The Hidden Dangers of Title 24: Why California’s Energy Code Isn’t Working—Yet

Evan DeMarco
May 6, 2025

⚠️ What Is Title 24?

Title 24 is part of the California Building Standards Code, specifically focused on energy efficiency in residential and nonresidential buildings. It's designed to:

  • Reduce greenhouse gas emissions
  • Improve indoor air quality
  • Increase energy efficiency
  • Move California toward net-zero energy goals

Under Title 24, builders are now required to:

  • Use heat pump water heaters (HPWHs) instead of gas water heaters
  • Optimize building envelope performance
  • Install solar PV on most new homes
  • Reduce total building energy use intensity (EUI)

The intent is commendable. But the execution? That’s where the problems begin.

🧯 The Heat Pump Water Heater Mandate: A Case Study in Compliance Without Performance

California’s 2022 Title 24 update made electric water heating mandatory for most new single-family homes. The default tech? Heat pump water heaters (HPWHs).

These systems work by drawing heat from ambient air and transferring it to water using a refrigeration cycle. In theory, they’re up to 3x more efficient than traditional electric resistance heaters.

But here’s the catch:

🧩 HPWHs aren’t always practical:

  • Require large mechanical closets or garage space
  • Struggle in cold climates or unconditioned zones
  • Have slow recovery times and high upfront costs
  • Often fail to deliver hot water during peak demand

Worse yet, they typically demand:

  • Dedicated 240V circuits
  • Backup electric resistance heating
  • Large breaker panel capacity, which many remodels can’t support

All of this pushes builders to over-engineer systems, eat up valuable square footage, or risk code violations.

🧠 So What’s the Real Danger of Title 24?

It assumes that compliance = performance.
But as any builder knows, just because something passes code doesn’t mean it works for your project or client.

Here’s what we’re seeing on the ground:

  • Builders forced to use undersized or underperforming HPWHs
  • Customers getting frustrated with cold showers or slow heating
  • Solar PV systems misaligned with hot water loads
  • Increased grid strain from high-resistance backups

This is where Solthera comes in.

🔋 Solthera: Built for Compliance. Designed for Reality.

Solthera’s thermal battery uses phase change material (PCM) to store thermal energy during the day—using grid, solar, or heat pump input—and deliver it on demand for:

  • Domestic hot water
  • Radiant heating
  • Space conditioning buffers

🧱 Solthera Is Plug-and-Play Where HPWHs Are Not

Solthera solves problems HPWHs create:

  • No need for ducting, compressors, or air volume access
  • No moving parts = lower maintenance, longer lifespan
  • Wall-mounted = saves valuable space in tight builds
  • Works in cold or unconditioned areas with no performance loss

📐 Case Study: Title 24-Compliant ADU

🏗️ Project: 650 sq ft backyard ADU
📍 Location: Sacramento, CA
💡 Challenge: Meet Title 24 with limited panel capacity and no room for tanked HPWH

🔧 Solution: Solthera thermal battery charged by 2 solar panels + daytime grid
✅ Result:

  • Passed Title 24 with minimal upgrades
  • Saved 18 sq ft of mechanical space
  • Delivered 40 gallons/day of hot water with 0 peak demand load

🌍 Title 24 Needs Better Tools. Not Just Bigger Rules.

We’re not saying Title 24 is wrong. We’re saying it needs better implementation pathways.
One-size-fits-all mandates rarely work in construction—especially across climate zones and building types as diverse as California’s.

Solthera empowers builders to:

  • Achieve electrification goals
  • Improve building performance
  • Hit code targets with confidence
  • Avoid unnecessary complexity

And it does all of that with no gas, no emissions, and no moving parts.

🛠️ Built for Builders. Approved by Code. Loved by Occupants.

Solthera was created to solve the real-world friction between policy and performance. And it’s already doing just that in dozens of California projects.