Green energy supplier Bulb is raising the price of its only tariff, with all 450,000 existing customers to be hit by the rise in August, MoneySavingExpert can reveal.

The Vari-Fair tariff - Bulb's standard and only tariff, with a variable rate - will rise by 5.1% for new customers from today (Monday 11 June). Existing customers - and those already in the process of switching to Bulb - will see the same price rise on Sunday 12 August.

The rise follows other high-profile price hike announcements, with all of the big six raising their rates in recent months. In May, SSE became the last of the giants to announce it was putting up its prices, and last week Ovo raised its standard rates.

Though prices remain lower than the big six standard tariffs, many can switch and save - you can leave penalty-free as Bulb doesn't have any exit fees.

To find the best deal for you, do a full market comparison using our free Cheap Energy Club.

I am a Bulb customer - how am I affected?

All of Bulb's 450,000 customers are on its Vari-Fair tariff, so you will be impacted by the price increase. All variable tariffs, as the name suggests, are subject to price changes, though energy providers must give customers at least 30 days' notice. In this case Bulb has provided customers with 60 days' notice.

On 12 August existing Bulb customers will see a 5.1% increase, which means the typical household dual fuel bill will go up by an average £45/year, to £923/year.

This rise also hits the 16,000 of you that switched to Bulb in our Big Switch Event 10 back in April. Yet despite the hike, Bulb remains competitive - it's still around £260/year cheaper than the average big six standard tariff.

However, when the price rise comes into effect it could be worth using our free Cheap Energy Club to check you're still on the right deal for you. Bulb's new average price will be £115/year more than the market's cheapest currently, so you may be able to switch and save - and you won't have to pay any exit fees to leave.

Before you do switch though, it's worth looking at other factors, too. Bulb may still be a good bet for many - it offers 100% renewable electricity and a very good track record of customer service. In our most recent poll it ranked third, with 90% rating it 'great'.

Why does Bulb say prices are going up?

Bulb co-founder Hayden Wood said: "Bulb is committed to supplying energy at a fair price. That’s why we have one tariff for all our members, which reflects the true cost of energy. When wholesale energy costs change, our tariff does, too.

"These costs have climbed throughout 2018, and are now 21% higher than they were in February. As a result, from August, our price will be going up by £4 per month for the average Bulb member.

"All our members receive 60 days' notice of the rise, double what Ofgem recommend. And because we don't charge exit fees, our members can leave at any time, at zero cost.

"Despite this rise, we remain one of the cheapest suppliers in the UK. We’ll continue to deliver simpler, cheaper, greener energy for all our members."