How Smart Las Vegas Homeowners Are Beating Peak Energy Rates with Pre-Cooling

Most people adjust their thermostat reactively. It gets hot, the thermostat goes down, and the AC runs. However, there’s a more effective option that saves money, cuts down on your stress, spares your equipment, and keeps your home more comfortable through the worst hours of a Las Vegas summer. It’s called pre-cooling, and once you understand how NV Energy’s rate structure works, you’ll realize why you need to be doing it.

NV Energy’s Peak Rates

NV Energy uses time-of-use pricing during the summer months (usually from June through September). During peak hours (3:00 PM to 8:00 PM on weekdays), the cost per kilowatt-hour is a lot higher than during off-peak periods. Evenings, overnight, and early morning hours are cheaper, sometimes substantially so.

A system trying to keep your home at 74 degrees against 112-degree outdoor temperatures between 3 and 7 PM is doing its hardest, most expensive work when the rates are highest. Pre-cooling changes that. Instead of fighting peak heat during peak rate hours, you cool the house aggressively in the morning or early afternoon when rates and temps are lower and let the house coast on stored cooling when rates are higher.

The Thermal Mass Principle

The walls, floors, furniture, and building materials that make up your house all have thermal mass (they absorb and release heat gradually rather than instantly). A house that’s been cooled to 70 or 71 degrees by 1:00 PM will hold a comfortable temperature well into the late afternoon, even without the AC running hard (depending on insulation quality and window exposure).

How to Set It Up

The easiest option is with a programmable or smart thermostat: set the system to cool to a lower setpoint (70 or 71 degrees) between 10 AM and 2 PM. Then set it to a higher setpoint (76 or 77) between 3 and 8 PM, letting the house warm up gradually on its stored cooling. After 8 PM, when peak rates end and evening temperatures begin dropping, go back to a lower temp.

Most smart thermostats can be programmed to run this kind of schedule automatically. Some NV Energy programs offer smart thermostat incentives just for customers who let the utility make minor adjustments during peak usage/heat events, too.

The Catch

Pre-cooling does come with a catch. A well-functioning, properly sized system has no problem pulling a home down to 70 or 71 degrees by early afternoon. It runs for a sustained cycle, hits the setpoint, and the house is well-charged going into peak hours.

If your system can’t reach a lower setpoint during the cooler part of the day, that tells you that something’s off. The system is underperforming relative to what it should be doing during its easiest hours. Low refrigerant, a dirty condenser coil, a degraded compressor, or significant duct leakage could all be contributing.

A system that can’t pre-cool effectively is also a system that’s going to struggle through peak hours, no matter what thermostat strategy you’re using. If you’re finding that pre-cooling isn’t working the way it should, that’s a reason for an AC service call to find out what’s going on, and whether the answer is a repair or talking about replacement equipment that can meet the demand.