If you are lucky and fortunate enough to live in an actual house with land, and work (or are thinking about working) remotely, seriously consider investing in an actual separate building for your office.
> I got a ton of quotes for installing a mini split. They ranged from $4-$7k, which was higher than I expected after researching the cost of a quality small unit and knowing this would be a tiny job for an HVAC contractor, especially because I had my electrician prewire the electrical. I was considering installing a DIY system (Mr. Cool DIY system with pre-charged AC lines), But found an HVAC contractor who would install a system for a much lower price than the other quotes I received (and he had great reviews on Thumbtack). In the end, I got a Daikin Mini-split, a common system with many replacement parts. The installation took about 5 hours, and my tech did a great job. I am glad I researched and got a lot of quotes for this one.
I'm still planning on building out an office/studio, but it will be a much larger investment despite being able to DIY much of it.
https://tuhat.net/@sbr/p/big-tech-sucks
The rack warms it in the winter so I don't need any extra cooling, and I run the AC in the summer.
$20K still seems like a lot to get some mosquito bites walking through the yard to work. Lack of plumbing, coffee, etc (some of those are fixable of course) is a bit of a turnoff but perhaps the walk is part of the charm.
I find that with kids mostly in school and knowing the rules the exterior space isn’t a requirement, but I don’t have a ton of meetings these days so YMMV. Mostly this is cope because I don’t have 20K to drop on a cool office! :)
Nice work and thanks for the post!
We bought an old house and did a full remodel and planned for an office and a work kitchen (my wife is a chef) separated from the main house (and each other).
It's been a game changer
Monitors are relatively cheap these days, you can get a name brand 32" 4K monitor for around $300 - if someone busts in and steals it, the door/window repair will probably cost more than the monitor.
Structurally a wet fart will hold up plenty of snow when we're talking spans on the order of 10ft. A garden shed that can literally roll away in a tornado is only a few hundred dollars of material different from one that can't.
Of course Tuff Shed (or anyone else) isn't gonna make a special product line for one town in CO or wherever that wants to de-facto outlaw the construction of shed by people less than a certain wealth level. Those people can have their stuff built from scratch at great cost. Of the dozen lost sales they were likely some of the most problematic anyway.
In my opinion it's commuting to the office which sucks, and not working in the office: I had a couple years where I walked in to work every day, and that was basically ideal. (It was, ironically, a job I started while living on the opposite side of the country: I then moved to a place about a mile from the office, quite a pleasant walk through the heart of the city.)
What did it do to you that you needed to insult it?
You still need a structural building permit, beyond any electrical or plumbing permits, if it's both heated and used either as a living space or "for a business".
The city added the "for a business" wrinkle in 2024 and is very squirrely about whether using it as a work-from-home office counts as "for a business". It _does_ include working from it without bringing employees or clients into the buildling, but the way it's written implies that it's for people running a business out of their home address and not working for someone else's business.
It's a gray-enough area that I hope you got some solid legal advice. We ended up getting the permit to cover our bases in case I had to move to freelance/consulting self-employment.
But 8x10 for $20,000 just goes to show how expensive USA is for construction. There’s a point where I would review coworking space cost (not as convenient, I know) to just living and owning property abroad.
- What type of floor? (2x4? 2x6? will it hold me and my chair without collapsing?)
- What roof type? How big should the overhang be? What's easier to build yourself vs looks nicer but a real pain to build?
- How many windows should be in my office?
- How do I build something within my budget?
- What size of shed should I go with for my purpose? (workshop? office?)
I'm working on https://myhomecat.com - which lets you do all of this. If you enter your address and the kind of shed you want (i.e. 10x12 office), you should be able to get something fully code-compliant that figures out all of your details. It's still early so it doesn't cover every edge case, but the idea is there and it works really well from the feedback I've gotten.
I'm glad you measured CO2. I've recently noticed I tend to get headaches when working or sleeping in small poorly-ventilated spaces, and I'm surprised how often I encounter new structures without ventilation. I guess tightly-sealed buildings are still a relatively new idea.
In the PNW you could probably be comfortable >90% of days with a cracked window, fan, adjustable shades, and a little electric radiator, but if I was doing this project I'd probably opt for the modern heat pump / ERV combo as well.
There are many comments on the price point. I would like to comment on one thing.
"$20k is too much"
I agree $20k is an investment. Could I have done it for cheaper? Absolutely. Would a DIY shell been cheaper? Would doing more of the work myself have been cheaper? Could I have saved by putting in the smaller stock windows and not having a skylight? Of course!
But I am a dad with a young kid, he was 1 when I built the office. I didn't want to spend my limited free time on this project. There was a trade-off between paying for labor and the time it would take to do it myself. At this point in my life I always look at these decisions through a lens of: is the cost savings worth my time. In this case I valued my time more than the cost savings. I was lucky enough to be in a situation where I would rather spend money for someone else to build this then spending my nights and weekends on this project.
I am almost 4 years in I would have paid over $20k for a co-working space. We were able to stay in our smaller house with a ridiculously low mortgage rate. We made the right choice for us.
Cheap is relative. Sometimes your time is worth more. There are litteraly entire companies built on this premise, cough DoorDash
I don't recall how technical it is[^1] because I read it years ago, but Michael Pollan wrote an entire book about building himself a writing room:
https://michaelpollan.com/books/a-place-of-my-own/
[^1]: Being familiar with Pollan's writing, it's likely at least as much philosophical and meditative as technical and practical.
I spent about 14-15k NZD 2 years ago to get it setup. I wish I had done it years ago.
These days, I may as well not even have a door. I put auto-shutting hinges on it, but that failed as reminder/deterrent long ago.
We've got a 10x20 out back that was supposed to be my workshop, but it's filled with all the things most Americans put in their garages - because we don't have one. I'm seriously considering a deep purge and converting at least 1/2 of to an office; the distractions and context switching are disastrous.
This constrains the companies you can work at to ones with a local office, if you do not want to move house. If you want to live within walking distance of many companies, you could easily be looking at paying millions of dollars for a poor quality house.
There is a happy medium if you like offices (see below): co-working spaces.
> it's commuting to the office which sucks, and not working in the office
Most company offices are fucking horrific - open plan, atrocious coffee, noisy, full of people who won’t stay home when they are sick.
The biggest problems I see is wanting to frame out the walls with 2x6's for thicker insulation, ceiling trusses at 16 oc for snow load and thicker for insulation as well (or lose the headroom and build a traditional ceiling/attic), and of course more heating load from the heat pump.
Can I ask you how you're designing it right now? I could whip up some designs for you for free.
I figured it had to be because the US devices are very different but they seem to be the same, and the explanation given by the usual automaton suspect was that the climate control business in the US is basically a cartel with highly inflated prices and shady regulations around how they can be sold.
Not sure if the claim is valid, but the price diff is remarkable so there must be some explanation. Usually everything you can buy is cheaper in the US.
My mother-in-law lives in rural Missouri and had her 6x10 bathroom remodeled in 2025. Full gut replacement of everything. Total cost: $5600. I got a quote for something similar in a bit larger bathroom in our house in Seattle. Quoted price: $31,000.
Labor is a good chunk of cost, and the OP presented that he simply didn't have the time available to him to do that work himself. On the other hand, I built 20-ish feet of fencing for our backyard this summer, matching an existing design we had done several years ago. Quoted price from the same company that did it the first time: $9800. I did the work myself. My total cost: $1400.
That works out great, right? I also have a significant investment in all the right tools: compound mitre saw, construction-grade table saw, nail guns, impact/hammer/regular drills, angle grinders, power sanders, every drill bit in captivity -- I don't really lack for anything. These make a huge difference in the workmanship of the final outcome.
And that was just a fence. I've considered building an external office here at our house. When I start to take into account the scope of converting an outdoor shed to an acceptable backyard office, I hit the brakes. Electrical power under proper permits, adequate security, something that holds up under our weather, potential water/sewer access, and sufficient space to work (I can't live without a whiteboard)...there is more scope than meets the eye.
All things considered, I think the OP did a pretty good job here in terms of cost control and recognizing what he could do (windows) vs. needed someone else to do (proper electrical.)
In some parts of the world, people consider spending time outdoors to be a positive thing.
Why start and invest in a construction project for a building that may not be staffed long term? Perhaps renting a small coworking space in town is the safer financial move. And have your employer pay for it.
It doesn’t take long to install a mini-split condenser with a single air handler. Precast pad for the condensing unit, set the condensing unit on the pad (or buy a wall mount if you need to mount it off the ground), run sealtite to the condenser from the disconnect switch and pull in wire, drill two holes for the line sets and one hole for the power/signal cable that runs from the condenser to the air handler, mount the air handler, connect the line sets, plug in the power/signal cable, install and wire the thermostat. Seal the holes with silicone and turn the mini-split on.
It’s less than a day of work, finding a mechanical contractor to install equipment you furnish for $160-175/hr shouldn’t be hard, contractors just like ripping off homeowners because they don’t know any better.
You don’t really even need a mechanical contractor with precharged line sets, just ensure the disconnect switch is off and locked out before touching any line voltage wiring, and make sure you mount anything heavy to studs and not plywood or drywall.
It cost me ~650$ total.
The next time I bought a minisplit (3.5kW one), I already had the tools and it cost me only 450$. A proper one meant for use during harsh winter would probably costs a bit more though, at around 1000$.
So I have set up a few of them for my family and friends so far. The units come pre-charged with gas for ~5M of ducts, there is nothing hard to set them up.
I also set up ESP32 controllers so I could attach them to Home Assistant, bypassing any Chinese cloud apps, etc.
My feedback is merely: boy it'd be nice to have the option to just order a pre-built.
I've been in the game for almost 40 years now, and I'll say I've never had an office paid for by my employer that is as nice as that toughshed. I've never been in a dedicated office with a door, except when working from home.
Edit: ProTip: If you are doing concrete, rent a "Mud Mixer". Me an the kids were able to pour the 8x12x5" (130 bags of 80lbs) in well under a day, probably would have been even less if we had moved the bagged concrete to the pour site before the pour happened rather than as we were pouring.
I'm not a fan of commuting either but for me it's definitely the working in an office that sucks
Maybe if it wasn't an open office bullpen style place but I've only worked in places without private or semi private offices, or even cubes
You can yell at a contractor or the mirror but there's a tax.
Labor is expensive. You could probably close to double the size for an additional $10,000, you’d need another yard and a half of concrete for the foundation (6” depth*80 sqft = 40 cubic feet) and more material for the building, but not twice as much material, or labor. Electrical service could stay the same.l and the mini-split wouldn’t have to be much bigger.
If the office was in a place where I could reasonably expect to find other jobs as well, then that could be part of my consideration, but I would never choose to live somewhere based primarily on whatever my current job is.
I've seen some properties where they build ponds underneath the indoor hallway with glass flooring to see the fish and stuff in the pond. Obviously wild things like that cost a bit more then a simple awning or covered walkway.
but over the next few years i learned so many hobby art projects: insulation, electrical, sheetrock. a few inspections, a few consults. a few surprises that people in this state can just go buy the stuff at a box store!
and then eventually, my 12x6 foot office appeared, the same width as a 1960s metal tanker desk. finally!
and ... i instantly hated working out there. i didnt make it 6 weeks. it's just an office for storing crap, now: i work out of the house, where the kitchen, dogs, bathroom, are. but the journey was worth it, even if the destination was not.
Thank you for the cool post.
[1] e.g. https://www.pioneerminisplit.com/products/pioneer-ecoasis-50...
I have a neighbor 100k+ into a foundation retrofit for his living room.
Also worth mentioning 2026 - 4 = 2022. Not a great year to be stick building from a cost perspective.
The main thing I’d advise people against and say you could have possibly saved on is the structure. Tuff Shed is usually over priced and could be built usually with $2k-3k of material and labor. But the time you did this may have made that hard too, all the contractors were slammed.
You got raked over the coals. You can downvote me, but as someone who knows how to build structures man, I feel so sorry for people reading your message thinking this is OK.
This is really, really poor quality for the cost.
I’m not even a commercial builder. A bag of Portland cement concrete is $5/bag. You don’t need to pay $2k for such a small foundation.
I wrote up my experience building a backyard office because I wish I had come across more articles like this when planning my build. I hope this post helps you on your journey:
I have worked remotely for most of my career and always dreamed of having my own backyard office. A place on my property but completely separate from my home. Until this year, that idea seemed too unnecessary… then our baby grew into a toddler. We have a small house in Portland. We love it, and it works for us, but it became clear that it could use more space. My wife and I briefly considered buying a new home but decided to stay. But for us to stay, I needed a better working environment. Our space is small. The bedrooms and living room are very close together. It gets loud with our toddler at home with my wife during the day, and listening to one half of a Zoom call wasn’t music to my partner’s ears. I had tried coworking spaces but didn’t love the vibe or the idea of spending hours in a phone booth. I don’t see myself returning to a local office in Portland, so we decided to invest in a backyard office. It was way cheaper than buying a new home.
I looked into many options. My budget’s two most viable paths were an Autonomous.ai prefab office Pod or building an office by utilizing a shed frame. The Autonomous pods are gorgeous and come prewired with electricity. You just plug them into an outlet in your house. But I wanted proper heating and air conditioning. I had spent hot summers working with a portable AC unit blasting in the background, and it just wasn’t for me. Their base starts at $16.5k; adding $5k shipping, paying someone to assemble it (I didn’t have time to DIY), and adding a mini-split HVAC system, and we were getting closer to $30k. It was not bad, but it was more than I wanted to spend, not knowing how long we plan on staying in our house.
Deciding against an Autonomous Pod left me with the shed conversion option. This was appealing for a couple of reasons.

I decided on using Tuff Shed for the main frame. I was able to design and configure my structure using their online designer. They also have a local showroom in town, so I walked through some models to get an idea of what I wanted. I originally wanted their studio shed model, but after seeing it in person, I decided against it. The great thing about their online design tool is it lets you build a quote on the spot for exactly how much it will cost. The windows Tuff Shed offers weren’t as large as I wanted, so I worked with their team to rough out larger openings for windows that I purchased separately.
I read online about people wishing they had gone bigger with their shed or office. I went with a smaller size 8 feet by 10 feet, it is cozy and sure I do wish it was bigger, but we also have a small backyard, and I really didn’t want to sacrifice more space in the yard than I had to. I measured off an 8 by 10-foot space in one of the rooms in our house and hung some blankets to get an idea of how the space would feel, and I decided 8’ by 10’ would work.
I went with the Premier Pro Tall Ranch shed. This allowed me to have tall ceilings, making the small space feel bigger. I settled on a fully lit windowed door, added a small skylight, and roughed out 2 large windows (6 by 4 feet and 4 by 4 feet). I added a ridge vent and house wrap.
Once I had the frame configured, I went to order it but realized I needed to have a foundation ready before they could schedule the build. I wanted a concrete pad, and they require 3 weeks for the concrete to dry before they will install. So, I hired a concrete contractor.
The shed installation went smoothly. Tuff Shed prefabricates the sheds per order in a local warehouse, so installation of my shed only took about 5 hours. I had an issue; one of the rough openings of the windows was too small, but they quickly sent someone to expand and reframe the area for me.
I ordered the windows separately from Home Depot, and to save a little money, I decided to install them myself with one of my friends. Hanging windows seems intimidating, but after some research and YouTube videos, I realized the process was quite simple if you take time and adequately prep the weatherproof window. This saved me about $700.

Once the windows were installed, it was time to run electricity. Our main electrical panel was redone a couple of years ago when we bought and renovated our home, so we have plenty of space to run more power out of our existing panel. I hired an electrician who ran 60 amps out to the shed. They dug a trench to run the power legally, wired up the shed with 4 outlets, LED lights, and a disconnect for a mini-split HVAC unit, and handled all the permitting.
Once the electrical passed permit inspection, I filled in the trench halfway (apparently, you don’t want a larger power supply and ethernet line running too closely together) and ran a ground-rated Ethernet cable out to the office. Fast internet was a must.
Note: In Portland, I didn’t need a permit for the building because it was under the size threshold, but I did need an electrical permit. Check your local jurisdictions.

I was planning on insulating the office myself and hiring a drywall contractor to do the drywall, install the flooring, and trim myself, but I realized I have a toddler and limited free time. I don’t have time for this. So, I found a contractor to do all of that for me.
I installed soffit vents myself to allow airflow from the roof to prevent moisture buildup and had my contractor install rafter vents.
I went with a Smartcore Luxury Vinyl plank flooring and a Smartcore premium foam flooring underlayment. I am definitely happy with both choices.

Finally, it was time to install AC. I got a ton of quotes for installing a mini split. They ranged from $4-$7k, which was higher than I expected after researching the cost of a quality small unit and knowing this would be a tiny job for an HVAC contractor, especially because I had my electrician prewire the electrical. I was considering installing a DIY system (Mr. Cool DIY system with pre-charged AC lines), But found an HVAC contractor who would install a system for a much lower price than the other quotes I received (and he had great reviews on Thumbtack). In the end, I got a Daikin Mini-split, a common system with many replacement parts. The installation took about 5 hours, and my tech did a great job. I am glad I researched and got a lot of quotes for this one.
One thing I did buy was an INKBIRD CO2 monitor. I highly recommend one if you are working in a small space. I wanted to read how much CO2 is in the air because I built this as a sealed space. And it’s now clear I need to install an HRV or, ERV, or exhaust ventilation fan; for now, I just crack a window when CO2 levels get higher, but I’ll be addressing this soon.



Overall, I am super happy with my space, and I came in within my planned budget. I could have saved some money by doing more of the work myself, being okay with a space heater and window/portable AC option, and using a gravel foundation, but these were areas I decided to spend money on.
Here is the complete cost breakdown of my office build:
| Concrete foundation (contracted) | $2,000.00 |
|---|---|
| Tuff Shed shell (contracted) | $6,148.00 |
| Custom Windows | $533.00 |
| Window installation supplies | $77.00 |
| Electrical work and materials (contracted) | $4,350.00 |
| Insulation, Drywall, flooring, trim installation (contracted) | $3,650.00 |
| Flooring materials | $420.00 |
| HVAC mini-split system and labor (contracted) | $2,300.00 |
| Total project | $19.478.00 |
Things I am glad I did
I am stoked with my office. I would much rather hire a general contractor or company that builds ADUs to handle this for me. Managing this was a ton of work, and after a house renovation, I don’t love these projects. But I got an office I really like for under $20k; if I hired a company to handle everything for me, I was looking at $40-$50k. That wasn’t the path for me this time around.
In fact, probably better to just put your desk in the bathroom for maximum efficiency!
I know someone who builds horse shelters that are larger than that, but a fraction of the cost, delivered. I've actually been thinking that if I wanted an outside office, I'd ask him to custom build one with the fourth wall closed (horse shelters are 3-sided) and I'd insulate and sheetrock it myself. IIRC he did our 10x30 one for about $2k, including delivery.
Around here, the cutoff for needing a permit for a "permanent structure" is 10'x12' which is a pretty good sized outside office.
Building code for snow load is a factor of location and elevation here. We are around 130 lb/sq ft.
Roof pitch can help with shedding, but then you've got other problems (roof avalanches can and do kill, not to mention snow up against materials that don't want to be wet all winter).
But down that path lies a cabin innawoods.
Electrical + AC is a firm line where that goes from shed to detached office.
<https://singlefamily.fanniemae.com/originating-underwriting/...>
only as likely as literally every other scenario. the difference is you can continue to use your backyard office for your new job
They're literally designed to be easy to install, but in the US licensing requirements tend to be insane (in my state it's 2 years apprenticeship experience for their 'easier to get' mini-split license) and HVAC companies make more off whole home systems.
These things are regularly installed DIY by homeowners (illegally most of the time but you know), it doesn't take two years of experience to be able to install these without issue. 2 weeks, or half a dozen installs surely would be more than enough.
I went with PVC because it's the easiest to work with, NEC only required it be buried 12in below the surface for residential, but I went to 24". I oversized the PVC a bit so I had room to run more cables as well. I filled the trench with gravel, ran the PVC over that, then filled over it with some more gravel. A thin layer of dirt, marking tape and then the rest of the dirt. Rent a trencher if you have hard ground.
If you're having a licensed electrician do the work of connecting house and office power then you can ask them to run the conduit for it at the same time.
You're going to have to break that down for me.
It took me a while to find a company to install a mini split I purchased on my own, and I paid $$ for labor. This was only because I didn't have the time.
That said, mini splits are so cheap (sub $500) that its easier to just purchase a new one than repair.
i tried to find a page that wasn't terrible for this, still kind of bad though:
https://www.gloryoptics.com/info/how-deep-does-spectrum-bury...
Smaller jobs are more expensive per square foot because not all costs scale with size. Which is why you see all these godawful TJ Homes being built where they just rip out the house, build a 3 story structure (including basement) that takes every square inch of the lot.
> I had tried coworking spaces but didn’t love the vibe or the idea of spending hours in a phone booth.
>160 hours of education/vocational training and 2 years’ verifiable experience in the trade
To get the license to install minisplits (two years experience generally means working an apprenticeship).
It's no wonder install costs are so much in the US. And as you've experienced, they're hardly rocket science to install. The 160 hours training would be more than enough, I'm not sure why 2 years experience gets tacked on the end.
And then lose all the regulatory benefit of whatever shed exemption you're trying to use, get absolutely screwed on regulatory compliance and code whatnot that you're leveraging by having it be a detached outbuilding. And then get sneered at by HN when you say the rules as they apply to your situation are stupid.
Maybe he could have saved a few thousand with different subs (maybe) but your comments are nonsensical. I see tons of janky builds people post on Reddit and this is not one of them. You should spend your commenting time over there.
An 8x10 6” slab has 1.5 cubic yards of concrete. Making concrete takes more than a bag of Portland cement, you also need gravel, sand, a mixer, a wood frame, a source of water, shovels, floats, et cetera. If you want rebar, add in steel and rebar tools and wire.
You could frame up the wood yourself and have Cemstone deliver the concrete but you still need to spread it out, float it, and finish it.
Instead of buying or renting all of that, I would sub it out. I subcontract out light pole bases and concrete pads for transformers, EV chargers, and other equipment all of the time.
You are wrong about the impact of moderately high CO2 levels.
You can buy all the Quickcrete you want (not sure the last time you priced it), but it won’t make you good at pouring a level pad. That alone puts me off trying to do it some days.
If nothing else, at least a well-ventilated room expels my farts and other airborne waste products.
And people don't want to sleep longer, they want to feel well-rested. So I think higher sleep efficiency is better.
My calculus is to evaluate time, cost, and quality. If someone can match or beat me on 2/3 of those dimensions then I'll hire them.
That's not too bad, that's just a floor (and that's for a flat roof, it gets less demanding with pitch).
Fantastic.
The city isn't in the business of busting doors and issuing citations if you replace kitchen cabinets without a permit. They basically act if someone credibly complains, which is mostly if you're doing some exterior additions / changes that annoy a neighbor.
Sure, if the odds are 50/50, or you go to jail, or the fines are $50k or something, then yeah, do it right from the start.
But if there's a 2% chance of getting caught, getting caught costs you 150%, and not getting caught costs you 10%...the choice is pretty obvious here, isn't it?
They won't stop you from selling the house as-is but some buyers will walk, some will demand you get it permitted, most will at least want a real inspection done. Getting as-built work permitted after the fact will cost 2-3x as much in permit costs than it would have if done properly, and it may require you to remove drywall to expose things for inspection, but as long as it meets code you won't have to rip everything out and have it redone by a licensed person. In most places you can do work on your own house, so it's the lack of permit that needs to be remedied.
Where? No electrician is inspecting every house that goes up for sale in the US. Sure you can ask an electrician to inspect a house electrical… but that doesn’t bar a house sale anywhere I’ve ever seen.
It's got to suck to do the inspectors job. Having to keep up with whatever the code creators come up with, while also getting abused by every home owner and contractor in the area because they hate X,Y or Z. While trying to dodge political leverage from elected officials trying to get whatever pet mess they want done.
It's not a job I'd want, and I bet they get paid trash to boot.
Code compliance and inspections exist for a reason, and if you are lucky, the current inspector/code compliance dept in your local govt realizes it's to ensure the building doesn't fall down around your ankles when you least expect it and not to screw you over.
This is the danger of "cheap projects" - they can grow legs before you know it, and you end up paying half the cost of increasing the square footage of the house (or the garage).
Like if I'm bringing my bins to the road for pickup, I never bother putting on a jacket or w/e regardless of weather. If it does happen to actually be a torrential downpour, I just switch to a new t-shirt when I'm back inside.
Idk for Americas, but here in rural EU no one would give a fuck. Some will ask for help.
Easy to test for, though I'm not sure if you can do it for free like skillcat used to offer.
Environmental law is the same way. You're mostly (details depend on jurisdiction) not supposed to pave anything without getting permission but if they pushed the issue on everyone who put a pad under their car port the rules would get changed.
They also don't 100% enforce the speed limit either.
Permit inspectors are basically unaccountable. There's no requirement that what you sign off meets code or that you'll sign off if it meets code.
As a builder, best thing is if you can fix whatever needs fixing while the inspector is there. If not, there's a non-zero chance you get a different inspector for the reinspection who likes it the way the first inspector said you couldn't do it.
And in my state, I copy pasted what was required for a 'residential' HVAC license (idk if you meant commercial HVAC or just making money on installs).
But they do not remove the panel cover to look inside, nor do they open up any receptacle box anywhere to look at any of the wiring inside. So they wouldn't know (nor discover) if the wiring job was done well or done in a shoddy manner.
You get a finished and conditioned room, and it most likely added value to his house.
I just sold a 120 year old house. “I don’t know” is a valid answer to the disclosure requirement but it better be true.