Changes to the Renewable Energy Sources (RHI) scheme earlier this year meant a "crude deal" for participants, the deputy committee said.
The Northern Ireland Affairs Committee has stated that the Department of the Economy should "reconsider" the deep reduction in payments.
It comes after the companies have said that the cuts left behind.
Parliament Speaker Simon Hoare said that companies in Northern Ireland now have payments that are "half less" than in Britain or the Republic of Ireland.
The Department of the Economy said it had received a committee report and would respond when considering the findings.
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The Westminster investigation began after the legislation allowing the cut of subsidies was passed through parliament on a single day in March 2019, prompting claims that there is not enough time for proper oversight.
The committee also urged Northern Ireland Minister Karen Bradley to end the practice of speedy adoption of Northern Ireland legislation by using the so-called "urgent procedure".
The Northern Ireland Office said he would respond after considering the report.
The reduction in 2019 meant that payments of most frequently used boilers in Northern Ireland fell from £ 13,000 a year to 2,200 pounds.
An equivalent scheme in the UK will pay at least £ 5,300 – which is the difference of several tens of thousands of pounds over a 20-year program period.
The Committee expressed concern about evidence suggesting that it could affect competitiveness of poultry production in Northern Ireland, a key part of the agri-food industry.
About 800 of 2,100 participants in the RHI scheme have chicken farms, most of them supplied by the manufacturing div Moy Park.
Later this year, a court dispute will be heard about the legality of recent changes.
"Reading by reading"
Speaking to BBC Radio Ulster's Sunday News program, Andrew Trimble of the Renewable Heat Sources Association said that the changes have affected the lives of some of the participants.
"Many participants have provided evidence to this committee on the basis of anonymity, because it is uncomfortable to accept the guarantees of the department," he said.
"Let the letters and some of the participants in the scheme bring a rather lukewarm reading."
"They reported that they had to sell their farms, that the banks had returned home, which they put as security against very significant investments in renewable energy."
The department announced it had to act because the existing subsidies were violated by the EU competition law on state aid to companies.
Failure to do so would mean that there would not be a legal basis for the continuation of payments, and subsidies would have to be stopped.
It was said that the difference in subsidies was due to the fact that GB companies put in boilers earlier, when technology is being collected.
Most also used gas that was considerably cheaper than wood pellets and therefore demanded greater incentives for replacement.
In the Northern Ireland scheme, the equivalent fuel is oil, which is closer to the price of pellets, so the subsidy rate can be reduced.
However, many poultry producers who entered RHI used liquid petroleum gas (UNP).
It is not a subsidy
Boiler owners believed they had a government guarantee that payments would increase with inflation, and many made long-term investment decisions based on income.
The Department of the Economy stated that the scheme was never intended for business subsidies but was designed solely to encourage companies to move from fossil fuels to renewable heat.
The subsidy was only intended to cover the difference between traditional and renewable boilers, fuel price differences and 12% return on investment.
However, the original scheme was badly designed and oversized, leading to over-compensation that threatened Northern Ireland's budget, which officials said was a potential bill of up to £ 700million although the number is controversial.
A reduction in the subsidy rate has avoided the risk of massive excessive spending, but it means that the available cashier will not be withdrawn now.
The Northern Ireland Affairs Committee said that, regardless of the outcome of the court dispute, the department had a "moral imperative" to consider any other reasonable investment companies they made when examining their payments.