WARSAW (Reuters) - Japanese air-conditioning systems and heat pump maker Daikin's Polish unit will invest over one billion zloty to build a factory producing heat pumps near Lodz in central Poland, a source familiar with the matter said.    Demand for heat pumps - which rely on electricity to transfer heat - has been booming in Europe amid soaring gas prices, with consumers waiting months for their installation.

In Poland, the number of heat pump devices to heat houses nearly doubled last year to over 79,000 units.

A Japanese company plans to build a heat pump factory, two sources familiar with the matter told Reuters. One person said the investor was Daikin, while a source close to the government said the investment would exceed 1 billion zloty ($213.13 million).

The local headquarters of Daikin in Poland could not be reached for comment outside office hours. A spokesperson for the Polish government and a representative for the Lodz special economic zone (LSSE) were not immediately available for comment.

The European Commission in May unveiled a 210 billion euro ($213.86 billion) plan for Europe to end its reliance on Russian fossil fuels by 2027, and to use the move away from Moscow to speed up the transition to green energy.

Those investments include 56 billion euros for energy savings and heat pumps.

Heat pumps, sometimes described as reverse air conditioners, use electricity to concentrate heat potential and are comparatively more energy efficient than gas boilers.      Polish Prime Minister Mateusz Morawiecki is due on Thursday to hold a news conference to accompany the inauguration at the LSSE of the largest foreign investment in the country in recent years. No details have been given on the investor involved.    Meeting the targets set by RepowerEU - the EU's plan unveiled in May - would require around 20 million heat pumps to be installed in the EU by 2026 and nearly 60 million by 2030, according to the European Heat Pump Association.

($1 = 4.6919 zlotys)

($1 = 0.9819 euros)

(Reporting by Marek Strzelecki and Anna Koper; Editing by Deepa Babington)