Radiant Heating for New Construction in San Francisco

Ideal for ADUs & Garage Conversions

San Francisco’s ADU boom means thousands of garage conversions and in-law unit builds happening across the Sunset, Richmond, and Potrero Hill. Radiant floor heating is the standard solution — there’s no room for ductwork, and radiant delivers consistent, code-compliant heat with zero space impact.

• Tubing goes under the concrete or subfloor — invisible and maintenance-free
• No register holes, no ductwork chases, no ceiling returns required
• Passes SF DBI inspection for habitable space heating requirements
• Works with standard residential boilers or combi-boilers for combined heat and hot water

San Francisco’s most common heating solution for ADUs and garage conversions

Efficiency in SF’s Climate

SF’s fog and marine layer keep temperatures mild but consistently cold. Radiant heating is highly efficient in this environment — the steady, moderate cold loads are ideal for low-temperature radiant operation, getting maximum efficiency from condensing boilers and heat pumps.

• Low temperatures mean radiant operates at peak efficiency year-round
• Condensing boilers achieve 95%+ efficiency with radiant’s lower water temps
• No heat loss through ducts — all energy goes directly to the floor
• Pairs perfectly with solar for near-zero operating cost

90-97% efficiency with condensing boilers

SF Code Compliance

New construction and ADUs in SF require permits through DBI. All mechanical systems must meet SF Green Building Ordinance requirements. We handle all Title 24 compliance for the heating system, select code-compliant equipment, and coordinate directly with your GC and the building inspector.

• Title 24 mechanical compliance included on every bid
• DBI permit filing and inspection scheduling managed by our team
• SF Green Building Ordinance requirements met with every equipment selection
• We work with your architect’s plans and coordinate with your GC team

Title 24 and Green Building Ordinance experts

Pre-Pour Design & Layout

For slab-on-grade ADUs and new builds, we design the tubing layout before the concrete pour. We coordinate with your GC on the pour schedule and install the tubing tied to the rebar — this is the ideal installation for highest efficiency and durability.

Subfloor Panel Systems (for Above-Grade)

For second-story additions or sites where slab work isn’t possible, we use Warmboard or similar subfloor panel systems. These high-conduction panels allow the tubing to be installed over the existing structure with excellent heat transfer.

Boiler or Heat Pump Integration

We engineer the complete system — selecting and installing the heat source (combi-boiler, system boiler, or air-to-water heat pump), manifolds, zone controls, and thermostats. Everything is designed as a complete integrated system.

Testing & DBI Walk-Through

We pressure-test the tubing before the concrete pour, perform a full system commissioning after, and arrange for the DBI mechanical inspection. We accompany the inspector to answer any questions.

Combi-Boilers

The most popular choice for SF ADUs. A combi-boiler from Navien or Lochinvar handles both radiant floor heat and domestic hot water in one compact wall-mounted unit.

Air-to-Water Heat Pumps

The future of SF heating — air-to-water systems use electricity to extract heat from the air and deliver it to the radiant loop. Highly efficient in SF’s mild climate and qualify for substantial federal tax credits.

System Boilers with Zones

For larger properties with multiple units or extensive square footage, a system boiler with a zone manifold system provides precise, independent control for each space — from a garage unit to a primary residence.

How early in the construction schedule do I need to involve you?

For slab systems, we need to be involved before the concrete pour — ideally during framing. For subfloor systems, we can come in after framing but before drywall. Contact us at the permit stage and we’ll coordinate directly with your GC.

What’s the best heat source for an ADU in the Sunset or Richmond?

A combi-boiler is the most common choice — it handles heat and hot water in one unit with minimal equipment space. An air-to-water heat pump is increasingly popular for full electrification, especially when paired with solar.

Is radiant heating required for ADU habitable space in SF?

Not specifically, but SF’s climate requires adequate heating in all habitable spaces. Radiant is typically the most practical solution for garage conversions where there’s no space for ductwork. We’ll advise on the best approach for your specific project.

Can the same system serve both the ADU and the main house?

Yes, with a properly designed multi-zone system. We engineer separate zones for the main house and ADU with independent thermostats and zone valves — each unit controls its own comfort independently.