@Adam Ng has a good point about cash-flowing investments a little closer to home and would be the rout I would go if I lived in the area.  

@Rich Ng thanks a lot for the advice.

Thanks @Rich Ng,Appreciate your inputs.

As an energy auditor, I get these calls all the time,Popular things are:-extra fridger/freezers in the garage (typically a free or old one they dont realize uses a ton of electric),-Hotwater tanks & Heating (is NG an option) If not look at airleakage and insulation-Failed wel lpumps or sump pumps that never stop running,-Non-Energy star Dehumidifiers,-electric space heaters that get left on or forgot about-A ton of Incidence light bulbsAnd the biggest one, Is typically not the KWH at all, but people switching to other non regulated providers such as ambit who have a habit of slowly creeping up to double/triple the market rate.

We use NG.

It's currently wired 3-phase, and being a boiler room, is plumbed with both NG and water.I'll likely provide the labor to relocate these pieces but they'll remain under his ownership. 

@Matthew Paul, @Kyle Hipp : The decision between NG, oil or electric will be heavily influenced by location.

I would definitely eliminate the propane heater if possible.However, we have a large 'higher end' 2700 sqft rental that has steam heat (NG boiler/rads) & the previous owners installed a couple of pellet stoves.

@Cynthia Ng You are not responsible for finding them housing after the lease has expired.

@Vincent Ng - Cap rates are specific to the market and there is way more involved than what you're calculating.