AC question

[nash668]

Hey!

I have a member of the family who's building a house in ICF. House is air tight, and asked me to price and size an AC.

I tried pricing a Lennox Xc25 and apparently I need to be a dealer to even see one. I told him Rheem was his second best choice and he was looking at a 19 SEER online. House is 2300Sqft and 4100SQft with the basement. I don't do many of these so any help would be awesome!

Thank you.

[Admin]

With a new build I'm sure the HVAC contractor will have a HVAC design which will size the equipment.

A basic rule of thumb would be square footage divided by 950 and then deduct 30% for being ICF.

Is the basement on a slab or in the ground?  I normally wouldn't include the basement.

2300/950 = 2.4 ton - 30% = 1.7 ton.

Keep in mind the Lennox XC25's smallest size is 2 ton.  With the higher end 2 stage or variable capacity compressors you can get away with oversizing.  Otherwise I prefer to undersize.

[nash668]

As easy as that would be I wouldn't be asking the question. They're doing everything themselves. As much as they legally can... Contracting out what needs to be.

Basement is slab.

I'll thrown in that this doesn't have your standard 8.5' ceilings. They are 16' high in over half the house.

[Admin]

The next size above 2 ton is a 3 ton with the Lennox XC25 model.  If we include the basement I would go with the 3 ton.  But I would send the working drawings to an HVAC designer to make sure.

Also they will probably want a in floor heating system to protect the slab.  Check out the Legalett system,

http://www.legalett.ca