TL;DR
Switching tariffs saves hundreds a year, costs nothing, and should be the first thing you do. Solar saves thousands a year but costs £5,000–£14,000 upfront.
The two stack. Cumulative savings cross over around year 4–6 — after that, solar pulls away and never looks back. A smart tariff plus solar is the actual best answer.
Two different levers. Switching is free and immediate — you save £100–£300 a year for the price of twenty minutes on a comparison site. Solar is a capital project — £5,000 to £14,000 out the door, £600–£1,400 back every year, forever. They’re not competing strategies. They’re sequential ones.
Switching is low-effort free money. Do it first. Solar doesn’t replace switching — it stacks on top. The real question isn’t “which one”. It’s “when does solar start to beat tariff-hopping alone, and am I going to be in this house long enough for it to matter?”
If you rent, this page ends here for you. Focus on tariff switching. Solar isn’t your call to make. For everyone else, run your numbers with our savings calculator once you’ve read this.
The honest head-to-head
A typical UK 3-bed semi switching from the SVR to the cheapest 12-month fix saves around £200/year and costs nothing. The same home installing a 4 kWp system with a battery spends £10,000 up front and saves £1,150–£1,300/year on bills plus £150–£220 on Smart Export Guarantee earnings. Tariff switching saves 8–12% off a bill. Solar with a battery saves 60–80%. Over 25 years, tariff-hopping alone gives you roughly £5,000. Solar gives you £20,000+.
What energy tariffs can save you
Tariffs are the lowest-effort saving going. No roof, no installer, no capital. Three flavours matter in 2026: moving off the SVR onto a fix, shifting to time-of-use pricing, and understanding where the price cap is actually sitting.
Switching from SVR to a fixed deal
The Standard Variable Rate is where suppliers dump customers who don’t switch. It tracks the Ofgem price cap exactly — a ceiling, never a bargain. Moving to a 12-month fix typically saves £100–£300/year on a medium-use home, more if your annual usage tops 4,000 kWh. The SVR is almost never the cheapest option. Check your next bill. If it says “standard” or “variable”, you’re overpaying.
Time-of-use tariffs
Time-of-use (TOU) pricing charges you different rates at different times. A few that UK homes actually use:
- Octopus Go — four-hour overnight window (typically 00:30–04:30) at around 7.5p/kWh, with day rate around 28p. Built for EV drivers.
- Octopus Agile — half-hourly pricing that tracks the wholesale market. Prices go negative on windy nights. Needs a battery or an EV to work properly.
- Octopus Cosy — heat-pump-friendly with three cheap windows a day (04:00–07:00, 13:00–16:00, 22:00–00:00).
- Intelligent Octopus Go — six-hour smart window (23:30–05:30) for EV charging, same 7p/kWh territory. The smart charger and car talk to Octopus directly.
TOU tariffs shine when you have something to shift — an EV, a battery, a hot-water tank on a timer. Without any of those, stay on a flat fix.
The 2026 price cap in context
As of Q1 2026, Ofgem’s default tariff cap sits around 27–28p/kWh for electricity and 6–7p/kWh for gas, with standing charges layered on top. Ofgem reviews it quarterly. The cap has moved in a 24–34p band for three years straight. Plan for volatility, not reductions.
What solar can save you
Solar is the opposite shape. Big number up front, bigger savings later, locked in for 25 years. Here’s what we see on real installs.
Annual savings by system size
Figures below assume 27p/kWh import, 15p/kWh export (Octopus Outgoing Fixed), UK average irradiance, and a 10 kWh LFP battery except where noted.
- 3 kWp (no battery) — £400–£500/year. Self-consumption 25–35%, rest exported. Payback 9–11 years.
- 4 kWp + 5–10 kWh battery — £1,100–£1,300/year including SEG. The sweet spot for a 3-bed semi. Payback 6–8 years.
- 6 kWp + battery — £1,400–£1,600/year. Good for a detached home with higher usage or an EV.
- 8 kWp + 13.5 kWh battery — £1,600–£2,000+/year. Fits heat-pump or EV-heavy households. Surplus export earnings alone can hit £300–£500/year on a good export tariff.
Our payback deep-dive has three worked scenarios if you want the full maths.
Locked-in vs variable savings
Here’s the thing tariff-shoppers miss. A fixed deal is fixed for 12 months. Then you’re back shopping. Solar is fixed for 25 years at 0p/kWh. If the price cap hits 35p in 2028, your solar savings grow with it — tariff savings don’t. Solar is an inflation hedge. Tariffs are a rate comparison.
The 10-year crossover
This is where the comparison gets interesting. In the early years, tariff-switching looks great — instant savings, zero cost. Solar looks awful — you’re £10,000 down. Then the curves cross.
Cumulative savings (illustrative, 3-bed semi, 4 kWp + battery)
Assumes £200/year tariff-switch delta, £1,150/year solar saving including SEG, 4% energy inflation, one inverter replacement at year 13. Your numbers will differ.
The crossover sits around year 4–6 for most UK homes with a proper south/east/west roof and a battery. Heavier usage and bigger systems crossover faster. Smaller arrays without batteries drag crossover out to year 7–9. After the crossover, solar never loses again.
There’s no crossover for a renter. If the landlord owns the roof, solar isn’t your lever — it’s theirs. Stick with tariff-switching and demand a better EPC.
Solar + smart tariff: the actual best answer
You don’t have to pick. The biggest savings we see come from homes running solar, a battery, and a smart tariff together. The battery buys cheap grid electricity overnight when solar isn’t generating, and sells surplus at peak when export rates spike. Two real stacks worth naming.
Octopus Flux
Flux is built for solar + battery homes. Three rate bands: cheap overnight import (around 16p), standard daytime (around 28p), premium peak export (around 33p) between 16:00 and 19:00. Your battery charges off solar all day, then discharges into the grid at peak export while the house runs on stored energy. On a typical 5 kWp install with a 10 kWh battery, Flux adds £200–£400/year over a flat export tariff. Needs a compatible hybrid inverter and a SMETS2 smart meter.
Intelligent Octopus Go (for EV + solar households)
If you drive an EV, Intelligent Go is the move. A six-hour cheap import window (23:30–05:30) at roughly 7p/kWh covers EV charging, battery top-up, and next-morning hot water. Solar fills the rest during the day. Pair this with a decent export tariff like Outgoing Fixed (15p) or Agile Outgoing, and households routinely hit 80–90% energy independence. Payback on the full solar stack drops below six years.
Who should just switch tariff (not buy solar)
Solar isn’t universal. Plenty of people should forget about it and focus on the free wins.
- Renters. You don’t own the roof. Push your landlord for efficiency upgrades, then shop tariffs annually. That’s your lever.
- Flats with no dedicated roof space. Shared roofs rarely work for solar. A plug-in battery might, and tariff switching definitely will.
- Planning to move within 2 years. Solar adds value to a sale but you won’t recover the cash outlay in that window. Take the tariff win and install solar in your next home instead.
- Tiny daytime usage, no EV, no battery plan. If you’re out 9–5 and you won’t fit storage, solar exports 70% of what it makes at 5–15p. Payback stretches past 13 years. A fixed tariff plus a smart meter is the better call.
- North-only or heavily shaded roof. Generation drops 30–40% on north-facing installs. Our sizing team has turned these surveys down. Switch tariff instead.
Who should buy solar
The maths bites hardest for this group. If three or more of these describe you, solar is the biggest single money move your home can make.
- You own the property and plan to stay 5+ years. That’s long enough to cross the payback line and start banking the savings.
- South, east, or west-facing roof with minimal shading. East/west arrays spread generation across the day — often better for self-consumption than pure south.
- Annual bills £1,500 or higher. Bigger bills mean more kWh for solar to displace. A 4 kWp system pays for itself fastest in homes using 3,500–6,000 kWh/year.
- EV, heat pump, or plans for either. Electrified heating and driving turbocharge solar ROI. Households running the full electric stack see 70–90% bill reduction.
- Cash sitting in a 4% savings account. Solar returns ~12% tax-free in year one and climbs with every price cap increase. The comparison isn’t close.
Read our installation process page if you want to see what an actual survey and install looks like, or check out battery storage options since the maths leans heavily on having one.
Estimate your scenario
Rather than argue averages, run your own numbers. The calculator below takes your roof size and daytime usage pattern and returns payback, 25-year profit, and break-even year. Pair whatever it gives you with whatever fix you’re on now — that’s your actual comparison.
Grants can shrink the upfront. See our UK solar grants guide for ECO4, 0% VAT, and regional schemes.
Estimated annual savings
£1,180/yr
That's £98/mo back in your pocket
Includes ~£87/yr export income from surplus sold to the grid
£11k
System cost
0% VAT
~8yrs
Payback
£32k
25-yr profit
Your 25-Year Savings Journey
See when your investment pays for itself
Estimate based on UK average solar yield and current electricity costs. Actual savings depend on roof orientation, shading, and usage. Book a free survey for a precise quote.
Frequently asked questions
Is it worth switching tariffs every year?
Yes, if you're on the SVR or your fixed deal has ended. Running a comparison every 12 months takes 20 minutes and typically saves £100–£300/year. Price-comparison sites like Uswitch or MoneySavingExpert's Cheap Energy Club cover the market. Set a calendar reminder for a month before your fix ends — suppliers rarely chase you.
Can solar lock in my energy costs?
Partly. Every kWh your roof generates is locked at 0p for 25 years. For a typical 4 kWp system with a battery, that covers 60–80% of your household usage. The remaining 20–40% still rides the Ofgem price cap. Solar is a hedge, not an off-switch.
Will the Ofgem price cap keep falling?
Unlikely on any sustained basis. Ofgem's cap has bounced between 24p and 34p/kWh for electricity since 2023. Gas extraction costs, grid reinforcement spend, and net-zero levies all push the long-run direction up. Betting your household finances on cheaper future tariffs is a risky plan.
Does Octopus Agile work well for solar homes?
Agile Import (half-hourly pricing) pairs nicely with a battery — you buy cheap off-peak and sell back at peak. For a solar-only home without storage, Octopus Flux is usually the better fit because it pays a premium export rate at peak (16:00–19:00). Check your supply region's Agile rates before switching.
Do I still need a smart meter if I switch tariff?
For any time-of-use tariff — Octopus Go, Agile, Flux, Cosy, Intelligent Go — yes. A SMETS2 smart meter is mandatory because the supplier needs half-hourly readings. For a plain fixed tariff, a traditional meter still works, though most suppliers prefer smart.
Can I combine a cheap tariff AND solar?
Yes — that's the best outcome. Solar cuts your import volume 60–80%; a smart export tariff pays you for surplus; a time-of-use import tariff charges your battery overnight for pennies. Octopus Flux and Intelligent Octopus Go are both designed for this stack.
What's the cheapest way to reduce bills today?
Switch off the SVR first — it costs nothing. Then add draught-proofing and a smart thermostat. Then solar, if the home is yours and you plan to stay 5+ years. Tariff switching gives you £100–£300/year free. Solar gives you £600–£1,400/year but needs £5,000–£14,000 upfront.
Is the Standard Variable Rate ever a good deal?
Almost never. The SVR sits at the Ofgem cap, which is a ceiling — not a competitive rate. Any fixed deal below the cap beats it. The only edge case: if cap forecasts show a steep fall and fixed deals haven't repriced yet, the SVR might briefly win. That's rare.
How quickly does solar beat tariff switching on total savings?
Cumulative savings from switching typically reach £2,000–£3,000 over 10 years. Solar hits that same figure by year 3–4 and then keeps climbing — £6,000–£10,000 over 10 years, £15,000–£25,000 over 25 years. After the crossover point, solar pulls away permanently.
Ready to stack the savings?
We’re MCS-certified installers across Surrey, Kent, Sussex, Essex, Berkshire, London, Bristol and Yorkshire — every quote includes a written generation estimate, an honest payback projection against your current tariff, and a breakdown of what we’d fit and why.
