If modelling and calculators is your thing then try this https://buildanytool.com/. You can make the AI do all the work and take it beyond a first order calculation you may have. It’s when it starts to become unmanageable and a grind to cover all the bases and present a GUI. Also good fun to have such power to command at your finger tips. I gave it this prompt and it made an attempt - even critiquing itself and suggesting a rerun:
Compare electricity cost between timed and always-on geyser for South Africa. Include inputs for geyser capacity, thermostat temp, electricity tarrif, geyser location (in roof, on roof facing sun, on wall facing sun, on wall not facing sun, inside). Insulated and not insulated. Entry for no of showers and number of baths in morning and evening. Entry for shower and bath start time in the morning and evening. Assume a fixed duration for a shower (show this number). Assume typical full bath. Entry for number of washing machine loads per month. Entry for no of dish washer usage per month. Entry for number of sink fulls per day. Entry for 2 timed on and off slots in the day - one in the morning and one in the evening. Populate all inputs/entries with defaults. Allow comparison for each season and for a full year
Ja I had look at something like this for calculating solar setup on the plaas. Feed pump, freezers, workshop. You put in numbers and it spits out what you need. Lekker in theory but I found you still need someone who actually knows what they doing to check the output. These tools make assumptions that dont always fit a farm situation. My borehole pump alone gives the calculators a headache. Still, better than guessing on the back of envelope. Worth playing around with.
Much is specialised modelling with some heuristic. Not everything individually will have an impact of any concern. So it’s also how accurate does the answer need to be - to what decimal place. In some cases a ballpark is enough and still better than quessing. By knowing the things that really matter and edge cases you can ignore you can make adjustments in an informed way. All will have however suffer from garbage in and garbage out and sme real world inputs are hard to come by so validation itself can be hit and miss leading to much confirmation bias.
Funny thing, I’ve been preaching this for years to blokes wanting to size a solar setup. The calculator is only as good as the numbers you feed it, and most people guess their loads. Johan’s spot on about that borehole pump, the startup surge on a motor like that can be three or four times the running current, and half these tools just take the nameplate watts and call it a day. Same story with fridges and freezers cycling.
I tell people, before you trust any answer, go clamp meter your actual draw over a day or two. That’s the real homework. The tool then gives you a decent ballpark, and like Nebula says, ballpark beats guessing.
That said, I do like having the power to model things quick. Beats the old days of scribbling on the back of a fag packet at the DB board. Just don’t go ordering panels and an inverter off a number a computer spat out without someone who knows checking it first.