Hydroponic Electricity Costs UK

Hydroponics uses electricity. How much depends on your setup. Here's the honest breakdown for UK growers, with real numbers from real systems.

## Quick Reference: Monthly Running Costs

*Based on 16 hours light, 24 hours fans/pump, 28p/kWh*

The honest truth: A small herb garden costs less than a Netflix subscription to run. Larger setups have real running costs, but they also produce significant quantities of food.

## What Actually Uses Power

**Grow lights (80-90% of electricity use):** The main consumer. 100-600W typically, running 12-18 hours daily depending on crop. This is where efficiency matters most.

**Air pumps (DWC systems):** Small draw. 5-15W running continuously. Negligible cost - a few pounds per month.

Water pumps (NFT, drip systems): Variable by system. 10-50W, running continuously or on timers. Still minor compared to lighting.

Fans and ventilation: Essential in tents. 20-80W typically, running continuously. Adds up but necessary.

Heating (if needed): Thermostat controlled, so variable. Depends entirely on your growing space and ambient temperature.

## UK Electricity Rates

As of 2026, typical UK electricity costs around 28p per kWh. This varies by supplier, tariff, and whether you're on a fixed or variable deal.

The formula: Watts × hours per day × days ÷ 1000 × rate = cost

Example: 200W light × 16 hours × 30 days ÷ 1000 × 0.28 = £26.88 per month

## Real Setup Examples

Kratky windowsill herbs (0W): Zero electricity if using natural light. Just water, nutrients, and patience. The most economical option possible.

Monthly cost: £0 Annual cost: £0

Countertop hydroponic unit (25W total): Built-in LED around 20W, small pump 5W. Runs 16 hours light, 24 hours pump.

Light: 20W × 16h × 30 = 9.6kWh = £2.69 Pump: 5W × 24h × 30 = 3.6kWh = £1.01

Monthly cost: Around £3.70 Annual cost: Around £45

Small 60x60cm tent with LED (115W total): 100W LED light, 15W inline fan. Grows herbs and small vegetables.

Light: 100W × 16h × 30 = 48kWh = £13.44 Fan: 15W × 24h × 30 = 10.8kWh = £3.02

Monthly cost: Around £16.50 Annual cost: Around £198

Medium 80x80cm tent with LED (225W total): 200W LED, 25W fan system. Serious hobby production.

Light: 200W × 16h × 30 = 96kWh = £26.88 Fans: 25W × 24h × 30 = 18kWh = £5.04

Monthly cost: Around £32 Annual cost: Around £384

Large 120x120cm tent with HPS (680W total): 600W HPS (draws around 660W including ballast), 80W fans for heat extraction.

Light: 660W × 12h × 30 = 237.6kWh = £66.53 Fans: 80W × 24h × 30 = 57.6kWh = £16.13

Monthly cost: Around £83 Annual cost: Around £996

## LED vs HPS: The Real Cost Comparison

The upfront vs running cost trade-off:

400W LED setup: - Light purchase: Around £350 - Coverage: 120x120cm - Monthly electricity: Around £54 - Annual electricity: Around £645 - 3-year total: Around £350 + £1,935 = £2,285

600W HPS setup: - Light purchase: Around £60 - Coverage: 120x120cm (similar light output) - Monthly electricity: Around £67 (light only) - Annual electricity: Around £804 - Plus extraction for heat: Add £200/year - 3-year total: Around £60 + £3,012 = £3,072

The math is clear: LED costs more upfront but saves around £250-350 per year. Break-even typically happens within 12-18 months. After that, LEDs save money continuously.

HPS makes sense only if: - You're on an extremely tight initial budget - You're growing in a cold space and want the heat - You already own HPS equipment

## Reducing Costs

**Right-size your lighting:** Match wattage to growing area. A 400W light in a 60x60cm tent wastes electricity without improving results.

Use timers precisely: Lettuce and herbs need 12-14 hours, not 18. Running lights longer than necessary wastes money without helping plants.

Consider your schedule: If you're on an Economy 7 or similar tariff with cheap off-peak rates, run lights during cheaper hours. Plants don't care if lights are on at night.

Insulate growing spaces: A well-insulated tent holds temperature, reducing heating costs in winter and cooling needs in summer.

Choose LED: The efficiency difference is substantial. 200W of LED light output requires roughly 400W of HPS electricity.

## Is It Worth It?

Small herb garden perspective: Running cost around £3-15 per month. You'll harvest £20-50 worth of fresh herbs monthly. Clearly economic.

Medium vegetable setup: Running cost around £30-40 per month. Monthly harvest varies but typically £50-100+ worth of produce for a productive setup.

Large production setup: Running cost around £60-100 per month. Need significant yields to justify economically, but possible with good management.

The real value: Economics aside, fresh lettuce picked 30 seconds before eating is different from supermarket lettuce picked days ago. Fresh basil whenever you want it. Tomatoes that actually taste of something. These have value beyond pounds.

## What to Avoid

Oversizing equipment: Bigger isn't better if you're paying to run capacity you don't need.

Running lights 24/7: Plants need dark periods. 18 hours is maximum for most crops. 14-16 is usually sufficient.

Ignoring standby power: Cheap timers and controllers draw power continuously. Not huge, but it adds up.

Heating inefficiently: Electric heaters in poorly insulated spaces waste money. Insulate first, heat second.

## Our Recommendations

Start small and scale up. Begin with a countertop unit or small tent. Understand the running costs before investing in larger systems.

Invest in LED. The efficiency savings pay for themselves. Modern LEDs also run cooler, reducing ventilation needs.

Monitor actual usage. A plug-in energy monitor (around £15) shows exactly what your setup uses. Real data beats estimates.

Match ambition to economics. A 120x120cm tent is impressive but costs around £80+ monthly to run. Make sure you'll use the production.

Take our quiz for setup recommendations that balance your goals with realistic running costs.