Generators for Dummies :O
The reason for such situation is THD, or Total Harmonic Distortion. Thousands of people in America (where blackouts are more frequent than in Canada) ended up having to replace their furnaces. In particular those with a variable speed furnace.
A very good place to start reading about THD is the following http://support.fluke.com/find-sales/Dow ... NG_A_W.PDF
THD is supposed to be about 4%. I measured the hydro at home and is around 4.3%. I also measured 'regular' Champion generators (not inverter) and the THD would vary between 13% and 30%+. The same results will apply to any brands of generators as long as they are not 'inverters'. The higher the load on the generator, the more THD. Mind you, I connected a single 13W CFL bulb and had a THD of 18%. As a rule, the higher the THD and the longer something is connected to a generator, the faster you will kill whatever is plugged into the generator. Of course, it is not a matter of just being plugged into a gen., but drawing electricity produced by the gen..
There are tools to measure the THD, such as, https://www.itm.com/product/amprobe-acd ... aQodz5sEVw this one is on the expensive side, but if you search you should be able to find one in the $200.
The bottom line is learn about THD before shopping for a generator. This way you won't end up spending $$$$ to replace what you have killed while using a generator during a blackout. Hope it helps.