what will a 4000 watt generator run in a house

first of all , you have to know that a generator has two ratings, the starting watt and the running watt,  the starting watts is the maximum power the generator can produce while the running watts is the load the generator can support when it is running.

 Most generators are rated using the running watts, therefore to know what appliances can be run using  a 4000 watt generator, you will need to know the wattage of each of  your appliances.

For example an electric fan rated 100 watt may have a peak watt of 150, a electric cooker rated 300 watt may have a peak watt of 350 watts, a refrigerator rated 1000 watt may have a ratings of 1500 watt, a television rated 400 watt may have a peak watt of 500 watts,

 All appliances need more power when starting and less when running.

What to do is to do one of the following

 First calculate the total wattage of the appliance in your house,

 How to do this is to add up the total peak watt of each of the appliances and the and to also add up the rated watts of each of the appliance

 If the sum of the peak watts is less than the generator peak watts and the sum of the rated watts is less than the generator running watts, then you can comfortably use your generator.

And the 2^nd method is make a scale of preference, this is when the total wattage of your appliance is more than the gen power, you choose the electric appliance to run at a time,

 For example if the sum of wattage for fan, television, electric irons and refrigerators is above 4000 watts, you can decide to let go one of the above or use switch off one. The choice is yours.