Basic Heat Pump advice needed.

I find myself in need of a solution and I have spent a lot of time looking around at different systems and reading here. If you all might have some good advise, it would be great.

I'm located in the North San Francisco Bay area. Temps are rather mild here. We will have a few nights of 30F in the winter and a week or two of weather touching the 100f range, and a maybe a month or two in the 80 to 90 range.. My last house had no insulation or A/C, I fully insulated it and it did not need A/C after that. I had expected the same with this new place being just 15 minutes away. (The house is good, but this out building sucks!)

The challenge is my warehouse is a cheap metal building, about 1,500 sq ft with 15 foot tall walls. Lots of sun exposure. I have insulated it with 2" foam with an R value of 13.1 (best that would fit into the 2" space), but there is a LOT of thermal bridging from the tubular steel structures the walls are built from. There is a huge roll up door that takes the morning sun. I have stacked some spare foam against the inside of it, and put a 90% shade screen on the outside to keep the sun off it. This has helped.

We just had our first heat wave of 100F temps and all efforts to fight the heat in this building failed. It simply delays the heat by about 1 hour. $6,000 in insulation really didn't buy much. (maybe 10 degree lower than outside at best)

I have a solar system on the main house and it runs some micro inverters and tied to the grid, it is about 6k watts. It produces more than I currently use. Living in California we pay ALOT for energy of any form. My solar contract does pay me for overproduction, but if I add to the system more than 10% production, I lose the payment as they will reclassify the system.

Rather than double down on the insulation and probably still have a poor performing building, I noticed the solar A/C units and this started a spiral of research and confusion.

I have a lot of roofs here and plenty of space to add more solar, but I can't tie them to the grid. So these solar heat pumps are very tempting to me for this reason. My thought is rather simple. Insulating this building is pretty much a lost cause. I think I'd be better off spending the cash on some of these heat pumps and a solar field to power them. I'd be happy if I could hold the summer temps down to 80F, and hopefully semi comfortable in the winter months too. (Winters are more in the 40 to 60f range.)

Basic calcs suggest I'd need 36,000 BTU give or take to make the space comfortable. I don't need house comfortable.

One thought I keep having is to install some of these little 12,000 BTU hybrid units as I like the simple 110 grid supply. Start with a single and see what it will do for the building. Just knocking down the humidity might do the trick. I can always add a second or third unit as we see how things perform.

With this said, not that big a deal to add a 220 circuit to feed a bigger unit.

Other times I'm thinking I'd be better off to invest in something like a larger Panasonic and let it eat into my surplus electrical during the summer months.

This is a very basic steel building. This one had zero insulation when it was built. Just a condensation blanket on the roof. I don't have much budget to chase after this goal. I'd rather save my money to make the next building much better from the start.

Any advice would be great. What would you do in this situation?

Cheapest mini split you can buy and give it a go. If it works well, add another. I have an 18k btu in my 3 car garage and it is a life saver. Even set to 80, it makes the garage a whole different place to work.

Off grid system with batteries to power whatever ac unit you need.

Sure you could do alot of solar powered minisplits. I would vote for a large unit. Off grid so you don't loose your NEM.

I would go with two EG4 DIY solar kits 24k BTU each for $3000 7 panels each have 14 panels. They come with pre-charged lines you don't need any special tools. They can switch over to AC power at night no batteries required. You could install one 24k see how it works out.

I would stay away from the cheap ones off Amazon seller support is poor they are throw away units because the companies are mostly shell companies buy from Midea and slap their name on it. The other brand I recommend for DIY is Pioneer sold at Home Depot you get a 5 year warranty need tools to install them or hire someone. If you don't want to do DIY you want to hire someone I would call around find a contractor first most of them won't install something you mail ordered. They like to install Daikin brand mostly read the fine print before you buy if your going to go with another brand lot of them require a licensed contractor to install unless they clearly state DIY. I like Pioneer because they are in the US out of Florida actually talk to someone on the phone not poorly written emails show up every 2 - 3 days by email.

The biggest issue with most metal buildings is air sealing.
The roof, walls and floor all have huge gaps. Metal has a radiant reflective factor working in your favor, but a huge conductive loading of summer heat. The condensation layer as you put it does VERY little to reduce solar gain.

Look up Matt risinger on YouTube, he has some amazing videos on roof insulation, and wall improvements.

You can list your building specs, location zip code, and building orientation here and I can give it a go, or head over the the AOP section of hvac-talk.com and post the info there for a huge set of contractors who will perform a full load calculation, and energy guide for ya.
(I’m mod over there also)

You should be to use an EG4 mini-split, 24k, so 8-200watt panels or larger. They need 800watts to run plus more under load, 30a 120v grid as backup. Or don't use solar and have the option. I love my 12k EG4 on 4-200watt panels and cools and heats 600 sq/ft no issues.