The company, which currently has a 2% share of the UK retail energy market, is a multi-service provider that offers a bundle of energy, broadband, mobile and home insurance services.
"We currently supply 650,000 customers across the UK and are very clear that we have the opportunity to increase that significantly on the basis of our long-term peace of mind tariff structure now offering the very best value in the market," said Chief Executive Andrew Lindsay.
"Our medium-term target of supplying 1 million customers is suddenly very much closer than it was," he told Reuters.
Some larger energy suppliers are being tasked by energy market regulator Ofgem to take on the customers of smaller rivals that have failed in recent weeks and months.
In the UK retail energy market, small providers that had launched in recent years have been hit by the jump in costs. From more than 70 suppliers in 2018, there are just over 30 now.
Energy companies pay a wholesale price to buy gas and electricity, which they then re-sell to consumers. Many energy suppliers announced increases in retail tariffs in recent months, passing a higher wholesale cost on to consumers.
Ofgem and business minister Kwasi Kwarteng have warned parliament that the soaring gas prices would force more suppliers out of business and that the industry should prepare for a tougher environment.
Utility Warehouse, founded in 2002, says its tariff structure has helped it weather the price spike and continue its business as normal.
It managed to achieve that through a 20-year wholesale energy agreement with Germany-based utility supplier E.ON that hedges energy purchases against price volatility. That contract is valid until 2033.
Lindsay said that a number of "short-termist suppliers ... who have focused on investing solely in gaining market share" had left many good companies operating in the background unable to compete effectively.
"Now that handicap has been removed, these companies are now very well positioned to grow much faster, and play a key part in the vital transition to net-zero (emissions)," he added.
(Reporting by Marwa Rashad; Editing by Nina Chestney and Steve Orlofsky)
By Marwa Rashad