I am just starting to getinto monitoring my home energy use. I am looking to put my finding against the power company and see if I can help my wallet, So what are entry level devices that I can expand easily. I am pretty handy with an esp and a soldering iron so a DIY solution doesn’t scare me. I wired my house with a new breaker panel. So let me have it if you will, I would like to get started
Thanks
Nice hope but IMHO this is not the right approach. The energy meter in your electrical cabinet, that the electricity provider uses to charge you, is well calibrated to high precision. And you won’t find consumer hardware that is calibrated to that extend, most are not at all. So out of curiosity, keep track on your devices, maybe change a bit of daily behaviour, it’s helpful but it won’t change anything in your wallet. Sorry to disturb your ideas but be realistic… Cheers!
PS: I am not an expert, you may find industry level hardware that measures to similar quality but it will cost you. Doesn’t help your wallet either 
So you want to do an energy audit?
You haven’t mentioned anything about your location, so no idea what voltage, current, local regulation, or device availability is appropriate.
What make and model is your power meter? How old is it? Name of utility? How are the current readings obtained by the power company to bill you? Manually, or remote wireless access? Do they bill by time of day, fifteen minute or whole hour chunks, peak usage, fixed rates, daily supply or just consumption charges, or what? Do you have separate off-peak rates as well? Free periods during the middle of the day? Peak charges in the morning and evening busy times? Do you have the ability to offset your bills with feed-in tariffs from solar and battery supply from your end? Does the utility have a portal that allows for consumption figures accessible via the web, either using an API or web scraping? How often is it updated?
Do you just want to monitor whole-of-house consumption, or individual devices, or even each circuit breaker?
Single, two, or three phase? Maximum power from the supplier in amps?
What technology do you already have, in the way of devices, routers, hubs, access points, and existing wiring across the building such as twisted pair, or other structured cabling?
Do you have a lot of variables that can affect your ability to control consumption, such as teenagers that are tech savvy but lacking situational awareness and don’t have to share the bills, or a partner that is technology averse? Just knowing how much you consume doesn’t solve the problem - you have to be able to take measures to reduce consumption to save money.
Do you have existing smart devices that need integration and already measure their own power consumption?
Where is the HomeAssistant server and equipment going to be located? Are you considering a dashboard display in a central location or scattered in a few rooms? UPS power backup, for your router and network equipment too?
How much room do you have in your breaker panel? Do you have a DIN rail for mounting devices with a few spare slots? If space is already tight, do you have adjacent room for added wiring and equipment?
How do you currently heat and cool the premises? What technology for your stove and oven? Kettle? Microwave? How many fridges and freezers? Hot water? Pool pump and filter? Spa? Ceiling fans? Light dimmers? Underfloor heating? Air conditioning? Any other major energy consumption devices?
Do you have equipment nearing the end of useful life that may benefit being replaced with alternate technology that is more efficient, such as heat pumps or geothermal that may have a higher up-front cost, but easily amortized over the useful expected life of the unit? What payback periods would you consider acceptable?
Have you considered passive methods of reducing your energy bills, such as adding insulation, shading, blinds and shutters, double glazing, and sealing cracks? Trees and shrubbery?
What material is your walls and roof made of? Do you have a lot of roof space above your ceilings?
Is your house orientation and shade from adjacent trees appropriate for shade and solar access? Do you have wind breaks and verandahs, or close neighbors, or live in a multi-dwelling building? Do you have consistent prevailing winds and weather from one direction?
Is solar power and battery storage part of the equation? Electric vehicle?
City or country? Do you have a choice who bills you, and what rates are on offer? Do you have the best rates on offer? Are there any concessions or subsidies you may not be aware of? It is worth asking regularly, especially if there is fierce competition. Haggle. This is the fastest way to save money that a lot of people ignore.
Does your utility company offer a energy audit, either free or for a small fee? An experienced consultant may be able to offer you a lot of advice, either via a phone consultation, or a visit. The energy supplier usually has a lot of reading material on their web site for various money saving clues that are appropriate for your area. Have you called in your local HVAC installer for a free quote and advice on how you can save money? You don’t have to become an expert if you ask for the advice of others more experienced.
How much of the day is the house occupied? Can it be left to ‘wind down’ in consumption when not occupied?
Are your consumption patterns fairly consistent, or are you geared up for maximum peaks, some which may only be reached infrequently?
Prices for the different forms of energy supply, such as gas, electricity, community based energy sources can vary, depending on your supplier and location. For some locations, electricity may be cheap, for others gas. For others community supply such as central heated water supply, and battery storage. For others, burning wood, coal, or oil to keep warm, generate hot water and cook may be more effective. Evaporative cooling does not work well in some climes either.
Single or multi-storey? Is the premises compact or spread out? Will wireless signals reach from one end of the house to the other? Pass through multiple walls or floors?
How long do you anticipate living here? No point in doing a lot of modifications if you expect to be moving in a short time.
How much do you anticipate on saving once you have this knowledge of your consumption and how much you can save? Is it considerably more than the time and expense of installing equipment to measure and control it? If not, you may be wasting your time and money.
Just some things to consider.