Bob NH
In the Trades
There is about a factor of 5 ratio for the cost of an automatic system vs a manual system that will be adequate for most people.I have always felt if you can afford an generator spend the big bucks do it right and get an automatic transfer switch (ATS). But then I use to sell and service ATS's so I am a bit bias.
I have a 5.5 kW diesel electric start that can be fueled from my #2 fuel oil tank. It cost $750. Add $80 for the interlock and the conduit and wiring that I did myself and I have less than $1000 in the system.
In todays market it looks to me like the least expensive auto-start system is the Generac Guardian with propane power, starting at around $5000 for installed systems. If anyone wanted a true "whole house" system with automatic transfer switch installed by a dealer it would probably be a lot more.
For the difference in cost I can stand a 5-minute delay while I start the generator and switch it over, for an outage that may occur twice a year.