Mimi split and propane heater help

[Dex181]

Mini split and propane heater help

I have been hanging out getting info and looking autosuggestion everyone has made on different builds. With that being said this is the first time I have asked for help. I have a 3200 square foot garage with no windows and three 12x9 garage doors, 1 12x14 garage door. All insulated. The garage is prefab metal with 4in insulation in the walls and ceiling. I am in the process of building a shop space that'll be 20 x 40 inside the structure that will also be insulated in the ceiling and all 4 walls. This will have one of the 9 x 12 doors and a insulated or solid wood 36 x 80 entry door. I have looked all over the web to help in sizing and can not find a calculator to meet my needs. I am located in Virginia Beach where the summer averages around 88 but can reach 95 - 99 for weeks at a time. Winter average is 40 with weeks in the 20's or teens. Now for the help.
1. What size mini split and brand do any of you have or suggest for the shop space? This space will be utilized year round and would like to keep he space in the summer 70 to 72ish. Winter 60 to 65.
2. What size and type of hanging propane heater do you advise for the 3200 foot garage. Mainly looking to keep the boat from freezing so about 45ish most of the time unless I do an indoor party and would like the ability to heat to 65 to 68 for the peeps without running constantly.

Hope someone can help clear up the mud for me. Thanks in advance!

 

[justinjoyal]

Re: Mini split and propane heater help

Ceiling height of the 20x40 room ?

4” insulation... around R12 ?

Missing data but considering what we got my -guess- would be 18k.

 

[walrus]

Get a professional to do a heat load calculation

 

[dcg9381]

There are also Manual J calculators online that can get pretty close (for free).
I have a 40x60 building, 16' walls. 3-4" of open cell foam, 3 14x14 doors that are R5, one person-door.

I've installed 2 x 24k BTU (4 tons total). I'm in Texas, so hotter than you, but my guess is that I need 3 of them.

Brand is an interesting discussion. There is only one brand of DIY-warrantable Mini-split (Mr. Cool) - it looks to me that you pay about 15-25% more for the consumer warranty, but this beat the 100-200% mark up of having one done commercial.

I went with Daikin for mine. They come pre-charged. 24k heat-pump units with everything run about $1200-$1300. Because I bought online and self-installed = NO WARRANTY.


Mini-splits might cover your need for heat in the winter, at least good enough for the boat. If I wanted rapid heating and it was 20 outside, you'd need a propane or other aux heat source.

 

[jjrbus]

I read the Mr Cool DIY warranty and I do not see it as a big selling point. Too many loopholes in it especially #3. I will throw my Daikin with no warranty out and buy a new one if I have too.

I do see a lot of online Mr Cool DIY repair info online in the future, which will be a good thing.

Of course only my opinion and worth what you are paying for it.
https://mrcool.com/warranty/

 

[dcg9381]

I made the same decision that you did, which is basically self-insure (no warranty).
I have read about people making Mr.Cool warranty claims and them providing replacement parts, so I know their warranty is functional.

The Daikin comes pre-filled, you do need a vac pump (under $100), and you add no refrigerant if your line sets are <20 feet (off the top of my head). You can get them in various efficiencies running from 14 SEER to 22 SEER.

Ductless units do not (typically) contain heat strips, so in cold climates they are limited heating function as temps dip below freezing.

There are two other major brands that are more expensive but also more main stream. I've never used them so can't compare. There are also off-brands sold on the internet.