Before Judges King, Newman and Fall.
The opinion of the court was delivered by: Newman, J.A.D.
 Argued: October 28, l998
On appeal from the Superior Court of New Jersey, Law Division, Burlington County.
This appeal involves an action brought by plaintiffs, a minority group of tenants, who refused to comply with new lease provisions, against defendant, the landlord of the mobile home park where plaintiffs reside. Plaintiffs argued that two proposed lease provisions were unreasonable. The first provision required tenants to convert their heating systems from oil to natural gas, at his or her expense, and remove their thirty-year-old oil tanks. The tenants also objected to a second provision requiring them to anchor or tie- down their homes upon resale in compliance with State law.
After a non-jury trial, Judge Wells found that the lease provisions were reasonable conditioned upon defendant extending the time deadline for the oil to gas conversion for one year and defendant continuing to make the original $250 rent abatement available to tenants upon completion of the conversion within the specified time period. Plaintiffs appeal, arguing that the lease provisions are unreasonable and defendant cross-appeals, contending that the trial court erred in extending the time period by which plaintiffs can convert and by requiring defendant to provide the tenants who convert within the specified time a $250 rent rebate. We affirm both appeals.
Hanover Mobile Village (the Park) located in North Hanover, New Jersey opened for business as a mobile park home in or about 1962. Park management sold mobile homes to people seeking to reside in the Park and thereafter rented spaces to homeowners for placement of their mobile homes. In 1985, defendant, Hanover Village Associates, L.L.C. (defendant or landlord) purchased the ninety-nine lot mobile home park.
Each mobile home sits on dirt or a gravel bed. The homes sold or installed before 1985 were not tied down or anchored. Anchors or tie-downs are devices which are installed on manufactured homes "to limit the lateral and vertical movement of the home during heavy winds." The purpose of the tie-down is to prevent property damage during inclement weather. When the Park was developed, there was no natural gas service available. Consequently, Park owners installed kerosene or oil fuel heating systems in the homes before they were sold, and provided outdoor storage tanks for the kerosene or oil. At the time defendant purchased the Park, defendant was unable to obtain insurance coverage with respect to spillage of pollutants or contaminants such as kerosene, and at no point during its ownership was it able to secure such insurance coverage. The heating and fuel storage systems were included with the purchase of each home.
In 1995, when natural gas became available to the Park, defendant sought to upgrade the existing above-ground storage tanks on the premises. Subsequently, defendant distributed a memorandum to tenants, which required that existing oil tanks be replaced with "new Underwriters Laboratory approved outdoor tanks on a 4" thick concrete pad .... " Defendant also required a minimum of $100,000 insurance protection covering Hanover for any damage caused by a fuel spill. Alternatively, defendant proposed that homeowners convert to the use of natural gas and offered a $250 rent rebate and free oil tank removal to encourage the change.
Shortly thereafter, defendant learned that Public Service would agree to run gas mains and branches into the Park if approximately one-third of the Park's home owners agreed to use natural gas for heating. In May 1995, defendant forwarded new leases to plaintiffs requiring that each tenant execute the lease as a condition of continued occupancy. The two lease provisions at issue here required homeowners to: (1) convert from their existing heating fuel to either natural gas or electricity by July 31, 1997; and (2) tie-down their homes, if the homes were not already tied down, upon resale. Both requirements were to be met at the homeowner's expense. The homeowners who refused to execute the new lease were threatened with eviction and consequent value loss of their homes. A minority of tenants refused to execute the new lease and brought this legal action. A. Conversion of Existing Oil Tanks to Natural Gas.
The lease provisions issued to the tenants in 1995 requiring them to convert their oil tanks to natural gas or electricity, provide as follows:
LEASE FOR HANOVER VILLAGE ASSOCIATES, L.L.C. 13. F. All Mobile Homes are required to convert to Natural Gas Heat and cooking or electric heat and cooking at the expense of the tenants by July 31, 1997.
9. b. All oil tanks and propane tanks used for heating and providing cooking to the mobile home must be removed on or before July 31, 1997 or on resale of the mobile home, whichever comes first. Tenants are required to convert to natural gas or electricity for heating and cooking and remove the tanks at their own expense.
Tenants who converted by the fall of 1995 were given a $250 rent abatement and their old tanks were removed by the landlord. A majority of the tenants converted during this time thereby taking advantage of the rent rebate. The cost of a complete conversion, including sales tax, permits, labor and materials, is between $1,200 and $1,500. The conversion, including all piping, permits and proper removal of existing tanks, could cost up to $2,144, however.
Both parties presented evidence concerning the condition of the existing tanks and the risks they currently pose. The parties were in agreement that the existing tanks are beyond their life expectancy. The life expectancy of an oil tank of the type involved in this matter is between twenty to thirty years depending upon whether the tank is properly maintained. The average age of the oil tanks in the Park is between twenty and thirty years.
Douglas Harm of Brinkerhoff Environmental, a hydrologist, testified for defendant. He described two environmental risks associated with the existing oil tanks: oil leakage and well-water contamination. He testified that, based upon his inspection of the park, the oil tanks probably have been leaking or they have the potential to leak at any time. He stated that: the potential for a discharge from those tanks is great. They are really accidents waiting to happen. They're leaning, they're sitting on cinder blocks, heavily rusted, sitting on the ground. In my experience, I've seen tanks like that leak many times.
He also noted that the Park's tanks (which are UL-80's) are usually placed indoors, in basements, not outdoors where the current tanks are located. In his opinion, if natural gas was ...