1. Observe and protect
Document symptoms, limit further damage where it is safe to do so, and collect relevant history.
2. Evaluate the house and site
Connected load, fuel supply, transfer equipment, pad and drainage, required clearances, utility coordination, permits, startup testing, and maintenance access shape a dependable installation.
3. Put the scope in writing
Spell out prep, protection, materials, access, permits, testing, cleanup, finish work, exclusions, and change-order pricing.
4. Weigh what's actually proposed
Verify credentials, then compare the reasoning behind each bid -- not only the total.
5. Confirm the close-out
Testing, cleanup, paperwork, warranty terms, and ongoing maintenance should all be confirmed before calling the job finished.