Looking for help in heating a 540sq ft apartment. Was once our attatched garage.For my wheelchair bound mom-in-law. Was told they don't make a mobile home furnace small enough as the energy analysis said between 19,000 btu's and 24,000 btu's. We checked into wall units and they just won't work well enough for the type of heating she is used to.(forced air is what she is used to)so we know unless we can find a furnace that we are not aware of that can be used in the way we need it to, we are really stuck! Please! any and all replies would be helpful! We need to use LP gas.