Eichler Home Services in Marin County

The three things that fail in an Eichler heating system

An Eichler heating complaint comes down to one of three parts: the boiler, the controls, or the tubing in the slab. Each fix disrupts on a very different scale, so the first job is deciding which one is at fault.

The heat source. Boiler, circulator pump, expansion tank, zone valves, aquastat, thermostat. All of it sits above the slab, visible and serviceable. Short-cycling, no ignition, a pump that hums without moving water, a waterlogged expansion tank: these are repairs, and they are the outcome we hope for.

The distribution. The tubing buried in the concrete. When a buried loop develops a pinhole, the system keeps running and the house keeps partially heating, which is why these leaks go unnoticed for so long. The lost water gets replaced by the automatic fill valve, quietly topping the loop off the domestic supply.

The envelope. Less a failure than a permanent condition. Many of these homes still have original single-glazed floor-to-ceiling walls and a low-slope roof with little insulation above the decking. A good boiler there still loses the heat it makes, which the owner experiences as "the heating does not work."

Our heating and cooling work across Marin County leans on that split: a boiler will not fix a glass wall, and glass will not fix a failed circulator.

Finding a slab leak without opening the floor

The most useful number in an Eichler is one almost nobody tracks: how often the system takes on make-up water. A closed hydronic loop is supposed to stay closed. If it drinks from the cold supply regularly, that water is going somewhere, and under the slab is the likeliest somewhere. What we look at, in order:

• Whether the fill valve is feeding the system, and how often. We isolate it and watch what pressure does with the loop sealed.
• Whether the loop holds a static test pressure with the boiler off and cold, over hours rather than minutes.
• Rust staining, mineral crust, or wet fittings where the loops surface out of the concrete near the boiler.
• Warm patches, damp patches, or an unexplained hairline in the slab, plus the perimeter outside, where subsurface water often shows first.

We do not cut concrete on a hunch. A failed pressure test says a loop is compromised; it does not say the whole system is finished, and those two conclusions lead to very different projects.

Slab, panel, path, glass

Once diagnosis is done, every Eichler heating decision comes down to four questions asked in this order. Answer them plainly on paper and the equipment choice tends to make itself.

The slab. Does the buried loop hold pressure? If it does, keeping hydronic heat is genuinely on the table and a boiler replacement is a contained job. If it does not, you are choosing between repairing the failed section and moving heat delivery somewhere else entirely.

The panel. Every electric option, ductless heat pump, heat pump water heater, induction range, vehicle charger, is capped by what the electrical service can carry. This is where plans die most often.

The path. Where does a refrigerant line set physically go? Where does condensate drain? Where does a flue terminate? With no attic, no crawlspace, and a low-slope roof, routing is a design constraint that eliminates some equipment outright, not a detail to work out later.

The glass. A load calculation on an Eichler as it stands and one on the same house after the glazing is upgraded can produce meaningfully different equipment. Settle whether glass work belongs to this project before anything is sized, or you get a system that short-cycles in three years.

Permits, code, and inspection

Marin's Eichler tracts do not all answer to the same building department, and that is the first thing to establish.

• Terra Linda is inside the City of San Rafael. Permits and inspections run through the San Rafael Building Division, and since February 2026 both permit applications and inspection scheduling run through the city's OpenGov system, which replaced the eTRAKiT platform it used before.
• Lucas Valley, Marinwood, and Strawberry are unincorporated. They permit through Marin County Building and Safety rather than through any city.
• Novato is incorporated. Confirm the path with its building department rather than assuming county process applies there.
• San Rafael's no-plan-review list is narrower than it looks. On plumbing it names "C/O water heater 100-gallon capacity and under" and "C/O tank-less water heater." On mechanical, "C/O of Furnace, A/C units and Ducting. (must be in same location)" and "New A/C units." Boilers and ductless heat pumps are absent, so we confirm the review path before putting a date on the calendar.
• Title 24 governs replacement equipment. California's 2025 Building Energy Efficiency Standards took effect January 1, 2026, per the California Energy Commission. That cycle put new single-family construction on a single fuel baseline, requiring a heat pump prescriptively for both water heating and space heating, which is not automatically the rule in an existing home.
• All of Marin sits inside the Bay Area Air Quality Management District. Its 2023 amendment to Regulation 9, Rule 6 set zero-NOx requirements for residential water heaters, on dates spread across 2027 and 2031 depending on size and equipment type. They apply at the point of sale, not to the unit already in the house.
• Nobody's gas water heater is banned. We check what is in force the day the permit is pulled.
• Seismic anchoring is not optional. California Health and Safety Code section 19211 requires "all new and replacement water heaters, and all existing residential water heaters" up to 120 gallons to be braced, anchored, or strapped per the California Plumbing Code.
• Refrigerant is in transition. R-22 production and import in the United States ended in 2020, and R-410A is phasing down under the AIM Act toward lower global warming potential refrigerants, because newly manufactured residential and light commercial equipment has to sit under a 700 GWP limit.

What the cost is made of

The equipment nameplate is rarely what moves an Eichler quote. These are, roughly in order of impact.

Whether the buried loop survived is the largest fork in the road. A boiler exchanged into a sound loop is a defined scope on a predictable schedule. A loop that will not hold pressure turns the project into a heat delivery redesign, and the two outcomes are nowhere near each other.

Electrical scope comes next. Adding a subpanel to a service with headroom is a straightforward day. Changing the service pulls in the utility, the meter, and a longer calendar, and it sets the schedule for everything downstream.

Then roof work. Line sets, condensate, and flues all pass through a low-slope assembly and have to be flashed to last, and the existing roofing warranty is a real consideration rather than a footnote. Penetration count, and how far equipment sits from where the refrigerant lands, changes labor meaningfully.

Concealment costs more than owners expect, since finish work on exposed post-and-beam construction is nothing like patching drywall in a tract colonial. Zoning carries a price too: one outdoor unit feeding several indoor heads costs differently from multiple single-zone systems, and open plans built around a central atrium often argue for more zones. Finally, materials that will be cut or demolished in a house of this era should be tested before they are disturbed. If scope grows past what you planned to spend at once, financing options are worth understanding before work starts.

Rebates and incentives, and their real status

MCE is the community choice energy provider for Marin, and its programs are the first place to look. MCE's heat pump rebates cover heat pump water heaters and heat pump heating and cooling systems, ductless equipment included. Eligibility is written for "MCE customers who own and have lived in their single-family detached homes for at least 12 months in MCE's service area," and installation has to be performed by a participating contractor.

The sequencing terms deserve more attention than they get, because Eichler owners tend to plan several upgrades together. MCE states that "If your home has solar or EV charging, the equipment must have been installed for at least 12 months," and that a participant cannot "install other home electrification projects (including solar, battery storage, or EV charging) for 12 months after your heat pump unit" is completed. Read, the order in which you do the heat pump, the array, and the charger is a rebate decision, not a scheduling preference. If solar in Marin County sits anywhere on your five-year list, it belongs in the conversation on day one.

What is worth confirming at permit time is the utility and state side, which is where the money that does exist sits.

Maintenance specific to these houses

Track the make-up water. Note the pressure reading on the boiler gauge a few times a season and write it down. An owner who knows the loop has been static for two years holds information nobody else on the street has, and one who catches the fill valve working has found a slab leak early enough to have options.

An annual hydronic visit covers combustion and venting, expansion tank pre-charge, the circulator, relief valve, zone valve operation, and control calibration. Boilers reward this more than furnaces do, because a system quietly running long costs money well before it fails outright.

If ductless equipment has been added, the list changes shape: filters at the indoor heads, coil and blower wheel cleaning, condensate line clearing, and outdoor unit clearance, which matters more here than usual because Eichler side yards are narrow and fences sit close.

Roof penetrations get looked at during the same visit, since anything passing through a low-slope assembly is a place water can eventually find. On the plumbing side, water heater strapping, the temperature and pressure relief discharge line, and the main shutoff get verified, tying into our broader plumbing work in Marin County. Our maintenance plans keep those checks on a schedule instead of on memory.

The Eichler neighborhoods we serve

Terra Linda is the best known of the San Rafael tracts, and its flat streets and repeating floor plans mean the same failure patterns show up house after house. Marinwood and Lucas Valley run north along the Lucas Valley Road corridor with more varied lots and, in places, tighter equipment access. Strawberry, near Mill Valley, sits closer to the bay with the moisture exposure that implies. Novato adds its own tracts at the north end of the county.

We work all of them out of our Petaluma headquarters, alongside the rest of our Marin County service area. Marin's mild winters are part of why heat pump conversions perform well here: equipment spends most of the season inside its efficient range and rarely leans on auxiliary electric heat.

How to choose a contractor for an Eichler

Ask whether they will pressure-test the buried loop before recommending you abandon it. A contractor who reaches for replacement before testing is selling a product, not solving a problem.

Ask for a load calculation rather than a square-footage rule of thumb, and whether it was run on the house as it stands or as you hope to improve it. Both are legitimate. Not knowing which one you got is not. Ask who pulls the permit and from which department: a bidder who cannot say whether your address answers to San Rafael or to the county has not looked at it.

Ask to see the roof detail in writing before signing, meaning where each penetration lands, how it gets flashed, and what happens to your roofing warranty. Ask whether mechanical, electrical, and plumbing work is self-performed or subcontracted, because in an Eichler all three trades touch the same six feet of wall. And ask what plan B costs if the loop test comes back bad.

What North Bay homeowners say

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