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A heat pump tariff tends to be the last thing an off grid Devon household looks into, usually a year after the system went in. The better moment comes earlier, before the design gets drawn, because the tariff sets a large share of the running cost. What you need first is a smart meter, and that comes ahead of the heat pump itself.
Key Takeaways
- A heat pump tariff either bands the day into cheap and peak hours, discounts your regional rate inside set windows, or credits money back afterwards.
- On 19 September 2026, Cosy Octopus ran three cheap windows totalling eight hours a day at 51% below the regional day rate, with a peak rate from 16:00 to 19:00.
- Every heat pump tariff needs a working smart meter sending readings every 30 minutes, and some suppliers ask for your MCS certificate as proof.
- Half hourly settlement moves part of your heating cost into the cheap bands on its own, before you change a single setting.
- Standing charges do not change, peak bands cost more than a standard rate, and suppliers withdraw these tariffs, as OVO did in February 2026.
- The system design decides how much of your heating moves into the cheap hours, and the thick cob and stone walls of older Devon homes hold it there.
This guide covers what four of the main UK heat pump tariffs do, the eligibility gates that stop people getting on them, how Devon households off the gas grid use the cheap windows, and what the arrangement does not fix. Every rate and window here came off the supplier’s own page on 19 September 2026.
What a Heat Pump Tariff Actually Is
A heat pump tariff is an electricity tariff priced for a home that heats with electricity instead of a boiler. Suppliers price them this way for commercial reasons: a heat pump draws a modest load for hours at a time, and steady demand is cheaper to buy wholesale. Three different products get sold under the one label.
Three products, one label (illustration of a day’s prices)
The day is carved into bands. The cheap ones sit well under the standard rate, with an expensive band in the early evening.
Cosy Octopus, E.ON Next Pumped
You stay on your region’s standard rate, and a set discount comes off every unit the meter records inside fixed hours.
EDF Heat Pump Tracker, British Gas Heat Power
You pay the normal rate all year, and the supplier credits money back afterwards, calculated on heat pump usage alone.
OVO Heat Pump Plus, ended from 1 February 2026
The difference between the shapes matters more than the headline discount, because which one pays depends on how much of your heating you can move into the cheap hours. That comes down to the fabric of your house and how the system is set to run.
The Heat Pump Tariffs on the Market Right Now
These were four of the main tariffs open to households with an air source heat pump when this was written. The windows and rates below come from each supplier’s own page.
Four tariffs across one day
Cheap 04:00 to 07:00, 13:00 to 16:00 and 22:00 to midnight, priced 51% below the day rate in your region. Peak 16:00 to 19:00, set 50% above it.
10p per unit off your region’s standard rate from 04:00 to 07:00 and 13:00 to 16:00, with no peak band at all. The underlying rate is reviewed quarterly.
Half price on everything the meter records from midnight to 07:00 and 13:00 to 16:00, around 70 hours a week, arriving as a weekly bill credit.
Cheapest 22:00 to 06:00, off peak through most of the day, and a peak band 16:00 to 19:00 above the supplier’s standard rate. Twelve month term, no exit fee.
Read off the four tariff pages on 19 September 2026. Rates and windows change, so check each supplier’s own page before you sign up.
This corner of the market moves fast, so treat the shapes as the durable part and the numbers as a snapshot. The shape tells you how a tariff behaves in your house long after any single rate has been revised.
What You Need Before a Supplier Will Put You on One
Every heat pump tariff rests on one piece of kit, a smart meter that reports by the half hour. Without half hourly data your supplier cannot tell which units you burned at 2am and which at 5pm, so the cheap window has nothing to price. The rest of the gate varies by supplier.
A working smart meter
Sending your supplier a reading every 30 minutes, so each unit is priced by the half hour it was used in.
EDF says it may ask for evidence of the installation, either an MCS certificate or a photo.
EDFYou join the supplier, your meter connection gets checked, and the tariff opens up after that.
Join, then applyE.ON Next asks for both plus half hourly data collection, and British Gas excludes prepayment meters.
E.ON Next, British GasOn rural Devon properties the signal can be the problem, so establish it before you plan around a tariff.
Rural propertiesYour MCS certificate comes off the scheme’s database within 10 working days of commissioning, so that paperwork lands days after the system first runs. Eco Pro is an MCS-certified installation company, and James works as a freelance NAPIT MCS assessor, auditing other installers’ heat pump work.
How a Heat Pump Tariff Actually Lowers What You Pay
The first mechanism asks nothing of you. An off grid Devon house runs its heating at low output through a winter day, so much of the electricity lands in the cheap bands anyway. Half hourly settlement banks that on its own, before you touch a single control.
The second is deliberate, and Octopus sets it out in its own guidance for the Cosy tariff.
Octopus’s Cosy guidance on one day (illustration, not a measured house)
Drawn from Octopus’s guidance for its Cosy windows. How far your own house drifts through a peak depends on how well it holds heat.
Thick cob and stone walls, common in the older stock around Otterton and East Budleigh, hold that banked heat well through a peak window. How it lands against what you currently pay for oil is a different sum, and our guide to heat pump running costs against oil works it through.
Where the Savings Leak Away
A heat pump tariff takes money off some of what you pay, and several costs sit outside its reach. Five of them catch people out.
The standing charge
The standing charge does not move. British Gas states that Heat Power customers still pay the full daily standing charge, and the same goes for the others.
Every tariffThe early evening peak
Two of the four price an early evening peak band above the standard rate, so a household still heating hard at six in the evening gives back what it gained at 5am.
Two of the fourA system run too hot
A tariff cannot rescue a badly specified system. Run a heat pump hot to cover radiators nobody sized properly, and the extra electricity it burns eats the discount.
The designHeat that escapes early
A farmhouse past Newton Poppleford with an uninsulated loft hatch loses its banked heat before the peak ends, so the cheap warmth runs out early.
The buildingA tariff that gets withdrawn
OVO ran Heat Pump Plus, a rebate that cut what its heat pump customers paid per unit, and ended it from 1 February 2026. Specify a system that stands up on an ordinary tariff, and treat the heat pump tariff as the improvement on top.
OVO, from 1 February 2026None of those shows up on a tariff comparison page. What the installation itself costs sits in our air source heat pump cost guide.
What Changes When You Are Off the Gas Grid in Devon
A house in the lanes past Woodbury or up an Otter valley track comes at this differently to a semi on mains gas. You already run one account for electricity and buy the rest of your heat by the tanker load, at whatever the price happens to be on the day of delivery.
The gain is in what you are exposed to. An oil bill has no ceiling over it. Electricity on a standard variable tariff is capped, and a heat pump tariff prices a large slice of your usage below that capped rate.
£9,000
For off gas grid homes replacing oil or LPG, on applications up to 31 March 2027, with £7,500 for other eligible properties in England and Wales. Eligibility depends on the property. We are MCS certified, so we apply and deduct it from your quote.
Our guide to the £9,000 grant has the detail on who qualifies.
Choosing the Tariff That Suits Your Own House
People tend to ask which heat pump tariff is cheapest. The answer depends on how much of your heating you can move into the cheap hours, because that decides which shape pays.
Which shape suits which house
Deep dips and a sharp peak
Thick walls carry the warmth banked in a cheap window through the peak, which is the house a multi rate tariff suits.
A flat discount, no peak band
Banked heat drains away before the peak ends, so a flat discount with no peak band usually does better.
Those three decide how hard you can pre heat the place and how long the warmth stays in it, which is why both answers come out of the design work.
James does the free home assessment himself and talks the tariff question through then, alongside the fixed estimate. How the design and the week on site run is set out on our air source heat pump installation page.
Frequently Asked Questions
An electricity tariff priced for homes that heat with electricity. It either splits the day into cheap and expensive bands, takes a set discount off your region’s standard rate during fixed hours, or credits money back against heat pump usage alone.
Book my free home assessmentYes. Every heat pump tariff on the UK market needs a working smart meter set to send your supplier a reading every 30 minutes. Without that data the supplier cannot price the cheap windows.
Book my free home assessmentThere is no single answer, because the shapes suit different houses. A well insulated home that holds heat can use deep cheap dips; a draughtier one usually does better on a flat discount with no peak band.
Book my free home assessmentNot always. EDF says it may ask for evidence of your heat pump, which can be an MCS certificate or a photo. Your certificate arrives within 10 working days of commissioning on any MCS registered installation.
Book my free home assessmentYes. On all four tariffs the cheap price applies to everything the meter records inside the window, so laundry and the immersion count too. British Gas pays its half price hours as a weekly bill credit, worked out on all the electricity used in those hours. OVO’s rebate counted heat pump usage alone, and it was withdrawn in February 2026.
Book my free home assessmentIt is worth understanding before you commit to a heat pump, because it changes the running cost picture for a house currently buying oil or LPG by the tank. We go through it at the free home assessment.
Book my free home assessmentAsk the Tariff Question Before the System Is Designed
Nobody can tell you which heat pump tariff suits your house without knowing how that house loses heat and how the system will be set to run. Get the tariff and running cost questions answered for your own property at a free home assessment, while the design is still on paper.
Book my free home assessmentPrefer to talk it through first? Ring 01395 202030. James answers, and he is the person who will price the job.
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“We were doing a huge amount of work to our new house and an Air Source Heat Pump was something we wanted to consider to move away from gas – due to cost and the unstable prices.”
Reece Atkins · Google review
