Im looking at installing a mrcool diy 24000 unit after seeing the price of having one professionaly installed. The 2 HVAC guys however dissagree on where to put the head unit. Its a split level house with 2 500sqft levels. One said put it on the main floor and let it blow up the stairs. The other said put it above the stairs so that is blows into the bedrooms and falls down the stairs. Anyone have any advice as i tend to trust the 2nd one as cold air doesnt move up easy.

 

I would vote for upstairs as you said, cold air drops.
Geo

 

You might find that too much cool air will wind up down stairs, unless you can close some upstairs doors.
Sid

 

Welcome to the forums.

One unit for two floors is not really the way to install a system. Two heads on a single compressor is really what you need there. With the unit just in the upstairs hallway you will more than likely need a fan or two downstairs to move the air around.

 

I am not an AC tech, but I did sleep at a Holiday Inn Express last night and I suffer from common sense.

Unless you have some architecturally stunning open floor design, one head is going to give extremely poor results.

I do not think the Mr Cool DIY series comes in a multi head so 2 separate systems would be the option.

Where did the 1 ton per 500 sq ft come from? Do a whole house load calculation to be sure. https://www.youtube.com/watch?v=d-gPwNZgDGA

Only my opinion and worth what you are paying for it.

 

I just used the unit size based on what the bids from the 2 different HVAC contractor's gave me. Both wanted to use 24000btu units located in different location. They both told me one head should be good enough for the size and layout. currently the main level is cooled by a 10000 btu window unit and the upstairs with 2 different 5000 btu window units.

 

They show up in a white van with fancy looking vinyl graphics and look really professional in their company shirts, so we assume they know what they are doing. Well some do and far too many don't.

8 different AC contractors gave me estimates for a 3 ton central system in my house. When they were replacing a 2.5 ton unit and the Manual J clearly calls for a 2.5 ton!

I have a 12,000 btu and 2 9,000 btu Daikins and so far they are never strained to keep the house cool. That just happens to be 2.5 tons of AC.

Inverter mini heat and cool units modulate meaning they adjust to conditions. A 9000 btu unit can vary from 2000 to 11,000 btu output which should make putting in the right size a piece of cake. But they are far more efficient at the higher outputs, according to the net.

Again not an AC tech, just another homeowner trying to get by.

 

Have fun. Mini splits are the biggest scam unless you can install and service the unit yourself. Welcome to the nightmare.

 

I lived in Asia with mini splits and seen no problem with them. The are the AC of choice all over the world so must not be that bad.

You are right, if you cannot install and maintain them yourself, better have deep pockets. I am cleaning one now and they are basically unserviceable. If the inside unit needs repair it is cheaper to have it replaced.