The scheme is set to close on 31 March 2021, after six months in operation.
The government set a target to reach net zero greenhouse gases by 2050, part of which includes raising the energy performance certificate for all new tenancies in the private rented sector (PRS) to a C or above by 2025.
By 2028, this requirement will be extended to all PRS properties.
At present, around 67% of private rented properties in England and Wales, around 3.2 million in total, are a band D or below.
The £2bn Green Homes Grant scheme was launched in September 2020, providing up to £5,000 per property, or no more than two thirds of the cost of the work done.
Improvements covered were categorised as primary, such as cavity wall insulation, and secondary, such as draught proofing.
Angus Stewart, chief executive of Property Master, said: “We know the Green Homes Grant scheme was not without its problems.
“It was difficult to access, hard to find the correctly registered tradespeople and the process of redeeming vouchers was cumbersome.
“But rather than reform the scheme the government has chosen to scrap it and leave landlords with a “green gap” of finding anything up to £10,000 per property to meet these new requirements in just a few years.
“Around half of all landlords own just one property and they are already dealing with increased taxes on private rented property and for many the continuing coronavirus crisis that has pushed some 800,000 people into rent arrears.
“Indeed, landlords could be forgiven for thinking the new energy regulations in the absence of government support is just an extra backdoor tax on the private rented sector.
“For many this will be a squeeze too far on their finances and they may well choose this moment to exit the market which will reduce the number of homes for rent.”
