KleenAir Systems International has increased the number of shares it holds in Inspirit Energy, spending a total of £440,000 in the alternative energy firm.
The further investment follows progress made by Inspirit, which is seeking European Gas Appliance Directive approval for its energy-efficient micro combined heat and power unit.
The company has also begun taking orders, with manufacturing expected to start in Q3 of this year.
The latest investment by KleenAir has increased its Inspirit shareholding from 10.55 per cent to approximately 18.7 per cent.
Inspirit us focused on small-scale CHP for the SME market.