I always hear that due to liability and taxes etc, investment properties should go into an LLC.What is the best way to turn my existing home into a rental?

Ronald Rohde   It does exist. 

There should be other options, however with an LLC and fourplex - yes, DSCR is by far most likely to be your best option unless you do the heavy lifting with local banks and credit unions (and these are increasingly not great options for this type of stuff as they move painfully slow and are under lots of regulations and restrictions)2) I haven't yet reached out local banks, but seeing the quotes from brokers makes me wondering if Banks may be better? 

I know very little about legal precedent but I'd expect the major meter manufactures (selling into the utility space) to be well incentived to challenge these items best they can, and they have money.Here are the issues, and the reasons that the difference between an air forced system and a boiler/hydronic system are not meaningful for this discussion (ie efficacy issues of sub metering exist for either when method of measurement is measuring heat at point of delivery):In either case, the blower (or pump for a boiler) is the method of 'moving' either air (central air) or water/glycol or equivalent (boiler etc). 

A $200,000 duplex might have identical rents in municipality “A” and municipality “B” but the property tax rates will vary, local regulations will dictate licensing requirements, labor rates will vary & the particular location will dictate insurance premiums since insurance carriers will weigh local replacement costs and whether the municipality is viewed as being a “plaintiff friendly” in arriving at insurance premiums.Better situated assets will attract better tenants.

But those basically don't exist anymore.

@Paul BogardTo rent out multiple bedrooms in Philadelphia, understand zoning regulations, consult a knowledgeable real estate agent, hire a property manager, and consider multi-unit properties, student housing, and co-living spaces.

That way they're not soliciting you w/o a pre-existing relationship, and you still get to look at their work. 

near 0% and 0% options with DPA's exist (down payment assistance) programs.

Check local short-term rental regulations.3.