty of commercial buildings with flat or low-slope roofs, and the M4PG3 package gas/electric units mounted on them collect water around the bottom pan. When debris clogs the drain lines, water sits, rust forms, and eventually the pan rots through. Water leaks into the structure below. We fix the unit, repair the roof curb and flashing, and correct the drainage so it doesn’t return.
- M801P induced draft motor whine. The M801P gas furnace uses an induced draft motor that pulls combustion gases through the heat exchanger. When the motor’s bearings wear, it produces a high-pitched whine on startup that gets louder over weeks. Left alone, the motor locks out and the furnace won’t fire. We replace the draft motor assembly with an OEM or a quality aftermarket match, and we check the pressure switch and venting while we’re in there.
- Breaker trips on M4HP3 heat pumps. Tripping breakers usually point to a failing compressor, a grounded wire, or a contactor that’s welded itself shut. On M4HP3 heat pumps, we check amp draw on the compressor, test the capacitor, and inspect the contactor for pitting. Sometimes it’s an inexpensive contactor. Sometimes the compressor’s done. You’ll know which one before we ever quote a replacement.
Ameristar Parts & Our Repair-vs-Replace Approach

Ameristar systems use standard, non-proprietary components, which is good news for Thousand Oaks homeowners. When you need a capacitor, contactor, fan motor, or pressure switch, quality aftermarket parts from Titan HD and Supco match or exceed the original specs at a lower price. We stock those on our trucks for fast turnaround. When the job touches the sealed refrigeration system, a valve, or a coil, we use OEM Ameristar parts. Mixing aftermarket parts into the refrigerant circuit on a recovering system is a shortcut that costs more later.
Repair versus replace is a judgment call, and we make it the way we’d make it for our own building. An M4AC3 compressor failure at year nine? A compressor swap costs enough and leaves you with the same aging coil and blower that replacement starts to make more sense. A failed capacitor on a four-year-old unit? That’s a repair, five minutes to diagnose, one visit to fix. We’ll never push a replacement when a $40 part fixes the problem. And we’ll never install a $40 part when the system’s already dying. Call (805) 309-3386 for an honest read, and a written price before we touch anything.
Our Ameristar Service Process – Step by Step
- 1
Diagnosis with measurements, not guesses. We check refrigerant pressures, superheat and subcooling, compressor amp draw, capacitor microfarad readings, and temperature split across the coil. Every number goes on the service ticket.
- 2
The fix, with a written price first. Before we do anything beyond diagnosis, you get a written line-item price for the repair. No verbal number that grows on the invoice. You approve it, we do the work.
- 3
Installation done to code. When we replace an Ameristar unit or install a new one, we handle the electrical disconnect, the condensate drainage, the gas connection, and the roof curb and flashing if it’s a package unit. Ventura County’s hillside grading and fire-safety codes get respected, not cut around.
- 4
Testing before we leave. We run the system through a full cycle, verify supply air temperature, check amp draw, test the safeties, and confirm the thermostat calls. You see the numbers. We don’t leave until the system starts and stops correctly on its own.
- 5
Warranty in writing. Every completed job has a written guarantee with terms stated clearly: what’s covered, what’s excluded, and for how long. The 365-Day Done Right Promise applies. If something’s not right within a year, we come back and make it right at no charge.
See the difference
Before
After
Before
After
Before
AfterAmeristar Products We Service & Install in Thousand Oaks
We work on the full M4-series lineup that dominates Thousand Oaks residential and light commercial installs:
- Ameristar M4AC3 Air Conditioner: 13-14 SEER single-stage condenser, available in 1.5 to 5 ton capacities. Capacitor and contactor swaps are our most common service on this unit.
- Ameristar M4HP3 Heat Pump: single-stage heat pump that handles both cooling and heating. We see reversing valve issues and breaker trips on older units.
- Ameristar M801P Gas Furnace: 80% AFUE single-stage furnace with an induced draft motor. Bearing whine and ignition failures are the common complaints.
- Ameristar M4PG3 Package Gas/Electric: rooftop package unit for commercial and some residential flat-roof applications. Rust, drain issues, and roof leaks around the curb are what we fix most.
We Also Service These Brands
We’re not married to one manufacturer. The same crews that repair Ameristar systems also handle KraftMaid cabinetry, Cambria and Silestone countertops, and Kohler fixtures on our remodeling projects. It’s all building, and it’s all under one roof. If your Thousand Oaks home has a mix of brands, we can handle the whole list in one call.
FAQs – Ameristar Construction Service in Thousand Oaks

Most Ameristar M4AC3 condensers in Thousand Oaks last 10 to 14 years before a major component failure, depending on how hard they’re run during heat waves and whether the coil has been kept clean. We see failures earlier when capacitors and contactors are ignored, and later when equipment gets annual maintenance. If your unit is over 10 years old and needs a compressor or coil, replacement often costs less per year of remaining life than repair. Call (805) 309-3386 and we’ll give you the straight math on your specific unit.
Yes. We handle M4PG3 package gas/electric replacements on commercial flat roofs throughout Thousand Oaks, including the roof curb, flashing, and drain correction that prevents the next rust-through. This is one area where our Ameristar service in West Hills and general contracting and roofing experience matters. We quote the unit swap and the roof work as one written price. Call (805) 309-3386 and we’ll come measure the curb and assess the roof in the same visit.
Yes, this is almost always the induced draft motor bearings wearing out on the M801P gas furnace. We replace the draft motor assembly, check the pressure switch and venting, and have the furnace firing quietly again. If the whine has been going on for weeks, the motor may be close to locking out, so don’t wait until the first cold night. Call (805) 309-3386 for a diagnostic visit.
The three usual causes are a failing compressor pulling locked-rotor amps, a welded contactor, or a shorted wire or capacitor. We test all three in one visit by measuring amp draw at startup, checking the capacitor’s microfarad rating, and inspecting the contactor for pitting. Some fixes are under $200. Some aren’t. You’ll know which before anything gets replaced. Call (805) 309-3386 and we’ll diagnose it properly.
Yes, we service M4HP3 heat pumps throughout Thousand Oaks, including reversing valve issues, defrost problems, capacitor failures, and low refrigerant from coil leaks. Heat pumps run nearly year-round here, so they tend to fail more on components than straight air conditioners. We inspect the entire system on every visit, not just the symptom. Call (805) 309-3386 for service.
No. Using an independent service provider does not void your Ameristar manufacturer’s warranty. We install parts that meet or exceed the original specifications, and we document every repair with the same detail an authorized dealer would. The Magnuson-Moss Warranty Act protects your right to independent service, and we’re fully transparent about what we do. If your unit is still under Ameristar’s factory warranty, we’ll help you file the claim and install the warrantied part.
Roof replacement on a typical Thousand Oaks home runs $8,000 to $20,000, while targeted roof repair costs $400 to $1,800. Metal roof installation is higher, typically $15,000 to $40,000, and tile roof repair ranges from $600 to $2,500. The exact number depends on your roof’s size, pitch, underlayment condition, and the extent of the Ameristar unit work. Here’s the line-item breakdown:
| Service | Typical Thousand Oaks Price Range |
|---|---|
| Roof Replacement | $8,000 – $20,000 |
| Roof Repair | $400 – $1,800 |
| Metal Roof Installation | $15,000 – $40,000 |
| Tile Roof Repair | $600 – $2,500 |
These are honest ranges based on what we quote every week in Thousand Oaks. Call (805) 309-3386 for a written line-item estimate on your specific property, free of charge.
Book Your Ameristar Service in Thousand Oaks, CA
Your Ameristar system is built to work hard in Thousand Oaks heat, but it won’t last forever, and the small failures become big ones when they’re ignored. Call (805) 309-3386 for a free estimate. Isaac and the crew at Mason Remodeling Co Thousand Oaks will show up on time, introduce themselves by name, put the price in writing, and do exactly what we said we’d do.
Written by Isaac Pruett, Owner at Mason Remodeling Co Thousand Oaks, serving Thousand Oaks since 2004.


