As stated $300 is very low for a conversion… We’ve price it out for some of our rentals and I plan on doing the work my self here’s what I’m planning on cost wise.
Electric Furnace $420-472 (12k unit)
Hotwater Heater $225
Upgrade 40amp wire to 60 amp (4gauge@$2 linear ft.) $40-75
conduit for wire $20-40
60 amp breaker box (needed if less than 200 amp service panel) $60
Misc (dryer plugs, stove plugs, extra wire, etc) $50
That brings the total to $940- 1050 for an all gas type unit, for oil conversion and the units that just have a gas furnace about the cheapest I can see is $550ish. The only reason I’m considering the conversions on RENTALS is to limit the total move in cost to the tenant thus making us more competitive, oil heat in particular is becoming a big draw back to rentals in my area and it’s very hard to rent an oil unit in the fall and winter leading to long vacancies during this time. For rentals it makes sense due to 3-4 month vacancies ($900-$1500 in lost rent) on oil units, for LD’s it doesn’t make sense from an income stance IMHO as there is little added value to the sales price or salability of the unit.
(as a side note, if you have to replace the feed lines from the transformer to the meter box or the breaker main panel, the cost is most likely going to increase greatly unless your power provider will change the wiring for you)