Octopus Cosy Review 2026: Heat Pump Tariff Economics in Plain Numbers

How Octopus Cosy works

Cosy is a time-of-use tariff structured around heat pump consumption patterns. Unlike Economy 7, which provides one overnight cheap window, Cosy provides two windows per day - early morning and early afternoon. Heat pumps pre-warm the property during these windows, reducing reliance on the expensive standard rate during morning and evening peaks.

The tariff is available through the Octopus Energy app. Customers can view half-hourly consumption data and track which proportion of their usage falls within the cheap windows. A Nest, Hive, or manufacturer thermostat can be programmed to align heat pump run times with the windows.

Off-peak rate by region (2026)

Octopus publishes regional rates that reflect local network distribution costs. Rates in 2026 across the main regions:

• North West and Yorkshire: approximately 7.0-7.5p/kWh off-peak
• Midlands and East: approximately 7.5-8.0p/kWh off-peak
• London and South East: approximately 8.5-9.0p/kWh off-peak
• South West: approximately 8.0-8.5p/kWh off-peak
• Scotland: approximately 7.0-7.5p/kWh off-peak

Verify the exact rate for a given postcode via the Octopus tariff comparison tool before switching, as rates are updated with each Ofgem price cap quarter.

Annual savings calculation

At 4,000 kWh annual heat pump consumption (BEIS median, 2025) with 60% shifted to off-peak windows:

• Off-peak usage: 2,400 kWh at 8p/kWh = £192
• Standard rate usage: 1,600 kWh at 23p/kWh = £368
• Total heat pump electricity cost on Cosy: approximately £560
• Same consumption on standard price cap rate (24.5p/kWh): £980
• Annual saving: approximately £420

The saving is sensitive to how much consumption shifts to off-peak. Households achieving 70-75% off-peak shift (fully automated thermostat control) can save closer to £500/year.

Smart meter requirement

Cosy requires a smart meter to measure half-hourly consumption. SMETS2 meters (installed from 2018 onward) are compatible with all suppliers. SMETS1 meters (installed before 2018) may require an upgrade depending on the meter operator. Octopus will arrange a free smart meter installation for customers without one, subject to appointment availability (typically 4-8 weeks in 2026).

Switching to Octopus Cosy

The process follows the standard Ofgem switching framework. Octopus provides a final bill from the previous supplier within six weeks. There are no exit fees on standard variable tariffs; fixed-rate tariff exits may carry a fee set by the outgoing supplier. The switch takes effect within 21 days of application under Ofgem's switching guarantee.

Cosy versus Agile and Tracker

Octopus Agile tracks the half-hourly wholesale price and can fall below Cosy's off-peak rate during low-demand periods - sometimes reaching negative rates. However, Agile also spikes during peak demand, which creates risk for households without automated load management. Cosy provides a predictable off-peak rate with no downside volatility, making it more suitable for most heat pump households.

Octopus Tracker follows the monthly wholesale average and can be cheaper than Cosy in low-price months but offers no time-of-use discount structure. Heat pump owners with a flexible schedule generally benefit more from Cosy's window structure than from Tracker's flat wholesale rate.

What is the Octopus Cosy off-peak rate in 2026?

The Octopus Cosy off-peak rate in 2026 is approximately 7-9p/kWh depending on region, compared to a standard rate of approximately 22-24p/kWh outside the cheap windows. Exact rates vary by postcode and are updated each Ofgem price cap quarter.

When are the Octopus Cosy cheap windows?

The Octopus Cosy cheap windows run 04:00-07:00 and 13:00-16:00 daily. These two windows provide three hours each of off-peak electricity per day, totalling six hours of cheap-rate electricity suited to heat pump pre-warming cycles.

Is Octopus Cosy worth it without a heat pump?

Octopus Cosy is designed for heat pump households. Without a heat pump or other flexible load that can be shifted to the two daily windows, the saving versus a standard tariff is limited. Households without a heat pump are typically better served by Octopus Go (for EV charging) or Octopus Agile (for active energy management).

Can I get Octopus Cosy if I rent?

Yes, if the property has a smart meter and a heat pump. The tariff is available to all domestic Octopus customers regardless of tenure. Renters whose landlord owns the heating system should confirm with the landlord that switching tariff is permitted under the tenancy agreement.