Heat Pump Installation and Repair in Los Altos, CA

A Homeowner’s Guide to Heat Pump Installation and Repair in Los Altos

The City’s 2025 energy code amendments

Los Altos adopted the 2025 California Energy Code with local amendments on October 28, 2025 (Ordinance 2025-542, Municipal Code ch. 12.16). For an existing single-family home, the changes favor a heat pump whenever cooling equipment is installed or replaced:

• Air conditioner path: a new or replacement air-cooled AC must also meet airflow and fan efficacy targets and refrigerant charge verification, plus attic insulation to R-49 (unless R-38 is already there) and air sealing of the ceiling; with an all-new duct system, R-8 ducts and a fan efficacy of 0.35 W/CFM or less instead.
• Heat pump path: thermostat, refrigerant charge and airflow verification under state rules, without the insulation and sealing add-ons.
• Supplementary heat: a heat pump backed by a gas furnace or electric strips must lock out that backup above 35°F outdoors.

Two exceptions allow a straight AC: a panel too small for the heat pump but large enough for the AC (Article 220 calculations), or a heat pump that would need to be at least 12,000 Btu/h larger than the AC. Both are documented before the permit. We found no record of the Energy Commission accepting these amendments yet, so confirm with the Building Division how they apply to your permit.

Permits and the state’s tests

The Building Division (650-947-2752) takes the residential permit application by email. Its mechanical section asks whether the job is a new AC or heat pump, an electric heat pump replacing a gas furnace, or a like-for-like furnace, and whether ducts will be replaced. A site plan and spec sheets are required for every AC and heat pump.

The 2025 Energy Code then sets the checks:

• Load calculations for new systems.
• Refrigerant charge verification by an ECC-Rater on heat pumps in all climate zones.
• Duct leakage of 10% total or 7% to outside on existing ducts, or a smoke test and visual check where that can’t be met.
• Refrigerant recovery by an EPA 608 Type II or Universal technician.

New ducted and ductless heat pumps also use refrigerants under the Air Resources Board’s 750 global warming potential limit, in effect since January 1, 2025. See heat pump installation and duct repair.

Placing the outdoor unit

Chapter 11.14 (2023) governs heating and air conditioning units, generators and similar equipment that need a building permit:

• Setback: equipment taller than 18 inches stays at least 5 feet from any property line.
• Screening: all equipment is screened from public view.
• Roof units: shielded and architecturally screened, with a certified acoustical consultant’s signed letter showing noise compliance.
• Replacements: new equipment replacing old must meet the chapter.

The City’s final inspection checklist adds that air conditioners go where Planning approved, with decibel documentation for the inspector, and that line insulation is protected from sunlight and damage.

Night noise limits

The noise ordinance (chapter 6.16) lists compressors, fans and air conditioners as fixed noise sources. Measured on any other property, the R1 single-family limits are:

• 10 p.m. to 7 a.m.: 45 dBA, not to be exceeded more than 30 minutes in any hour.
• 7 a.m. to 10 p.m.: 55 dBA.

Shorter bursts get small allowances, and a steady whine or hum cuts each limit by 5 dB. A heat pump also runs on winter nights, so we favor variable-speed outdoor units and spots away from neighbors’ bedrooms. The property owner must fix any violation, by baffling, relocating or replacing the unit.

Rebates: City, SVCE and state

Los Altos gets its power through Silicon Valley Clean Energy. Its Home Rebates for heat pump HVAC require:

• a heat pump replacing a gas furnace or electric resistance heat, ducted or ductless mini-split;
• 16 SEER2 or better, 17 SEER, or an inverter unit; no single-stage or dual-fuel systems;
• reservation before installation and proof of permit.

The City’s extra rebates were fully claimed; the Council approved new funding on October 13, with updates expected in November. TECH Clean California’s single-family incentives remain fully reserved. See SVCE heat pump rebates and mini-splits.

Sources

City of Los Altos: Building · Residential permit application · Residential final inspection requirements · Mechanical equipment regulations · Residential building electrification rebates · Heat pump rebates. Municipal Code: ch. 12.16, Energy Code · ch. 11.14, Mechanical Equipment · ch. 6.16, Noise Control. Silicon Valley Clean Energy: Home Rebates · Appliance Specifications (April 2026). California Energy Commission: 2025 Single-Family HVAC. California Air Resources Board: Air-conditioning Equipment (HFC Regulation). Bay Area Air District: Building Appliances Rule Implementation. TECH Clean California incentives. Checked October 2026.