Any person that owns or operates an OWHH shall not use a fuel other than the following:
I. Clean wood;
II. Wood pellets made from clean wood;
III. Home heating oil, natural gas, or propane that complies with all applicable sulfur limits and is used as a starter or supplemental fuel for dual-fired OWHHs; or
IV. Other fuels as approved by the commissioner through rules adopted pursuant to RSA 541-A.