Smart Homes, Smarter Timing: How BC Hydro’s New Rates Work with Thermal Mass

As custom home builders specializing in high-performance homes, we’re always looking for ways to make houses more energy-efficient, more durable, and smarter to operate — without making things more complicated than they need to be.

Pairing high thermal mass with BC Hydro’s new time-of-day pricing does exactly that. It's a low-tech, high-impact way to cut energy costs and increase year-round comfort.

BC Hydro’s Time-of-Day Pricing: A Quick Breakdown

BC Hydro’s optional time-of-day rate plan means you’ll pay different rates depending on when you use electricity:

• Peak (4–9 PM): +5¢/kWh surcharge

• Off-peak (11 PM–7 AM): -5¢/kWh discount (~50% savings)

• All other times: standard rate

If you can shift heating, cooling, or EV charging to overnight hours, you’ll see meaningful savings — without needing complex tech upgrades.

How Thermal Mass Helps You Save

Our homes are built with high thermal mass — concrete walls and floors that absorb, store, and slowly release heat.

This means you can heat or cool your home during off-peak hours when electricity is cheapest. The thermal mass stores that energy and releases it gradually throughout the day, when rates are higher.

Think of it as a passive thermal battery — no moving parts, no energy use, and no maintenance.

A well-designed thermal mass home can take up to three days to lose just 1°C when the exterior temperature is 7°C.

A Note on Shading: Why It Matters

Thermal mass is powerful, but without proper solar shading, it can work against you.

Unshaded south- and west-facing windows can cause overheating, with the slab continuing to radiate heat long after sunset. That’s where passive solar design comes in — using glazing, orientation, and shading to block unwanted heat in summer and invite it in during winter.

Learn more about passive solar design →

Real Savings in Action

We recently crunched the numbers on a home before optimizing its energy model — and the results speak for themselves:

• Heating: 10,240 kWh/year→ At standard rates: $1,200/year→ Shifted to off-peak: $688/year→ That’s over 40% savings — just by using the heat when electricity is cheapest.

• Cooling: 849.3 kWh/year→ At standard rates: $99.50/year→ Off-peak: $57.08/year→ That’s a 43% drop — no tech upgrade needed.

And that’s before we improve airtightness, enhance solar gain through smart design, or fine-tune the mechanical systems.

Designed for Performance — Without the Overkill

Our homes don’t require large, expensive heating or cooling systems. Thanks to thermal mass, airtight construction, and passive design strategies, we keep things simple and cost-effective.

Here’s what that looks like in practice:

• In-floor electric heating with hydronic backup: Comfort now, flexibility later. Electric wire is used as the primary heat source, while hydronic tubing is installed in the slab — so you're future-ready for a boiler or heat pump if needed.

• Cooling rough-ins done upfront: We pre-run lines for future mini-split or heat pump units. If you ever want cooling, it's ready — no tearing into drywall.

• Durable, high-efficiency hot water tanks: We use Rheem Marathon tanks for hot water. They’re super-insulated, long-lasting, and low maintenance.

• Exterior passive shading: We’re testing smart exterior shading options to cut unwanted solar gain in summer — reducing the need for cooling.

• Solar-ready (where it makes sense): If your roof is accessible and cleanable, we prep for solar. No point in installing panels that can’t be maintained.

• Heating demand target: 17 kWh/m²/year: That’s nearly Passive House level (15) and far better than conventional homes. Airtight construction gets us there.

Optimized Systems. Long-Term Efficiency.

Pairing thermal mass with time-of-day electricity pricing isn’t just smart — it’s simple.

Whether it’s charging your EV overnight, heating your slab while you sleep, or soaking up the sun through south-facing glass, your home works with nature — not against it.

No complicated systems. No big maintenance bills. Just a well-built home that delivers comfort, performance, and savings — for decades to come.