There is an estimation book put out by NECA but it’s mostly for commercial jobs. The raw data comes from large union contractors. Only one that’s trustworthy. Most of the software uses the same book. The problem is it’s for larger jobs.
The easiest way to quote jobs is start with what you need. Get prices on all the parts. Add 10-25% because you always miss a couple items unless it’s cookie cutter work. Also on some items like hardware you estimate a few bucks and on some items like say #14 BX you are buying in bulk so have to estimate a cost. Add 3% shipping and whatever your local sales tax is or just add 10% shipping and taxes. Add 15% profit/handling that pays you for the time to order and manage it. Get an account at a couple supply houses too. On the labor side two ways to do it. One is estimate your hours. This is where experience comes in. I do it by man-days or half days. Face it on a resi job it still takes you an hour on the road, a half hour getting in and setting up, then do the job even if it’s ten minutes, then clean up, pack up, get paperwork, and on the road again. Realistically no job except maybe inspections is under a half day. That’s why you can up front tell someone it’s say $150-250 minimum charge. Then multiply by your rate and you have your quote. The other way is you need to have a good feel for the materials/labor breakdown. Some jobs like inspections are 100% labor. Some like installing generators are 80% parts. But most electrical work is 60% materials. So if you divide your materials estimate by 0.6, you get a total cost estimate.
Either way plan on making money 80% of the time. If you miss more than that either your estimating is way off or your bids are too low.
I just do a spreadsheet on every job. I have the item, number, quoted price, bid price (multiplied by quoted number), what I paid, and a difference. That way I can easily tell what I still need to buy and where I made out to the good or bad. One time things are what they are. At worst you adjust the contingency if you are consistently low. But if you are missing a lot of materials or giving it away too much you need to fix your estimates. Labor is the sane way. After say 5 jobs you can also just run average %profit on materials, actual vs. estimated labor hours, etc. You can realistically “fix” these by tweaking your estimating process going forward. Review every job every time but also pay attention to trends and don’t sweat the small stuff.
Also, not sure where you are geographically but I’ll give you a huge hint. You are going the wrong way. Yes residential is good money for small businesses. But what you are suggesting is you have zero experience in that market. Since you have commercial experience what I would suggest is going off that. One idea is get a home inspector license/certificate (cheap) and then hit up all the real estate agents for business. The hours are very flexible. After you inspect you can offer follow ups to make repairs. Since there are no bidders and you already did an inspection, you almost have the business to yourself. And you can do a lot more than electrical if you want, or sub it out and just take the easy money. I worked for a guy that made his whole career this way. Similarly schools would be another easy way to start. They are often bid jobs but simple to do. Just have to find out how to get on the list which is just phone calls. General school maintenance is too small for commercial guys, too big/scary for residential. You have an inside track already. Just hard to get business right now. Other institutions like prisons, malls, hospitals, and retail are similar. Avoid Walmart (trust me). Many of these are not shut down, Maybe sub out to plumbers, HVAC, pump repair, or pool companies. They need electricians on a lot of jobs but not enough work to hire one full time. They sub out. Hang out at a motor shop and ask around. Also look for small wastewater treatment plant operators. I’ve gotten wet maybe twice in three years and we do these a lot. Both times was my own fault for not wearing rubber boots when I should have. Usually you don’t touch anything nasty on the electrical end. Food operations too. They are wide open right now. Best option would be a restaurant equipment guy if you are small. They don’t need a license for the equipment but they usually sub someone if it’s premises wiring.
The thing is that these are all small commercial or institutional customers. They are much more aligned with your experience and skill. You can probably estimate these jobs a lot easier because you have the experience. Then once you get more established you can mess around with houses whenever the opportunity comes up but the commercial businesses are going to be steady work.
Business is slow especially with some customers to be sure. The largest tire plants in the US have been totally shut down for over a month. Same with all automotive except I think Tesla. But we’ve had every wood plant shutdown cancelled because they are all running wide open. Repair spending is all at emergency rates (get here as soon as you can). I think it would take an evacuation to shut down a tissue plant right now.
Plus the big thing with residential is very few repeat customers. Business growth is really slow. You are stuck with whatever you get off Angies List or Home Advisor for instance. Plenty of posts on here should tell you those services are a great way to lose money. You need to go where the customers are which is why getting in as a sub or working off referrals is so much better. It’s one thing if you are big enough to advertise. Quite another to get on Yelp and hope for a call. If you can get in good with referral or sub jobs or into most institutional or commercial customers it’s going to be a steady source of calls all the time. You get up to speed much faster. This solves your immediate concern, Then once you have an established business you can afford to advertise and take on residential.
