Why Track Energy?

Electricity is the largest ongoing cost of indoor growing. A single 120x120 cm tent running a 480W LED, inline fan, clip fans, humidifier, and dehumidifier can consume 8–15 kWh per day, translating to $30–$80 per month depending on your electricity rate. Over a 4-month grow cycle, energy costs can exceed the value of the harvest if not managed carefully.

Knowing exactly where your energy goes lets you make informed decisions: Is the dehumidifier running too much? Could you dim the light during the last week? Is it cheaper to run the exhaust at a constant low speed or cycle it on and off?

How GrowVPD Pro Tracks Energy

While the Android app runs your automation, it keeps an energy log for each switchable device that is on, using one of two methods:

1. Smart Plug Power Reporting

Some Tuya smart plugs report real-time power consumption (watts) and cumulative energy usage (kWh). GrowVPD Pro shows these readings in the plug’s control panel, and where it can read the plug’s power it uses the measured watts for the energy log. This is the most accurate method.

Look for Tuya plugs with energy monitoring in the product description. Not all smart plugs report power — the cheapest models only provide on/off control.

2. Estimated Energy from Nominal Power

For devices that do not report power directly, GrowVPD Pro uses the device’s nominal power rating where the app knows it — for example from the model name of a Mars Hydro light or the port type of an AC Infinity controller. It multiplies this by the recorded on-time to estimate energy consumption.

The estimate does not take fan speed or dimming into account, so for variable-speed devices and dimmed lights it is on the high side.

Tip: For the most accurate tracking, run your biggest consumers through a Tuya plug that reports power. Even estimated tracking is far better than no tracking at all.

Understanding Your Energy Breakdown

On iPhone, the Energy Monitor in the Automation tab sums up the energy log for the last 30 days (the log is recorded by the Android app and reaches your iPhone through sync):

  • Total and average daily kWh: How much energy your devices used, with an estimated monthly cost at your electricity price
  • Daily consumption: A day-by-day chart of the logged energy
  • Device breakdown: How much each device used, helping you identify which devices dominate your energy bill

Typical Energy Distribution

For a standard tent setup, energy is typically split like this:

  • LED grow light: 50–65% of total energy (the single biggest consumer)
  • Dehumidifier: 15–25% (runs heavily during flower)
  • Inline exhaust fan: 5–10%
  • Humidifier: 3–5% (mostly during seedling/veg)
  • Clip fans, heaters, other: 5–10%

Estimating Costs

Once you know your daily kWh, calculating cost is straightforward:

Daily cost = Daily kWh x Electricity rate (per kWh)

Example: 12 kWh/day at $0.15/kWh = $1.80/day = $54/month = $216 for a 4-month cycle.

On iPhone, the Energy Monitor does this for you once you enter your electricity price. For a whole grow cycle, the harvest record in the diary adds up the costs you enter — electricity, nutrients, water (from the water you logged) and other — and shows the cost per gram of dried harvest.

Optimizing Energy Usage

1. Dim Your Lights When Possible

Most modern LED drivers support dimming. Running at 75% power instead of 100% saves 25% of your biggest energy consumer. Many plants do not need full power during the first 2 weeks of flower (stretch phase) or during late flower when the plant is ripening.

2. Right-Size Your Dehumidifier

An oversized dehumidifier cycles on and off frequently, wasting energy on each startup. A properly sized unit runs longer at lower intensity, which is more efficient. See the humidity control guide for sizing recommendations.

3. Use Variable-Speed Fans

Running an inline fan at speed 4 instead of speed 10 can reduce its power consumption by 60–70%. AC Infinity fans with built-in controllers automatically adjust speed based on conditions, running at the minimum speed needed to maintain your target.

4. Schedule for Off-Peak Hours

If your electricity provider charges different rates at different times (time-of-use pricing), schedule your lights-on period during off-peak hours. In many regions, electricity is cheapest between 11 PM and 7 AM. Running a 12/12 flower schedule from midnight to noon instead of 6 AM to 6 PM can save 20–40% on electricity.

Tip: GrowVPD Pro's light schedule feature lets you set precise on/off times for each light. Pair this with time-of-use electricity rates for maximum savings.

5. Improve Tent Insulation

If your tent is in a cold garage or basement, the heater runs constantly to maintain temperature. Insulating the floor (foam mats), sealing air leaks, and using a more insulated tent shell reduces heating costs significantly.

Comparing Grows by Energy Efficiency

The ultimate energy metric is grams per kWh — how much dried harvest you produce for each kilowatt-hour consumed. GrowVPD Pro does not calculate it for you, but when you record harvest data it shows grams per watt (g/W) and grams per plant, and a plug that reports energy (or, on iPhone, the Energy Monitor) gives you the kWh to divide by.

Typical ranges:

  • Beginner setup: 0.5–0.8 g/kWh
  • Optimized setup: 1.0–1.5 g/kWh
  • Advanced/commercial: 1.5–2.5 g/kWh

Tracking this metric across multiple grows shows you whether your efficiency is improving and which changes had the biggest impact.